Search

Fetal ventriculomegaly is a central nervous system disorder commonly seen in prenatal imaging, and the prognosis ranges from normal health to severe dysfunction. Currently, fetal predictive markers associated with postpartum individual neurodevelopmental function are still not available, which increases the difficulty of prenatal diagnosis and clinical management. Constant advancements in magnetic resonance imaging (MRI) technology have brought better accuracy and reliability of MRI applied in the diagnosis, prognosis assessment, and etiology investigation of ventriculomegaly. MRI plays a critical role in prognostic management and prenatal consultation. Nevertheless, due to the potential safety hazards and economic and technical constraints of MRI, it is not the first choice for prenatal imaging diagnosis. Moreover, there are different opinions regarding the measurement results and grading criteria of ultrasound and MRI. At present, it is accepted that three-dimensional volume may provide reliable information for prognosis. However, accurate segmentation and measurement of brain structure remain serious challenges, and no consensus on the MRI measurement of lateral ventricle volume has been reached. In this paper, based on the latest research reports from China and around the world, we reviewed the progress in applying MRI in the prenatal diagnosis and treatment of ventriculomegaly. This review offers a theoretical foundation for further exploration of the role of lateral ventricle volume measurement in disease diagnosis and management. We suggest that researchers combine two-dimensional width with three-dimensional volume in the future to identify the optimal cutoff value for prognostic prediction of fetal ventriculomegaly., Competing Interests: 利益冲突　本文作者肖雪是本刊编委会青年编委。该文在编辑评审过程中所有流程严格按照期刊政策进行，且未经其本人经手处理。除此之外，所有作者声明不存在利益冲突。, (© 2024《四川大学学报（医学版）》编辑部 版权所有Copyright ©2024 Editorial Office of Journal of Sichuan University (Medical Sciences).)

Purpose: The established automatic AI tooth segmentation algorithm was used to achieve rapid and automatic tooth segmentation from CBCT images. The three-dimensional data obtained by oral scanning of real isolated teeth were used as the gold standard to verify the accuracy of the algorithm., Methods: Thirty sets of CBCT data and corresponding 59 isolated teeth were collected from Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The three-dimensional tooth data in CBCT images were segmented by the algorithm. The digital information obtained by scanning the extracted teeth after processing was used as the gold standard. In order to compare the difference between the segmentation results and the scanning results of the algorithm. The Dice coefficient(Dice), sensitivity (Sen) and average symmetric surface distance (ASSD) were selected to evaluate the segmentation accuracy of the algorithm. The intra-class correlation coefficient(ICC) was used to evaluate the differences in length, area, and volume between the single tooth obtained by the AI system and the digital isolated tooth. Due to the existence of CBCT with different resolution, ANOVA was used to analyze the differences between groups with different resolution, and SNK method was used to compare them between two groups. SPSS 25.0 software package was used to analyze the data., Results: After comparing the segmentation results with the in vitro dental scanning results, the average Dice value was (94.7±1.88)%, the average Sen was (95.8±2.02)%, and the average ASSD was (0.49±0.12) mm. By comparing the length, area and volume of a single tooth obtained by the digital isolated tooth and the AI system, the ICC values of the intra-group correlation coefficients were 0.734, 0.719 and 0.885, respectively. The single tooth divided by the AI system has a good consistency with the digital model in evaluating the length, area and volume, but the segmentation results were still different from the real situation in terms of specific values. The smaller the voxel of CBCT, the higher the resolution, the better the segmentation results., Conclusions: The CBCT tooth segmentation algorithm established in this study can accurately achieve the tooth segmentation of the whole dentition in CBCT at all resolutions. The improvement of CBCT resolution ratio can make the algorithm more accurate. Compared with the current segmentation algorithms, our algorithm has better performance. Compared with the real situation, there are still some differences, and the algorithm needs to be further improved and verified.

The segmentation of dental models is a crucial step in computer-aided diagnosis and treatment systems for oral healthcare. To address the issues of poor universality and under-segmentation in tooth segmentation techniques, an intelligent tooth segmentation method combining multiple seed region growth and boundary extension is proposed. This method utilized the distribution characteristics of negative curvature meshes in teeth to obtain new seed points and effectively adapted to the structural differences between the top and sides of teeth through differential region growth. Additionally, the boundaries of the initial segmentation were extended based on geometric features, which was effectively compensated for under-segmentation issues in region growth. Ablation experiments and comparative experiments with current state-of-the-art algorithms demonstrated that the proposed method achieved better segmentation of crowded dental models and exhibited strong algorithm universality, thus possessing the capability to meet the practical segmentation needs in oral healthcare.

Objective: To evaluate the outcome of Augmented reality technology in the recognizing of oral and maxillofacial anatomy., Methods: This study was conducted on the undergraduate students in Peking University School of Stomatology who were learning oral and maxillofacial anatomy. The image data were selected according to the experiment content, and the important blood vessels and bone tissue structures, such as upper and lower jaws, neck arteries and veins were reconstructed in 3D(3-dimensional) by digital software to generate experiment models, and the reconstructed models were encrypted and stored in the cloud. The QR (quick response) code corresponding to the 3D model was scanned by a networked mobile device to obtain augmented reality images to assist experimenters in teaching and subjects in recognizing. Augmented reality technology was applied in both the theoretical explanation and cadaveric dissection respectively. Subjects' feedback was collected in the form of a post-class questionnaire to evaluate the effectiveness of augmented reality technology-assisted recognizing., Results: In the study, 83 undergraduate students were included as subjects in this study. Augmented reality technology could be successfully applied in the recognizing of oral and maxillofacial anatomy. All the subjects could scan the QR code through a connected mobile device to get the 3D anatomy model from the cloud, and zoom in/out/rotate the model on the mobile. Augmented reality technology could provide personalized 3D model, based on learners' needs and abilities. The results of likert scale showed that augmented reality technology was highly recognized by the students (9.19 points), and got high scores in terms of forming a three-dimensional sense and stimulating the enthusiasm for learning (9.01 and 8.85 points respectively)., Conclusion: Augmented reality technology can realize the three-dimensional visualization of important structures of oral and maxillofacial anatomy and stimulate students' enthusiasm for learning. Besides, it can assist students in building three-dimensional space imagination of the anatomy of oral and maxillofacial area. The application of augmented reality technology achieves favorable effect in the recognizing of oral and maxillofacial anatomy.

Purpose: The movement trend of the posterior teeth and the distribution of the periodontal membrane stress were studied by using three-dimensional digital technology., Methods: CBCT data of 88 patients admitted to our hospital from June 2017 to June 2022 were selected, and input into Mimics20.0 software for preliminary extraction of all parts and stored with STL files; then the data were repaired and optimized through Geomagic Studio 2014 software. With the help of normal phase extension, the invisible appliance and periodontal membrane were constructed. Finally, the six FEM models were simulated and observed by the current teeth in different groups. Statistical analysis was performed with SPSS 21.0 software package., Results: The effect force of the largest periodontal membrane was distributed in the neck of the tooth, followed by the apical area, with the maximum effect force value in the NA group. In all accessory groups, the periodontal membrane maximum paradigm isoeffect force values of all patients in the accessory vertical rectangular group were significantly smaller than the values obtained in the horizontal rectangular group., Conclusions: The design of orthodontic tooth accessories has a strong inhibition effect on the position movement of anterior teeth during recovery, which improves the accuracy of tooth three-dimensional movement to a certain extent. Meanwhile, the normal equivalent stress of the periodontal membrane of patients in the initial application of the invisible appliance without brackets is large.

Purpose: To compare the mucosal morphological difference in distal-extension area of mandibular dentition defect taken by intra-oral digital scanning and selective pressure impression techniques., Methods: Seventeen patients with Kennedy Class I and Class II dentition defect in lower jaw were included, including twenty-two distal-extensions. Intraoral digital scanning and functional impression technique were taken in each patients, respectively. Laboratory cast scanner was used to scan the plaster casts made from the selective pressure impression to obtain the three-dimensional data. All the data were stored in STL format. The 3D data collecting from intra-oral digital scanning and selective pressure impression from the same patient were compared by Geomagic Control 2014 software. Root mean square of 2.5mm diameter area was calculated in 5,10,15 mm from terminal tooth. Pearson's correlation test was used to analyze the correlation of the distance and morphological difference with SPSS 20.0 software package., Results: Mean mucosal morphological difference of jaw distal-extension edentulous area taken by intra-oral digital scanning and selective pressure impression techniques was (0.37±0.12) mm. There was positive correlation between distance from terminal tooth and mucosal morphological difference(P＜0.05). Morphological differences in 5, 10, 15 mm from terminal tooth were (0.14±0.11) mm, (0.22±0.13) mm and (0.39±0.16) mm, respectively., Conclusions: In this study, there was positive correlation between the length of distal-extension edentulous area and mucosal morphological difference, while the kind of ridge defect and mucosal thickness may also affect the morphological difference quantity.

Objectives: To develop a deep learning model for automated age estimation based on 3D CT reconstructed images of Han population in western China, and evaluate its feasibility and reliability., Methods: The retrospective pelvic CT imaging data of 1 200 samples (600 males and 600 females) aged 20.0 to 80.0 years in western China were collected and reconstructed into 3D virtual bone models. The images of the ischial tuberosity feature region were extracted to create sex-specific and left/right site-specific sample libraries. Using the ResNet34 model, 500 samples of different sexes were randomly selected as training and verification set, the remaining samples were used as testing set. Initialization and transfer learning were used to train images that distinguish sex and left/right site. Mean absolute error (MAE) and root mean square error (RMSE) were used as primary indicators to evaluate the model., Results: Prediction results varied between sexes, with bilateral models outperformed left/right unilateral ones, and transfer learning models showed superior performance over initial models. In the prediction results of bilateral transfer learning models, the male MAE was 7.74 years and RMSE was 9.73 years, the female MAE was 6.27 years and RMSE was 7.82 years, and the mixed sexes MAE was 6.64 years and RMSE was 8.43 years., Conclusions: The skeletal age estimation model, utilizing ischial tuberosity images of Han population in western China and employing the ResNet34 combined with transfer learning, can effectively estimate adult ischium age.

Conventional maximum intensity projection (MIP) images tend to ignore some morphological features in the detection of intracranial aneurysms, resulting in missed detection and misdetection. To solve this problem, a new method for intracranial aneurysm detection based on omni-directional MIP image is proposed in this paper. Firstly, the three-dimensional magnetic resonance angiography (MRA) images were projected with the maximum density in all directions to obtain the MIP images. Then, the region of intracranial aneurysm was prepositioned by matching filter. Finally, the Squeeze and Excitation (SE) module was used to improve the CaraNet model. Excitation and the improved model were used to detect the predetermined location in the omni-directional MIP image to determine whether there was intracranial aneurysm. In this paper, 245 cases of images were collected to test the proposed method. The results showed that the accuracy and specificity of the proposed method could reach 93.75% and 93.86%, respectively, significantly improved the detection performance of intracranial aneurysms in MIP images.

Objective To establish a model for predicting the growth of pulmonary ground-glass nodules (GGN) based on the clinical visualization parameters extracted by the 3D reconstruction technique and to verify the prediction performance of the model. Methods A retrospective analysis was carried out for 354 cases of pulmonary GGN followed up regularly in the outpatient of pulmonary nodules in Zhoushan Hospital of Zhejiang Province from March 2015 to December 2022.The semi-automatic segmentation method of 3D Slicer was employed to extract the quantitative imaging features of nodules.According to the follow-up results,the nodules were classified into a resting group and a growing group.Furthermore,the nodules were classified into a training set and a test set by the simple random method at a ratio of 7∶3.Clinical and imaging parameters were used to establish a prediction model,and the prediction performance of the model was tested on the validation set. Results A total of 119 males and 235 females were included,with a median age of 55.0 (47.0,63.0) years and the mean follow-up of (48.4±16.3) months.There were 247 cases in the training set and 107 cases in the test set.The binary Logistic regression analysis showed that age (95% CI =1.010-1.092, P =0.015) and mass (95% CI =1.002-1.067, P =0.035) were independent predictors of nodular growth.The mass (M) of nodules was calculated according to the formula M=V×(CT mean +1000)×0.001 (where V is the volume,V=3/4πR 3 ,R:radius).Therefore,the logit prediction model was established as ln[ P /(1- P )]=-1.300+0.043×age+0.257×two-dimensional diameter+0.007×CT mean .The Hosmer-Lemeshow goodness of fit test was performed to test the fitting degree of the model for the measured data in the validation set ( χ 2 =4.515, P =0.808).The check plot was established for the prediction model,which showed the area under receiver-operating characteristic curve being 0.702. Conclusions The results of this study indicate that patient age and nodule mass are independent risk factors for promoting the growth of pulmonary GGN.A model for predicting the growth possibility of GGN is established and evaluated,which provides a basis for the formulation of GGN management strategies.

Objective: The fully automatic segmentation of glioma and its subregions is fundamental for computer-aided clinical diagnosis of tumors. In the segmentation process of brain magnetic resonance imaging (MRI), convolutional neural networks with small convolutional kernels can only capture local features and are ineffective at integrating global features, which narrows the receptive field and leads to insufficient segmentation accuracy. This study aims to use dilated convolution to address the problem of inadequate global feature extraction in 3D-UNet., Methods: 1) Algorithm construction: A 3D-UNet model with three pathways for more global contextual feature extraction, or 3DGE-UNet, was proposed in the paper. By using publicly available datasets from the Brain Tumor Segmentation Challenge (BraTS) of 2019 (335 patient cases), a global contextual feature extraction (GE) module was designed. This module was integrated at the first, second, and third skip connections of the 3D UNet network. The module was utilized to fully extract global features at different scales from the images. The global features thus extracted were then overlaid with the upsampled feature maps to expand the model's receptive field and achieve deep fusion of features at different scales, thereby facilitating end-to-end automatic segmentation of brain tumors. 2) Algorithm validation: The image data were sourced from the BraTs 2019 dataset, which included the preoperative MRI images of 335 patients across four modalities (T1, T1ce, T2, and FLAIR) and a tumor image with annotations made by physicians. The dataset was divided into the training, the validation, and the testing sets at an 8∶1∶1 ratio. Physician-labelled tumor images were used as the gold standard. Then, the algorithm's segmentation performance on the whole tumor (WT), tumor core (TC), and enhancing tumor (ET) was evaluated in the test set using the Dice coefficient (for overall effectiveness evaluation), sensitivity (detection rate of lesion areas), and 95% Hausdorff distance (segmentation accuracy of tumor boundaries). The performance was tested using both the 3D-UNet model without the GE module and the 3DGE-UNet model with the GE module to internally validate the effectiveness of the GE module setup. Additionally, the performance indicators were evaluated using the 3DGE-UNet model, ResUNet, UNet++, nnUNet, and UNETR, and the convergence of these five algorithm models was compared to externally validate the effectiveness of the 3DGE-UNet model., Results: 1) In internal validation, the enhanced 3DGE-UNet model achieved Dice mean values of 91.47%, 87.14%, and 83.35% for segmenting the WT, TC, and ET regions in the test set, respectively, producing the optimal values for comprehensive evaluation. These scores were superior to the corresponding scores of the traditional 3D-UNet model, which were 89.79%, 85.13%, and 80.90%, indicating a significant improvement in segmentation accuracy across all three regions ( P <0.05). Compared with the 3D-UNet model, the 3DGE-UNet model demonstrated higher sensitivity for ET (86.46% vs. 80.77%) ( P <0.05) , demonstrating better performance in the detection of all the lesion areas. When dealing with lesion areas, the 3DGE-UNet model tended to correctly identify and capture the positive areas in a more comprehensive way, thereby effectively reducing the likelihood of missed diagnoses. The 3DGE-UNet model also exhibited exceptional performance in segmenting the edges of WT, producing a mean 95% Hausdorff distance superior to that of the 3D-UNet model (8.17 mm vs. 13.61 mm, P <0.05). However, its performance for TC (8.73 mm vs. 7.47 mm) and ET (6.21 mm vs. 5.45 mm) was similar to that of the 3D-UNet model. 2) In the external validation, the other four algorithms outperformed the 3DGE-UNet model only in the mean Dice for TC (87.25%), the mean sensitivity for WT (94.59%), the mean sensitivity for TC (86.98%), and the mean 95% Hausdorff distance for ET (5.37 mm). Nonetheless, these differences were not statistically significant ( P >0.05). The 3DGE-UNet model demonstrated rapid convergence during the training phase, outpacing the other external models., Conclusion: The 3DGE-UNet model can effectively extract and fuse feature information on different scales, improving the accuracy of brain tumor segmentation., Competing Interests: 利益冲突　所有作者均声明不存在利益冲突, (© 2024《四川大学学报（医学版）》编辑部 版权所有Copyright ©2024 Editorial Board of Journal of Sichuan University (Medical Sciences).)

Objective: To investigate the spatial distribution pattern of local tumor progression (LTP) for hepatocellular carcinoma (HCC) ≤5 cm after microwave ablation. Methods: A retrospective analysis was performed on 169 HCCs with matched MRI before and after ablation from December 2009 to December 2019. A tumor MRI was reconstructed using three-dimensional visualization technology. LTP was classified as contact or non-contact, early or late stage, according to whether LTP was in contact with the edge of the ablation zone and the occurrence time (24 months). The tumor-surrounded area was divided into eight quadrants by using the eight-quadrant map method. An analysis was conducted on the spatial correlation between the quadrant where the ablative margin (AM) safety boundary was located and the quadrant where different types of LTP occurred. The t-test, or rank-sum test, was used for the measurement data. 2-test for count data was used to compare the difference between the two groups. Results: The AM quadrant had a distribution of 54.4% LTP, 64.2% early LTP stage, and 69.1% contact LTP, suggesting this quadrant was much more concentrated than the other quadrants ( P  < 0.001). Additionally, the AM quadrant had only 15.2% of non-contact type LTP and 17.1% of late LTP, which was not significantly different from the average distribution probability of 12.5% (100/8%) among the eight quadrants ( P = 0.667, 0.743). 46.6% of early contact type LTP was located at the ablation needle tip, 25.2% at the body, and 28.1% at the caudal, while the location distribution probabilities of non-early contact LTP were 34.8%, 31.8%, and 33.3%, respectively. Conclusion: LTP mostly occurs in areas where the ablation safety boundary is the shortest. However, non-contact LTP and late LTP stages exhibit the feature of uniform distribution. Thus, this type of LPT may result from an inadequate non-ablation safety boundary.

Objective: To develop an efficient and robust method based on three dimensional facial landmarks for evaluating chin region asymmetry at the soft tissue level and to compare it with the traditional mirror-overlap analysis method in order to test its availability., Methods: Standard symmetrical face was used for mental tubercle coordinate transformation so as to filter soft tissue three dimensional spatial angle and construct corresponding three dimensional spatial angle wireframe template. Ten patients aged 12-32 years with clinical chin region asymmetry diagnosis at the Department of Orthodontics of Peking University Hospital of Stomatology from November 2020 to November 2021 were randomly selected. Three dimensional soft tissue face scan data of the patients were collected by three dimensional face scanner and the landmark points were automatically determined by the Meshmonk non-rigid registration algorithm program, and in this way, the asymmetric three dimensional spatial angle wireframe template and corresponding spatial angle parameters were generated. Mirror-overlap analysis of face scan data was also performed in Geomagic Studio 2015 software and deviation color maps were generated. This study took mirror-overlap analysis as the gold standard method, the response rate of chin region asymmetry was eva-luated by the outcomes of the mirror-overlap analysis and three dimensional spatial angle wireframe template analysis., Results: Nine three dimensional spatial angle indicators were selected through coordinate transformation, and the response rate was calculated using mirror-overlap analysis as the gold standard method. Among these ten selected patients, the response rate of the total chin region asymmetry was 90% (9/10). Using the deviation value of mirror-overlap analysis as a reference, the response rate of chin region asymmetry in the X dimension was 86%, the response rate of chin region asymmetry in the Y dimension was 89%, and the response rate of chin region asymmetry in the Z dimension was 100%., Conclusion: The three dimensional soft tissue spatial angle wireframe template proposed in this study has some feasibility in evaluating chin region asymmetry at the soft tissue level, and its ability to recognize asymmetry separately in the three dimensional direction is better than the mirror-overlap analysis method, and the indicators recognition rate still needs to be further improved.

Naked-eye 3D display technology has excellent 3D visual effects and does not require wearable devices assistance. It can present the depth, position and complex structure information of 3D medical images, allowing viewers to obtain information about tissues and organs from different points, reducing cognitive load, contributing to medical teaching and opening up innovative methods for planning and diagnosis. Naked-eye 3D augmented reality display can display medical images in real 3D space, achieving virtual and real vision. It helps a lot to medical research. The applications of naked-eye 3D display technology in three major aspects of medical diagnosis, clinical surgery and rehabilitation training is reviewed in the study. It provides the direction for the subsequent research in medical field, thus assisting medical research and improving medical practice.

Reconstructing three-dimensional (3D) models from two-dimensional (2D) images is necessary for preoperative planning and the customization of joint prostheses. However, the traditional statistical modeling reconstruction shows a low accuracy due to limited 3D characteristics and information loss. In this study, we proposed a new method to reconstruct the 3D models of femoral images by combining a statistical shape model with Laplacian surface deformation, which greatly improved the accuracy of the reconstruction. In this method, a Laplace operator was introduced to represent the 3D model derived from the statistical shape model. By coordinate transformations in the Laplacian system, novel skeletal features were established and the model was accurately aligned with its 2D image. Finally, 50 femoral models were utilized to verify the effectiveness of this method. The results indicated that the precision of the method was improved by 16.8%-25.9% compared with the traditional statistical shape model reconstruction. Therefore, the method we proposed allows a more accurate 3D bone reconstruction, which facilitates the development of personalized prosthesis design, precise positioning, and quick biomechanical analysis.

Objective: To evaluate the influence of tooth position and retention depth of the dental pulp cavity on the accuracy of intraoral digital impression of endocrown preparation., Methods: Dental pulp cavities with retention depths of 2, 3, 4 and 5 mm were prepared on 8 auatomic resin tooth models, including 4 right maxillary first molar (16) and 4 right mandibular first molar (46).Each cavity were scanned for 10 times using 3shape trios3, with micro-CT scans as the reference.All the scan data were exported, and the reference models were obtained by 3D reconstruction with Mimics 2021 software.Gomagic Wrap 2017 was used to analyze the 3D models.The average absolute deviation values were calculated to evaluate the accuracy of the digital models., Results: There was no significant difference in the authenticity and precision between models 16 and 46.The mean maximum positive and negative deviations of the model 16 were less than those of the model 46( P <0.05), and for both the models 16 and 46, the mean maximum positive deviation was significantly greater than the mean maximum negative deviation ( P <0.05).The authenticity of the 5 mm group was lower than that of the 2 mm, 3 mm and 4 mm groups ( P <0.05).The precision was higher in 2 mm group than in 4 mm and 5 mm groups ( P <0.05), and higher in 3 mm group than in 5 mm group ( P <0.05).The mean maximum positive and negative deviations in 2 mm group were lower than those in 5 mm group ( P <0.05)., Conclusion: The position of teeth has little influence on intraoral digital impression of the endocrown.The retention depth of the dental pulp cavity affects the accuracy of intraoral digital impression of the endocrown, and a greater depth results in a greater deviation.

Purpose: To evaluate the accuracy of static guided implant placement with intraoral scanning technology and to analyze the influencing factors of guided surgery., Methods: Totally 27 cases were included in this retrospective study. The implant designs were made in 3Shape Implant Studio and then guided implant surgeries were performed with CAD-CAM templates. Postoperative implant positions were detected with an intraoral scanner (3Shape TRIOS) and deviation of implantation was evaluated using established CAD/CAM based evaluation method. SAS 9.4 software package was used for data analysis., Results: The mean deviation of entrance point and apical point was (1.182±0.609) mm and (1.658±0.741) mm, respectively. Angular deviation was (5.712±3.347)°. Implant quadrant, location of the implant site, guidance degree, supporting type and implant size influenced direction deviation, while angular deviation was mainly affected by guidance degree and number of missing teeth., Conclusions: Accuracy of static guided implant placement can be influenced by many factors. More research is needed to improve the accuracy of static guided implantation.

Objective: To establish a 3D/2D registration method for preoperative CT and intra-operative X-ray images in imageguided spine surgery., Methods: We propose a 3D/2D registration algorithm based on 3D image reconstruction. The algorithm performs 3D image reconstruction of 2D orthogonal view X-ray images, thus converting the problem into 3D/3D registration. By constructing an end-to-end framework that combines the two tasks of reconstruction and registration, the geodesic distance is measured in the 3D manifold space to complete the registration., Results: We conducted experiments on the public dataset CTSpine1k. The tests on two test sets with different initial registration errors showed that for data with small initial errors, the proposed algorithm achieved a rotation estimation error of 0.115±0.095° and a translation estimation error of 0.144±0.124 mm; for data with larger initial errors, a rotation estimation error of 0.792±0.659° and a translation estimation error of 0.867±0.701 mm were achieved., Conclusion: The proposed method can achieve robust and accurate 3D/2D registration at a speed that meets real-time requirements to improve the performance of spine surgery navigation.

Oro-maxillofacial cone-beam CT (CBCT) is the most widely used three-dimensional imaging method in the field of oral and maxillofacial radiology. It has been widely used in China, while radiation safety, examination indications and other issues still lack comprehensive regulations and standards. Over the years, clinical guidelines and position statements for the rational use of CBCT examinations have been issued in the world, providing standardized instructions for local practitioners. This paper reviewed these guidelines to provide reference for the formulation of relevant guidelines in China.

Objective: To explore an automatic landmarking method for anatomical landmarks in the three-dimensional (3D) data of the maxillary complex and preliminarily evaluate its reproducibility and accuracy. Methods: From June 2021 to December 2022, spiral CT data of 31 patients with relatively normal craniofacial morphology were selected from those who visited the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology. The sample included 15 males and 16 females, with the age of (33.3±8.3) years. The maxillary complex was reconstructed in 3D using Mimics software, and the resulting 3D data of the maxillary complex was mesh-refined using Geomagic software. Two attending physicians and one associate chief physician manually landmarked the 31 maxillary complex datasets, determining 24 anatomical landmarks. The average values of the three expert landmarking results were used as the expert-defined landmarks. One case that conformed to the average 3D morphological characteristics of healthy individuals' craniofacial bones was selected as the template data, while the remaining 30 cases were used as target data. The open-source MeshMonk program (a non-rigid registration algorithm) was used to perform an initial alignment of the template and target data based on 4 landmarks (nasion, left and right zygomatic arch prominence, and anterior nasal spine). The template data was then deformed to the shape of the target data using a non-rigid registration algorithm, resulting in the deformed template data. Based on the unchanged index property of homonymous landmarks before and after deformation of the template data, the coordinates of each landmark in the deformed template data were automatically retrieved as the automatic landmarking coordinates of the homonymous landmarks in the target data, thus completing the automatic landmarking process. The automatic landmarking process for the 30 target data was repeated three times. The root-mean-square distance (RMSD) of the dense corresponding point pairs (approximately 25 000 pairs) between the deformed template data and the target data was calculated as the deformation error of the non-rigid registration algorithm, and the intra-class correlation coefficient ( ICC ) of the deformation error in the three repetitions was analyzed. The linear distances between the automatic landmarking results and the expert-defined landmarks for the 24 anatomical landmarks were calculated as the automatic landmarking errors, and the ICC values of the 3D coordinates in the three automatic landmarking repetitions were analyzed. Results: The average three-dimensional deviation (RMSD) between the deformed template data and the corresponding target data for the 30 cases was (0.70±0.09) mm, with an ICC value of 1.00 for the deformation error in the three repetitions of the non-rigid registration algorithm. The average automatic landmarking error for the 24 anatomical landmarks was (1.86±0.30) mm, with the smallest error at the anterior nasal spine (0.65±0.24) mm and the largest error at the left oribital (3.27±2.28) mm. The ICC values for the 3D coordinates in the three automatic landmarking repetitions were all 1.00. Conclusions: This study established an automatic landmarking method for three-dimensional data of the maxillary complex based on a non-rigid registration algorithm. The accuracy and repeatability of this method for landmarking normal maxillary complex 3D data were relatively good.

In light of the increasing digitalization of dentistry, the automatic determination of three-dimensional (3D) craniomaxillofacial features has become a development trend. 3D craniomaxillofacial landmarks and symmetry reference plane determination algorithm based on point clouds has attracted a lot of attention, for point clouds are the basis for virtual surgery design and facial asymmetry analysis, which play a key role in craniomaxillofacial surgery and orthodontic treatment design. Based on the studies of our team and national and international literatures, this article presented the deep geometry learning algorithm to determine landmarks and symmetry reference plane based on 3D craniomaxillofacial point clouds. In order to provide reference for future clinical application, we describe the development and latest research in this field, and analyze and discuss the advantages and limitations of various methods.

Objective: To investigate the feasibility of MRI three-dimensional (3D) reconstruction model in quantifying glenoid bone defect by comparing with CT 3D reconstruction model measurement., Methods: Forty patients with shoulder anterior dislocation who met the selection criteria between December 2021 and December 2022 were admitted as study participants. There were 34 males and 6 females with an average age of 24.8 years (range, 19-32 years). The injury caused by sports injury in 29 cases and collision injury in 6 cases, and 5 cases had no obvious inducement. The time from injury to admission ranged from 4 to 72 months (mean, 28.5 months). CT and MRI were performed on the patients' shoulder joints, and a semi-automatic segmentation of the images was done with 3D slicer software to construct a glenoid model. The length of the glenoid bone defect was measured on the models by 2 physicians. The intra-group correlation coefficient ( ICC ) was used to evaluate the consistency between the 2 physicians, and Bland-Altman plots were constructed to evaluate the consistency between the 2 methods., Results: The length of the glenoid bone defects measured on MRI 3D reconstruction model was (3.83±1.36) mm/4.00 (0.58, 6.13) mm for physician 1 and (3.91±1.20) mm/3.86 (1.39, 5.96) mm for physician 2. The length of the glenoid bone defects measured on CT 3D reconstruction model was (3.81±1.38) mm/3.80 (0.60, 6.02) mm for physician 1 and (3.99±1.19) mm/4.00 (1.68, 6.38) mm for physician 2. ICC and Bland-Altman plot analysis showed good consistency. The ICC between the 2 physicians based on MRI and CT 3D reconstruction model measurements were 0.73 [95% CI (0.54, 0.85)] and 0.80 [95% CI (0.65, 0.89)], respectively. The 95% CI of the difference between the two measurements of physicians 1 and 2 were (-0.46, 0.49) and (-0.68, 0.53), respectively., Conclusion: The measurement of glenoid bone defect based on MRI 3D reconstruction model is consistent with that based on CT 3D reconstruction model. MRI can be used instead of CT to measure glenoid bone defects in clinic, and the soft tissue of shoulder joint can be observed comprehensively while reducing radiation.

The registration of preoperative magnetic resonance (MR) images and intraoperative ultrasound (US) images is very important in the planning of brain tumor surgery and during surgery. Considering that the two-modality images have different intensity range and resolution, and the US images are degraded by lots of speckle noises, a self-similarity context (SSC) descriptor based on local neighborhood information was adopted to define the similarity measure. The ultrasound images were considered as the reference, the corners were extracted as the key points using three-dimensional differential operators, and the dense displacement sampling discrete optimization algorithm was adopted for registration. The whole registration process was divided into two stages including the affine registration and the elastic registration. In the affine registration stage, the image was decomposed using multi-resolution scheme, and in the elastic registration stage, the displacement vectors of key points were regularized using the minimum convolution and mean field reasoning strategies. The registration experiment was performed on the preoperative MR images and intraoperative US images of 22 patients. The overall error after affine registration was (1.57 ± 0.30) mm, and the average computation time of each pair of images was only 1.36 s; while the overall error after elastic registration was further reduced to (1.40 ± 0.28) mm, and the average registration time was 1.53 s. The experimental results show that the proposed method has prominent registration accuracy and high computational efficiency.

Objective: To explore an efficient and automatic method for determining the anatomical landmarks of three-dimensional(3D) mandibular data, and to preliminarily evaluate the performance of the method., Methods: The CT data of 40 patients with normal craniofacial morphology were collected (among them, 30 cases were used to establish the 3D mandibular average model, and 10 cases were used as test datasets to validate the performance of this method in determining the mandibular landmarks), and the 3D mandibular data were reconstructed in Mimics software. Among the 40 cases of mandibular data after the 3D reconstruction, 30 cases that were more similar to the mean value of Chinese mandibular features were selected, and the size of the mandibular data of 30 cases was normalized based on the Procrustes analysis algorithm in MATLAB software. Then, in the Geomagic Wrap software, the 3D mandibular average shape model of the above 30 mandibular data was constructed. Through symmetry processing, curvature sampling, index marking and other processing procedures, a 3D mandible structured template with 18 996 semi-landmarks and 19 indexed mandibular anatomical landmarks were constructed. The open source non-rigid registration algorithm program Meshmonk was used to match the 3D mandible template constructed above with the tested patient's 3D mandible data through non-rigid deformation, and 19 anatomical landmark positions of the patient's 3D mandible data were obtained. The accuracy of the research method was evaluated by comparing the distance error of the landmarks manually marked by stomatological experts with the landmarks marked by the method of this research., Results: The method of this study was applied to the data of 10 patients with normal mandibular morphology. The average distance error of 19 landmarks was 1.42 mm, of which the minimum errors were the apex of the coracoid process [right: (1.01±0.44) mm; left: (0.56±0.14) mm] and maximum errors were the anterior edge of the lowest point of anterior ramus [right: (2.52±0.95) mm; left: (2.57±1.10) mm], the average distance error of the midline landmarks was (1.15±0.60) mm, and the average distance error of the bilateral landmarks was (1.51±0.67) mm., Conclusion: The automatic determination method of 3D mandibular anatomical landmarks based on 3D mandibular average shape model and non-rigid registration algorithm established in this study can effectively improve the efficiency of automatic labeling of 3D mandibular data features. The automatic determination of anatomical landmarks can basically meet the needs of oral clinical applications, and the labeling effect of deformed mandible data needs to be further tested.

Objective: To review the research progress of digital occlusion setup in orthognathic surgery., Methods: The literature related to digital occlusion setup in orthognathic surgery in recent years was consulted, and the imaging basis, methods, clinical applications as well as existing problems were reviewed., Results: Digital occlusion setup in orthognathic surgery includes manual, semi-automatics, and fully automatic methods. The manual method mainly relies on visual cues for operation, which is difficult to ensure the best occlusion set up, though relatively flexible. The semi-automatic method utilizes the computer software for partial occlusion set up and adjustment, but the occlusion result is still largely depended by manual operation. The fully automatic method completely depends on the operation of computer software, and targeted algorithms for different occlusion reconstruction situations are needed., Conclusion: The preliminary research results have confirmed the accuracy and reliability of digital occlusion setup in orthognathic surgery, but there are still some limitations. Further research is needed in terms of postoperative outcomes, doctor and patient acceptance, planning time and cost-effectiveness.

The structure of orbit is complex and its function is critical. Quantitative determination of orbital volume is valuable to diagnosis and treatment of orbital diseases, but a standardized and reproducible orbital volume measurement method is still not available. Recently, with the development of three-dimensional reconstruction, many researchers gradually convert their insight into three-dimensional orbital measurement. This paper reviews the common methods of three-dimensional orbital measurement used by investigators, including some innovative ideas, and their clinical applications in order to make a comprehensive overview of the current orbital measurement technology, explore the possible improvement direction, and better serve the clinical.

In recent years, the task of object detection and segmentation in medical image is the research hotspot and difficulty in the field of image processing. Instance segmentation provides instance-level labels for different objects belonging to the same class, so it is widely used in the field of medical image processing. In this paper, medical image instance segmentation was summarized from the following aspects: First, the basic principle of instance segmentation was described, the instance segmentation models were classified into three categories, the development context of the instance segmentation algorithm was displayed in two-dimensional space, and six classic model diagrams of instance segmentation were given. Second, from the perspective of the three models of two-stage instance segmentation, single-stage instance segmentation and three-dimensional (3D) instance segmentation, we summarized the ideas of the three types of models, discussed the advantages and disadvantages, and sorted out the latest developments. Third, the application status of instance segmentation in six medical images such as colon tissue image, cervical image, bone imaging image, pathological section image of gastric cancer, computed tomography (CT) image of lung nodule and X-ray image of breast was summarized. Fourth, the main challenges in the field of medical image instance segmentation were discussed and the future development direction was prospected. In this paper, the principle, models and characteristics of instance segmentation are systematically summarized, as well as the application of instance segmentation in the field of medical image processing, which is of positive guiding significance to the study of instance segmentation.

The geometric bone model of patients is an important basis for individualized biomechanical modeling and analysis, formulation of surgical planning, design of surgical guide plate, and customization of artificial joint. In this study, a rapid three-dimensional (3D) reconstruction method based on statistical shape model was proposed for femur. Combined with the patient plain X-ray film data, rapid 3D modeling of individualized patient femur geometry was realized. The average error of 3D reconstruction was 1.597-1.842 mm, and the root mean square error was 1.453-2.341 mm. The average errors of femoral head diameter, cervical shaft angle, offset distance and anteversion angle of the reconstructed model were 0.597 mm, 1.163°, 1.389 mm and 1.354°, respectively. Compared with traditional modeling methods, the new method could achieve rapid 3D reconstruction of femur more accurately in a shorter time. This paper provides a new technology for rapid 3D modeling of bone geometry, which is helpful to promote rapid biomechanical analysis for patients, and provides a new idea for the selection of orthopedic implants and the rapid research and development of customized implants.

Digital medicine has gone through more than 20 years in China.Digital intelligent technologies such as three-dimensional(3D) visualization, virtual reality, augmented reality and mixed reality have been gradually promoted and applied in pancreatic diseases, constantly affecting and changing the traditional mode of diagnosis and treatment of pancreatic diseases to digital intelligent mode.In order to better standardize the digital intelligent diagnosis and treatment of pancreatic diseases, on the basis of the "Expert consensus of precise diagnosis and treatment for pancreatic head cancer using three-dimensional visualization technology", Pancreatic Surgery Group of Surgery Branch of Chinese Medical Association, and Digital Medical Branch of Chinese Medical Association,etc., organized domestic experts engaged in this field to formulate this expert consensus, focusing on revisions and supplements to introduce in detail the quality of 3D visualization, virtual reality, augmented reality, mixed reality and navigational surgery in the diagnosis and treatment of pancreatic surgical diseases.The control system and key points of clinical application are provided for the reference of pancreatic surgeons who are currently developing or preparing to develop digital intelligent technology, so as to better standardize and promote the clinical application of this technology.

Objective: The characteristics of 3D-FLAIR MRI images of the inner ear of patients with vestibular neuritis were preliminarily studied to explore the possible pathogenesis of vestibular neuritis, and the correlation analysis was conducted in combination with vestibular function to provide a basis for accurate diagnosis of vestibular neuritis. Methods: A total of 36 patients with vestibular neuritis (VN) from December 2019 to October 2020 were collected from the Vertigo Department of Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University. There were 36 cases (18 females, 18 males) with unilateral acute vestibular neuritis, 17 cases of left ear and 19 cases of right ear. According to the results of 3D-FLAIR MRI in the inner ears, the patients were divided into the enhanced group and the non-enhanced group (the health side served as the normal control group). The results of vestibular function examination in the two groups were compared. SPSS19.0 software was used for statistical processing to analyze the relationship between the vestibular function and the characteristics of 3D-FLAIR imaging in the inner ears. Results: Abnormal enhancement of 3D-FLAIR was found in 31 cases (86.1%) of the 36 cases, including 14 cases of both vestibular nerve and vestibular terminal organ enhancement, eight cases of superior vestibular nerve enhancement alone, seven cases of vestibular terminal organ enhancement alone, and two cases of cochlear enhancement alone. Observation of abnormal reinforcement of vestibular nerve showed: twenty-one cases of superior vestibular nerve reinforcement, one case of superior and inferior vestibular nerve reinforcement. No abnormalities were found in 3D-FLAIR of inner ear in 5 cases. According to the analysis of vestibular function results, there were 19 cases (52.8%) with total vestibular involvement, sixteen cases (44.4%) with superior vestibular involvement alone, and one case (2.8%) with inferior vestibular involvement alone. Comparison of vestibular function between the five cases (non-enhancement group) and the 31 cases (enhanced group) in the 3D-FLAIR group of the inner ears showed that the CP values of caloric tests in the enhanced group were higher (60.81±3.49 vs 34.12±7.37), with statistically significant difference ( t =-2.898, P <0.01). Conclusion: In patients with vestibular neuritis, 3D-FLAIR MRI scan of the inner ear provides visual imaging evidence for clinical practice, considering that the lesion site of vestibular neuritis is not only in the vestibular nerve, but also in the vestibular end organ. Patients with 3D-FLAIR enhanced in the inner ear may have more significant vestibular function damage.

Objective: To explore the establishment of an efficient and automatic method to determine anatomical landmarks in three-dimensional (3D) facial data, and to evaluate the effectiveness of this method in determining landmarks. Methods: A total of 30 male patients with tooth defect or dentition defect (with good facial symmetry) who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology from June to August 2021 were selected, and these participants' age was between 18-45 years. 3D facial data of patients was collected and the size normalization and overlap alignment were performed based on the Procrustes analysis algorithm. A 3D face average model was built in Geomagic Studio 2013 software, and a 3D face template was built through parametric processing. MeshLab 2020 software was used to determine the serial number information of 32 facial anatomical landmarks (10 midline landmarks and 22 bilateral landmarks). Five male patients with no mandibular deviation and 5 with mild mandibular deviation were selected from the Department of Orthodontics or Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from June to August 2021. 3D facial data of patients was collected as test data. Based on the 3D face template and the serial number information of the facial anatomical landmarks, the coordinates of 32 facial anatomical landmarks on the test data were automatically determined with the help of the MeshMonk non-rigid registration algorithm program, as the data for the template method to determine the landmarks. The positions of 32 facial anatomical landmarks on the test data were manually determined by the same attending physician, and the coordinates of the landmarks were recorded as the data for determining landmarks by the expert method. Calculated the distance value of the coordinates of facial anatomical landmarks between the template method and the expert method, as the landmark localization error, and evaluated the effect of the template method in determining the landmarks. Results: For 5 patients with no mandibular deviation, the landmark localization error of all facial anatomical landmarks by template method was (1.65±1.19) mm, the landmark localization error of the midline facial anatomical landmarks was (1.19±0.45) mm, the landmark localization error of bilateral facial anatomical landmarks was (1.85±1.33) mm. For 5 patients with mild mandibular deviation, the landmark localization error of all facial anatomical landmarks by template method was (2.55±2.22) mm, the landmark localization error of the midline facial anatomical landmarks was (1.85±1.13) mm, the landmark localization error of bilateral facial anatomical landmarks was (2.87±2.45) mm. Conclusions: The automatic determination method of facial anatomical landmarks proposed in this study has certain feasibility, and the determination effect of midline facial anatomical landmarks is better than that of bilateral facial anatomical landmarks. The effect of determining facial anatomical landmarks in patients without mandibular deviation is better than that in patients with mild mandibular deviation.

Digital intelligent hepatobiliary surgery has evolved over decades.It has experienced an evolution course from digital virtual human technology to the establishment of a quality-controlled and homogeneous three-dimensional visualization system for precision diagnosis and treatment of diseases, from three-dimensional visualization to the clinical transformation of digital intelligent technology and changes in the diagnosis and treatment model, from empirical diagnosis of diseases to the application of deep learning for the intelligent diagnosis and treatment of diseases, from empirical surgery to real-time multi-modal image guidance during surgery, and from the morphological diagnosis of tumors to accurate diagnosis from molecular imaging.During the whole process, only through continuous innovation in research, theory and technology can the "life" of digital intelligent surgery be endowed with new vitality.In the future, the definition of tumor boundary from the molecular and cellular levels and the early diagnosis and treatment of liver tumor through the functional visualization of key molecules will have significant clinical value for changing the prognosis of liver cancer.In addition, in order to realize intelligent navigation for hepatectomy and break through the technical bottleneck, it is of great clinical significance to develop an intelligent robot real-time navigation hepatectomy system with automatic navigation technology, machine learning intelligent planning technology and multimodal image fusion technology.This provides unprecedented opportunities and challenges for the development of digital intelligent hepatobiliary surgery.

Objective: To evaluate the effect of vascular localization using computerized tomography angiography (CTA) combined with refined three dimensional (3D) printing in guiding the resection and reconstruction of complex oral cancer. Methods: From December 2013 to July 2017, the clinical data of 30 patients with complex oral cancer enrolled in the Hunan Cancer Hospital were retrospectively analyzed. 15 patients received CTA+ 3D assisted surgery, while the other 15 patients underwent traditional surgery. In CTA+ 3D assisted surgery group, CT and Magnetic Resonance Imaging (MRI) data were combined with CTA to print refined solid 3D model and surgical guide plate. The preoperative and intraoperative virtual surgical system and the operative experience were combined for preoperative evaluation and surgery. In traditional surgery group, preoperative evaluation and surgery were performed according to imaging data and surgeons' clinical experience. Operative time, intraoperative blood loss, hospital stay and local recurrence rate were compared between the two groups. Results: In CTA+ 3D assisted surgery group, one patient gave up surgical treatment after intuitively watching the lesion through the 3D model, and the remaining 14 patients underwent surgery as planned. All the 15 patients in traditional surgery group received surgery. But the preoperative plans of three patients were temporarily and passively modified due to insufficient preoperative evaluation. The average intraoperative blood loss was(320.1±27.2)ml in CTA+ 3D assisted surgery group and(430.2±30.3)ml in traditional surgery group. Mean operation time was(440.3±19.2)min and(552.2±23.3)min, respectively. Mean hospitalization time was (20.4±3.2)d and (25.1±3.7)d, respectively. The differences were all statistically significant (all P <0.05). 1 year and 3 years local recurrence rates were 9.1% and 28.6% in CTA+ 3D assisted surgery group, as well as 14.3% and 50.4% in traditional surgery group with statistical significance ( P <0.05). Conclusion: For complex oral cancer patients with difficulty in opening the mouth or postoperative recurrence, CTA vascular localization combined with fine 3D printing technology has significant advantages in the surgical process, surgical effect and postoperative evaluation index compared with traditional method using imaging data and clinical experience.

Objective: To explore the application value of computed tomography angiography (CTA) and three-dimensional reconstruction in repairing high-voltage electrical burn wounds in necks, shoulders, axillas, and upper arms with tissue flaps. Methods: From December 2014 to December 2018, 12 patients with high-voltage electrical burns in necks, shoulders, axillas, and upper arms were hospitalized. The size of wounds ranged from 13 cm×10 cm to 32 cm×15 cm after complete debridement. Before tissue flap repair, the subclavian artery-axillary artery-brachial artery and their branches were examined by CTA. The main target vessels and their branches were conducted by three-dimensional reconstruction, and the development of the axis vessels for the tissue flaps planning to dissect and their branches were observed. For wounds in upper arms, amputation stump bone exposed wounds, and wounds in axillas and the anterior, the latissimus dorsi myocutaneous flap is the first choice for repair, if the thoracodorsal artery and internal and external branches are well developed according to CTA examination. Latissimus dorsi myocutaneous flaps were used in 6 patients with the area of myocutaneous flap ranging from 16 cm×12 cm to 32 cm×17 cm. All the donor sites were covered by split-thickness skin graft of thighs. For large wounds in occiputs, necks, and scapulas, the contralateral lower trapezius myocutaneous flap is the first choice for repair, if the superficial descending branch and deep branch of the contralateral transverse cervical artery are well developed according to CTA examination. For small wounds in necks and scapulas, the ipsilateral lower trapezius myocutaneous flap can be used for repair, if the superficial descending branch of the ipsilateral transverse cervical artery is well developed according to CTA examination. Lower trapezius myocutaneous flaps were used in 4 patients with the area of myocutaneous flap ranging from 18 cm×12 cm to 25 cm×17 cm. The donor site of one patient was sutured directly and the donor site of the other 3 patients was covered by split-thickness skin graft of thighs. For wounds in the posteromedial side of upper arms and the anterior side of axillas, the lateral thoracic skin flaps can be used for repair, if the latissimus dorsi myocutaneous flap can not be utilized for reasons of back burn or no muscle is needed for dead space, when the blood supply of side chest skin is reliable according to CTA examination. Lateral thoracic skin flaps were used in 2 patients with the area of skin flap ranging from 16 cm×12 cm to 17 cm×14 cm. The donor site of one patient was sutured directly and the donor site of the other one patient was covered by split-thickness skin graft of thigh. Results: During the operation of tissue flap repair in 12 patients, the orientation and starting position of the axis vessels were consistent with those observed by CTA examination before operation. All the tissue flaps survived after operation. During follow-up of 1 to 24 months, the patients were satisfied with no serious scar contracture affecting the function nor secondary infection or chronic ulcer. Conclusions: CTA and its three-dimensional reconstruction technique can clearly reconstruct the subclavian artery-axillary artery-brachial artery and their branches before repair of high-voltage burn wounds in necks, shoulders, axillas, and upper arms. It can be used to observe whether the vessels are embolized or not and the starting position and orientation of blood vessels, which can provide an important reference for the selection of tissue flap transplantion.

Objective: To investigate the value of tumor perfusion parameter measured by using double contrast-enhanced ultrasound (DCEUS) QontraXt three-dimensional pseudocolor quantitative analysis to the therapeutic effect evaluation of preoperative neoadjuvant chemotherapy (NAC) in advanced gastric cancer (AGC) patients. Methods: Eighty-nine AGC patients underwent 3 cycles of preoperative NAC (XELOX) followed by complete resection of lesion. The DCEUS QontraXt three-dimensional pseudocolor was performed one or two weeks before the NAC and operation were applied, respectively. The peak enhancement (PE), time to peak (TP), sharpness of the bolus (β) and area under the enhancement curve (AUC) of primary gastric tumor were measured by QontraXt three-dimensional pseudocolor quantitative analysis. These DCEUS parameters between respond and non-respond groups before and after NAC therapy were compared. The prediction accuracy of DCEUS to the therapeutic effect evaluation of preoperative NAC was determined by the receive operating characteristic (ROC) curves. Results: Among 89 AGC patients, 52 patients responded to NAC therapy, while 37 patients resisted to NAC therapy. Twelve cases in respond group and 26 cases in non-respond group were mucinous carcinoma. Forty cases in respond group and 11 cases in non-respond group were non-mucinous carcinoma ( P <0.05). In responder group, the PE and TP before NAC were (53.7±9.3)% and (14 521±2 667) ms, and (32.2±5.5)% and (17 235±1 898) ms after NAC. The ratio of changes of PE (ΔPE) and TP (ΔTP) were 0.43±0.17 and 0.36±0.14, respectively. In non-respond group, the PE and TP before NAC were (54.4±7.2)% and (13 869±3 247) ms, and (45.3±6.1)% and (15 127±1 423) ms after NAC therapy. The ratio of ΔPE and ΔTP were 0.24±0.20 and 0.22±0.12. The PE and TP after NAC, the ratio of ΔPE and ΔTP were significant different among these two groups (all of P <0.05). The ROC curves showed that the ratio of ΔPE in assessing the respond of gastric cancer patients to NAC was superior compared to other parameters (AUC=0.784, P =0.004). The optimal cut-off value of the ratio of ΔPE was 24% and its sensitivity and specificity to the therapeutic effect evaluation of NAC in gastric cancer were 82.7% and 64.9%. Conclusion: DCEUS QontraXt three-dimensional pseudocolor quantitative analysis might be a novel, noninvasive and reliable method to evaluate the therapeutic effect of preoperative NAC in AGC patients.

Objective: To explore application effects of CT angiography (CTA) and three-dimensional reconstruction technique in repairing scar around the mouth and chin with expanded forehead axial flap. Methods: From June 2013 to October 2017, 9 patients with hyperplastic scar around the mouth and chin after deep burns on face were admitted to our unit. The sizes of scars of patients ranged from 8 cm×7 cm to 13 cm×8 cm. One cylindrical skin soft-tissue dilator with nominal volume of 400 to 500 mL was implanted in forehead area of each patient. Five to six months after the dilator was implanted, scar around the mouth and chin was resected, and the dilator was removed. The secondary wound after scar resection was repaired by expanded forehead axial flap with bilateral superficial temporal vessel pedicles. Three of the nine patients received microstomia diorthosis at the same time. Before the operation, CTA and three-dimensional reconstruction were applied to obtain three-dimensional images of superficial temporal arteries and the branches in the donor site, which could identify the travel, adjacent location, and vascular anastomosis of the above-mentioned vessels to guide flap design. The sizes of flaps of patients ranged from 25 cm×9 cm to 30 cm×8 cm. Two to three weeks after the operation, flap pedicles were cut off, restored, and trimmed. The donor site was sutured directly. Ten to twelve days after the flap repair operation, the flap site received depilation treatment with semiconductor freezing point laser once a month for 4 to 6 times. Results: Flaps of all patients survived well, with no blood circulation disorder. The flaps of three patients were slightly bulky, while they were with natural appearance after flap thinning operation in 3 months post flap repair operation. During follow-up of 6 months to 2 years after the operation, color, texture, and thickness of the flaps were close to normal skin around scars. The appearance of perioral and mental region, and opening function of mouth improved significantly, with no recurrence of scar. Frontotemporal incision was hidden, hair on head grew normally, and reconstructed hairline was natural. Conclusions: Scar around the mouth and chin repaired with expanded forehead axial flap were with good appearance and function in operation area and good shape in donor site. CTA and three-dimensional reconstruction technique can provide clear three-dimensional images of superficial temporal arteries and the branches in expanded forehead axial flaps, which can provide reliable basis for preoperative designing of flap, reduce operative risk, and improve survival rate of flap, thus having clinical application value.

Objectives: To search age-correlated facial features and construct an age estimation model based on the three-dimensional （3D） facial images of Xinjiang Uygur males, and to structure individual face images of old age and young age., Methods: Pretreatment was performed to collect 105 3D facial images of Xingjiang Uygur males aged between 17-57 years by Artec Studio software. The facial images were transferred to high-density 3D dot matrix data by FaceAnalysis software, and each image could be represented with 32 251 vertexes. Central correction of the facial images was done and all the data were aligned to a standard coordinate frame by generalized Procrustes analysis （GPA）. The age estimation model was established by partial least square regression （PLSR）. Furthermore, the changes of age-correlated facial features were presented on the heat map of average face, and the reconstruction of facial images at different ages was performed based on this model., Results: With age, the average faces showed a series of changes including the nasolabial sulcus deepening, cheek sinking, cheekbone protruding and eye corner drooping. The Pearson correlation coefficient （ r ） between estimated age and chronological age was 0.71. The mean absolute deviation （MAD） of age estimation was 6.37 years. The results of age estimation in >30-40 years group showed a best accuracy （MAD=4.27 years）, and the deviations increased with age after 40 years. The composite facial images represented a significant result with age on facial morphological features and aging., Conclusions: The results of this study reveal the age-correlated facial features and aging markers in Uygur population, which help to construct a reliable age estimation model., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine.)

Objective: To explore the safety and efficacy for radiofrequency ablation of paroxysmal supraventricular tachycardia (PSVT) guided by Carto Univu three-dimensional mapping system.
 Methods: A total of 99 patients with PSVT underwent radiofrequency catheter ablation (RFCA) were assigned to a Carto Univu group (51 patients) and a two-dimensional X-ray group (48 patients) according to the mapping method. The operation time, X-ray exposure time, X-ray exposure dose, dose area product (DAP), operation success rate and complication rate were compared between the two groups.
 Results: The Carto Univu group and the two-dimensional X-ray group were not significant difference in the operation time, the X-ray exposure time of placing catheter, the X-ray DAP of placing catheter, the number of discharge, the discharge power, and the total discharge time (P>0.05). The mapping and ablation time, total exposure time, mapping and ablation DAP and total DAP in the Carto Univu group were significantly lower than those in the two-dimensional X-ray group (P<0.01). In the right accessory pathway cases, the mapping and ablation DAP and the total DAP in the Carto Univu group decreased compared with X-ray group (P<0.05), but it decreased more profound (P<0.01) in the left accessory pathway cases and the dual atrioventricular nodal pathways cases. Seven cases in the Carto Univu group achieved "zero X-ray", including 5 cases of the dual atrioventricular nodal pathways and 2 cases of the left accessory pathway. The immediate success rate for the two groups was 100%. After 3-12 months of follow-up, there was no recurrence in the Carto Univu group but 3 suspected recurrences in the two-dimensional X-ray group. In addition, no complications occurred in the two groups. 
 Conclusion: Carto Univu electroanatomic mapping system can guide PSVT safely and effectively during radiofrequency ablation and reduce radiation exposure to both doctors and patients. It is especially suitable for dual atrioventricular nodal pathways, which may even achieve "zero X-ray". Perhaps Carto Univu will be the first choice for RFCA of dual atrioventricular nodal pathways.

Objective: Accurate segmentation of multiple gliomas from multimodal MRI is a prerequisite for many precision medical procedures. To effectively use the characteristics of glioma MRI and im-prove the segmentation accuracy, we proposes a multi-Dice loss function structure and used pre-experiments to select the good hyperparameters (i.e. data dimension, image fusion step, and the implementation of loss function) to construct a 3D full convolution DenseNet-based image feature learning network. This study included 274 segmented training sets of glioma MRI and 110 test sets without segmentation. After grayscale normalization of the image, the 3D image block was extracted as a network input, and the network output used the image block fusion method to obtain the final segmentation result. The proposed structure improved the accuracy of glioma segmentation compared to a general structure. In the on-line assessment of the open BraTS2015 data set, the Dice values for the entire tumor area, tumor core area, and enhanced tumor area were 0.85, 0.71, and 0.63, respectively.

Objective: To analyze the advantages of spatial measurement of anatomical parameters in a 3D model in surgical planning for laparoscopic partial nephrectomy (LPN)., Methods: From February, 2016 to October, 2017, 37 patients diagnosed with T1 renal mass underwent LPN based on 3D reconstruction after enhanced CT scanning using the Uromedix-3D system (group A), and another 38 patients received LPN with conventional CT planning (group B). The anatomical parameters were measured in the reconstructed 3D model and the demographic data, surgical outcome and postoperative data were compared between the two groups., Results: In group A, the average time for 3D model reconstruction was (29.3∓9.7) min; the length, width and depth of the renal defect in 3D model were 3.2∓1.1 cm, 2.6∓0.9 cm and 1.7∓0.7 cm, respectively; The distance of the tumor from the collecting system was 3.8∓2.2 mm; The mean R.E.N.A.L score of the patients was 7∓1.5, and 3 patients had accessory renal artery and 2 had early branching of the renal artery. LPNs were completed via the retroperitoneal approach in all the 75 patients without conversion to open or total nephrectomy. Group A and group B showed significant differences in warm ischemic time (26.7∓6.4 vs 31.9∓7.0 min), tumor-excision time (8.4∓2.6 vs 10.4∓2.8 min), renal defect suture time (18.3∓3.9 vs 21.5∓3.4 min), 24-h volume of retroperitoneal drainage (88.6∓40.2 vs 134.3∓58.3 mL) and 48-h volume of retroperitoneal drainage (127.9∓54.5 vs 198.1∓86.3 mL), but not in the demographic data, operation time, intraoperative blood loss or postoperative hospital stay., Conclusions: 3D reconstruction of the renal masses can be completed efficiently and accurately using this system. Compared with conventional CT-based measurement, 3D spatial measurement of the anatomical structures helps to increase the precision in the performance of LPN and reduce the warm ischemia time.

Objective: To investigate the changes of facial soft tissue before and after orthognathic surgery in patients with skeletal Class Ⅲ malocclusion., Methods: Between August 2016 and April 2017, 30 patients with skeletal Class Ⅲ malocclusion who underwent maxillary LeFort Ⅰ osteotomy and sagittal split mandible osteotomy were selected as study subjects. Among them, 11 were male and 19 were female with an average age of 22.6 years (range, 18-35 years). Full head CT scan and facial soft tissue three-dimensional image scan were performed within 2 weeks before surgery and at 6 months after surgery. A three-dimensional facial image model was established using Artec Studio 11.0 and CMF Proplan 3.0 software to analyze the facial soft tissue changes before and after surgery. The soft tissue anatomical landmarks in each area of the face were measured and compared before and after surgery., Results: The area of facial soft tissue change after surgery was the maxillary nose and the lower jaw area, and the two sides did not exceed the vertical boundary of the outer canthus. After surgery, the horizontal points of bilateral alar bases and bilateral cheeks changed significantly ( P <0.05). The sagittal points of subnasale, pronasale, bilateral alar bases, upper lip margin significantly forwarded ( P <0.05); the sagittal points of the bilateral cheilions, lower lip margin, midpoint of chin-lip groove, pogonion, and menton significantly backwarded ( P <0.05). The vertical points of the upper lip margin, bilateral cheilions, lower lip margin, bilateral cheeks, and bilateral inner canthus points significantly descended ( P <0.05), and the vertical point of the menton significantly elevated ( P <0.05). After surgery, the nasal column was significantly shortened, the upper lip got longer and the alar base widened when compared with those before surgery ( P <0.05)., Conclusion: The overall change of face after double jaw surgery is shorter and fuller, and the mandible of facial soft tissue change is larger than that of maxillary, which suggests that the postoperative facial changes should be taken into account in the surgical design.

Objectives: To establish a method for the age estimation of adult living donor based on pubic MSCT three-dimensional reconstruction and verify its accuracy and reliability., Methods: The volume rendering （VR） image data of pubic symphysis surface were collected from 300 volunteers aged over 17 years old. According to different age groups, the age estimation of these volunteers was performed by the method and formula of pubic symphysis surface., Results: In the 300 volunteers, the difference between biological age and actual age was <1 year in 117 cases, >1-2 years in 178 cases, >2 years in 5 cases., Conclusions: MSCT three-dimensional reconstruction technology of pubic symphysis surface can be used to estimate the age of adult living donor, which can provide a high accurate and reliable result., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine.)

Objective: To explore the application of real-time three-dimensional ultrasound in locating the course, the brand and the blind end of internal opening of congenital preauricular fistula. Methods: Congenital preauricular fistula patients from Changhai Hospital were studied. All the cases were evaluated using two-dimensional and three-dimensional ultrasound before surgeries. The surgery findings were utilized as the gold standard. The imaging features of 3D ultrasound were described to determine the accuracy of the blind end location, the course of the main fistula tract and the branch tracts. The diagnosis was compared with the surgery findings. Results: In 89 cases, among which there were 21 branch fistulae. There were 68 bend fistulae without branch. The diagnostic accuracy of both two-dimensional ultrasound and three-dimensional ultrasound was 100%. The accuracy in locating the blind end of internal opening, the course of the branch tracts with 3D ultrasound was 92.1%(82/89), 85.7%(18/21) , compared to 80.9%(72/89), 57.1%(12/21) with 2D ultrasound. It was obvious that 3D ultrasound had more advantages. These differences were statistically significant (χ(2)=4.8, P <0.05; χ(2)=4.2, P <0.05). Conclusions: Compared with 2D ultrasound, 3D ultrasound can accurately locate the blind end of internal opening, the course, and the branch of preauricular fistula, clearly display the morphology and the spatial structure of preauricular fistulaand its surroundings. It has high clinical application value in preoperative imaging examination.

Objective: To investigate the correlation between Ground Glass Opacity (GGO) component proportion and quantitative classification of lepidic growth pattern in pathological stage Ⅰpulmonary adenocarcinoma. Methods: Pathological and HRCT data of 183 stage Ⅰ invasive adenocarcinoma patients from January 2005 to December 2012 were retrospectively reviewed. The proportion of GGO was calculated from diameter and volume.The correlation between GGO component proportion and lepidic growth pattern in pathological were analyzed by Spearman correlation. Results: Among 183 patients, the proportion of GGO component calculated by maximum diameter method and three-dimensional computerized quantification was 0.43±0.35 and 0.20±0.18, respectively. The percentage of lepidic growth pattern component using semi-quantitative analysis of pathological sections was 0.29±0.25.The proportion of GGO by diameter and three-dimensional computerized quantification was significantly correlated with the percentage of lepidic growth pattern component ( r =0.599, P < 0.001; r =0.620, P <0.001). Conclusions: There was a positive correlation between the content of lepidic growth pattern and the content of GGO in the small adenocarcinoma. Three-dimensional computerized quantification was a better method in preoperational evaluation.

Objective: To measure the inner diameter of tracheal(TD) in Chinese adults by multi-slice spiral CT(MSCT), multi-planar reconstruction(MPR) with special window technique and analyze its influencing factors. Methods: A total of 824 normal adults(male 435, female 389) and 16 patients with small peripheral pulmonary nodules(SPN) receiving chest multi-slice spiral CT (MSCT) in the physical examination at the First Affiliated Hospital of Guangzhou Medical University between January, 2014 and December, 2015 were included and their records were retrospectively analyzed. The 16 patients with SPN received bronchoscopy and the images were recorded followed by measurement of tracheal diameter using software. MSCT and MPR images were obtained by the 3Dview software, and the inner diameter of the trachea at 4 horizontal positions were measured by special window technique (window width 500 Hu, window level 100 Hu): thoracic entrance (TD(1)), aortic arch (TD(2)), 2 cm higher than the carina of trachea (TD(3)) and the narrowest trachea (TD(4)). Results: The results of bronchoscopy and software measurement in 16 patients were consistent with those of MSCT and MPR combined with special window technique ( P >0.05). The TD at 4 positions in adult males were larger than those of adult females ( P <0.01). The TD values at each position for males and females were as follows: (18.9±1.7) and (15.6±1.3) mm ( t =30.9, P <0.01) for TD(1), (18.8±1.6) and (16.1±1.2) mm ( t =28.0, P <0.01) for TD(2), (19.0±1.6) and (16.3±1.3) mm ( t =26.5, P <0.01) for TD(3), (18.4±1.5) and (15.5±1.1) mm ( t =31.3, P <0.01) for TD(4), respectively. The age, weight and BMI were not significantly correlated with the tracheal diameter ( P >0.05). The height was linearly correlated with the tracheal diameter: for males, TD(1)=0.071× height (cm) + 6.964 ( r =0.249, P <0.05), TD(2)=0.064 × height (cm) + 7.898 ( r =0.246, P <0.05), TD(3)=0.074 × height (cm) + 6.533 ( r =0.279, P <0.05), TD(4)=0.056 × height(cm) + 8.811( r =0.226, P <0.05); while for females, TD(1)= 0.046× height (cm) + 8.331 ( r =0.183, P <0.05), TD(2) = 0.058 × height (cm)+ 6.950( r =0.248, P <0.05), TD(3)=0.059 × height (cm)+ 7.052 ( r =0.235, P <0.05), TD(4) =0.044× height (cm) + 8.520 ( r =0.208, P <0.05). Conclusion: MSCT and MPR combined with special window technique are accurate and feasible for the measurement of adult tracheal diameter. The diameter of the trachea in males is larger than that in females, and it is positively correlated with height, but not with age, body weight and BMI. The tracheal diameter can be evaluated by linear regression equation.

Objective: To explore a new method of whole-process digital esthetic prosthodontic rehabilitation combined with periodontic surgery for complicated anterior teeth esthetic defects accompanied by soft tissue morphology, to provide an alternative choice for solving this problem under the guidance of three-dimensional (3D) printing digital dental model and surgical guide, thus completing periodontic surgery and digital esthetic rehabilitation of anterior teeth., Methods: In this study, 12 patients with complicated esthetic problems accompanied by soft tissue morphology in their anterior teeth were included. The dentition and facial images were obtained by intra-oral scanning and three-dimensional (3D) facial scanning and then calibrated. Two esthetic designs and prosthodontic outcome predictions were created by computer aided design /computer aided manufacturing (CAD/CAM) software combined with digital photography, including consideration of white esthetics and comprehensive consideration of pink-white esthetics. The predictive design of prostheses and the facial appearances of the two designs were evaluated by the patients. If the patients chose the design of comprehensive consideration of pink-white esthetics, they would choose whether they would receive periodontic surgery before esthetic rehabilitation. The dentition design cast of those who chose periodontic surgery would be 3D printed for the guide of periodontic surgery accordingly., Results: In light of the two digital designs based on intra-oral scanning, facing scanning and digital photography, the satisfaction rate of the patients was significantly higher for the comprehensive consideration of pink-white esthetic design (P<0.05) and more patients tended to choose priodontic surgery before esthetic rehabilitation. The 3D printed digital dental model and surgical guide provided significant instructions for periodontic surgery, and achieved success transfer from digital design to clinical application. The prostheses were fabricated by CAD/CAM, thus realizing the whole-process digital esthetic rehabilitation., Conclusion: The new method for esthetic rehabilitation of complicated anterior teeth esthetic defects accompanied by soft tissue morphology, including patient-involved digital esthetic analysis, design, esthetic outcome prediction, 3D printing surgical guide for periodontic surgery and digital fabrication is a practical technology. This method is useful for improvement of clinical communication efficiency between doctor-patient, doctor-technician and doctors from different departments, and is conducive to multidisciplinary treatment of this complicated anterior teeth esthetic problem.

The maxilla is the most important bony support of the mid-face skeleton and is critical for both esthetics and function. Maxillary defects, resulting from tumor resection, can cause severe functional and cosmetic deformities. Furthermore, maxillary reconstruction presents a great challenge for oral and maxillofacial surgeons. Nowadays, vascularized composite bone flap transfer has been widely used for functional maxillary reconstruction. In the last decade, we have performed a comprehensive research on functional maxillary reconstruction with free fibula flap and reported excellent functional and acceptable esthetic results. However, this experience based clinical procedure still remainssome problems in accuracy and efficiency. In recent years, computer assisted techniques are now widely used in oral and maxillofacial surgery. We have performed a series of study on maxillary reconstruction with computer assisted techniques. The computer assisted techniques used for maxillary reconstruction mainly include: (1) Three dimensional (3D) reconstruction and tumor mapping: providing a 3D view of maxillary tumor and adjacent structures and helping to make the diagnosis of maxillary tumor accurate and objective; (2) Virtual planning: simulating tumor resection and maxillectomy as well as fibula reconstruction on the computer, so that to make an ideal surgical plan; (3) 3D printing: producing a 3D stereo model for prebending individualized titanium mesh and also providing template or cutting guide for the surgery; (4) Surgical navigation: the bridge between virtual plan and real surgery, confirming the virtual plan during the surgery and guarantee the accuracy; (5) Computer assisted analyzing and evaluating: making a quantitative and objective of the final result and evaluating the outcome. We also performed a series of studies to evaluate the application of computer assisted techniques used for maxillary reconstruction, including: (1) 3D tumor mapping technique for accurate diagnosis and treatment of maxillary tumor; (2) Maxillary reconstruction with free fibula flap used computer assisted techniques; (3) Computer assisted orbital floor reconstruction after maxillectomy. The results suggested that computer assisted techniques could significantly improve the clinical outcome of maxillary reconstruction.

Objective: To explore a new method for rapid extracting and rebuilding three-dimensional (3D) digital root model of vivo tooth from cone beam computed tomography (CBCT) data based on the anatomical characteristics of periodontal ligament, and to evaluate the extraction accuracy of the method., Methods: In the study, 15 extracted teeth (11 with single root, 4 with double roots) were collected from oral clinic and 3D digital root models of each tooth were obtained by 3D dental scanner with a high accuracy 0.02 mm in STL format. CBCT data for each patient were acquired before tooth extraction, DICOM data with a voxel size 0.3 mm were input to Mimics 18.0 software. Segmentation, Morphology operations, Boolean operations and Smart expanded function in Mimics software were used to edit teeth, bone and periodontal ligament threshold mask, and root threshold mask were automatically acquired after a series of mask operations. 3D digital root models were extracted in STL format finally. 3D morphology deviation between the extracted root models and corresponding vivo root models were compared in Geomagic Studio 2012 software. The 3D size errors in long axis, bucco-lingual direction and mesio-distal direction were also calculated., Results: The average value of the 3D morphology deviation for 15 roots by calculating Root Mean Square (RMS) value was 0.22 mm, the average size errors in the mesio-distal direction, the bucco-lingual direction and the long axis were 0.46 mm, 0.36 mm and -0.68 mm separately. The average time of this new method for extracting single root was about 2-3 min. It could meet the accuracy requirement of the root 3D reconstruction fororal clinical use., Conclusion: This study established a new method for rapid extracting 3D root model of vivo tooth from CBCT data. It could simplify the traditional manual operation and improve the efficiency and automation of single root extraction. The strategy of this method for complete dentition extraction needs further research.

Complete three-dimensional(3D) tooth model provides essential information to assist orthodontists for diagnosis and treatment planning. Currently, 3D tooth model is mainly obtained by segmentation and reconstruction from dental computed tomography(CT) images. However, the accuracy of 3D tooth model reconstructed from dental CT images is low and not applicable for invisalign design. And another serious problem also occurs, i.e. frequentative dental CT scan during different intervals of orthodontic treatment often leads to radiation to the patients. Hence, this paper proposed a method to reconstruct tooth model based on fusion of dental CT images and laser-scanned images. A complete3 D tooth model was reconstructed with the registration and fusion between the root reconstructed from dental CT images and the crown reconstructed from laser-scanned images. The crown of the complete 3D tooth model reconstructed with the proposed method has higher accuracy. Moreover, in order to reconstruct complete 3D tooth model of each orthodontic treatment interval, only one pre-treatment CT scan is needed and in the orthodontic treatment process only the laser-scan is required. Therefore, radiation to the patients can be reduced significantly.

The segmentation of the intracoronary optical coherence tomography(OCT) images is the basis of the plaque recognition, and it is important to the following plaque feature analysis, vulnerable plaque recognition and further coronary disease aided diagnosis. This paper proposes an algorithm about multi region plaque segmentation based on kernel graph cuts model that realizes accurate segmentation of fibrous, calcium and lipid pool plaques in coronary OCT image, while boundary information has been well reserved. We segmented 20 coronary images with typical plaques in our experiment, and compared the plaque regions segmented by this algorithm to the plaque regions obtained by doctor’s manual segmentation. The results showed that our algorithm is accurate to segment the plaque regions. This work has demonstrated that it can be used for reducing doctors’ working time on segmenting plaque significantly, reduce subjectivity and differences between different doctors, assist clinician’s diagnosis and treatment of coronary artery disease.

Objective: To evaluate the clinical characteristics of patients with positional obstructive sleep apnea hypopnea syndrome (P-OSAHS). Methods: The study retrospectively analyzed 171 men diagnosed as having OSAHS in Beijing Tongren Hospital, Capital Medical University, during July 2012 to June 2014. That the apnea hypopnea index (AHI) during supine position of ≥ 2 times by the AHI during lateral position was employed as the standard for P-OSAHS. Subjective symptoms, physical examinations, polysomnography (PSG), and three-dimensional computer tomography (3-D CT) were compared between P-OSAHS group and control group with non-positional OSAHS. Results: Of 171 patients with OSAHS, 47(27.5%) had P-OSAHS and 124 (72.5%) presented with non-positional OSAHS. There were significant differences between two groups in BMI, neck circumference, AHI, the lowest oxygen saturation, the percentage of time with oxygen saturation below 90% (CT90), and the minimal anterior-posterior airway dimension of the glossopharynx ( P <0.05). The AHI was the only predictive parameter for P-OSAHS ( P <0.01). There were significant differences in the incidence of P-OSAHS between patient with mild or moderate disease (AHI<30), severe disease (AHI≥30 but<60), and extremely severe disease (AHI≥60) (81.8% (18/22) vs 45.3% (24/53) vs 5.2% (5/96), P <0.05). Conclusion: The severity of OSAHS closely related to the incidence of P-OSAHS, with significant differentce in the incidence of P-OSAHS between the patients with different severity of OSAHS.