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A new pneumonia-type coronavirus, COVID-19, recently emerged in Wuhan, China. COVID-19 has subsequently infected many people and caused many deaths worldwide. Isolating infected people is one of the methods of preventing the spread of this virus. CT scans provide detailed imaging of the lungs and assist radiologists in diagnosing COVID-19 in hospitals. However, a person’s CT scan contains hundreds of slides, and the diagnosis of COVID-19 using such scans can lead to delays in hospitals. Artificial intelligence techniques could assist radiologists with rapidly and accurately detecting COVID-19 infection from these scans. This paper proposes an artificial intelligence (AI) approach to classify COVID-19 and normal CT volumes. The proposed AI method uses the ResNet-50 deep learning model to predict COVID-19 on each CT image of a 3D CT scan. Then, this AI method fuses image-level predictions to diagnose COVID-19 on a 3D CT volume. We show that the proposed deep learning model provides 96% AUC value for detecting COVID-19 on CT scans.

3D CT scan is actually the gold standard for preoperative diagnosis of pelvic discontinuity (PD) in hip revision surgery. Aim of this study was to compare the accuracy of 3D-modeling with traditional and 3D CT scan. We retrospectively identified 56 patients who underwent total hip arthroplasty revisions with Paprosky Type-3 periacetabular bone defects. Preoperative X-rays, CT scans and 3D-models were blindly reviewed by two orthopedic surgeons to detect possible pelvic discontinuities. Results were compared with surgical notes. Independent sensitivities, specificities, positive predictive values and negative predictive values were calculated for X-rays, CT scan and 3D models. Analysis of interobserver reliability was performed. Fifty-six patients met inclusion criteria. In nine patients, surgical notes indicated a pelvic discontinuity. On 3D CT scans, PD was identified in 25 cases for observer 1 and in 24 cases for observer 2. Analyzing 3D-models, PD was identified in eleven patients by both observers. The nine patients, with PD reported on the surgical report, were all identified with both the techniques. The specificity of standard 3D CT was 0.66 for observer 1 and 0.68 for observer 2 and increased to 0.96 for both observers with the utilization of 3D-models. The positive predictive value increased from 0.36 (observer 1) and 0.38 (observer 2) with the CT evaluation to 0.82 in the 3D-models evaluation. The analysis of 3D models was characterized by a perfect intraobserver reliability (intraobserver correlation coefficient = 1). The observers showed substantial agreement for PD classification; the kappa values were 0.96 and 0.77, respectively, for CT scan and 3D-model evaluation. 3D-modeling showed higher specificity than traditional and 3D CT scans in identification of PD in Paprosky Type-3 periacetabular bone defects.

Diagnosis of acetabular retroversion based on crossover sign in the anteroposterior radiograph of the hip joint is well described. Accuracy of the crossover sign to identify global retroversion of the acetabulum in comparison to version of the acetabulum in reconstructed three-dimensional computed tomography (3D CT) scan of the hip was the aim of this study. X-rays of 500 hips were assessed regarding presence of crossover sign and its location in the upper, middle, or lower third of the acetabulum. Mean of anteversion and true retroversion (defined as less than one standard deviation below the mean of acetabular anteversion) of the acetabulum using reconstructed 3D CT scan by mathematical software was determined among 500 hips. The positive and negative crossover signs were compared to the retroversion obtained by CT scan. The average of acetabular anteversion was 12.5 ± 4.2 degrees. True global retroversion in 3D CT scans was defined as a version below 8.3 degrees. Although positive crossover sign was seen in 193 out of 500 (38 %), only 69 out of 500 (13.8 %) of hips had version below 8.3 (true retroversion) and 124 subjects had an acetabular version above 8.3. The sensitivity and specificity of crossover signs were about 82 and 70 %, respectively. The crossover sign could pick up hips with less than normal anteversion with acceptable sensitivity but it has no enough specificity for being used as the sole indication for treatment.

Recently, computed tomography (CT) has been used for non-destructive inspection. The rapid development of CT scanning hardware and software, CT became one of the major inspection solutions for non-destructive inspection. Because non-destructive inspection does not damage the product, it is beneficial in time and money in product quality testing. Most of all, this non-destructive inspection is important if the prod-uct should be preserved the original condition. CT scanning can detect porosities, voids, flaws, inclusions, and inside cast-ings in three-dimension. However, because 3D CT scanning takes much time, it can be used for only the inspection of sam-ples. To overcome this problem, we propose a new method to inspect all the products by using dual X-ray imaging. The dual X-ray or stereo X-ray imaging uses two X-ray images from the orthogonal views. Accurate calibration of 2D-3D registration is also required. Once the 3D CT scan of a master is registered to the dual X-ray images of a sample, the matching score is com-puted to inspect the sample.

Introduction When one of the anterior cruciate ligament (ACL) bundles is torn, it seems appropriate to preserve the remaining bundle to improve the vascularization and proprioception of the graft, and to reproduce the attachment sites of the torn bundle. After ACL reconstruction, the functional result is worse when the tunnels are positioned further away from the native ACL's isometric attachment points. The goal of this study was to use CT 3D reconstructions to analyse the position of the femoral tunnel following partial ACL reconstruction and to compare it to complete ACL reconstruction cases. We hypothesized that the femoral tunnel positioning was optimal during partial ACL reconstruction. Methods In this prospective single-centre study, 16 patients who underwent isolated anteromedial bundle reconstruction were evaluated during the immediate postoperative period using 3D reconstruction of CT images. During this same period, 180 patients who underwent complete ACL reconstruction in the same surgery unit served as a control group. Results In the partial ACL reconstruction group, 6 tunnels (37.5%) were in the optimal position and 10 tunnels (62.5%) were not. In the complete ACL reconstruction group, 124 femoral (68.9%) were in the optimal position and 56 (31.1%) were not ( P Discussion Femoral tunnel positioning is not always optimal in patients who undergo partial ACL reconstruction. Three-dimensional CT reconstruction is a good tool to help surgeons detect and learn from their errors. Level of evidence III (case-control study).

Postoperative reossification is a common clinical correlate following surgery. It has been suggested that an underexpression of transforming growth factor-β3 (TGF-β3) may be related to craniosynostosis and postoperative reossification. Adding TGF-β3 may delay reossification and improve postoperative growth. The present study was designed to test this hypothesis. Thirty 10-day-old New Zealand white rabbits with hereditary coronal suture synostosis were divided into three groups: (1) suturectomy controls (n = 14), (2) suturectomy treated with bovine serum albumin (n = 8), and (3) suturectomy treated with TGF-β3 protein (n = 8). At 10 days of age, a 3-mm × 15-mm coronal suturectomy was performed, and serial three-dimensional (3D) computed tomography (CT) scans and cephalographs were taken at 10, 25, 42, and 84 days of age. Calvaria were harvested at 84 days of age for histomorphometric analysis. Mean differences were analyzed using a group by age analysis of variance. Analysis of the 3D CT scan data revealed that sites treated with TGF-β3 had significantly (P < .05) greater defect areas and significantly (P < .05) greater intracranial volumes through 84 days of age compared with controls. Histomorphometry showed that sites treated with TGF-β3 had patent suturectomy sites and significantly (P < .001) less new bone in the suturectomy site compared with controls. Serial radiograph data revealed significant (P < .05) differences in craniofacial growth from 25 to 84 days in TGF-β3-treated rabbits compared with controls. Data show that TGF-β3 administration delayed reossification and improved craniofacial growth in this rabbit model. These findings also suggest that this molecular-based therapy may have potential clinical use.

Wajah terletak lebih ke anterior secara anatomis oleh sebab itu mudah mendapatkan trauma. Os Zigoma merupakan tulang yang menonjol pada wajah dan akan menahan gaya bentur terbesar pada wajah. Tulisan ini melaporkan penatalaksanan fraktur kompleks zigomatikomaksilaris sinistra dengan miniplate osteosynthesis. Seorang laki-laki 22 tahun dirujuk ke Bagian Bedah Mulut RSUP Dr Sardjito dengan riwayat kecelakaan lalulintas tiga minggu sebelum masuk RS. Pasien mengeluh daerah pipi kiri terasa tebal dan dirasa lebih datar dari pipi kanan. Pemeriksaan klinis terdapat parestesi nervus infraorbita sinistra , displace tulang daerah infraorbital rim sinistra , diskontinuitas regio sinus maksilaris sinistra. Radiografis CT axial dan koronal serta CT Scan 3D tampak fraktur melibatkan infraorbital rim sinistra, fraktur sinus maksila sinistra , fraktur pada sutura zigomaticofrontalis dan pada sutura zigomatikotemporalis. Penatalaksanaannya dilakukan open reduction internal fixation (ORIF) fraktur kompleks zigomatikomaksilaris dengan miniplate osteosynthesis di bawah anestesi umum. Pasca operasi gejala parestesi berangsur- angsur berkurang, defek infraorbital rim terkoreksi dan pipi kiri tampak kembali prominen. Prognosis kasus ini dubia ad bonam . ORIF dengan miniplate osteosynthesis dapat memulihkan deformitas wajah dengan hasil malar eminensia kembali prominen dan membuat kondisi dekompresi nervus infraorbita sinistra yang mendukung proses pemulihan sensorisnya. Management of Zygomaticomaxillaris Sinistra Complex Fractures with Osteosynthesis Miniplate . Face lies in a prominent position so that this area is often susceptible to trauma. Os zygomaticum is an area that holds the heaviest impact on facial trauma. This paper reports one case about zygomaticomaxillary complex fractures management with miniplate osteosynthesis. A 22 years old man was referred to the Department of Oral Surgery Dr Sardjito Hospital with a history of traffic accident three weeks before admission. He felt that his left cheek was thick and flatter than the right one. Clinical examination found that the left infraorbita nerve was paresthesized, the bone on the left infraorbital rim region was displaced and the left maxillary sinus region was discontinued. Radiography examination using CT axial and coronal, and 3D CT scan showed both of the left infraorbital rim and maxillary sinus were fractured, as well as the zygomaticotemporalis suture and the zygomaticofrontalis suture. An Open Reduction Internal Fixation (ORIF) of the zygomaticomaxillary complex fractures with miniplate osteosynthesis was performed under general anesthesia. The result showed that the postoperative paresthesia symptoms were gradually diminished, the infraorbital rim defects were corrected and the prominent left cheek was recontructed. The prognosis was dubia ad bonam. It can be concluded that ORIF with miniplate osteosynthesis reconstructs the facial deformity, recovers the malar eminence prominency. The nerves decompression will favor the recovery process of the left infraorbita sensory

The outcome of single-bundle anterior cruciate ligament (ACL) reconstruction depends largely on the anatomic placement of bone tunnel. The lateral intercondylar ridge (LIR) and bifurcate ridge (BR) are useful bony landmarks for femoral tunnel placement. The purpose of our study was to compare the bony landmarks of ACL footprint on femur by three-dimensional computed tomography (3D CT) scan and arthroscopy in chronic ACL-deficient knees. Fifty patients above 18 years of age who were diagnosed of having ACL tear were selected for the study. All the cases were more than 6 months old since the injury. Preoperative 3D CT scan of the affected knee was obtained for each of them. They underwent single-bundle anatomic ACL reconstruction. Measurements were done on the preoperative 3D CT and arthroscopy to quantify the position of the LIR and BR. The proximodistal distance of lateral femoral condyle was 21.41+/−2.5 mm on CT scan and 22.02+/−2.02 mm on arthroscopy. On preoperative 3D CT scan, the midpoint of the LIR was found to be located at a mean distance of 11.17±2.11 mm from the proximal margin of the lateral femoral condyle. On arthroscopy, it was at 10.18+/−1.52 mm from the proximal margin the lateral femoral condyle. The “bifurcate ridge”(BR) was not visible in any of the cases during arthroscopy or CT scan. We concluded that LIR is an easily identifiable bony landmark on arthroscopy in all cases. It can also be identified on CT scans. BR is not identified both on arthroscopy and CT scans in chronic ACL tears. The arthroscopic measurements of bony landmarks are quite close to those of CT scan. Midpoint of LIR is at 52.185% of the proximodistal distance on CT scan evaluation and it is at 46.21% on arthroscopic evaluation.

We describe a deep learning approach for automated brain hemorrhage detection from computed tomography (CT) scans. Our model emulates the procedure followed by radiologists to analyse a 3D CT scan in real-world. Similar to radiologists, the model sifts through 2D cross-sectional slices while paying close attention to potential hemorrhagic regions. Further, the model utilizes 3D context from neighboring slices to improve predictions at each slice and subsequently, aggregates the slice-level predictions to provide diagnosis at CT level. We refer to our proposed approach as Recurrent Attention DenseNet (RADnet) as it employs original DenseNet architecture along with adding the components of attention for slice level predictions and recurrent neural network layer for incorporating 3D context. The real-world performance of RADnet has been benchmarked against independent analysis performed by three senior radiologists for 77 brain CTs. RADnet demonstrates 81.82% hemorrhage prediction accuracy at CT level that is comparable to radiologists. Further, RADnet achieves higher recall than two of the three radiologists, which is remarkable., Comment: Accepted at IEEE Symposium on Biomedical Imaging (ISBI) 2018 as conference paper

Knowledge of the normal and pathological three-dimensional (3D) gleno-humeral relationship is imperative when planning and performing a total shoulder arthroplasty. Currently, two-dimensional (2D) parameters are used to describe this anatomy and despite the fact that these 2D measurements have a wide distribution in the normal population, they are commonly accepted. This broad distribution can be explained on one hand by anatomical factors and on the other hand, by positional errors. A 3D CT-scan reconstruction and evaluation can overcome this shortcoming and can be used to determine more accurately the surgical planes on the normal and pathological shoulder joint. There is, however, no consensus on which references should be used when studying this 3D relationship. This thesis describes the normal 3D gleno-humeral relationship and the best glenoid plane to use in surgery, based on 3D CT-scan. Furthermore, a glenoid aiming device that can be of surgical help in the reconstruction of the normal glenoid anatomy was developed based on these measurements.

Purpose To compare the measurement of glenoid bone surface area (GBSA) and glenoid bone loss (GBL) between 3-dimensional computed tomography (3D CT) and an autosegmentation approach for 3D magnetic resonance imaging (MRI) of patients with recurrent shoulder instability. Methods Eight subjects (2 women and 6 men; age range, 15-72 years [mean, 44 ± 19 years]) were consecutively enrolled who had both CT and MRI of the shoulder for clinical shoulder instability. Inclusion criteria were patients with shoulder instability or other shoulder injury who had both a CT scan and MRI performed of the same shoulder. All patients underwent a 3D CT scan and a 3-Tesla 3D MRI with additional volumetric and autosegmented sequences. En face views of the glenoid for both CT and MRI were auto- and manually measured for overall GBSA and GBL using best-fit circle technique; the amount of GBL was compared with loss of GBSA and was expressed as a percentage of bone loss. Results There were no differences in GBL measured by 3D CT (41 mm2, 6.6%) vs 3D MRI (40 mm2, 6.5%, P = .852). The mean GBSA was not different among the manual- and autocalculated 3D CT (644 mm2 vs 640 mm2, P = .482). In addition, the manual MRI scan glenoid area was similar to the autocalculated 3D MRI (622 mm2 vs 618 mm2, respectively; P = .482). Overall regression analysis demonstrated excellent correlation between CT and MRI for both GBSA and GBL calculations (R2 = 0.84-0.90). Conclusions 3D MRI of the glenoid is nearly identical to 3D CT scans for measurement of GBSA and GBL, making 3D MRI a reliable alternative to a CT scan for a preoperative shoulder evaluation of the glenoid pathology. This study shows that a 3D MRI could be a radiation-free and reliable alternative to a preoperative CT shoulder scan. Level of Evidence Level III, case-control study.

In this paper we propose a new classification of neurogenic peri-articular heterotopic ossification (HO) of the hip based on three-dimensional (3D) CT, with the aim of improving pre-operative planning for its excision. A total of 55 patients (73 hips) with clinically significant HO after either traumatic brain or spinal cord injury were assessed by 3D-CT scanning, and the results compared with the intra-operative findings. At operation, the gross pathological anatomy of the HO as identified by 3D-CT imaging was confirmed as affecting the peri-articular hip muscles to a greater or lesser extent. We identified seven patterns of involvement: four basic (anterior, medial, posterior and lateral) and three mixed (anteromedial, posterolateral and circumferential). Excellent intra- and inter-observer agreement, with kappa values > 0.8, confirmed the reproducibility of the classification system. We describe the different surgical approaches used to excise the HO which were guided by the 3D-CT findings. Resection was always successful. 3D-CT imaging, complemented in some cases by angiography, allows the surgeon to define the 3D anatomy of the HO accurately and to plan its surgical excision with precision. Cite this article: Bone Joint J 2015; 97-B:899–904.

Background: Remnant preservation may confer important advantages in the anterior cruciate ligament (ACL)–reconstructed knee. However, the presence of a large remnant may obscure visualization and impair the ability to correctly place tunnels during surgery. Purpose: To determine whether tunnel placement during anatomic ACL reconstruction using the single anteromedial bundle biological augmentation (SAMBBA) technique is consistent and precise when a large native remnant is preserved. Study Design: Case series; Level of evidence, 4. Methods: Included in this study were 99 patients undergoing an ACL reconstruction during which at least 50% of the native ACL was preserved. The femoral tunnel was created using an outside-in specific guide. The tibial tunnel was positioned in the anteromedial region of the ACL footprint, and the remnant was carefully preserved while drilling and passing the semitendinosus graft through it. Postoperatively, 3-dimensional computed tomography (3D CT) was used to evaluate tunnel placement. The mean tunnel locations were calculated and the standard deviation was used to evaluate precision of positioning. Inter- and intrareader agreement were determined to assess reliability of evaluation of tunnel position. Results: The center of the femoral tunnel was positioned at a mean 19.4% (SD, 2%) of the depth of the notch and a mean 23.1% (SD, 3.5%) of the lateral wall height. The center of the tibial tunnel was positioned at a mean 36.3% (SD, 3.8%) of the anteroposterior length of the tibial plateau and at a mean 47.0% (SD, 2.7%) of the mediolateral width. The small standard deviations demonstrate that this technique allows precise tunnel placement. The tunnel positions achieved were consistent with previous anatomic studies of femoral and tibial anteromedial bundle insertion. Intra- and interobserver reliability were high. Conclusion: Three-dimensional CT evaluation demonstrated that despite the presence of a large remnant, placement of femoral and tibial tunnels for anatomic ACL reconstruction using the SAMBBA technique is consistent and precise.

International audience; IntroductionTreatment of medial tibiofemoral osteoarthritis with a high-tibial osteotomy (HTO) is most effective when the optimal angular correction is achieved. However, conventional instrumentation is limited when multiplanar correction is needed.HypothesisUse of patient-specific cutting guides (PSCGs) for HTO provides an accurate correction (difference < 2°) relative to the preoperative planning.Materials and methodsBetween February 2014 and February 2015, 10 patients (mean age: 46 years [range: 31–59]; grade 1 or 2 osteoarthritis in Ahlbäck's classification) were included prospectively in this reliability and safety study. All patients were operated using the same medial opening-wedge osteotomy technique. Preoperative planning was based on long-leg radiographs and CT scans with 3D reconstruction. The PSGCs were used to align the osteotomy cut and position the screw holes for the plate. The desired correction was achieved in the three planes when the holes on the plate were aligned with the holes drilled based on the PSCG. Preoperatively, the mean HKA angle was 171.9° (range: 166–179°), the mean proximal tibial angle was 87° (86–88°) and the mean tibial slope was 7.8° (1–22°). The postoperative correction was compared to the planned correction using 3D CT scan transformations. Intraoperative and postoperative complications were assessed at a minimum follow-up of 1 year.ResultsThe procedure was successfully carried out in all patients with the PSCGs. On postoperative long-leg radiographs, the mean HKA was 182.3° (180–185°); on the CT scan, the mean tibial mechanical angle was 94° (90–98°) and the mean tibial slope was 7.1° (4–11°). In 19 out of 20 postoperative HKA and slope measurements, the difference between the planned and achieved correction was < 2° based on the 3D analysis of the three planes in space; in the other case, the slope was 13° instead of the planned 10°. The intra-class correlation coefficients between the postoperative and planned parameters were 0.98 [0.92–0.99] for the HKA and 0.96 [0.79–0.99] for the tibial slope. There were no surgical site infections; one patient had a postoperative hematoma that resolved spontaneously.DiscussionThe results of this study showed that use of PSCGs in HTO procedures helps to achieve optimal correction in a safe and reliable manner.Level of evidenceIV – Prospective cohort study.Keywords: Medial tibiofemoral osteoarthritis, High tibial osteotomy, Opening-wedge osteotomy, Patient-specific surgical guides, 3D printing

Cranioplasty is considered a simple reconstructive procedure, usually performed in a single stage. In some clinical conditions, such as in children with multifocal flap osteolysis, it could represent a surgical challenge. In these patients, the partially resorbed autologous flap should be removed and replaced with a precustomed prosthesis which should perfectly match the expected bone defect. We describe the technique used for a navigated cranioplasty in a 3-year-old child with multifocal autologous flap osteolysis. We decided to perform a cranioplasty using a custom-made hydroxyapatite porous ceramic flap. The prosthesis was produced with an epoxy resin 3D skull model of the patient, which included a removable flap corresponding to the planned cranioplasty. Preoperatively, a CT scan of the 3D skull model was performed without the removable flap. The CT scan images of the 3D skull model were merged with the preoperative 3D CT scan of the patient and navigated during the cranioplasty to define with precision the cranioplasty margins. After removal of the autologous resorbed flap, the hydroxyapatite prosthesis matched perfectly with the skull defect. The anatomical result was excellent. Thus, the implementation of cranioplasty with image merge navigation of a 3D skull model may improve cranioplasty accuracy, allowing precise anatomic reconstruction in complex skull defect cases.

To assess whether there is a significant difference between the alignment of the individual femoral and tibial components (in the frontal, sagittal and horizontal planes) as calculated pre-operatively (digital plan) and the actually achieved alignment in vivo obtained with the use of patient-specific positioning guides (PSPGs) for TKA. It was hypothesised that there would be no difference between post-op implant position and pre-op digital plan.Twenty-six patients were included in this non-inferiority trial. Software permitted matching of the pre-operative MRI scan (and therefore calculated prosthesis position) to a pre-operative CT scan and then to a post-operative full-leg CT scan to determine deviations from pre-op planning in all three anatomical planes.For the femoral component, mean absolute deviations from planning were 1.8A degrees (SD 1.3), 2.5A degrees (SD 1.6) and 1.6A degrees (SD 1.4) in the frontal, sagittal and transverse planes, respectively. For the tibial component, mean absolute deviations from planning were 1.7A degrees (SD 1.2), 1.7A degrees (SD 1.5) and 3.2A degrees (SD 3.6) in the frontal, sagittal and transverse planes, respectively. Absolute mean deviation from planned mechanical axis was 1.9A degrees. The a priori specified null hypothesis for equivalence testing: the difference from planning is > 3 or

Background Type B glenoids according to Walch are subclassified into a group with no posterior erosion (B1) and a group with important posterior erosion (B2) based on 2-dimensional axial computed tomography (CT) scan images. Three-dimensional (3D) CT scan reconstruction seems to improve the accuracy of the measurement of erosion because of its independence from positional errors. The aim is to quantify the direction and amount of posterior erosion of type B glenoids using a reproducible 3D measuring technique. Methods We performed 3D reconstruction of 72 type B glenoids (24 type B1 glenoids and 48 type B2 glenoids) using Mimics (Materialise, Haasrode, Belgium). The native glenoid plane and intermediate glenoid plane were determined by use of 3-Matic (Materialise). The normal glenoid version, eroded retroversion, and difference in retroversion were measured. Next, the maximum erosion and its orientation were quantified. Results There was always minimum erosion of 1.7 mm, and the mean erosion was 4.2 mm. There was a significant difference between the mean erosion in type B1 glenoids (3.5 mm) and type B2 glenoids (4.5 mm) ( P = .019). The mean orientation of the erosion was mostly to the posteroinferior side (119°; SD, 26.8). There was a significant difference between the mean orientation in type B1 glenoids (132°; SD, 25.2) and type B2 glenoids (113°; SD, 25.5) ( P = .004). Conclusions With the use of this newly developed reproducible measuring technique, the maximum erosion in type B glenoids can be adequately quantified. All glenoids showed signs of important erosion. Because the orientation of the maximum erosion in type B1 glenoids is situated more inferiorly, the 2-dimensional CT scan technique can be insufficient to evaluate this erosion.

The purpose of this article was to demonstrate an anterior cruciate ligament (ACL) reconstruction technique using oval tunnels. Aim of this single bundle technique is to fit the footprint anatomy of the ACL as closely as possible. TECHNIQUE AND PATIENTS: The presented technique is a single bundle technique using a semitendinosus graft. For femoral tunnel placement, a specific medial portal aimer (Karl Storz, Tuttlingen, Germany) is used. Aiming and drilling of the femoral tunnel are performed via the medial portal. Oval tunnels are created by stepwise dilatation with ovally shaped dilatators. The position of the femoral tunnel is visualized and controlled with the arthroscope via the medial portal. For the tibial tunnel placement, a specific aimer was used as well. With this technique, 24 patients were operated and all intra- and postoperative complications were analyzed prospectively. The tunnel position was documented postoperatively by CT scan.There were no significant intra- and postoperative complications associated with the oval tunnel technique. The postoperative 3D CT scan revealed that all femoral and tibial tunnels were located within the area of the anatomical ACL insertions.This article presents an ACL reconstruction technique using oval dilatators and medial portal aimers to create oval tunnels. These oval tunnels match the insertion site anatomy much closer than round tunnels do.Level IV, case series.

Aim: The aim of this study is to investigate anatomical lung variations and vascular patterns using volumetric 3D computed tomography (CT) representations. Methods & results: We considered 24 major thoracic surgery performed in our ward. In these, we discovered some interesting anatomical variations of the main pulmonary fissures. These findings were not visible on the plain x-ray or during routine examination of a preoperative CT scan. After re-examination of 3D CT scan reconstruction the anatomical variations were detected. Discussion: General thoracic surgeons must familiarize themselves with anatomical variations in lungs. 3D images may aid the general thoracic surgeon in performing safer surgeries. Conclusion: 3D CT scan should be performed before surgery if possible.

Simultaneous post-traumatic ipsilateral fracture of femur head and subcapital femur neck without hip dislocation is a rare presentation and easily missed on X-ray imaging. A 48 years old male, with a history of high-energy road traffic accident, presented to us with severe pain in the left hip region and inability to ambulate. Preliminary X-ray showed impacted subcapital fracture with varus angulation between femur head and neck. Further computed tomography (CT) scan imaging showed ipsilateral fracture of femur head and subcapital femur neck without hip dislocation. Primary total hip arthroplasty was performed. Presently patient is 5 years post-surgery and can ambulate without support. In conclusion, this fracture pattern, though rare, should be suspected in high-energy road traffic accident patients with shear forces acting at femur neck. It can best be diagnosed using 3D CT scan imaging. Primary total hip arthroplasty is an appropriate treatment in such patients.

Background: The aim of this study is to evaluate the geometry of the distal femur and the proximal tibia in the osteoarthritic knee using 3D reconstructive CT scan imaging. Methods: 449 patients with knee osteoarthritis were treated surgically in our center with patient-specific technology total knee arthroplasty. Preoperatively, all the patients underwent a CT scan according to a standard protocol. Using this database, the Hip-Knee-Angle (HKA), the Femur Valgus Angle (FVA), the Tibia Varus Angle (TVA), the Posterior Tibia Slope (PTS), and the angle between the posterior condylar axis and the anatomical transepicondylar axis (PCA) for each patient were recorded and statistically evaluated. Results: In overall, the mean HKA angle was 177.3±5.55, the mean FVA angle was 3.19±2.08, the mean TVA was 3.28±2.35, the PTS angle was 9.02±3.46, and the PCA angle was 2.86±0.78. Evaluation of the correlations between HKA and PCA (r=0.035), HKA and PTS (r=-0.047), and PCA and PTS (r=0.05) showed non-significant relationships (P=0.46, P=0.32, and P=0.29 respectively). No significant differences were revealed from the comparison of male patients with female patients, regarding the mean HKA, FVA, TVA, PTS, and PCA. Conclusion: The posterior condylar axis is a well-defined but not a reliable axis, while the transepicondylar and the anteroposterior are reliable, but not easily defined axes. Given the large ranges and standard deviations of the location of posterior condylar axis, and the important inter- and intraobserver variability in the intraoperative location of the transepicondylar and the anteroposterior axes, the use of a preoperative 3D CT scan is recommended.

Background Long-leg radiographs (LLR) are often used in orthopaedics to assess limb alignment in patients undergoing total knee arthroplasty (TKA). However, there are still concerns about the adequacy of measurements performed on LLR. We assessed the reliability and validity of measurements on LLR using three-dimensional computed tomography (3D CT)-scan as a gold standard. Methods Six different surgeons measured the mechanical axis and position of the femoral and tibial components individually on 24 LLR. Intraclass correlation coefficients (ICC) were calculated to obtain reliability and Bland–Altman plots were constructed to assess agreement between measurements on LLR and measurements on 3D CT-scan. Results ICC agreement for the six observer measurements on LLR was 0.70 for the femoral component and 0.80 for the tibial component. The mean difference between measurements performed on LLR and 3D CT-scan was 0.3° for the femoral component and − 1.1° for the tibial component. Variation of the difference between LLR and 3D CT-scan for the femoral component was 1.1° and 0.9° for the tibial component. 95% of the differences between measurements performed on LLR and 3D CT-scan were between − 1.9 and 2.4° (femoral component) and between − 2.9 and 0.7 (tibial component). Conclusion Measurements on LLR show moderate to good reliability and, when compared to 3D CT-scan, show good validity. Clinical trial registration number: institutional review board Atrium-Orbis-Zuyd, number: 11-T-15. Level of Evidence Prospective cohort study, Level II.

To determine if it is possible to measure glenoid bone loss by using the Bernageau view and to compare it to a 3D CT scan.Fifty healthy subjects with a mean age of 34 ± 8 years old and 31 (62 %) male were submitted to the Bernageau view X-ray of both shoulders. Three blinded evaluators measured the distance between the posterior and anterior glenoid rim. Ten patients with multiple episodes of unilateral traumatic anterior shoulder dislocation with a mean age of 34 ± 9.1 years old and 90 % male were submitted to the same X-ray technique to determine the percentage of glenoid bone loss. They were also submitted to a bilateral 3D CT scan to be compared to the radiographs.In the 50 asymptomatic subjects, the AP distance was 24.48 mm ± 3.32 mm in the left shoulder and 24.82 mm ± 3.16 mm in the right shoulder. Comparing the X-ray study and the 3D CT scan of the ten patients with multiple episodes, there was no significant statistical difference of the AP normal distance in both methods (p = 0.646), the AP erosion distance (p = 0.386), as well as the percentage of bone loss (p = 0.513). Moreover, the differences between the percentages of bone loss in the X-ray, compared with the 3D CT scan were, on average 2.28 % (range 0 to 6.05 %).The Bernageau radiographic view is an accurate and reproducible technique for measuring the presence of glenoid erosion, with similar results when compared to the 3D CT scan.

Object The treatment of basilar invagination in the pediatric age group is dependent on the possibility of preoperative reduction. Reducible lesions obviate a ventral decompression and require a dorsal-only approach for stabilization with or without a suboccipital decompression. Methods The authors describe a technique of intraoperative reduction of basilar invagination with the use of general anesthesia and neuromuscular blockade in the presence of crown halo traction. Using the O-arm device, a 3D CT scan is generated in the sagittal plane to demonstrate the reduction intraoperatively. This technique was successful in 6 pediatric patients with basilar invagination. Results The average age of the patients was 10.8 years, and they were followed for a mean period of 8.5 months. The patients had mild basilar invagination or partial reduction in extension on preoperative MR imaging. Intraoperative reduction was demonstrated in all patients by using the reported technique with intraoperative CT. All patients underwent occipitocervical fusion, and all but one underwent a suboccipital decompression. There were no complications related to the operation, and all but one reported improvement of symptoms on the last postoperative visit. Conclusions Intraoperative reduction performed using neuromuscular blockade and intraoperative traction is an effective method for further reduction of basilar invagination in the pediatric age group. This is the first reported application of intraoperative CT imaging performed using the O-arm device in craniocervical surgery in which successful reduction is demonstrated in detail.

The purpose of the study was to determine the normal three-dimensional relationship between the humeral and the glenoid plane of the individual patient. We measured the three-dimensional angle between the glenoid plane and the humeral plane (glenohumeral angle, °GH) and the angle between the plane of the scapula and the plane of the glenoid (glenoscapular angle, °GS) with the patient in a standardized position to the CT scan gantry. We hypothesized that a normal distribution with a small variation would exist for both angles.A total of 150 conventional CT scans of normal shoulders from patients aged between 18 and 80 years were examined and three-dimensional reconstructions were derived from it. The descriptive statistics and the variability of °GH and °GS were determined.The mean °GH was 57.9°, and the mean °GS was -3.77°. The overall reliability of the measurement was good. Descriptive statistics of this study confirm the normal distribution and a narrow variation of both parameters.This is the first study to determine the normal 3D relationship between the humerus and the glenoid (°GH). This new three-dimensional anatomical information of the normal glenohumeral relationship and glenoid can be used to distinguish normal from pathological anatomy, as well as alternative surgical guidance especially in bony deficient glenoids. Level of Evidence Level II Anatomical Study.

The purpose of this report is to discuss the diagnosis of Jaw cyst basal cell nevus syndrome. Two components of the syndrome are multiple odontogenic keratocysts and basal cell carcinomas. The discovery of multiple keratocysts is usually the first manifestation of the syndrome. In the case discussed, 3D CT scan taken to evaluate a diagnosed odontogenic keratocyst revealed more than one keratocysts. This led to the closer evaluation and diagnosis of Jaw cyst basal cell nevus syndrome.

Introduction Conventional cephalometry is an inexpensive and well-established method for evaluating patients with dentofacial deformities. However, patients with major deformities and in particular asymmetric cases are difficult to evaluate by conventional cephalometry. Reliable and accurate evaluation in the orbital and midfacial region in craniofacial syndrome patients is difficult due to inherent geometric magnification, distortion and the superpositioning of the craniofacial structures on cephalograms. Both two- and three-dimensional computed tomography (CT) have been proposed to alleviate some of these difficulties. Aims and objectives The aim of our study is to compare the reliability of anatomic cephalometric points obtained from the two modalities: Conventional posteroanterior cephalograms and 3D CT of patients with facial asymmetry, by comparison of intra- and interobserver variation of points recorded from frontal X-ray to those recorded from 3D CT. Materials and methods The sample included nine patients (5 males and 4 females) with an age range of 14 to 21 years and a mean age of 17.11 years, whose treatment plan called for correction of facial asymmetry. All CT scans were measured twice by two investigators with 2 weeks separation for determination of intraobserver and interobserver variability. Similarly, all measurement points on the frontal cephalograms were traced twice with 2 weeks separation. The tracings were superimposed and the average distance between replicate points readings were used as a measure of intra- and interobserver reliability. Intra-and interobserver variations are calculated for each method and the data were imported directly into the statistical program, SPSS 10.0.1 for windows. Results Intraobserver variations of points defined on 3D CT were small compared with frontal cephalograms. The intraobserver variations ranged from 0 (A1, B1) to 0.6 mm with the variations less than 0.5 mm for most of the points. Interobserver variations of points between first and second tracings defined on PA Ceph and 3D CT were less than 1.5 mm for all the points. A direct comparison of frontal cephalometry and 3D CT using intraobserver variation for the first observer showed that 3D CT was more reliable than frontal cephalometry for 11 points. Direct comparison of frontal cephalometry and 3D CT for the second observer showed a similar tendency with 14 points significantly more reliable for 3D CT. Comparison of frontal cephalometry and 3D CT using interobserver variation for the tracings showed that 3D CT was more reliable than frontal cephalometry. Summary and conclusion The study has shown that 3D CT is consistently more accurate and reliable than conventional frontal cephalometry. Unfortunately, the cost of a computerized tomography examination is considerable; this means that, at this stage, its use by surgeons and orthodontists is a last resort.

Subject-specific three-dimensional (3D) reconstructions of the ribs can be obtained from biplanar X-rays. The goal of this study was to evaluate the accuracy and the inter-observer reproducibility of this technique in comparison to CT-scan reconstructions. CT scans and biplanar X-rays were obtained from 50 ribs (from three cadaveric rib cages). Three experienced experimenters reconstructed each rib from biplanar X-rays. Morphometric parameters were then computed from the rib midlines. Differences were computed between parameters obtained from the 3D reconstructions based on biplanar X-rays and from CT scans. The accuracy was computed as the mean of this difference for the 50 ribs from all three experimenters. The inter-observer variability was assessed using the coefficient of variation (CV) between the three observers. The CT-scan reconstructions were considered to be the gold standard in spite of their limitations for rib reconstructions. According to the different linear parameters, the accuracy of the reconstructions was found to be between -6mm (-2%) and 3mm, (4%). The accuracy of the current method was close to that of CT-scan reconstructions. The inter-observer variability was between 3% and 6%. Frontal and lateral X-rays are commonly obtained clinically, so 3D reconstructions can be used without increased radiation exposure to the patient.

Introduction Seventeen patients diagnosed with cerebral palsy were studied to assess the results of X-rays vs. 3D CT scans of the hip. Materials and methods 3 X-ray parameters were compared with 4 3D CT scan parameters. Results The results obtained showed a significant correlation between X-rays and CT scans. According to the assessment of the Weinberg Central Edge (CE) angle there were 28 dysplastic hips and 6 normal hips. According to the Reimers index there were 29 dysplastic hips and 5 normal hips. According to the acetabular index there were 30 subluxated hips and 4 normal hips. Using CT scan parameters the mean value of the femoral neck-shaft angle was 147.09° (range: 127°-175°), a higher-than-normal figure. The mean value of the femoral anteversion angle was 33.43° (range 9°-50°), also higher than usual. The mean axial acetabular index was 120.29°, with a normal value of 101.6° at 9 years of age associated with acetabular flattening. The mean acetabular anteversion angle was 13.11° (range 7°-24°), which indicated a parity of results. Conclusions X-rays are necessary for the diagnosis and prognosis of hip dysplasia. Acetabular coverage and presurgery assessment and planning must be done based on 3D CT scans.

Optical Coherence Tomography (OCT) has extensive potential for producing clinical impact in the field of neurological diseases. A neurosurgical OCT hand-held forward viewing probe in Bayonet shape has been developed. In this study, we test the feasibility of integrating this imaging probe with modern navigation technology for guidance and monitoring of skull base surgery. Cadaver heads were used to simulate relevant surgical approaches for treatment of sellar, parasellar and skull base pathology. A high-resolution 3D CT scan was performed on the cadaver head to provide baseline data for navigation. The cadaver head was mounted on existing 3- or 4-point fixation systems. Tracking markers were attached to the OCT probe and the surgeon-probe-OCT interface was calibrated. 2D OCT images were shown in real time together with the optical tracking images to the surgeon during surgery. The intraoperative video and multimodality imaging data set, consisting of real time OCT images, OCT probe location registered to neurosurgical navigation were assessed. The integration of intraoperative OCT imaging with navigation technology provides the surgeon with updated image information, which is important to deal with tissue shifts and deformations during surgery. Preliminary results demonstrate that the clinical neurosurgical navigation system can provide the hand held OCT probe gross anatomical localization. The near-histological imaging resolution of intraoperative OCT can improve the identification of microstructural/morphology differences. The OCT imaging data, combined with the neurosurgical navigation tracking has the potential to improve image interpretation, precision and accuracy of the therapeutic procedure.

Due to its heterogeneities, the evaluation and characterization of carbonate reservoir rocks are always challenging in the petroleum industry. Therefore, in order to optimize the recovery of hydrocarbons in carbonate reservoirs, the pore network needs to be properly understood. In this research, 282 digital thin sections from computer tomography (CT) scan of carbonate rock from Subis Limestone in Sarawak were processed and analyzed in order to determine pore type variation, pore size, pore shape, pore distribution, and pore connectivity. The studied core plug of limestone shows vuggy pores with an average porosity of 9.25 % varying from 5.98 to 12.3 % within the 282 slices. This results show that using 3D CT scan modeling enhances the accuracy of pore classification and pore quantification as large amount of input data are used leading to more reliable output.

The anteroposterior talocalcaneal angle (Kite's angle) is still considered a common parameter for assessing clubfoot correction, although some dissenting opinions about its accuracy have been expressed. The purpose of this study was to evaluate the validity of the anteroposterior talocalcaneal angle for assessing correction of congenital clubfoot in adults who received the treatment as children. SUBJECTS AND METHODS. The anteroposterior talocalcaneal angle was measured in 48 treated idiopathic congenital clubfeet and 28 normal feet of 38 patients at the end of skeletal growth using both standing anteroposterior radiographs and 3D CT scan reconstructions. All the patients had been treated by manipulation, above-the-knee casting, and a complementary posteromedial release operation.The radiographic measurement of the anteroposterior talocalcaneal angle corresponded to the measurement of the same angle on the 3D CT scan reconstructions in only the normal feet and 12 clubfeet. In the other 36 clubfeet, a statistically significant difference of a mean of 15 degrees between the two measurements was noted, and the 3D CT scan reconstructions showed a superimposition of the talus and calcaneus, which had lost their normal anatomic divergence. In these cases, the marked medial angulation of the talar neck allowed a positive measurement of the anteroposterior talocalcaneal angle in the anteroposterior radiographic projection.According to our findings, the measurement of the anteroposterior talocalcaneal angle on radiography was misleading for assessing the degree of hindfoot correction in 75% of the treated congenital clubfeet. We believe that other imaging parameters should be considered instead of this angle to evaluate clubfoot correction.

Twenty-eight excised nonpathologic human proximal femurs were considered in order to apply and validate a 3D reconstruction method using low-dose biplanar radiographs. The 3D reconstruction technique based on radiographic contour identification (called Non Stereo-Corresponding Contour method) was compared with 3D CT scan reconstruction method. The results showed the feasibility and the accuracy (mean distance error=0.7 mm, 2RMS=20 mm) of this technique applied to the proximal femur. Application of this method on hip joint could allow, with a low dose, calculating 3D structural geometric parameters as femoral neck axis length or femoral neck diameter which are of high interest for planning of surgical acts or computed assisted surgery.

Objective: The intent of this study was to evaluate the effect of plastination on the morphology and structure of stored organs, to find out how much accuracy a plastinated specimen has, and to look into the changes that occurred because of plastination. Materials and Methods: A human fetus of gestational age 24 weeks was plastinated, and 3D CT scan evaluation of the fetus was done. Results: The results showed normal, well-defined, clearly identifiable organs, with no alteration in morphology and structure of organs. Conclusion: In our opinion, plastinated specimens are better way of visualization of morphology and structure of stored organs, which is a useful tool for teaching as well as for research purposes.

Recently developed integrated PET-CT scanners give co-registered multimodal data sets that offer complementary three-dimensional (3D) digital images of the chest. PET (positron emission tomography) imaging gives highly specific functional information of suspect cancer sites, while CT (X-ray computed tomography) gives associated anatomical detail. Because the 3D CT and PET scans generally span the body from the eyes to the knees, accurate definition of the intrathoracic region is vital for focusing attention to the central-chest region. In this way, diagnostically important regions of interest (ROIs), such as central-chest lymph nodes and cancer nodules, can be more efficiently isolated. We propose a method for automatic segmentation of the intrathoracic region from a given co-registered 3D PET-CT study. Using the 3D CT scan as input, the method begins by finding an initial intrathoracic region boundary for a given 2D CT section. Next, active contour analysis, driven by a cost function depending on local image gradient, gradient-direction, and contour shape features, iteratively estimates the contours spanning the intrathoracic region on neighboring 2D CT sections. This process continues until the complete region is defined. We next present an interactive system that employs the segmentation method for focused 3D PET-CT chest image analysis. A validation study over a series of PET-CT studies reveals that the segmentation method gives a Dice index accuracy of less than 98%. In addition, further results demonstrate the utility of the method for focused 3D PET-CT chest image analysis, ROI definition, and visualization.

We reported progressive metatarsal lenghtening by external fixator after osteotomy by open approach without bone interposition in a case of brachymetatarsia upon the third and fourth metatarsals. After a tomodensitometry planification, the biometry of the five metatarsal bones was done by X-ray and CT scan by measuring each metatarsal length (1 to 5) in the sagittal, horizontal and coronal plans and angles. The average amount of lengthening was 17 mm for the third and 15 mm the fourth at the end, 40% of the original length (range, 36 to 44%). In the same time, we treated hallux valgus by osteotomy. Decrease of motion and joint deformity did not occur. The control of the CT scan allowed choosing the real orientation and length of the two metatarsal bones to obtain an adequate parabola. Measurements with CT scan were more reliable than Xray.

International audience; Accurate measurement of physiological parameters such as the bronchial lumen and bronchial wall areas helps in the diagnosis of lung diseases. Algorithms allowing such measures are the result of complex processing sequences composed of (i) bronchial volume extraction (ii) bronchial volume skeletonization (iii) wall extraction. The proposed sequences however still show weaknesses in terms of precision, extent and automation. In this paper we address various problems encountered at each step of the processing sequence and propose a new sequence for measuring lumen on bronchial section. Finally, this sequence is tested on two datasets of 10 anonymous exams1 collected from 10 different healthy volunteers and 10 different patients suffering from asthma that were attended by different practitioners.