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Objectives We aimed to evaluate the feasibility of simultaneous multi-slice readout segmentation of long variable echo-trains (SMS-RESOLVE) for diffusion-weighted imaging (DWI) of nasopharyngeal carcinoma (NPC) and determine the optimal acceleration factor of SMS-RESOLVE DWI compared with conventional RESOLVE DWI. Materials and methods One hundred and five patients with histologically confirmed NPC were enrolled. DWIs including conventional RESOLVE DWI, SMS-RESOLVE DWI with acceleration factors of 2 and 3 (2 × SMS-RESOLVE and 3 × SMS-RESOLVE) were acquired at b-values of 0 and 800 s/mm2. The subjective image quality, including overall image quality, lesion conspicuity, and lesion distortion scores, and objective image quality, including signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast in these three protocols, were assessed and compared. The apparent diffusion coefficients (ADCs) of the primary tumor and right masseter muscle and normalized ADCs in the three protocols were measured and compared. Results The 2 × SMS-RESOLVE provided comparable image quality and ADCs with a 48.3% reduction in scan time compared with conventional RESOLVE DWI. The 3 × SMS-RESOLVE showed significantly poorer image quality and the highest ADCs with a 56.9% reduction in scan times compared with conventional RESOLVE DWI. Conclusion The SMS-RESOLVE DWI with an acceleration factor of 2 yielded the best compromise between image quality and scan time reduction and could be an alternative to conventional RESOLVE DWI for nasopharyngeal carcinoma.

Background: The determination of sex and estimation of age are parameters that help in the identification of individuals in all fields of forensic science. The aim of this study was to calculate standard measurements according to sex and age in morphometric analysis of the 4th costa using multi-slice computed tomography (MSCT). Material and Method: Measurements were taken on MSCT images of patients aged 20-70 years, who had undergone CT imaging for various reasons. Using the morphometric characteristics of the 4th costa and junction with the spine on the thorax CT images, measurements were taken of the angulation of the right and left 4th costa, the distance between the sternum and the vertebra, the distance between the two costae, the distance between the two ends of the right and left 4th costa separately, and the depth of the two costae. Adding age and gender to these variables, 10 parameters were evaluated in total. Results: As a result of the analyses, the mean values of right costovertebral angle, sternum-vertebra distance, inter-costal distance, left and right costa lengths, and left costa depth were found to be statistically significant according to sex. In the differentiation of age groups, the right costovertebral angle, the sternum- vertebra distance, and the right and left costa lengths were found to be statistically significant. Conclusion: The results of this study of a Turkish population showed that the morphometric properties of the 4th costa show differences in the determination of age and sex. With the benefit of these differences, it is possible to differentiate males and females, and even age groups. As there are societal differences, standard morphometric values have to be determined so it will be necessary to conduct these studies more widely and obtain appropriate standard values for every population.

Non-contrast computerized tomography (NCCT) is in rampant use in daily practice for the diagnosis of various chest diseases. In the era of COVID-19 pandemic, the use of chest NCCT has increased many fold. The reason was because it will resolve many issues and quick diagnosis can be made. The same was also required to see the behavior of the disease as well as in the follow-up. Basically two parameter are in use to described the amount of radiation dose received by the patient in volumetric CT. These are, one is CT Dose Index (CTDIvol) & its unit is mGy, and the second is dose length product (DLP). With normal pitch factor i.e. 1, the CTDIw is use on the description of CTDIvol. Multiplication of scan length and CTDIvol parameter is known as Dose Length Product (DLP). There was much concern about the radiation dose received by the individual. A total of twenty-six individuals were studied. The measurement of direct chest circumference before each CT chest examination and correlation of CT chest protocol parameter in combination use was an effective tool to reduce the amount of radiation dose in patients. Chest circumference values can also be correlated with body mass index (BMI) values for more accuracy in the reduction of radiation dose. Lower chest circumference patients should be irradiated with the least amount of radiation dose and so on.

PURPOSE To demonstrate the possibility of performing multi-slice in-vivo human brain MRI using hyperpolarized (HP) xenon-129 (129 Xe) in two different orientations and to calculate the signal-to-noise ratio (SNR). METHODS Two healthy female participants were imaged during a single breath-hold of HP 129 Xe using a Philips Achieva 3.0T MRI scanner (Philips, Andover, MA). Each HP 129 Xe multi-slice brain image was acquired during separate HP 129 Xe breath-holds using 3D gradient echo (GRE) imaging. The acquisition started 10 s after the inhalation of 1 L of HP 129 Xe. Overall, four sagittal and three axial images were acquired (seven imaging sessions per participant). The SNR was calculated for each slice in both orientations. RESULTS The first ever HP 129 Xe multi-slice images of the brain were acquired in axial and sagittal orientations. The HP 129 Xe signal distribution correlated well with the gray matter distribution. The highest SNR values were close in the axial and sagittal orientations (19.46 ± 3.25 and 18.76 ± 4.94, respectively). Additionally, anatomical features, such as the ventricles, were observed in both orientations. CONCLUSION The possibility of using multi-slice HP 129 Xe human brain magnetic resonance imaging was demonstrated for the first time. HP 129 Xe multi-slice MRI can be implemented for brain imaging to improve current diagnostic methods.

Background: Bronchiectasis is pathological, irreversible dilatation of the bronchi due to destruction of the bronchial wall and the elastic connective tissue. Recurrent infection and inflammation and the resulting chemical and cellular cascade lead to permanent architectural changes in the airways. Bronchiectasis can confer substantial potential morbidity, usually secondary to recurrent infection. Objective: The aim of the current work was to evaluate the role of Multi-Slice Computed Tomography (MSCT) examination in detection and diagnosis of pulmonary bronchiectasis. Patients and methods: This study included 60 patients with bronchiectasis detected in their MSCT of the chest referred from the Chest Diseases Hospital to the Radiology Department, Mit Khalaf Hospital Complex, Al-Menoufia. Results: The most common etiology was post inflammatory bronchiectasis 26 patients (43.3%), followed by traction bronchiectasis 21 patients (35%). The distribution of bronchiectasis in post inflammatory cases was mostly affecting the lower lobes 16 (61.4%) of 26 patients. Regarding traction bronchiectasis, affection was mostly in the upper lobes including 10 (47.4%) of 21 patients. In chronic obstructive pulmonary disease, distribution was mostly in lower lobes with 4 (50%) of 8 patients. In aspiration, distribution was in bilateral lower lobes. In cystic fibrosis, it affected the bilateral upper lobes and in Kartagener syndrome, the distribution was on bilateral lobes. The most common morphological type of bronchiectasis was the cylindrical type which was detected in (25%) of cases followed by the signet ring type with (23.3%) of the cases. Conclusion: It could be concluded that the role of MSCT in the diagnosis of the pulmonary bronchiectasis is central, accurate and non-invasive.

This paper presents a mining technology that enables the continuous conversion from top coal caving (TCC) to multi-slice mining (MSM). The technology helps operations overcome challenges with mining thick bifurcated coal seams, particularly the challenge of rock-parting seams affecting the caving of TCC mining methods. Findings show that the relationship between the rock-parting thickness and the caveability of top coal can be divided into 3 phases, including a complete caving phase, a transition phase, and a stable phase. This continuous conversion technology was applied in the Zhongwei Coal Mine in which TCC was used to extract the initial 260 m of the study area where the rock-parting seam was relatively thin before a transition to MSM was made due to the rock-parting seam becoming significantly thicker. The continuous conversion to MSM involved the working face advancing upward at an angle of 10° until the rock-parting seam could serve as the immediate floor for the upper slice of the coal seam. The rock-parting seam floor also acted as the immediate roof for the working face of the subsequently mined lower slice. The application of this continuous conversion mining technology obtained good application results.

Background: Posterior Mediastinal lesions are relatively common and represent 23-30% of all mediastinal lesions; 40% of these lesions are an incidental finding. Multidetector CT (MDCT) has shorter imaging time and better spatial resolution than MRI, especially in mediastinum; it is more widely available & less expensive. The additional role of CT is in performing CT guided biopsies if needed. This study aimed to evaluate the role of MSCT in the diagnosis of mediastinal lesions based on the characteristic imaging appearances, which can lead to a correct diagnosis and optimal management. The post-processing technique further improves the diagnosis and surgical planning. Patients and Methods: This study included 30 patients with posterior mediastinal lesions evaluated according to clinical data, diagnostic imaging procedure (MSCT), and histopathological evaluation. Most of the cases in this study had a lesion raised from the LN and vessels by 23.3%. Results: Metastatic lymphadenopathy was the commonest lesion in our study, 13.3%, followed by lymphoma 10.3% and neurogenic tumors 10%. Benign lesions were 60%, while the malignant lesion represents 40% of all cases. Multiple CT features of each posterior mediastinal lesion were used to predict the nearest histological diagnosis. The accuracy of MSCT in our study was 93.3%. Conclusion: MSCT has a practical and significant role in the assessment & evaluation of the posterior mediastinal lesions according to the anatomical origin, the CT feature of the lesion (solid or cystic), density, the effect on the surroundings, the distribution pattern, and extent of the lesion.

Background Assessment of the interatrial septum (IAS) has become an attractive area of interest for a variety of important interventional procedures. Newer imaging modalities like multi-slice computed tomography (MSCT) and cardiac MRI (CMR) can provide higher resolution and wider field of view than echocardiography. Moreover, high-field (3-Tesla) CMR can even enhance spatial and temporal resolution. The characteristics of the interatrial septum were retrospectively studied in 371 consecutive subjects (201 men, 31–73 years old) in whom MSCT was performed primarily for non-invasive evaluation of the coronary arteries. All subjects underwent both MSCT and MRI scans within 0–30 day’s interval. A 3D volume covering the whole heart was acquired across the heart with and without contrast enhancement. Also, patients underwent cardiac MSCT examinations using 64-row MSCT scanners. Results The mean scan time of MSCT was 10.4 ± 2.8 s and 9.7 ± 2.9 min for CMR. The mean length of IAS by CMR and CT was 39.65 ± 4.6 mm and 39.28 ± 4.7 mm, respectively. The mean maximal thickness of IAS by CMR and CT was 3.1 ± 0.97 mm and 3.15 ± 0.95 mm, respectively. The mean thickness of fossa ovalis by CMR and CT was 1.04 ± 0.36 mm and 1.04 ± 0.44 mm, respectively. The mean length of fossa ovalis by CMR and CT was 12.8 ± 3.7 mm and 12.8 ± 3.5 mm, respectively. Finally, the mean angle of IAS by CMR and CT was identical (155 ± 9.2°). Measurements of various morphological features of IAS showed no statistically significant difference between CMR and CT, with an excellent correlation and close relationship regarding IAS length, maximal IAS thickness, fossa ovalis thickness, fossa ovalis length, and IAS angle (r = 0.98, 0.98, 0.95, 0.96, and 0.92, respectively). Conclusion Whole-heart 3D acquisition at 3-T MRI using a free-breathing technique provides a valuable non-invasive imaging tool for excellent assessment of the interatrial septum—as compared to MSCT—that may have significant clinical implication for diagnostic purposes and therapeutic interventional procedures, as it may facilitate planning, improve outcome, and shorten its duration.

In this perfusion magnetic resonance imaging study, the performances of different pseudo-continuous arterial spin labeling (PCASL) sequences were compared: two-dimensional (2D) single-shot readout with simultaneous multislice (SMS), 2D single-shot echo-planar imaging (EPI) and multishot three-dimensional (3D) gradient and spin echo (GRASE) sequences combined with a background-suppression (BS) module. Whole-brain PCASL images were acquired from seven healthy volunteers. The performance of each protocol was evaluated by extracting regional cerebral blood flow (rCBF) measures using an inline morphometric segmentation prototype. Image data postprocessing and subsequent statistical analyses enabled comparisons at the regional and sub-regional levels. The main findings were as follows: (i) Mean global CBF obtained across methods was were highly correlated, and these correlations were significantly higher among the same readout sequences. (ii) Temporal signal-to-noise ratio and gray-matter-to-white-matter CBF ratio were found to be equivalent for all 2D variants but lower than those of 3D-GRASE. Our study demonstrates that the accelerated SMS readout can provide increased acquisition efficiency and/or a higher temporal resolution than conventional 2D and 3D readout sequences. Among all of the methods, 3D-GRASE showed the lowest variability in CBF measurements and thus highest robustness against noise.

Purpose To develop a single-shot multi-slice T 1 mapping method by combing simultaneous multi-slice (SMS) excitations, single-shot inversion-recovery (IR) radial fast low-angle shot (FLASH), and a nonlinear model-based reconstruction method. Methods SMS excitations are combined with a single-shot IR radial FLASH sequence for data acquisition. A previously developed single-slice calibrationless model-based reconstruction is extended to SMS, formulating the estimation of parameter maps and coil sensitivities from all slices as a single nonlinear inverse problem. Joint-sparsity constraints are further applied to the parameter maps to improve T 1 precision. Validations of the proposed method are performed for a phantom and for the human brain and liver in 6 healthy adult subjects. Results Phantom results confirm good T 1 accuracy and precision of the simultaneously acquired multi-slice T 1 maps in comparison to single-slice references. In vivo human brain studies demonstrate the better performance of SMS acquisitions compared to the conventional spoke-interleaved multi-slice acquisition using model-based reconstruction. Aside from good accuracy and precision, the results of 6 healthy subjects in both brain and abdominal studies confirm good repeatability between scan and re-scans. The proposed method can simultaneously acquire T 1 maps for 5 slices of a human brain ( 0.75 × 0.75 × 5 mm 3 ) or 3 slices of the abdomen ( 1.25 × 1.25 × 6 mm 3 ) within 4 seconds. Conclusions The IR SMS radial FLASH acquisition together with a nonlinear model-based reconstruction enable rapid high-resolution multi-slice T 1 mapping with good accuracy, precision, and repeatability.

Objective: To explore the effects of multi-slice helical computed tomography (MSCT) and phlebography on edema regression nursing of lower limbs varicosis, and to analyze the values of MSCT and phlebography on the diagnosis and treatment of lower limb varicosis. Methods: A total of 193 patients with lower limb varicosis treated in the Vascular Surgery Department were included as the research objects. According to different examination methods, the included patients were divided into the MSCT group, and the MSCT combined with the phlebography group, Then, patients in both groups received joint treatment of high ligation and varicectomy. The Gabor filtering-based algorithm and the Mean-Variance Efficient Frontier (MVEF) algorithm were used to smoothen the obtained images. Also, the operation rates and contradiction compositions of patients in both groups were analyzed. Patients who received surgical treatment were followed up for three months to one year; whether the deep vein thrombosis (DVT) occurred in them were observed, as well as the edema regression. Results: As for gender, grading, disease history, duration of disease, and onset age of both groups, no statistical significance was found (P > 0.05). Compared to group A, the positive detection rate of postoperative DVT was lower in group B, so did the operation rate. In group A, 32 cases of edema regressed significantly, and the disease condition was relieved. In group B, 35 cases of edema were regressed. Conclusion: Compared with MSCT, phlebography had a higher screening rate for indications of lower limb varicosis, which could effectively reduce the probability of DVT after operations and relieve the symptoms of edema in patients. In addition, although the sensitivity of MSCT was relatively low, it could be used for the primary screening diagnosis of lower limb varicosis.

Purpose To develop and validate a saturation-delay-inversion recovery preparation, slice tracking and multi-slice based sequence for measuring whole-heart native T1 . Method The proposed free-breathing sequence performs T1 mapping of multiple left-ventricular slices by slice-interleaved acquisition to collect 10 electrocardiogram-triggered single-shot slice-selective images for each slice. A saturation-delay-inversion recovery pulse is used for T1 preparation. Prospective slice tracking by the diaphragm navigator and retrospective registration are used to reduce through-plane and in-plane motion, respectively. The proposed sequence was validated in both phantom and human subjects (12 healthy subjects and 15 patients who were referred for a clinical cardiac MR exam) and compared with saturation recovery single-shot acquisition (SASHA) and modified Look-Locker inversion recovery (MOLLI). Results Phantom T1 measured by the proposed sequence had excellent agreement (R2 = 0.99) with the ground-truth T1 and was insensitive to heart rate. In both healthy subjects and patients, the proposed sequence yielded nine left-ventricular T1 maps per volume in less than 2 minutes (healthy volunteers: 1.8 ± 0.4 minutes; patients: 1.9 ± 0.2 minutes). The average T1 of whole left ventricle for all healthy subjects and patients were 1560 ± 61 and 1535 ± 49 ms by SASHA, 1208 ± 42 and 1233 ± 56 ms by MOLLI5(3)3, and 1397 ± 34 and 1433 ± 56 ms by the proposed sequence, respectively. The corresponding coefficient of variation of T1 were 6.2 ± 1.4% and 5.8 ± 1.6%, 5.3 ± 1.1% and 5.1 ± 0.8%, and 4.9 ± 0.8% and 4.5 ± 0.8%, respectively. Conclusion The proposed sequence enables quantification of whole heart T1 with good accuracy and precision in less than 2 minutes during free breathing.

Background Computed tomography (CT) findings and clinicopathological characteristics of gastric gastrointestinal stromal tumors (GISTs) have been reported in the past, however, studies on their association with prognosis are limited. We aimed to evaluate the correlation between multi-slice computed tomography (MSCT) findings and clinicopathological characteristics for the prognosis of gastric GISTs. Multiple independent factors influencing the prognostic assessment of gastric GISTs were recognized. Methods The CT images and clinicopathological data of 155 patients with gastric GISTs were retrospectively analyzed. Progression-free survival of patients was obtained using the Kaplan–Meier method and compared using the log-rank test. Univariate and multivariate analyses were performed to evaluate the prognostic significance of CT imaging and clinicopathological factors. Results Univariate analysis revealed that patient prognosis was associated with the size, shape, necrosis or cystic degeneration, margin, growth pattern, enhancement pattern, mitotic rate, and Ki-67 index of the tumor. Further, multivariate analysis indicated that tumor size and necrosis or cystic degeneration were significant independent prognostic factors for gastric GISTs. Conclusions Tumor shape, necrosis or cystic degeneration, growth pattern, enhancement pattern, and mitotic rate were non-negligible criteria for improving the prognostic accuracy for GISTs, whereas tumor size, margin, and Ki-67 index were significant independent predictors identifying high-risk patients, facilitating personalized treatment to improve the prognosis of gastric GISTs patients. Thus, a combination of MSCT findings and clinicopathological features may be a valuable tool for assessing the prognosis of patients with gastric GISTs.

Background Pedicle screw instrumentation is used widely in lumbar spine for stabilization to enhance arthrodesis and has been accepted in the thoracic spine in recent years. The purpose of this study was to assess the value of postoperative 320 multi-slice computed tomography (MSCT) in assessment of pedicle screw placement in patients with spinal fixation with clinical and surgical correlation. Results A total of 340 pedicular screws were inserted to 70 cases. 286 (84.12%) were in, 54 screws (15.88%) were violated, and revision surgeries were required for 5 displaced screws. On axial, coronal reconstruction and three-dimensional (3D) reformatted CT images 36, 47, and 54 displaced screws were detected, respectively. Both sensitivity and specificity for 3D reformatted images were 100%. For axial image, they were 97.6% and 89.4%, respectively, compared with surgical findings in 5 revised screws. Conclusion Multi-slice CT scan is a valuable and valid postoperative assessment tool of accuracy of spinal pedicle screw placement.

BACKGROUND Diffusion-weighted imaging (DWI) has become a useful tool in the detection, characterization, and evaluation of response to treatment of many cancers, including malignant liver lesions. DWI offers higher image contrast between lesions and normal liver tissue than other sequences. DWI images acquired at two or more b-values can be used to derive an apparent diffusion coefficient (ADC). DWI in the body has several technical challenges. This include ghosting artifacts, mis-registration and susceptibility artifacts. New DWI sequences have been developed to overcome some of these challenges. Our goal is to evaluate 3 new DWI sequences for liver imaging. AIM To qualitatively and quantitatively compare 3 DWI sequences for liver imaging: free-breathing (FB), simultaneous multislice (SMS), and prospective acquisition correction (PACE). METHODS Magnetic resonance imaging (MRI) was performed in 20 patients in this prospective study. The MR study included 3 separate DWI sequences: FB-DWI, SMS-DWI, and PACE-DWI. The image quality, mean ADC, standard deviations (SD) of ADC, and ADC histogram were compared. Wilcoxon signed-rank tests were used to compare qualitative image quality. A linear mixed model was used to compare the mean ADC and the SDs of the ADC values. All tests were 2-sided and P values of < 0.05 were considered statistically significant. RESULTS There were 56 lesions (50 malignant) evaluated in this study. The mean qualitative image quality score of PACE-DWI was 4.48. This was significantly better than that of SMS-DWI (4.22) and FB-DWI (3.15) (P < 0.05). Quantitatively, the mean ADC values from the 3 different sequences did not significantly differ for each liver lesion. FB-DWI had a markedly higher variation in the SD of the ADC values than did SMS-DWI and PACE-DWI. We found statistically significant differences in the SDs of the ADC values for FB-DWI vs PACE-DWI (P < 0.0001) and for FB-DWI vs SMS-DWI (P = 0.03). The SD of the ADC values was not statistically significant for PACE-DWI and SMS-DWI (P = 0.18). The quality of the PACE-DWI ADC histograms were considered better than the SMS-DWI and FB-DWI. CONCLUSION Compared to FB-DWI, both PACE-DWI and SMS-DWI provide better image quality and decreased quantitative variability in the measurement of ADC values of liver lesions.

Purpose: To achieve high spatial resolution (isotropic-2 mm) perfusion imaging using 2D simultaneous multi-slice (SMS) pseudo-continuous arterial spin labeling (pCASL) and slice dithered enhanced resolution (SLIDER) technique for super-resolution reconstruction.Methods: The SLIDER-SMS pCASL with a multiband factor of 4 was implemented at 3T with three numbers of slice shift (2/3/4) for the slice thickness of 4/6/8 mm, respectively. Super-resolution reconstruction was performed with singular value decomposition and different levels of Tikhonov regularizations. Temporal and spatial signal-to-noise ratio (SNR) as well as spatial blurring effects of super-resolution ASL images were measured in five healthy subjects and compared with those of reference high-resolution ASL images.Results: Compared to conventional 2D SMS ASL, super-resolution ASL images with isotropic-2-mm resolution yielded 42, 61, and 88% higher spatial SNR, and 18, 55, and 105% higher temporal SNR with slice shift number of 2/3/4, respectively. Spatial blurring effect increased for SLIDER reconstruction from two to four slice shifts.Conclusion: The proposed SLIDER-SMS pCASL technique can achieve whole-brain high-resolution perfusion images with ∼15-min scan time and improved SNR compared to standard 2D SMS pCASL. Caution needs to be exercised on quantifying and controlling blurring effects of SLIDER reconstruction.

Objectives Assess MDCT accuracy in staging cancers periampullary cancers. Introduction Periampullary malignancies are highly aggressive with poor outcomes. Surgery is the only curative option. It is crucial to define the patients who can advantage from a Whipple’s resection and who can avoid. Methodology and Results RCT investigated randomly 28 patients over 15 months. The patients were sub-divided into 2 groups. Group A, we relied mainly on the MDCT for preoperative staging, while in Group B staging laparoscopy was added before the abdominal exploration. Sensitivity of the MDCT and its accuracy were 100% in defining the signs of irresectability. For borderline staging, the accuracy of the scan was 62.5% and 71%, in groups A and B. The Overall accuracy of MDCT was 75%. It decreased to 68.1% for borderline lesions. The addition of staging laparoscopy to the diagnostic work up, increased the accuracy to 92.5%. The camera test was able to see occult findings which were missed in the images. liver Mets and malignant peritoneal fluid were localized in 18% and 9% respectively. 3 cases in group A and one in group B underwent unnecessary laparotomy. Thus, the false negative incidences were 21% and 7% in group A and B, with overall incidence 14.2%. Conclusion MDCT is highly sensitive and specific with high stage periampullary cancers. These parameters drop in border tumors with reduced accuracy in detecting the degree of vascular abutment and distant-occult findings. Addition of other adjuncts to decrease the rate of un-indicated laparotomy is advised.

PURPOSE: To combine multi-slice chemical exchange saturation transfer (CEST) imaging with quasi-steady-state (QUASS) processing and demonstrate the feasibility of fast QUASS CEST MRI at 3 T. METHODS: Fast multi-slice EPI CEST imaging was developed with concatenated slice acquisition after single radio-frequency irradiation. The multi-slice CEST signal evolution was described by the spin-lock relaxation during saturation duration [Formula: see text] and longitudinal relaxation during the relaxation delay time [Formula: see text] and post-label delay (PLD), from which the QUASS CEST was generalized to fast multi-slice acquisition. In addition, numerical simulations, phantom, and normal human subjects scans were performed to compare the conventional apparent and QUASS CEST measurements with different [Formula: see text] , and PLD. RESULTS: The numerical simulation showed that the apparent CEST effect strongly depends on [Formula: see text] , and PLD, while the QUASS CEST algorithm minimizes such dependences. In the L-carnosine gel phantom, the proposed QUASS CEST effects (2.68±0.12% [mean ± SD]) were higher than the apparent CEST effects [Formula: see text]. In the human brain imaging, Bland-Altman analysis bias of the proposed QUASS CEST effects was much smaller than the PLD-corrected apparent CEST effects (0.03% vs. −0.54%), indicating the proposed fast multi-slice CEST imaging is robust and accurate. CONCLUSIONS: The QUASS processing enables fast multi-slice CEST imaging with minimal loss in the measurement of the CEST effect.

An efficient multi-slice inversion–recovery EPI (MS-IR-EPI) sequence for fast, high spatial resolution, quantitative T1 mapping is presented, using a segmented simultaneous multi-slice acquisition, combined with slice order shifting across multiple acquisitions. The segmented acquisition minimises the effective TE and readout duration compared to a single-shot EPI scheme, reducing geometric distortions to provide high quality T1 maps with a narrow point-spread function. The precision and repeatability of MS-IR-EPI T1 measurements are assessed using both T1-calibrated and T2-calibrated ISMRM/NIST phantom spheres at 3 and 7 T and compared with single slice IR and MP2RAGE methods. Magnetization transfer (MT) effects of the spectrally-selective fat-suppression (FS) pulses required for in vivo imaging are shown to shorten the measured in-vivo T1 values. We model the effect of these fat suppression pulses on T1 measurements and show that the model can remove their MT contribution from the measured T1, thus providing accurate T1 quantification. High spatial resolution T1 maps of the human brain generated with MS-IR-EPI at 7 T are compared with those generated with the widely implemented MP2RAGE sequence. Our MS-IR-EPI sequence provides high SNR per unit time and sharper T1 maps than MP2RAGE, demonstrating the potential for ultra-high resolution T1 mapping and the improved discrimination of functionally relevant cortical areas in the human brain.

Purpose: We provide a review of the key computed tomography (CT) technologies developed since the late 1980s and offer an overview of one of the future technologies under development. The focus of this review is mainly on the hardware and system development. The topics on the historical event linked to the early days of CT development and other innovations that contributed to the CT development, such as advanced image reconstruction techniques, are covered by companion papers in this special issue. Approach: The review is divided into five major sections, each linked to a key innovation in CT: helical spiral data acquisition, multi-slice CT, wide-cone CT, dual-source CT, and spectral CT. Given the limited scope of this review, only one of the future technologies, photon-counting CT, is discussed in detail. Whenever possible, both theory of operation and clinical examples are provided. Results: Theoretical analyses, phantom results, and clinical examples clearly demonstrate the efficacy and clinical relevancy of five historical technology developments and one future technology in CT. These technologies have improved and will continue to improve CT performance in terms of isotropic volume coverage, improved temporal resolution, and material differentiation and characterization capabilities. Conclusions: Over the past 30 years, technological developments of CT have contributed to the success of CT in many clinical applications such as trauma, oncology, cardiac imaging, and stroke. Advanced clinical applications have and will continue to demand more advanced technology development.

Advanced diffusion MRI models are being explored to study the complex microstructure of the brain with higher accuracy. However, these techniques require long acquisition times. Simultaneous multi-slice (SMS) accelerates data acquisition by exciting multiple image slices simultaneously and separating the overlapping slices using a mathematical model. However, this slice separation is not exact and leads to crosstalk between simultaneously excited slices. Although this residual leakage is small, it affects quantitative MRI techniques such as diffusion imaging. In this study, the effects of SMS acceleration on the accuracy of propagator metrics obtained from the MAP-MRI technique was investigated. Ten healthy volunteers were scanned with SMS accelerated multi-shell diffusion MRI acquisitions. Group analyses were performed to study brain regions typically affected by SMS acceleration. In addition, diffusion metrics from atlas based fiber tracts of interest were analyzed to investigate how propagator metrics in major fiber tracts were biased by 2- and 3-band SMS acceleration. Both zero-displacement metrics and non-Gaussianity metrics were significantly altered when SMS acceleration was used. MAP-MRI metrics calculated from SMS-3 showed significant differences with respect to SMS-2. Furthermore, when shorter TR afforded by SMS acceleration was used, the characteristics of this bias have changed. This has implications for studies using diffusion MRI with SMS acceleration to investigate the effects of a disease or injury on the brain tissues., Comment: The MRI engineers noted that different methods were used for combining coil images with single-band and SMS. To avoid this confounding effect, single-band data were excluded from the main analyses. However, single-band to SMS-2 comparisons were not significantly different, suggesting coil image combination was not a main effect. Thus, single-band comparisons were shown in supplementary data

An analysis of the distribution of radiation doses in the area of ??CT Scan Multi-Slice 64 has been carried out in Sanglah Hospital Denpasar. The study was conducted by dividing the area around the room into 8 regions and paths that indicate the distance from the wall to the surveillance. Measurements were made at several points at intervals of 1 m. Each point is taken three times the data collection. From the results of the distribution analysis it was found that there was an increase in the radiation dose rate to the Dose Limit Value (DLV) with a significance level below 0.05 occurring in region C with an average dose rate of 142.32 µSv/h, region E with an average value of an average of 111.36 µSv/h and area D with an average value of 40.68 µSv/h which has a value above the DLV. Whereas the value of the dose rate of other regions is below the DLV. Areas with a 25 cm transverse brick type barrier wall that has a 2 m window above have an average dose rate of 129.55 µSv/h, a 5 cm wooden door with a 2 mm Pb layer has an average dose rate of 67, 91 ?Sv/h.

In this paper, the calculation of stray losses distribution in core type transformer windings with continuously transposed conductor (CTC) cable based on multi-slice methodology is presented. Particular attention has been paid to hot spots due to the distribution of stray current losses on each individual winding conductor of CTC cable. As an alternative to the commonly adopted invariable distribution of current on each conductor cross-section around the winding turns, this paper proposes detailed calculation of the current (direct, eddy and circulating) and how the conductor transposition influences the distribution of stray losses. A practical example shows how application of the proposed methodology becomes especially useful when evaluating loss concentration under short circuit between individual conductors within the CTC cable. Multi-slice numerical results are also compared to 3D FEM data.

Post-mortem multi-slice computed tomography (MSCT) is a new approach in forensic pathology for gunshot injuries. This study determines the role of MSCT in the characterisation of single gunshot injuries. We report three cases. In the first case, an 80-year-old man was found dead in his bedroom with a gun. External examination showed devastating head injuries. In the second case, an 81-year-old man was found dead in his apartment, without a gun. External examination showed gunshot injuries. In the third case, a 56-year-old man was found dead on a road. MSCT and autopsy were performed in all these cases. MSCT not only allowed the determination of entrance and exit wounds but also showed some artefacts. In conclusion, radiology is fundamental for the reconstruction of gunshot injuries, and the manner of death can only be ascertained by autopsy.

Non-invasive quantification of the in vivo myelin content may provide valuable information regarding healthy maturation of the brain, as well as insights into demyelination of several neurological disorders. However, these scans are often long thereby limiting acquisition of large brain parts in clinically feasible acquisition times. Therefore, fast acquisition of whole brain myelin content is important. To avoid errors related to slice-selective pulses, most of the previous whole brain studies on myelin content relied on a 3D acquisition. However, multi-slice (2D) acquisition methods are often faster, and less susceptible to motion artifacts. Therefore, multi-slice approaches can be beneficial in a clinical setting.We investigated the applicability and reproducibility of whole brain multi-slice GRASE myelin-water imaging with post-acquisition slice-profile correction in healthy volunteers (aged 25-32y). The applicability was evaluated using the agreement between the multi-slice GRASE and the reference method for myelin-water imaging, single-slice multi spin-echo (MSE) acquisition. Additionally, we assessed the effect of varying acquisition acceleration using parallel imaging on the reproducibility values.First, the multi-slice myelin-water maps showed good agreement with the single-slice reference method, with a bias of at most 1.2% in absolute MWF values. Second, we found an average within-subject coefficient of variation (CoV) of 5.9% and an average intra-class correlation coefficient (ICC) of 0.90 for myelin-water estimation using a multi-slice GRASE sequence without parallel acceleration (scan time 14:06 min), while acquisition with a parallel acceleration factor of 2 resulted in a slightly worse average within-subject CoV of 6.4% and an average ICC of 0.83 at half the scan time. Hence, a multi-slice GRASE acquisition with parallel acceleration factor 2 and a scan time of 7:30 min still provides an excellent reproducibility.

This study aims to evaluate the imaging findings of cone-beam computed tomography (CBCT) in displaying subtle structures of the tympanic segment of the facial nerve canal in human cadaver heads compared with multi-slice computed tomography (MSCT). Between January 2017 and July 2017, images of the tympanic segment of the facial nerve canal acquired from 73 human cadaver ears by both CBCT and MSCT were prospectively studied. Then, images of the lateral and inferior walls of the tympanic segment were scored using standard imaging slices through a four-point rating scale. Subsequently, the detailed findings of these two imaging modalities were recorded and compared, including interruptions of the bony walls, thread-like bony tubes connected with the walls, and separations in the cavity. The Wilcoxon signed-rank test was used to investigate the differences between scores derived by CBCT and MSCT. The mean score in the inferior and lateral walls by CBCT were significantly higher than that by MSCT (P = 0.000–0.005), which ranged from 2.0 (1.5, 2.5) to 3.5 (3.0, 4.0), and from 1.5 (1.0, 2.0) to 3.5 (2.5, 4.0), respectively. The interruption of the walls was most common at the anterior part of the inferior wall (38/73 cases). Furthermore, thread-like bony tubes were evident in 18 ears, which connected with the anterior part of the inferior wall (18/73 cases). Moreover, separation was found in 22 ears in the posterior part (22/73 cases). CBCT can readily demonstrate subtle imaging findings of the tympanic segment of the facial nerve canal.

CAD is mainly due to atherosclerosis, an inflammatory process that is based on the interaction between immune mechanisms and metabolic risk factors. Abnormal lipid levels, particularly elevated low-density lipoprotein [LDL-C] and decreased high-density lipoprotein [HDL-C], as well as higher level of inflammatory markers especially high sensitive CRP [hsCRP] are well-established risk factors for cardiovascular disease [CVD].The present work aims to study the relation between lipid profile, high sensitive C-reactive protein[hs-CRP] with coronary plaque characteristics as assessed by Multi slice Coronary CT angiography. Two hundreds and twenty patients presented with typical chest pain were evaluated by MSCT coronary angiography for assessment of calcium score , characters of atherosclerotic plaques as well as identification of vulnerable plaques.Lipid profile and hs-CRP were measured for those patients.

We propose a new topology-preserving method for 3D image segmentation. We treat the image as a stack of 2D images so that the topological computation can be carried only within 2D in order to achieve computational efficiency. To enforce the continuity between slices, we propose a compound multi-slice representation and a compound multi-slice topological loss that incorporates rich topological information from adjacent slices. The quantitative and qualitative results show that our proposed method outperforms various strong baselines, especially for structure-related evaluation metrics.

Laminar BOLD-fMRI has been applied to better depict the neuronal input and output circuitry and functional connectivity across cortical layers by measuring local hemodynamic changes. Despite extensive studies detecting laminar fMRI signals to illustrate the canonical microcircuit, the spatiotemporal characteristics of laminar-specific information flow across different cortical regions remain to be fully investigated in both evoked and resting states. Here, we developed a multi-slice line-scanning fMRI (MS-LS) method to detect laminar fMRI signals in adjacent cortical regions with high spatial (50 µm) and temporal resolution (100 ms) in anesthetized rats. Across different scanning trials, we detected both laminar-specific positive and negative BOLD responses in the surrounding cortical region adjacent to the most activated cortex under evoked condition. Specifically, in contrast to the typical Layer (L) 4 correlation across different regions due to the thalamocortical projections for trials with positive BOLD, a strong correlation pattern specific in L2/3 was detected for the trials with negative BOLD in adjacent regions, which indicate a brain state-dependent laminar-fMRI responses based on cortiocotical interaction from different trials. Also, we acquired the laminar-specific rs-fMRI signals across different cortical regions, of which the high spatiotemporal resolution allows us to estimate lag times based on the maximal cross-correlation of laminar-specific rs-fMRI signals. In contrast to the larger variability of lag times in L1 and 6, robust lag time differences in L2/3, 4, and 5 across multiple cortices represented the low-frequency rs-fMRI signal propagation from the caudal to the rostral slice. In summary, our work provides a unique laminar fMRI mapping scheme to better characterize trial-specific intra- and inter-laminar functional connectivity with MS-LS, presenting layer-specific spatiotemporal variation of both evoked and rs-fMRI signals.

Pulmonary cystic echinococcosis remains a serious threat to public health. A standardized, imaging-based classification method for pulmonary echinococcosis has not yet been developed despite the existence of a standardized ultrasound classification method and treatment plan for hepatic cystic echinococcosis. Chest computed tomography (CT) images from 34 cases of pulmonary cystic echinococcosis with 46 lesions were used for classification based on the World Health Organization (WHO) standardized ultrasound classification of hepatic cystic echinococcosis. CT findings were compared with intraoperative observations and postoperative pathological results to assess accuracy. Pulmonary cystic echinococcosis was common in women (14/34, 41.2%) and children (14/34, 41.2%) with a single cyst (28/46, 60.9%). Most lesions were classified as cystic echinococcosis 1(CE1, 19/46) or cystic echinococcosis 3(CE3, 21/46). Blood leukocytosis was mostly observed in CE3 lesions (100%, 9/9) (p &lt, 0.05). The preoperative CT diagnosis of pulmonary cystic echinococcosis had an accuracy rate of 100%. The preoperative CT typing, and postoperative pathological typing had a coincidence rate of 97.8% (45/46). Our study provided a classification method based on CT imaging for pulmonary cystic echinococcosis that can be used during pre-surgical planning to reduce patient’s postoperative complications and mortality.

Three-directional cine multi-slice left ventricular myocardial velocity mapping (3Dir MVM) is a cardiac magnetic resonance (CMR) technique that allows the assessment of cardiac motion in three orthogonal directions. Accurate and reproducible delineation of the myocardium is crucial for accurate analysis of peak systolic and diastolic myocardial velocities. In addition to the conventionally available magnitude CMR data, 3Dir MVM also provides three orthogonal phase velocity mapping datasets, which are used to generate velocity maps. These velocity maps may also be used to facilitate and improve the myocardial delineation. Based on the success of deep learning in medical image processing, we propose a novel fast and automated framework that improves the standard U-Net-based methods on these CMR multi-channel data (magnitude and phase velocity mapping) by cross-channel fusion with an attention module and the shape information-based post-processing to achieve accurate delineation of both epicardial and endocardial contours. To evaluate the results, we employ the widely used Dice Scores and the quantification of myocardial longitudinal peak velocities. Our proposed network trained with multi-channel data shows superior performance compared to standard U-Net-based networks trained on single-channel data. The obtained results are promising and provide compelling evidence for the design and application of our multi-channel image analysis of the 3Dir MVM CMR data.

Respiration-induced B$_0$ fluctuation corrupts MRI images by inducing phase errors in k-space. A few approaches such as navigator have been proposed to correct for the artifacts at the expense of sequence modification. In this study, a new deep learning method, which is referred to as DeepResp, is proposed for reducing the respiration-artifacts in multi-slice gradient echo (GRE) images. DeepResp is designed to extract the respiration-induced phase errors from a complex image using deep neural networks. Then, the network-generated phase errors are applied to the k-space data, creating an artifact-corrected image. For network training, the computer-simulated images were generated using artifact-free images and respiration data. When evaluated, both simulated images and in-vivo images of two different breathing conditions (deep breathing and natural breathing) show improvements (simulation: normalized root-mean-square error (NRMSE) from 7.8% to 1.3%; structural similarity (SSIM) from 0.88 to 0.99; ghost-to-signal-ratio (GSR) from 7.9% to 0.6%; deep breathing: NRMSE from 13.9% to 5.8%; SSIM from 0.86 to 0.95; GSR 20.2% to 5.7%; natural breathing: NRMSE from 5.2% to 4.0%; SSIM from 0.94 to 0.97; GSR 5.7% to 2.8%). Our approach does not require any modification of the sequence or additional hardware, and may therefore find useful applications. Furthermore, the deep neural networks extract respiration-induced phase errors, which is more interpretable and reliable than results of end-to-end trained networks., 19 pages

Prostate segmentation from magnetic resonance (MR) images plays an important role in prostate cancer diagnosis and treatment. Previous works typically overlooked large variations of prostate shapes, especially on the boundary area. Furthermore, the small glandular areas at ending slices also make the task very challenging. To overcome these problems, this paper presents a two-stage framework that explicitly utilizes prostate morphological representations (e.g., point, boundary) to accurately localize the prostate region with a coarse volumetric segmentation. Based on the 3D coarse outputs of the first stage, a 2D segmentation network with multi-slice association is further introduced to produce more reliable and accurate segmentation, due to large slice thickness in prostate MR images. Besides, several novel loss functions are further designed to enhance the consistency of prostate boundaries. Extensive experiments on large prostate MRI dataset show superior performance of our proposed method compared to several state-of-the-art methods.

Contains fulltext : 232884.pdf (Publisher’s version ) (Open Access) PURPOSE: To compare diffusion-weighted imaging of the breast performed with a conventional readout-segmented echo-planar imaging (rs-EPI) sequence to when using a prototype simultaneous multi-slice single-shot EPI (SMS-ss-EPI) acquisition. METHOD: From September 2017 to December 2018, 26 women with histologically proven breast cancer were scanned with the conventional rs-EPI and the SMS-ss-EPI at 3T during the same imaging examination. Four breast radiologists (4-13 years of experience) independently scored both acquired series of 25 women (one case was used for training) for overall image quality (1: extremely poor to 9: excellent) and artifacts (1: very disturbing to 5: not present). All lesions (n=52; 40 malignant, 12 benign) were also evaluated for visibility (1: not visible, 2: visible if location is given, 3: visible). In addition, lesion characteristics were rated, and a BI-RADS score was given. Results were analyzed using visual grading characteristics and the resulting area under the curve (AUCVGC), weighted kappa, McNemar test, and dependent-samples t-test when appropriate. RESULTS: Overall, radiologists significantly preferred the image quality in rs-EPI over that of SMS-ss-EPI (AUCVGC: 0.698, P=0.002). Infolding and ghosting, and distortion artifacts were significantly less apparent in the rs-EPI (AUCVGC: 0.660, P=0.022 and AUCVGC: 0.700 P=0.002, respectively). Lesions were, however, significantly better visible on the SMS-ss-EPI images (AUCVGC: 0.427, P=0.016). Malignant lesions had significantly higher visibility with SMS-ss-EPI (P=0.035). Sensitivity and specificity were comparable between both sequences (P=0.760 and P=0.549, respectively). CONCLUSIONS: Despite the perceived lower image quality and the increased presence of artifacts in the SMS-ss-EPI sequence, malignant lesions are better visualized using this sequence.

This paper studies the features of the circle of Willis and cerebral aneurysm in patients with cerebral aneurysms through films of Multi-slice Computed Tomography (MSCT) at the Department of Radiology, Bach Mai Hospital, from March 2017 to March 2018. The study results show that female/male ratio was 2.37: 1; the number of patients with only one aneurysm accounted for 90.68%; Saccular aneurysm was more common than lozenge-shaped aneurysm; the rate of aneurysm ruptures was 82.35%; the bulge was mainly distributed in the carotid artery (94.6%). The very small bulge (less than 3mm) and the small bulge (3-7mm) were most common and accounted for 33.33% and 49.62%, respectively. The variations of the circle of Willis were very diverse and complex, including 13 forms, four of which were the circle of Willis anterior part variants and nine transformations were the circle of Willis posterior variants. Abnormalities (aplasia, hypoplasia) of the anterior communicating arterial were 8.48% and abnormalities of the posterior communicating arterial were 82.6%. The paper concludes that the abnormal anatomical variations in the circle of Willis can facilitate the early diagnosis and treatment of cerebral aneurysm disease. Keywords Circle of Willis, cerebral aneurysm, MSCT. References [1] C.S. Hee, L.J. Ye, R.K. Hwa, et al. Diagnosis of Cerebral Aneurysm Via Magnetic Resonance Angiography Screening: Emphasis on Legal Responsibility Increases False Positive Rate, Neurointervention 13(1) (2018) 48-53. [2] T.A. Tuan, Research the value of the diagnosis of cerebral aneurysm by 64 slices computer tomography, Graduate thesis in resident doctor, Hanoi Medical University, 2008 (in Vietnamese).[3] M.W. Son, J.W. Park, K.J. Park, et al, Prognostic Factors of Clinical Outcome after Aneurysmal Clipping in the Aged Patients with Unruptured Intracranial Aneurysm, Journal of Neurointensive Care 3(1) (2020) 20-25. [4] H.M. Tu, N.X. Khoa, Study on the anatomical changes of the cerebral arteries on the MSCT 64 imaging, Thesis Master of Medicine, Hanoi Medical University, 2012 (in Vietnamese).[5] Z. Molnar, W. Thomas (1621-1675), the founder of clinical neuroscience, Nat Rev Neurosci 5(4) (2004) 329-335. [6] Q. Li, J. Li, F. Lv, et al., A multidetector CT angiography study of variations in the circle of Willis in a Chinese population, J Clin Neurosci. 18(3) (2011) 379–383.[7] A. Karatas, G. Coban, C. Cinar, et al., Assessment of the Circle of Willis with Cranial Tomography Angiography, ed Sci Monit. 21 (2015) 2647–2652, [8] S.A. Gunnel, M.S. Farooqui, R.N. Wabale, Anatomical variations of the circulus arteriosus in cadaveric human brains, Neurol Res Int.: 687281, http://doi.org/10.1155/2014/687281, indexed in Pubmed: 24891951 (2014).[9] I.Ö. Yeniçeri, Circle of Willis variations and artery diameter measurements in the Turkish population, Via Medica 76 (3) (2017) 420–425.

Apparent diffusion coefficients (ADC) can provide phenotypic information of brain lesions, which can aid the diagnosis of brain alterations in neonates with congenital heart diseases (CHDs). However, the corresponding clinical significance of quantitative descriptors of brain tissue remains to be elucidated. By using ADC metrics and texture features, this study aimed to investigate the diagnostic value of single-slice and multi-slice measurements for assessing brain alterations in neonates with CHDs. ADC images were acquired from 60 neonates with echocardiographically confirmed non-cyanotic CHDs and 22 healthy controls (HCs) treated at Children's Hospital of Nanjing Medical University from 2012 to 2016. ADC metrics and texture features for both single and multiple slices of the whole brain were extracted and analyzed to the gestational age. The diagnostic performance of ADC metrics for CHDs was evaluated by using analysis of covariance and receiver operating characteristic. For both the CHD and HC groups, ADC metrics were inversely correlated with the gestational age in single and multi-slice measurements (P < 0.05). Histogram metrics were significant for identifying CHDs (P < 0.05), while textural features were insignificant. Multi-slice ADC (P < 0.01) exhibited greater diagnostic performance for CHDs than single-slice ADC (P < 0.05). These findings indicate that radiomic analysis based on ADC metrics can objectively provide more quantitative information regarding brain development in neonates with CHDs. ADC metrics for the whole brain may be more clinically significant in identifying atypical brain development in these patients. Of note, these results suggest that multi-slice ADC can achieve better diagnostic performance for CHD than single-slice.

The aging process has an impact on mandibular bone morphology and can therefore affect shape sexual dimorphism. Understanding the effect of senescence on mandibular shape changes is particularly important to correctly estimate the sex of an individual and predict age-related conformational modifications. The purpose of this study was to assess age-related changes in mandibular shape and sexual dimorphism. The study sample comprised 160 Multi Slice Computed Tomography examinations of individuals aged 40 to 79 years. Geometric morphometric analysis of fourteen osteometric landmarks was used to examine sexual dimorphism and patterns of mandibular shape variation with age. Results showed that mandibular sexual dimorphism of shape remained significant with aging. Conformational changes occurred between 50 and 70 years and were different for male and female individuals. Females presented earlier and more marked age-related shape changes than males. These observations suggest that mandibular senescence is a sexually dimorphic process since its onset, rate, and the areas subjected to conformational changes differ from male to female individuals. Senescence-related changes present substantial variability, and further investigation is required to determine precisely the age that marks their onset.

Inverse problems spanning four or more dimensions such as space, time and other independent parameters have become increasingly important. State-of-the-art 4D reconstruction methods use model based iterative reconstruction (MBIR), but depend critically on the quality of the prior modeling. Recently, plug-and-play (PnP) methods have been shown to be an effective way to incorporate advanced prior models using state-of-the-art denoising algorithms. However, state-of-the-art denoisers such as BM4D and deep convolutional neural networks (CNNs) are primarily available for 2D or 3D images and extending them to higher dimensions is difficult due to algorithmic complexity and the increased difficulty of effective training. In this paper, we present multi-slice fusion, a novel algorithm for 4D reconstruction, based on the fusion of multiple low-dimensional denoisers. Our approach uses multi-agent consensus equilibrium (MACE), an extension of plug-and-play, as a framework for integrating the multiple lower-dimensional models. We apply our method to 4D cone-beam X-ray CT reconstruction for non destructive evaluation (NDE) of samples that are dynamically moving during acquisition. We implement multi-slice fusion on distributed, heterogeneous clusters in order to reconstruct large 4D volumes in reasonable time and demonstrate the inherent parallelizable nature of the algorithm. We present simulated and real experimental results on sparse-view and limited-angle CT data to demonstrate that multi-slice fusion can substantially improve the quality of reconstructions relative to traditional methods, while also being practical to implement and train., arXiv admin note: substantial text overlap with arXiv:1906.06601

Background To evaluate the feasibility of using simultaneous multi-slice (SMS) readout segmentation of long variable echo-trains (RESOLVE) diffusion-weighted imaging (DWI) to assess parotid gland tumors, compared with conventional RESOLVE DWI. Methods From September 2018 to December 2018, 20 consecutive patients with parotid tumors who underwent MRI scan for pre-surgery evaluation were enrolled. SMS-RESOLVE DWI and conventional RESOLVE DWI were scanned with matched imaging parameters, respectively. The scan time of two DWI sequences was recorded. Qualitative (anatomical structure differentiation, lesion display, artifact, and overall image quality) and quantitative (apparent diffusion coefficient, ADC; ratio of signal-to-noise ratio, SNR ratio; ratio of contrast-to-noise ratio, CNR ratio) assessments of image quality were performed, and compared between SMS-RESOLVE DWI and conventional RESOLVE DWI by using Paired t-test. Two-sided P value less than 0.05 indicated significant difference. Results The scan time was 3 min and 41 s for SMS-RESOLVE DWI, and 5 min and 46 s for conventional RESOLVE DWI. SMS-RESOLVE DWI produced similar qualitative image quality with RESOLVE DWI (anatomical structure differentiation, P = 0.164; lesion display, P = 0.193; artifact, P = 0.330; overall image quality, P = 0.083). Meanwhile, there were no significant difference on ADCLesion (P = 0.298), ADCMasseter (P = 0.122), SNR ratio (P = 0.584) and CNR ratio (P = 0.217) between two DWI sequences. Conclusion Compared with conventional RESOLVE DWI, SMS-RESOLVE DWI could provide comparable image quality using markedly reduced scan time. SMS could increase the clinical usability of RESOLVE technique for DWI of parotid gland.

Background This study evaluates the possibility for replacing conventional 3 slices, 3 breath-holds MOLLI cardiac T1 mapping with single breath-hold 3 simultaneous multi-slice (SMS3) T1 mapping using blipped-CAIPIRINHA SMS-bSSFP MOLLI sequence. As a major drawback, SMS-bSSFP presents unique artefacts arising from side-lobe slice excitations that are explained by imperfect RF modulation rendering and bSSFP low flip angle enhancement. Amplitude-only RF modulation (AM) is proposed to reduce these artefacts in SMS-MOLLI compared to conventional Wong multi-band RF modulation (WM). Materials and methods Phantoms and ten healthy volunteers were imaged at 1.5 T using a modified blipped-CAIPIRINHA SMS-bSSFP MOLLI sequence with 3 simultaneous slices. WM-SMS3 and AM-SMS3 were compared to conventional single-slice (SMS1) MOLLI. First, SNR degradation and T1 accuracy were measured in phantoms. Second, artefacts from side-lobe excitations were evaluated in a phantom designed to reproduce fat presence near the heart. Third, the occurrence of these artefacts was observed in volunteers, and their impact on T1 quantification was compared between WM-SMS3 and AM-SMS3 with conventional MOLLI as a reference. Results In the phantom, larger slice gaps and slice thicknesses yielded higher SNR. There was no significant difference of T1 values between conventional MOLLI and SMS3-MOLLI (both WM and AM). Positive banding artefacts were identified from fat neighbouring the targeted FOV due to side-lobe excitations from WM and the unique bSSFP signal profile. AM RF pulses reduced these artefacts by 38%. In healthy volunteers, AM-SMS3-MOLLI showed similar artefact reduction compared to WM-SMS3-MOLLI (3 ± 2 vs 5 ± 3 corrupted LV segments out of 16). In-vivo native T1 values obtained from conventional MOLLI and AM-SMS3-MOLLI were equivalent in LV myocardium (SMS1-T1 = 935.5 ± 36.1 ms; AM-SMS3-T1 = 933.8 ± 50.2 ms; P = 0.436) and LV blood pool (SMS1-T1 = 1475.4 ± 35.9 ms; AM-SMS3-T1 = 1452.5 ± 70.3 ms; P = 0.515). Identically, no differences were found between SMS1 and SMS3 postcontrast T1 values in the myocardium (SMS1-T1 = 556.0 ± 19.7 ms; SMS3-T1 = 521.3 ± 28.1 ms; P = 0.626) and the blood (SMS1-T1 = 478 ± 65.1 ms; AM-SMS3-T1 = 447.8 ± 81.5; P = 0.085). Conclusions Compared to WM RF modulation, AM SMS-bSSFP MOLLI was able to reduce side-lobe artefacts considerably, providing promising results to image the three levels of the heart in a single breath hold. However, few artefacts remained even using AM-SMS-bSSFP due to residual RF imperfections. The proposed blipped-CAIPIRINHA MOLLI T1 mapping sequence provides accurate in vivo T1 quantification in line with those obtained with a single slice acquisition.

Background Although magnetic resonance imaging (MRI) provides excellent soft-tissue contrast, long acquisition times are major disadvantages. Purpose To evaluate the usefulness of compressed sensing (CS) for contrast-enhanced oral and maxillofacial MRI by comparing the 3D T1 turbo field echo with compressed SENSE (CS-3D-T1TFE) sequence with the multi-slice spin echo (MS-SE) sequence as the reference standard. Material and Methods Thirty patients with orofacial lesions participated in this study. The scan times for MS-SE and CS-3D-T1TFE were 5 min 56 s and 1 min 43 s, respectively. The signal-to-noise ratio (SNR) was calculated for quantitative analysis and seven parameters (degree of lesion conspicuity, motion artifacts, metal artifacts, pulsation artifacts, quality of fat suppression, homogeneity of blood vessel signal intensity, and overall image quality) were evaluated using a 5-point scale (5 = excellent, 1 = unacceptable) by two observers for qualitative analysis. For comparisons between MS-SE and CS-3D-T1TFE, the paired t-test was used. Results The SNR of CS-3D-T1TFE was higher than or equal to that of MS-SE. The CS-3D-T1TFE scores for motion artifacts, pulsation artifacts, and homogeneity of blood vessel signal intensity were higher than the corresponding MS-SE scores in assessments by both observers. The MS-SE scores for fat suppression were higher than or equal to the CS-3D-T1TFE scores. There were no significant differences in lesion conspicuity, metal artifacts, and overall image quality between the two sequences. Conclusion CS-3D-T1TFE imaging, less than 30% of the scan time for MS-SE, showed no image degradation while retaining equal or higher SNR and image quality.

Perfusion cardiac MRI (CMR) is a radiation-free and noninvasive imaging tool which has gained increasing interest for the diagnosis of coronary artery disease. However, resolution and coverage are limited in perfusion CMR due to the necessity of single snap-shot imaging during the first-pass of a contrast agent. Simultaneous multi-slice (SMS) imaging has the potential for high acceleration rates with minimal signal-to-noise ratio (SNR) loss. However, its utility in CMR has been limited to moderate acceleration factors due to residual leakage artifacts from the extra-cardiac tissue such as the chest and the back. Outer volume suppression (OVS) with leakage-blocking reconstruction has been used to enable higher acceleration rates in perfusion CMR, but suffers from higher noise amplification. In this study, we sought to augment OVS-SMS/MB imaging with a regularized leakage-blocking reconstruction algorithm to improve image quality. Results from highly-accelerated perfusion CMR show that the method improves upon SMS-SPIRiT in terms of leakage reduction and split slice (ss)-GRAPPA in terms of noise mitigation.