Radiomics analysis for the prediction of locoregional recurrence of locally advanced oropharyngeal cancer and hypopharyngeal cancer.

PURPOSE: By radiomic analysis of the postcontrast CT images, this study aimed to predict locoregional recurrence (LR) of locally advanced oropharyngeal cancer (OPC) and hypopharyngeal cancer (HPC). METHODS: A total of 192 patients with stage III-IV OPC or HPC from two independent cohort were randomly split into a training cohort with 153 cases and a testing cohort with 39 cases. Only primary tumor mass was manually segmented. Radiomic features were extracted using PyRadiomics, and then the support vector machine was used to build the radiomic model with fivefold cross-validation process in the training data set. For each case, a radiomics score was generated to indicate the probability of LR. RESULTS: There were 94 patients with LR assigned in the progression group and 98 patients without LR assigned in the stable group. There was no significant difference of TNM staging, treatment strategies and common risk factors between these two groups. For the training data set, the radiomics model to predict LR showed 83.7% accuracy and 0.832 (95% CI 0.72, 0.87) area under the ROC curve (AUC). For the test data set, the accuracy and AUC slightly declined to 79.5% and 0.770 (95% CI 0.64, 0.80), respectively. The sensitivity/specificity of training and test data set for LR prediction were 77.6%/89.6%, and 66.7%/90.5%, respectively. CONCLUSIONS: The image-based radiomic approach could provide a reliable LR prediction model in locally advanced OPC and HPC. Early identification of those prone to post-treatment recurrence would be helpful for appropriate adjustments to treatment strategies and post-treatment surveillance.

Pretreatment diffusion-weighted imaging for prediction of relapsed and refractory primary central nervous system lymphoma.

Objectives: A subset of primary central nervous system lymphoma (PCNSL) has been shown to undergo an early relapsed/refractory (R/R) period after first-line chemotherapy. This study investigated the pretreatment clinical and MRI features to predict R/R in PCNSL, emphasizing the apparent diffusion coefficient (ADC) values in diffusion-weighted imaging (DWI). Methods: This retrospective study investigated the pretreatment MRI features for predicting R/R in PCNSL. Only patients who had undergone complete preoperative and postoperative MRI follow-up studies were included. From January 2006 to December 2021, 52 patients from two medical institutions with a diagnosis of PCNSL were included (median follow-up time, 26.3 months). Among these, 24 (46.2%) had developed R/R (median time to relapse, 13 months). Cox proportional hazard regression analyses were performed to determine hazard ratios for all parameters. Results: Significant predictors of R/R in PCNSL were female sex, complete response (CR) to first-line chemotherapy, and ADC value/ratio (p < 0.05). Cut-off points of ADC values and ADC ratios for prediction of R/R were 0.68 × 10-3 mm2/s and 0.97, with AUCs of 0.78 and 0.77, respectively (p < 0.05). Multivariate Cox proportional hazards analysis showed that failure of CR to first-line chemotherapy and low ADC values (<0.68 × 10-3 mm2/s) were significant risk factors for R/R, with hazard ratios of 5.22 and 14.45, respectively (p < 0.05). Kaplan-Meier analysis showed that lower ADC values and ratios predicted significantly shorter progression-free survival (p < 0.05). Conclusion: Pretreatment ADC values in DWI offer quantitative valuable information for the treatment planning in PCNSL.

Unnecessary radiation exposure during diagnostic radiography in infants in a neonatal intensive care unit: a retrospective cohort study.

Unnecessary radiation exposure (URE) during radiographic examination is an issue among infants in neonatal intensive care units (NICUs). The causes of URE have not been fully explored. This study investigated the incidence and identified the causes of URE in infants during diagnostic radiography in a NICU. This was a retrospective cohort study. We retrieved and analysed requests and radiographs taken at a tertiary NICU between September and November 2018. URE was defined as the rate of discordance between requests and images taken (DisBRI) and unnecessary radiation exposure in irrelevant regions (UREIR) during radiography. We compared the rates of URE between very low-birth-weight (VLBW, birth weight < 1500 g) infants and non-VLBW infants. A total of 306 radiographs from 88 infants were taken. The means ± standard deviations (SDs) of gestational age and birth weight were 35.7 ± 3.6 weeks and 2471 ± 816 g, respectively. Each infant underwent an average of 3.5 radiographs. The DisBRI rate was 1.3% and was mostly related to poor adherence to requests. The UREIR rates in thoraco-abdominal babygrams were 89.6% for the head, 14.8% for the elbows and 18.4% for the knee and were mainly related to improper positioning of and collimation in infants while performing radiography. The UREIR rates for the head, knee and ankle were higher in VLBW infants than in non-VLBW infants (94.6% vs. 85.6%, 27.0% vs. 11.5% and 5.4% vs. 0.7%, respectively, p < 0.05). CONCLUSIONS: URE during diagnostic radiography is common in sick infants and is mainly related to improper positioning and collimation during examinations. Adherence to protocols when performing radiographic examination or using ultrasonography may be a solution to reduce URE in infants in NICUs. WHAT IS KNOWN: • The risk of unnecessary radiation exposure (URE) during radiography has been a common and important issue in sick infants in neonatal intensive care units (NICUs). • The new point-of-care ultrasound (POCUS) technique decreases the need for chest films and prevents radiation exposure in neonates. WHAT IS NEW: • In the NICU, URE is still a common issue in critically ill infants during radiographic examinations. The causes of URE during diagnostic radiography are mainly due to improper positioning and collimation during examinations. • The incidence of URE in irrelevant regions is higher in very low-birth-weight (VLBW) infants than in non-VLBW infants.

Generative Adversarial Network (GAN) for Automatic Reconstruction of the 3D Spine Structure by Using Simulated Bi-Planar X-ray Images.

In this study, we modified the previously proposed X2CT-GAN to build a 2Dto3D-GAN of the spine. This study also incorporated the radiologist's perspective in the adjustment of input signals to prove the feasibility of the automatic production of three-dimensional (3D) structures of the spine from simulated bi-planar two-dimensional (2D) X-ray images. Data from 1012 computed tomography (CT) studies of 984 patients were retrospectively collected. We tested this model under different dataset sizes (333, 666, and 1012) with different bone signal conditions to observe the training performance. A 10-fold cross-validation and five metrics-Dice similarity coefficient (DSC) value, Jaccard similarity coefficient (JSC), overlap volume (OV), and structural similarity index (SSIM)-were applied for model evaluation. The optimal mean values for DSC, JSC, OV, SSIM_anteroposterior (AP), and SSIM_Lateral (Lat) were 0.8192, 0.6984, 0.8624, 0.9261, and 0.9242, respectively. There was a significant improvement in the training performance under empirically enhanced bone signal conditions and with increasing training dataset sizes. These results demonstrate the potential of the clinical implantation of GAN for automatic production of 3D spine images from 2D images. This prototype model can serve as a foundation in future studies applying transfer learning for the development of advanced medical diagnostic techniques.

A deep learning-based method for the diagnosis of vertebral fractures on spine MRI: retrospective training and validation of ResNet.

PURPOSE: To improve the performance of less experienced clinicians in the diagnosis of benign and malignant spinal fracture on MRI, we applied the ResNet50 algorithm to develop a decision support system. METHODS: A total of 190 patients, 50 with malignant and 140 with benign fractures, were studied. The visual diagnosis was made by one senior MSK radiologist, one fourth-year resident, and one first-year resident. The MSK radiologist also gave the binary score for 15 qualitative imaging features. Deep learning was implemented using ResNet50, using one abnormal spinal segment selected from each patient as input. The T1W and T2W images of the lesion slice and its two neighboring slices were considered. The diagnostic performance was evaluated using tenfold cross-validation. RESULTS: The overall reading accuracy was 98, 96, and 66% for the senior MSK radiologist, fourth-year resident, and first-year resident, respectively. Of the 15 imaging features, 10 showed a significant difference between benign and malignant groups with p < = 0.001. The accuracy achieved by using the ResNet50 deep learning model for the identified abnormal vertebral segment was 92%. Compared to the first-year resident's reading, the model improved the sensitivity from 78 to 94% (p < 0.001) and the specificity from 61 to 91% (p < 0.001). CONCLUSION: Our deep learning-based model may provide information to assist less experienced clinicians in the diagnosis of spinal fractures on MRI. Other findings away from the vertebral body need to be considered to improve the model, and further investigation is required to generalize our findings to real-world settings.

Clinical application of mask region-based convolutional neural network for the automatic detection and segmentation of abnormal liver density based on hepatocellular carcinoma computed tomography datasets.

The aim of the study was to use a previously proposed mask region-based convolutional neural network (Mask R-CNN) for automatic abnormal liver density detection and segmentation based on hepatocellular carcinoma (HCC) computed tomography (CT) datasets from a radiological perspective. Training and testing datasets were acquired retrospectively from two hospitals of Taiwan. The training dataset contained 10,130 images of liver tumor densities of 11,258 regions of interest (ROIs). The positive testing dataset contained 1,833 images of liver tumor densities with 1,874 ROIs, and negative testing data comprised 20,283 images without abnormal densities in liver parenchyma. The Mask R-CNN was used to generate a medical model, and areas under the curve, true positive rates, false positive rates, and Dice coefficients were evaluated. For abnormal liver CT density detection, in each image, we identified the mean area under the curve, true positive rate, and false positive rate, which were 0.9490, 91.99%, and 13.68%, respectively. For segmentation ability, the highest mean Dice coefficient obtained was 0.8041. This study trained a Mask R-CNN on various HCC images to construct a medical model that serves as an auxiliary tool for alerting radiologists to abnormal CT density in liver scans; this model can simultaneously detect liver lesions and perform automatic instance segmentation.

Imaging biomarkers for evaluating tumor response: RECIST and beyond.

Response Evaluation Criteria in Solid Tumors (RECIST) is the gold standard for assessment of treatment response in solid tumors. Morphologic change of tumor size evaluated by RECIST is often correlated with survival length and has been considered as a surrogate endpoint of therapeutic efficacy. However, the detection of morphologic change alone may not be sufficient for assessing response to new anti-cancer medication in all solid tumors. During the past fifteen years, several molecular-targeted therapies and immunotherapies have emerged in cancer treatment which work by disrupting signaling pathways and inhibited cell growth. Tumor necrosis or lack of tumor progression is associated with a good therapeutic response even in the absence of tumor shrinkage. Therefore, the use of unmodified RECIST criteria to estimate morphological changes of tumor alone may not be sufficient to estimate tumor response for these new anti-cancer drugs. Several studies have reported the low reliability of RECIST in evaluating treatment response in different tumors such as hepatocellular carcinoma, lung cancer, prostate cancer, brain glioma, bone metastasis, and lymphoma. There is an increased need for new medical imaging biomarkers, considering the changes in tumor viability, metabolic activity, and attenuation, which are related to early tumor response. Promising imaging techniques, beyond RECIST, include dynamic contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI), diffusion-weight imaging (DWI), magnetic resonance spectroscopy (MRS), and 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET). This review outlines the current RECIST with their limitations and the new emerging concepts of imaging biomarkers in oncology.

Simvastatin-Ezetimibe enhances growth factor expression and attenuates neuron loss in the hippocampus in a model of intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) is a common and severe neurological disorder associated with high morbidity and mortality rates. Despite extensive research into its pathology, there are no clinically approved neuroprotective treatments for ICH. Increasing evidence has revealed that inflammatory responses mediate the pathophysiological processes of brain injury following ICH. Experimental ICH was induced by direct infusion of 100 µL fresh (non-heparinized) autologous whole blood into the right basal ganglia of Sprague-Dawley rats at a constant rate (10 µL/min). The simvastatin group was administered simvastatin (15 mg/kg) and the combination therapy group was administered simvastatin (10 mg/kg) and ezetimibe (10 mg/kg). Magnetic resonance imaging (MRI), the forelimb use asymmetry test, the Morris water maze test, and two biomarkers were used to evaluate the effect of simvastatin and combination therapy. MRI imaging revealed that combination therapy resulted in significantly reduced perihematomal edema. Biomarker analyses revealed that both treatments led to significantly reduced endothelial inflammatory responses. The forelimb use asymmetry test revealed that both treatment groups had significantly improved neurological outcomes. The Morris water maze test revealed improved neurological function after combined therapy, which also led to less neuronal loss in the hippocampal CA1 region. In conclusion, simvastatin-ezetimibe combination therapy can improve neurological function, attenuate the endothelial inflammatory response and lead to less neuronal loss in the hippocampal CA1 region in a rat model of ICH.

Internal Derangement of the Shoulder Joint in Asymptomatic Professional Baseball Players.

RATIONALE AND OBJECTIVES: To evaluate the influence of throwing activity on shoulder morphology and the difference in shoulder morphology on MRI between asymptomatic professional baseball players and volunteers who play baseball as a recreational activity. MATERIALS AND METHODS: This retrospective case-control study included 68 asymptomatic professional baseball players (32 pitchers, 36 batters) and 30 male volunteers. Morphologic changes in the following shoulder structures were assessed on MRI: rotator cuff, glenoid labrum, humeral head, subacromial-subdeltoid bursa, subcoracoid bursa, long head of the biceps tendon, deltoid muscle, acromion, and clavicle. RESULTS: Partially torn supraspinatus, posterior glenoid or labral lesions, bone marrow edema, intraosseous cysts of the humeral head, and edematous subacromial-subdeltoid bursa were significantly more commonly observed in players (p = 0.01, p < 0.001, p = 0.03, p< 0.001, and p < 0.001). Players with more than 10 years of experience had a significantly higher incidence of patchy intermediate signal abnormality (odds ratio: 3.73, p = 0.03), partial tear in the supraspinatus tendon (odds ratio: 6.20, p = 0.03), and edematous change in the subacromial-subdeltoid bursa (odds ratio: 2.96, p = 0.03). CONCLUSION: The results from our study showed that repetitive throwing activities cause macroscopic structural lesions of the shoulder joints in asymptomatic baseball players. Significance of these lesions is to be determined.

Lhermitte-Duclos disease: A case report with radiologic-pathologic correlation.

Background: Lhermitte-Duclos disease (LDD) stems from the development of a rare benign lesion of uncertain pathogenesis that distorts the normal cerebellar laminar cytoarchitecture. We explored the lesion's appearance on conventional magnetic resonance imaging (MRI) combined with susceptibility-weighted imaging, diffusion-weighted imaging, perfusion imaging, or arterial spin labeling. Although many cases of LDD have been previously reported in the literature, the radiologic-pathologic correlation has been described in only a few of these cases. To the best of our knowledge, this is the first case report to provide detailed information about the radiologic-pathologic correlation of LDD. Case Report: A 48-year-old woman presented with left facial tics, occipital headache, and dizziness for 1 month. MRI revealed a left cerebellar lesion with hypointensity on T1-weighted images. On T2-weighted images, the mass was hyperintense with tigroid appearance due to alternating high and normal signal intensities. High signal intensity was noted on fluid-attenuated inversion recovery images. Magnetic resonance spectroscopy indicated decreased level of choline (Cho), N-acetyl aspartate, and myoinositol with elevated level of lactate on the affected side. The lesion showed a bright signal on diffusion-weighted images, whereas apparent diffusion coefficient mapping revealed no disturbance of diffusion. The pathology of the excised lesion was consistent with LDD. Conclusion: MRI with advanced techniques can provide not only preoperative diagnosis but also better pathologic correlation.

Familial Risk of Appendicitis: A Nationwide Population Study.

OBJECTIVE: To investigate the familial risk of appendicitis in the general population. STUDY DESIGN: A nationwide, cross-sectional study consisting of 24 349 599 Taiwan National Health Insurance beneficiaries in 2015 was conducted. Among them, 788 042 individuals had at least 1 first-degree relative with appendicitis. The familial relative risks (RRs) of appendicitis and familial transmission were estimated. RESULTS: The overall RR (95% CI) of appendicitis in individuals with any affected first-degree relatives was 1.67 (1.64-1.71) compared with the general population. The RRs for individuals with an affected twin, sibling, offspring, and parent were 3.40 (2.66-4.35), 1.98 (1.92-2.04), 1.55 (1.51-1.59), and 1.54 (1.50-1.58), respectively. The RRs for individuals with 1, 2, 3 or more affected first-degree relatives were 1.65 (1.62-1.68), 2.63 (2.37-2.91), and 6.70 (4.22-10.63), respectively. Furthermore, there was an age-dependent trend of the RRs, with the greatest RR in the youngest group. The estimated familial transmission (genetic plus shared environmental contribution to the total phenotypic variance of appendicitis) was 23.2%. CONCLUSION: Individuals with a family history of appendicitis have an increased risk of appendicitis. This risk is age-dependent and related to the genetic distance and numbers of affected relatives.

Evaluation of the association between quantitative mammographic density and breast cancer occurred in different quadrants.

BACKGROUND: To investigate the relationship between mammographic density measured in four quadrants of a breast with the location of the occurred cancer. METHODS: One hundred and ten women diagnosed with unilateral breast cancer that could be determined in one specific breast quadrant were retrospectively studied. Women with previous cancer/breast surgery were excluded. The craniocaudal (CC) and mediolateral oblique (MLO) mammography of the contralateral normal breast were used to separate a breast into 4 quadrants: Upper-Outer (UO), Upper-Inner (UI), Lower-Outer (LO), and Lower-Inner (LI). The breast area (BA), dense area (DA), and percent density (PD) in each quadrant were measured by using the fuzzy-C-means segmentation. The BA, DA, and PD were compared between patients who had cancer occurring in different quadrants. RESULTS: The upper-outer quadrant had the highest BA (37 ± 15 cm2) and DA (7.1 ± 2.9 cm2), with PD = 20.0 ± 5.8%. The order of BA and DA in the 4 separated quadrants were: UO > UI > LO > LI, and almost all pair-wise comparisons showed significant differences. For tumor location, 67 women (60.9%) had tumor in UO, 16 (14.5%) in UI, 7 (6.4%) in LO, and 20 (18.2%) in LI quadrant, respectively. The estimated odds and the 95% confidence limits of tumor development in the UO, UI, LO and LI quadrants were 1.56 (1.06, 2.29), 0.17 (0.10, 0.29), 0.07 (0.03, 0.15), and 0.22 (0.14, 0.36), respectively. In these 4 groups of women, the order of quadrant BA and DA were all the same (UO > UI > LO > LI), and there was no significant difference in BA, DA or PD among them (all p > 0.05). CONCLUSIONS: Breast cancer was most likely to occur in the UO quadrant, which was also the quadrant with highest BA and DA; but for women with tumors in other quadrants, the density in that quadrant was not the highest. Therefore, there was no direct association between quadrant density and tumor occurrence.

Osteoporotic sacral insufficiency fracture: An easily neglected disease in elderly patients.

Sacral insufficiency fractures (SIFs) are easily neglected by clinical physicians.The incidence of SIFs remains unclear in patients with symptomatic osteoporotic compression fractures of the lumbar-sacral area.This retrospective study was conducted by reviewing the medical records and radiological reports and by reading magnetic resonance (MR) images from August 2013 to July 2016. We identified 1233 cases with symptomatic vertebral compression fractures for which surgical interventions were performed. A total of 1144 cases were eligible for this study. Neglected diagnoses by radiologists and clinical physicians were calculated, respectively.The MR imaging (MRI) findings of SIFs were divided into the body (S1, S2, S3, and S4 levels) and alar areas (unilateral, bilateral, transverse, and none).A total of 34 (3.00%) cases with SIFs were identified through MRI. A significant difference was observed between 19 (6.53%) patients aged >80 years and 15 (1.76%) aged <80 years (P < .0001). Eight (23.53%) and 26 (76.47%) cases of SIFs were neglected by radiologists and clinical physicians, respectively. The S2 and S3 levels were the predominantly involved area (23/34; 67.65%). Furthermore, the bilateral alar area was the most commonly involved (19/34; 55.88%), as observed in coronal views of MRI.While treating other levels of osteoporotic compression fractures, radiologists and clinical physicians should be aware of SIFs, particularly when the patients are aged >80 years. The coronal oblique MR images of the thoracolumbar region should be carefully read to avoid neglecting SIFs.

The Association Between Barium Examination and Subsequent Appendicitis: A Nationwide Population-Based Study.

OBJECTIVE: The incidence and association between appendicitis and barium examination (BE) remain unclear. Such potential risk may be omitted. We conducted a longitudinal, nationwide, population-based cohort study to investigate the association between BE and appendicitis risk. METHODS: From the Taiwan National Health Insurance Research Database, a total of 24,885 patients who underwent BE between January 1, 2000 and December 31, 2010 were enrolled in a BE cohort; an additional 98,384 subjects without BE exposure were selected as a non-BE cohort, matched by age, sex, and index date. The cumulative incidences of subsequent appendicitis in the BE and non-BE cohorts were assessed using the Kaplan-Meier curves and log-rank test. Cox proportional hazards regression analyses were employed to calculate the appendicitis risk between the groups. RESULTS: The cumulative incidence of appendicitis was higher in the BE cohort than in the non-BE cohort (P = .001). The overall incidence rates of appendicitis for the BE and non-BE cohorts were 1.19 and 0.80 per 1000 person-years, respectively. After adjustment for sex, age, and comorbidities, the risk of appendicitis was higher in the BE cohort (adjusted hazard ratio = 1.46, 95% confidence interval = 1.23-1.73) compared with the non-BE cohort, especially in the first 2 months (adjusted hazard ratio = 9.72, 95% confidence interval = 4.65-20.3). CONCLUSIONS: BE was associated with an increased, time-dependent appendicitis risk. Clinicians should be aware of this potential risk to avoid delayed diagnoses.

Differential Effects of Bariatric Surgery Versus Exercise on Excessive Visceral Fat Deposits.

The aim of the present study was to compare differential impacts of bariatric surgery and exercise-induced weight loss on excessive abdominal and cardiac fat deposition.Excessive fat accumulation around the heart may play an important role in the pathogenesis of cardiovascular disease. Recent evidences have suggested that bariatric surgery results in relatively less decrease in epicardial fat compared with abdominal visceral fat and paracardial fat.Sixty-four consecutive overweight or obese subjects were enrolled in the study. Clinical characteristics and metabolic profiles were recorded. The volumes of abdominal visceral adipose tissue (AVAT), abdominal subcutaneous adipose tissue (ASAT), epicardial (EAT), and paracardial adipose tissue (PAT) were measured by computed tomography in the bariatric surgery group (N = 25) and the exercise group (N = 39) at baseline and 3 months after intervention. Subjects in both the surgery and exercise groups showed significant reduction in body mass index (15.97%, 7.47%), AVAT (40.52%, 15.24%), ASAT (31.40, 17.34%), PAT (34.40%, 12.05%), and PAT + EAT (22.31%, 17.72%) (all P < 0.001) after intervention compared with baseline. In both the groups, the decrease in EAT was small compared with the other compartments (P < 0.01 in both groups). Compared with the exercise group, the surgery group had greater loss in abdominal and cardiac visceral adipose tissue (AVAT, ASAT, PAT, EAT+PAT) (P < 0.001), but lesser loss in EAT (P = 0.037).Compared with the exercise group, bariatric surgery results in significantly greater percentage loss of excessive fat deposits except for EAT. EAT, but not PAT, was relatively preserved despite weight reduction in both the groups. The physiological impact of persistent EAT deserves further investigation.

Reproducibility of Brain Morphometry from Short-Term Repeat Clinical MRI Examinations: A Retrospective Study.

PURPOSE: To assess the inter session reproducibility of automatic segmented MRI-derived measures by FreeSurfer in a group of subjects with normal-appearing MR images. MATERIALS AND METHODS: After retrospectively reviewing a brain MRI database from our institute consisting of 14,758 adults, those subjects who had repeat scans and had no history of neurodegenerative disorders were selected for morphometry analysis using FreeSurfer. A total of 34 subjects were grouped by MRI scanner model. After automatic segmentation using FreeSurfer, label-wise comparison (involving area, thickness, and volume) was performed on all segmented results. An intraclass correlation coefficient was used to estimate the agreement between sessions. Wilcoxon signed rank test was used to assess the population mean rank differences across sessions. Mean-difference analysis was used to evaluate the difference intervals across scanners. Absolute percent difference was used to estimate the reproducibility errors across the MRI models. Kruskal-Wallis test was used to determine the across-scanner effect. RESULTS: The agreement in segmentation results for area, volume, and thickness measurements of all segmented anatomical labels was generally higher in Signa Excite and Verio models when compared with Sonata and TrioTim models. There were significant rank differences found across sessions in some labels of different measures. Smaller difference intervals in global volume measurements were noted on images acquired by Signa Excite and Verio models. For some brain regions, significant MRI model effects were observed on certain segmentation results. CONCLUSIONS: Short-term scan-rescan reliability of automatic brain MRI morphometry is feasible in the clinical setting. However, since repeatability of software performance is contingent on the reproducibility of the scanner performance, the scanner performance must be calibrated before conducting such studies or before using such software for retrospective reviewing.

Investigation of factors affecting hypothermic pelvic tissue cooling using bio-heat simulation based on MRI-segmented anatomic models.

This study applied a simulation method to map the temperature distribution based on magnetic resonance imaging (MRI) of individual patients, and investigated the influence of different pelvic tissue types as well as the choice of thermal property parameters on the efficiency of endorectal cooling balloon (ECB). MR images of four subjects with different prostate sizes and pelvic tissue compositions, including fatty tissue and venous plexus, were analyzed. The MR images acquired using endorectal coil provided a realistic geometry of deformed prostate that resembled the anatomy in the presence of ECB. A single slice with the largest two-dimensional (2D) cross-sectional area of the prostate gland was selected for analysis. The rectal wall, prostate gland, peri-rectal fatty tissue, peri-prostatic fatty tissue, peri-prostatic venous plexus, and urinary bladder were manually segmented. Pennes' bioheat thermal model was used to simulate the temperature distribution dynamics, by using an in-house finite element mesh based solver written in MATLAB. The results showed that prostate size and periprostatic venous plexus were two major factors affecting ECB cooling efficiency. For cases with negligible amount of venous plexus and small prostate, the average temperature in the prostate and neurovascular bundles could be cooled down to 25 °C within 30 min. For cases with abundant venous plexus and large prostate, the temperature could not reach 25 °C at the end of 3 h cooling. Large prostate made the cooling difficult to propagate through. The impact of fatty tissue on cooling effect was small. The filling of bladder with warm urine during the ECB cooling procedure did not affect the temperature in the prostate or NVB. In addition to the 2D simulation, in one case a 3D pelvic model was constructed for volumetric simulation. It was found that the 2D slice with the largest cross-sectional area of prostate had the most abundant venous plexus, and was the most difficult slice to cool, thus it may provide a conservative prediction of the cooling effect. This feasibility study demonstrated that the simulation tool could potentially be used for adjusting the setting of ECB for individual patients during hypothermic radical prostatectomy. Further studies using MR thermometry are required to validate the in silico results obtained using simulation.

A case-matched study of the differences in bone mineral density 1 year after 3 different bariatric procedures.

BACKGROUND: Studies have reported decreased bone mineral density (BMD) after laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB). Laparoscopic adjustable gastric banded plication (LAGBP) is a novel procedure resulting in a dual restrictive mechanism of weight loss without altering gastrointestinal anatomy. The objectives of this study were to compare the BMD changes at 1 year after LAGBP, LSG, and LRYGB. METHODS: The sample included 120 patients (40 patients [13 men/27 premenopausal women] each in LAGBP, LSG, and LRYGB groups). The mean preoperative age and body mass index were 30.0±6.5 years and 39.5±3.8 kg/m2, respectively. BMD was measured using dual energy X-ray absorptiometry at the lumbar anteroposterior spine and total hip preoperatively and 1 year postoperatively. RESULTS: The mean percentage of excess weight loss was 61.9%±16.8%, 77.1%±12.3%, and 72.7%±17.4% at 1 year after LAGBP, LSG, and LRYGB, respectively. The mean BMD at the lumbar anteroposterior spine remained unchanged in the LSG and LRYGB groups, but significantly increased in the LAGBP group. The mean BMD at the total hip significantly decreased in all groups compared to the preoperative values. However, the mean BMD was significantly higher in the LRYGB than in the LAGBP group. CONCLUSION: Bone loss at the hips was observed in all patients, including those with adequate micronutrient supplementation. LRYGB caused significantly greater bone loss than the other procedures.