Rafel Tappouni

Sleep apnoea and visceral adiposity in middle-aged male and female subjects

In obese male subjects, visceral adiposity has been associated with obstructive sleep apnoea (OSA), while studies in overweight males and females are limited. Our goal was to examine the association between OSA and visceral fat in a relatively nonobese population and assess the effects of 2 months placebo-controlled continuous positive airway pressure (CPAP) use on abdominal fat. 81 subjects, 22 middle-aged males and 20 post-menopausal females with OSA, and 19 male and 20 female controls were studied in the sleep laboratory for four nights. Abdominal (visceral (VAT) and subcutaneous (SAT) adipose tissue) and liver fat were assessed with computed tomography. OSA patients were re-assessed post-CPAP and post sham-CPAP. Apnoeic males had significantly higher VAT than controls, while apnoeic females had higher SAT than controls. In both sexes, OSA was associated with increased liver fat. In males, apnoea was associated with VAT whereas in females it was associated with subcutaneous, visceral and total fat. CPAP did not affect abdominal and liver fat. In overweight males, visceral adiposity is associated with OSA whereas in females it is associated with global adiposity. In overweight males, our therapeutic goal should be the reduction of visceral adiposity and its metabolic correlates, whereas, in females, weight loss may be sufficient. Short-term CPAP treatment does not affect general, abdominal or intra-hepatic adiposity.

Pseudoenhancement of renal cysts: influence of lesion size, lesion location, slice thickness, and number of MDCT detectors.

OBJECTIVE The purpose of this study was to determine the effect of renal cyst size and location on pseudoenhancement in human subjects. MATERIALS AND METHODS Simple renal cysts obtained with 16-, 40-, and 64-MDCT scanners were analyzed for the presence of pseudoenhancement. Cyst size, location, and attenuation in the unenhanced and nephrographic phases were recorded. Pseudoenhancement was defined as an attenuation increase of 10 HU or more on nephrographic phase compared with unenhanced images. RESULTS The pseudoenhancement rate was 22% (51/233). There was a statistically significant increase in the pseudoenhancement rate of lesions smaller than 10 mm (38/233) compared with those 10 mm and larger (13/233) (odds ratio, 6.4; p<0.0001). Twelve of 62 cysts measuring 10-14 mm exhibited pseudoenhancement. There was a statistically significant increase in the pseudoenhancement rate of central (39/53) compared with peripheral (12/51) cysts (odds ratio, 2.7; p<0.0001). The pseudoenhancement rates for the 16-, 40-, and 64-MDCT scanners were 20%, 19%, and 26% with no statistically significant difference between them. CONCLUSION Pseudoenhancement of renal cysts significantly correlates with size smaller than 1 cm and central location. Although pseudoenhancement increases with larger numbers of detectors, the correlation was not statistically significant. Cysts in the 1- to 1.5-cm range have a 19% likelihood of pseudoenhancement.

Use of a simulation laboratory to train radiology residents in the management of acute radiologic emergencies.

OBJECTIVE Simulation laboratories use realistic clinical scenarios to train physicians in a controlled environment, especially in potentially life-threatening complications that require prompt management. The objective of our study was to develop a comprehensive program using the simulation laboratory to train radiology residents in the management of acute radiologic emergencies. MATERIALS AND METHODS All radiology residents attended a dedicated simulation laboratory course lasting 3 hours, divided over two sessions. Training included basic patient management skills, management of a tension pneumothorax, massive hemorrhage, and contrast agent reactions. Participants were presented with 20 multiple-choice questions before and after the course. Pre- and posttest results were analyzed, and the McNemar test was used to compare correct responses by individual question. RESULTS Twenty-six radiology residents attended the class. The average pre- and posttest scores and the average difference between the scores for all residents were 13.8, 17.1, and 3.3, respectively (p < 0.0001). Incorrect answers on the pretest examination that were subsequently answered correctly concerned administration of epinephrine for severe reactions, management of a tension pneumothorax, oxygen therapy, ECG placement, cardiopulmonary resuscitation technique, and where to stand during a code situation. Persistent incorrect answers concerned vasovagal reactions and emergency telephone numbers at an off-site imaging center. CONCLUSION Simulation laboratories can be used to teach crisis management and crisis resource management for radiology residents and should be part of the education toolbox. Defined objectives lead to a comprehensive course dealing with the management of acute radiologic emergencies. Such programs can improve the role of radiologists as members of the health care team.

Accuracy of Apparent Diffusion Coefficient Value Measurement on PACS Workstation: A Comparative Analysis

OBJECTIVE The purpose of this article is to evaluate the accuracy of apparent diffusion coefficient (ADC) measurements made with a PACS workstation compared with measurements made with a dedicated workstation, which is currently considered the reference standard. MATERIALS AND METHODS A retrospective review was performed in liver lesions from 79 patients using three MRI platforms. The final diagnosis was established by liver biopsy in 31 patients and by dynamic MRI and follow-up, both clinical and radiologic as indicated, in 48 patients. Each lesion that was clearly demonstrable on the ADC map was measured with a commercial dedicated postprocessing workstation and again with a PACS system. A two-sample t test was used to determine the statistically significant differences between the two ADC measurements. RESULTS A total of 79 patients with 120 liver lesions were included. ADC values measured on the workstation were 0.4-4.38 × 10(-3) mm(2)/s. The ADC values measured on the PACS were 0.42-4.35 × 10(-3) mm(2)/s. The T value was -1.113, with 119 degrees of freedom, and the significance level was 0.268, which implies no significant difference between the two different measuring systems for all pathologic abnormalities and MRI scanners used. CONCLUSION ADC values measured on a routine PACS workstation are as accurate as the values obtained on a dedicated specialized workstation. ADC value measurement on the routine PACS will save time and lead to increased utilization, which, in turn, will lead to an improved understanding of the different disease processes and their clinical management.

Imaging of Unusual Perineal Masses

OBJECTIVE The purpose of this article is to describe the radiologic features of unusual tumors that occur in the perineum. CONCLUSION The perineal space is often overlooked because of the infrequency of abnormalities. Accurate image interpretation and visualization of extent of pathology is important for proper management. Trauma and infectious diseases occur in the acute setting, whereas tumors are common in the chronic setting. Cross-sectional imaging plays a crucial role in depicting perineal anatomy and evaluating the extent of disease.

Volumetric Fat Ratio and Not Body Mass Index Is Predictive of Ileocolectomy Outcomes in Crohn's Disease Patients

Background: Crohns disease (CD) patients are typically underweight; however, a growing cohort of overweight CD patients is emerging. The current study investigates whether body mass index (BMI) or volumetric fat parameters can be used to predict morbidity after ileocolectomy for CD. Methods: One hundred and forty-three CD patients who underwent elective ileocolectomy were identified from our Inflammatory Bowel Disease (IBD) Registry. Patient demographics and operative outcomes were recorded. Visceral (VA) and subcutaneous (SA) adiposity and abdominal circumference (AC) were analyzed on preoperative CT scans using Aquarius iNtuition software. A visceral/subcutaneous ratio (VSR) was calculated. Results: BMI correlated with SA (p = 0.0001), VA (p = 0.0001) and AC (p = 0.0001) but not VSR (p > 0.05). BMI, VA and AC did not predict surgical morbidity (p > 0.05). In multivariate regression analysis, family history of IBD (p = 0.009), high American Society of Anesthesiologists score (p = 0.02) and increased VSR (p = 0.03) were independent predictors of postoperative morbidity. Conclusions: The visceral/subcutaneous fat ratio is a more reliable predictor of postoperative outcomes in CD patients undergoing ileocolectomy than conventional adiposity markers such as BMI. Preoperative calculation of the visceral/subcutaneous fat ratio offers the opportunity to optimize high-risk surgical patients, thus improving outcomes.

Circumportal pancreas: imaging findings in 40 patients

AbstractPurpose To analyze the CT and MR imaging features of circumportal pancreas (CP) with emphasis on the relative frequency of variants of parenchymal fusion, ductal anatomy, and vascular anatomy.MethodsA retrospective review of CT and MR imaging findings of 40 patients with CP was performed. CT and MR images were reviewed by two radiologists in consensus. The course of the pancreatic duct in relation to the portal vein (anteportal vs. retroportal), location of the circumvenous pancreatic parenchyma in relation to the splenic vein (suprasplenic vs. infrasplenic), presence or absence of a visible accessory duct posterior to the portal vein, presence of vascular variants, history of pancreatitis and pancreatic surgery were recorded. Cases were classified into four categories: anteportal suprasplenic, retroportal suprasplenic, anteportal infrasplenic, and retroportal infrasplenic.ResultsOne case of suprasplenic fusion was excluded from the classification due to non-visualization of the pancreatic duct. 32/39(82%) of cases were classified as anteportal suprasplenic, 2/39(5%) as retroportal suprasplenic, 4/39(10%) as anteportal infrasplenic, and 1/39(3%) as retroportal infrasplenic. There were 12 vascular variants including nine with an intraparenchymal course (through the pancreatic head) of the common hepatic artery, one with an intraparenchymal course of the right hepatic artery, two replaced right hepatic arteries from the superior mesenteric artery, and one with an intraparenchymal course of the left gastric vein.ConclusionCircumportal pancreas is an important pancreatic fusion anomaly with distinctive imaging features. The most common variant of CP is the anteportal suprasplenic subtype, with other subtypes being much less common. Intraparenchymal course of the common hepatic artery is a common variant associated with CP. Recognition of CP is important to avoid potential complications in patients who undergo pancreatic surgery.

Measurement of visceral fat on preoperative computed tomography predicts complications after sigmoid colectomy for diverticular disease

BACKGROUND Visceral and subcutaneous abdominal fat parameters have been associated with worse surgical outcomes in colorectal cancer but have not been investigated in diverticulitis. METHODS Volumetric fat parameters were measured on preoperative computed tomography scans from 211 diverticulitis patients. Primary outcome was a serious postoperative complication (Clavien-Dindo grades 2-4). Variables including age, disease duration, American Society of Anesthesiology score, ostomy, immunosuppression, body mass index, and volumetric fat parameters were examined. SPSS was used for statistics. RESULTS The serious postoperative complication rate was 12.7%. On univariate analysis, several factors including older age (P = .0001), ostomy creation (P = .02), higher visceral fat (VF, P = .01), emergent surgery (P = .05), and higher American Society of Anesthesiology score (P = .05) were associated with complications. On multivariate regression analysis, only VF was independently associated with complications. CONCLUSIONS Diverticulitis patients with high VF are more likely to develop complications after sigmoidectomy. VF measurement may potentially be used as a tool to assist in surgical decision making and prediction of outcomes.

Scan Quality and Entrance Skin Dose in Thoracic CT: A Comparison between Bismuth Breast Shield and Posteriorly Centered Partial CT Scans

Objectives. To compare the effectiveness of the bismuth breast shield and partial CT scan in reducing entrance skin dose and to evaluate the effect of the breast shield on image quality (IQ). Methods. Nanodots were placed on an adult anthropomorphic phantom. Standard chest CT, CT with shield, and partial CT were performed. Nanodot readings and effective doses were recorded. 50 patients with chest CTs obtained both with and without breast shields were reviewed. IQ was evaluated by two radiologists and by measuring Hounsfield units (HUs) and standard deviation (SD) of HU in anterior subcutaneous region. Results. Breast shield and the partial CT scans reduced radiation to the anterior chest by 38% and 16%, respectively. Partial CT increased dose to the posterior chest by 37% and effective dose by 8%. Change in IQ in shield CT was observed in the anterior chest wall. Significant change in IQ was observed in 5/50 cases. The shield caused an increase of 20 HU (P = 0.021) and a 1.86 reduction in SD of HU (P = 0.027) in the anterior compared to posterior subcutaneous regions. Summary. Bismuth breast shield is more effective than the partial CT in reducing entrance skin dose while maintaining image quality.

Pitfalls in CT diagnosis of appendicitis: Pictorial essay

Despite the high diagnostic accuracy of CT for appendicitis, numerous pitfalls exist that may result in a misdiagnosis. This pictorial review outlines the potential pitfalls in the CT diagnosis of appendicitis that includes atypical position of the appendix and coexisting pathologies. Various mimickers of appendicitis and clinical dilemmas will be highlighted. Upon completion, the reviewer should have an improved ability to recognise appendicitis mimickers and identify equivocal or atypical findings.