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A 58-year-old male patient, previously healthy, presented with right flank pain of few hours duration. Initial workup showed an elevated creatinine and right hydroureteronephrosis. Computed tomography imaging revealed a retroperitoneal soft tissue mass encasing the right common iliac artery which is a first reported case in its anatomical distribution. Patient was referred to interventional radiology service where a percutaneous nephrostomy tube was placed followed by double J stenting. Subsequently, treatment with steroids was started. Follow up imaging a few months later revealed progressive resolution of the inflammatory process.

Purpose: The aim of our study is to investigate the impact of iodine quantification on image reconstruction when employing a vascular-specific contrast media phantom with varying iodine concentrations., Materials and Methods: A 30-cm phantom simulating arterial and venous blood vessel diameters was manufactured. Small (9 mm) and medium (12 mm) cylinders contained iodine concentrations from 10 to 100% while large (21 mm) cylinders were in quartiles from 25 to 100% diluted in blood equivalent medium. Each phantom was filled with either iohexol 350 mgI/mL (Group A) or iodixanol 320 mgI/mL (Group B) and then scanned separately. For each group, tube potential (80-140 kVp) and current (50-400 mAs) were changed and all image series were reconstructed with filtered back projection (FBP), hybrid-based iterative reconstruction (HBIR) and model-based iterative reconstruction (MBIR). Mean opacification was measured in all groups. All data were compared employing an independent t test and Pearson's correlation. Visual grading characteristic (VGC) and Cohens' kappa analyses were performed., Results: At 80 kVp, mean opacification using HBIR was significantly higher in Group B (2165 ± 1108 HU) than in Group A (2040 ± 1036 HU) (p < 0.009). At 140 kVp, MBIR and HBIR were greater in Group A (1704 ± 1033 HU and 1685 ± 1023 HU) versus Group B (1567 ± 1036 HU and 1567 ± 1034 HU) (p < 0.022). CNR using FBP, HBIR and MBIR was higher in Group B (46 ± 42 HU, 70 ± 163 HU and 83 ± 74 HU, respectively) than in Group A (43 ± 39 HU, 174 ± 130 HU and 80 ± 65 HU, respectively) (p < 0.0001-0.035). Qualitative image analysis demonstrated no difference in Cohen's kappa analysis. VGC was higher in Group A at all image reconstruction groups., Conclusion: Iohexol outperforms iodixanol in observer performance when assessing image reconstruction techniques and iodine concentrations in a vascular-specific contrast media phantom.

Background and Study Aims: Bowel wall thickening (BWT) on computed tomography (CT) has been frequently reported by radiologists. There are no clear guidelines regarding the level of thickening that is correlated with definite pathology. Radiologists usually rely on their overall subjective impression, and studies on inter-observer agreement (IOA) are lacking. This study evaluated IOA concerning BWT found on abdominal CT and identified the corresponding findings on endoscopy., Patients and Methods: Reports of abdominal CTs performed between January 2000 and December 2015 containing the term 'thickening' were retrieved from the radiology department database. Corresponding patients who later underwent endoscopy were included. IOA concerning BWT was evaluated using a randomly mixed sample of 80 patients with normal findings or pathological BWT on endoscopy. A search for predictive factors for the subsequent finding of malignancy on endoscopy was performed using multivariate analysis., Results: During the study period, 6142 CT scans described thickening, equivalent to a BWT prevalence of 13.7%. Ninety-one patients (mean age, 58 years) were included in the analysis. Thickening was found most commonly in the stomach (38.5%), followed by the rectum (22%) and small intestine (14%). Twenty-seven patients (29.7%) exhibited diffuse BWT, whereas 64 patients showed localised BWT (70.3%). Biopsy was performed for 64 of 91 patients with endoscopies. Among these patients, 8.8% exhibited normal findings, whereas inflammation and malignancy were discovered in 25 and 51.6% of patients, respectively, with a positive predictive value for malignancy of 0.36. The IOA concerning CT for predicting significantly pathological BWT was moderate (mean κ = 0.6). A strong association was evident between the presence of lymph nodes on CT and the presence of neoplastic lesions., Conclusion: Our study strongly recommends endoscopic follow-up of patients exhibiting BWT irrespective of the thickening location, especially if it is associated with lymphadenopathy. IOA between radiologists was moderate., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

Purpose: Investigate the impact of nonionic dimer and monomer on iodine quantification in different vessel sizes when employing a vascular specific phantom and varying iodinated contrast media (ICM) concentrations during computed tomography (CT)., Materials and Methods: We created a vascular specific phantom (30 cm) to simulate human blood vessel diameters (25 cylinders of different diameters: 10 × 9mm, 10 × 12mm and 5 × 21mm). The phantom was filled with two ICM separately: Group: Iohexol(monomer)350 mg ml -1 and B: Iodixanol(Dimer)320 mg ml -1 . Cylinders of same size were filled with increasing ICM concentration(10%-100%) while large cylinders were filled in quartiles(25%-100%). Phantom was scanned with different tube potential (80-140kVp), current (50-400mAs), reconstruction method [filtered back projection (FBP), hybrid-based iterative reconstruction (HBIR) and model-based iterative reconstruction (MBIR)] for each ICM. Chi-square was employed to compare mean opacification, contrast/noise ratio (CNR) and noise. Qualitative analysis was assessed by Visual grading characteristic (VGC) and Cohens-kappa analyses., Results: At 80 and140kVp significant difference in opacification between Group A (2054 ± 1040HU and 1696 ± 1027HU) and B (2169 ± 1105HU and 1568 ± 1034HU) was demonstrated (p < 0.001). However, at 100 and 120kVp no difference was noted (p > 0.05). When comparing image noise, it was higher in Group A compared to B (p < 0.05). CNR was higher in Group B (119.99 ± 126.10HU) than A (107.09 ± 102.56HU) (p < 0.0001). VGC: Group A outperformed B in image opacification in all vessel sizes and ICM concentrations except at medium vessels with concentration group 2(0.4-0.6 mg ml -1 ). Cohens'-kappa: agreement in opacification between each ICM group and iodine concentration 1(0-0.3 mg ml -1 ): κ = 0.253 and 0.014 respectively, concentration 2(0.4-0.6 mg ml -1 ):κ = -0.017 and -0.005 respectively and concentration 3(0.7-1 mg ml -1 ):κ = 0.031 and 0.115 respectively., Conclusion: Nonionic dimer (Iodixanol) surpasses monomer (Iohexol) in quantitative image quality assessment by having lower image noise and higher CNR during CT.

Aim: To investigate the frequency of different etiologies of acute scrotal pain in males presenting to the emergency department at American University of Beirut Medical Center in Beirut, Lebanon., Materials and Methods: In all, 94 patients between the ages 18 and 40 years presenting to the emergency room at American University of Beirut Medical Center with acute scrotum were recruited. The scrotum was inspected with palpation, and Doppler Ultrasound of the testicle was performed by a radiology resident to confirm the diagnosis. The study results were then collected after the official reports were signed by a board-certified radiology attending with expertise in ultrasound., Results: Of the 94 patients presenting with acute scrotal pain, 23.4% (95% confidence interval (0.70-0.87)) had no ultrasound findings and were considered normal. On the other hand, 54.3% (95% confidence interval (0.45-0.66)) were diagnosed with varicocele, 9.6% (95% confidence interval (0.04-0.16)) were diagnosed with epididymo-orchitis, and 9.6% (95% confidence interval (0.04-0.16)) had a history of trauma to the testicle. Patients presenting with acute scrotum had a pain duration of 13.2 ± 4.5 h, with 10.6% (95% confidence interval (0.04-0.17)) having associated urinary symptoms, 18.1% (95% confidence interval (0.09-0.25)) have had sexual activity within 48 h of presentation, and 10.6% (95% confidence interval (0.04-0.17)) were pre-diagnosed with varicocele., Conclusion: Varicocele is the most common cause of acute scrotal pain in patients presenting to American University of Beirut Medical Center in Beirut. This should direct varicocele to the top of our differential when a patient with acute scrotum presents to the emergency department. Nevertheless, ruling out torsion remains the first step in the workup.

Introduction: The purpose is to evaluate the prognostic significance of lung parenchymal density during percutaneous coaxial cutting needle lung biopsy (PNLB)., Materials and Methods: Retrospective analysis of 179 consecutive patients (106 males, 73 females; mean age 59.16 ± 16.34 years) undergoing PNLB was included. Mean lobar parenchymal lung density, mean densities anterior to the lesion and posterior to the chest wall in the needle trajectory path were measured in HU. Lesion location and needle trajectory were also measured. Fisher's exact test and Chi-square test were conducted to analyze the categorical variables. ANOVA test was done to examine continuous and normally distributed variables. Statistical significance was considered when p < 0.05., Results: Mean lobar parenchymal lung density (p < 0.05) and mean parenchymal lung density relative to the needle trajectory path were below -800 HU in patients who sustained a pneumothorax. Increase in the number of pleural passes was significantly associated with the risk of patients having pneumothorax (p < 0.05). The mean distance from the skin to the lesion and needle trajectory angle were not statistically different among patients with and without pneumothorax (p > 0.05)., Conclusion: Lobar parenchymal density and lung parenchymal density anterior to the lesion and posterior to the chest wall in the needle trajectory path could be used as predicting parameters in patients undergoing PNLB who sustained a pneumothorax. These findings can help interventional radiologist further assess risk of pneumothorax when preforming such procedure.

Purpose: This hybrid retrospective and prospective study performed on 200 consecutive patients undergoing renal CTA, investigates the opacification of renal vasculature, radiation dose, and reader confidence., Materials and Methods: 100 patients were assigned retrospectively to protocol A and the other 100 were allocated prospectively to protocol B. Both protocols implemented a contrast material and saline flow rate of 4.5 mL/sec. Protocol A utilized a 100 mL of low-osmolar nonionic IV contrast material (Ioversol 350 mg I/mL) while protocol B employed a patient-tailored contrast media formula using iso-osmolar non-ionic (Iodixanol 320 mg I/mL)., Results: Arterial opacification in the abdominal aorta and in the bilateral main proximal renal arteries demonstrated no statistical significance (p>0.05). Only the main distal renal artery of the left kidney in protocol B was statistically significant (p<0.046). In the venous circulation, the IVC demonstrated a significant reduction in opacification in protocol B (59.39 HU ± 19.39) compared to A (87.74 HU ± 34.06) (p<0.001). Mean CNR for protocol A (22.68 HU ± 13.72) was significantly higher than that of protocol B (14.75 HU ± 5.76 p<0.0001). Effective dose was significantly reduced in protocol B (2.46 ± 0.74 mSv) compared to A (3.07 ± 0.68 mSv) (p<0.001). Mean contrast media volume was reduced in protocol B (44.56 ± 14.32 mL) with lower iodine concentration. ROC analysis demonstrated significantly higher area under the ROC curve for protocol B (p<0.0001), with inter-reader agreement increasing from moderate to excellent in renal arterial visualization., Conclusion: Employing a patient-tailored contrast media injection protocol shows a significant refinement in the visualization of renal vasculature and reader confidence during renal CTA., Competing Interests: None declared., (Copyright® by the International Brazilian Journal of Urology.)

Coronary anomalies occur in about 1% of the general population and in severe cases can lead to sudden cardiac death. Coronary computed tomography angiography and magnetic resonance imaging have been deemed appropriate for the evaluation of coronary anomalies by accurately allowing the noninvasive depiction of coronary artery anomalies of origin, course, and termination. The aim of this article is to describe and illustrate a comprehensive array for the classification of coronary artery anomalies.

Human hydatid cyst disease is an international public health issue that particularly affects the developing countries. In this article, we discuss the epidemiology of hydatid disease in third world countries, the life cycle of echinococcus granulosus and how to make the clinical diagnosis of the disease, including laboratory tests and imaging modalities as well as uncommon presentation of this entity that we have encountered at the American University of Beirut Medical Center (AUBMC). We emphasize on the new World Health Organization classification of hepatic echinococcosis with examples from our clinical practice at AUBMC, and finally we describe the treatment, including medical and interventional therapies.

Objective: To investigate the visualization of mediastinal lymph nodes during thoracic CT employing a multiphasic contrast media (CM) protocol., Methods: Institutional review board approved retrospective study consisting of 300 patients with known chest malignancy. Patients were allocated to one of two CM protocols: Protocol A, consisted of dual bolus (Phase 1:100 ml CM followed by 100 ml saline chaser) i.v. injected at 2.5 ml s -1 ; Protocol B employed 100 ml of CM using a multiphasic injection protocol (Phase 1 and 2:60 ml contrast and saline, followed by Phase 3 and 4:40 ml contrast and saline injected at 2.5 ml s -1 ) with a fixed scan delay of 70 s for each acquisition. Attenuation profiles of the thoracic arteries and veins were calculated as well as the arterio-venous contrast ratios (AVCR). Receiver operating characteristic (ROC), visual grading characteristic (VGC), and Cohen's kappa analysis were assessed., Results: Arterial opacification was up to 24% (p < 0.032) higher in protocol B than A, whereas, in the veins it was significantly lower in protocol B than A, with a maximum reduction of up to 84% (p < 0.0001). There was no statistical significance between the central and peripheral pulmonary arteries [>263 Hounsfield units (HU)] in each protocol. Protocol B, demonstrated significant improvement in AVCR at various anatomical sites (p < 0.002). Radiation dose was significantly reduced in protocol B compared to A (p < 0.004). Both ROC and VGC demonstrated significantly higher Az score for protocol B compared to A (p < 0.0001) with an increased inter reader agreement from poor to excellent., Conclusion: Employing a multiphasic CM protocol significantly improves opacification of the thoracic vasculature and visualization of mediastinal lymph nodes during thoracic CT., Advances in Knowledge: Uniform opacification between thoracic arteries and veins increases the delineation between vasculature and lymph nodes, reduces radiation dose when employing a multiphase contrast media injection protocol.

The pathogenesis of multiple sclerosis is characterized by a cascade of pathobiologic events, ranging from focal lymphocytic infiltration and microglia activation to demyelination and axonal degeneration. MS has several of the hallmarks of an inflammatory autoimmune disorder, including breakdown of the BBB. Gadolinium-enhanced MR imaging is currently the reference standard to detect active inflammatory lesions in MS. Knowledge of the patterns and mechanisms of contrast enhancement is vital to limit the radiologic differential diagnosis in the staging and evaluation of MS lesion activity. The aim of this review was the following: 1) to outline the pathophysiology of the effect of lymphocyte-driven inflammation in MS, 2) to describe the effects of gadolinium on the BBB and glymphatic system, and 3) to describe gadolinium enhancement patterns and artifacts that can mimic lesions in MS., (© 2018 by American Journal of Neuroradiology.)

Objective: To evaluate the performance of non-contrast computed tomography (CT) by reporting the difference in attenuation between normal and inflamed renal parenchyma in patients clinically diagnosed with acute pyelonephritis (APN)., Material and Methods: This is a retrospective study concerned with non-contrast CT evaluation of 74 patients, admitted with a clinical diagnosis of APN and failed to respond to 48h antibiotics treatment. Mean attenuation values in Hounsfield units (HU) were measured in the upper, middle and lower segments of the inflamed and the normal kidney of the same patient. Independent t-test was performed for statistical analysis. Image evaluation included receiver operating characteristic (ROC), visual grading characteristic (VGC) and kappa analyses., Results: The mean attenuation in the upper, middle and lower segments of the inflamed renal cortex was 32%, 25%, and 29% lower than the mean attenuation of the corresponding cortical segments of the contralateral normal kidney, respectively (p<0.01). The mean attenuation in the upper, middle, and lower segments of the inflamed renal medulla was 48%, 21%, and 30%, lower than the mean attenuation of the corresponding medullary segments of the contralateral normal kidney (p<0.02). The mean attenuation between the inflamed and non-inflamed renal cortex and medulla was 29% and 30% lower respectively (p<0.001). The AUCROC (p<0.001) analysis demonstrated significantly higher scores for pathology detection, irrespective of image quality, compared to clinical and laboratory results with an increased inter-reader agreement from poor to substantial., Conclusion: Non-contrast CT showed a significant decrease in the parenchymal density of the kidney affected with APN in comparison to the contralateral normal kidney of the same patient. This can be incorporated in the diagnostic criteria of APN in NCCT in the emergency setting., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: The aim of this article was to investigate the opacification of the renal vasculature and the urogenital system during computed tomography urography by using a quadruple-phase contrast media in a triphasic scan protocol., Materials and Methods: A total of 200 patients with possible urinary tract abnormalities were equally divided between 2 protocols. Protocol A used the conventional single bolus and quadruple-phase scan protocol (pre, arterial, venous, and delayed), retrospectively. Protocol B included a quadruple-phase contrast media injection with a triphasic scan protocol (pre, arterial and combined venous, and delayed), prospectively. Each protocol used 100 mL contrast and saline at a flow rate of 4.5 mL. Attenuation profiles and contrast-to-noise ratio of the renal arteries, veins, and urogenital tract were measured. Effective radiation dose calculation, data analysis by independent sample t test, receiver operating characteristic, and visual grading characteristic analyses were performed., Results: In arterial circulation, only the inferior interlobular arteries in both protocols showed a statistical significance (P < 0.05). Venously, the inferior vena cava, proximal and distal renal veins demonstrated a significant opacification reduction in protocol B than in protocol A (P < 0.001). Protocol B showed a significantly higher mean contrast-to-noise ratio than protocol A (protocol B: 22.68 ± 13.72; protocol A: 14.75 ± 5.76; P < 0.001). Radiation dose was significantly reduced in protocol B (7.38 ± 2.22 mSv) than in protocol A (12.28 ± 2.72 mSv) (P < 0.001). Visual grading characteristic (P < 0.027) and receiver operating characteristic (P < 0.0001) analyses demonstrated a significant preference for protocol B., Conclusions: In computed tomography urography, augmented quadruple-phase contrast media and triphasic scan protocol usage increases the image quality at a reduced radiation dose.

Coronary CT angiography (CCTA) has the advantage over invasive coronary angiography in that its non-invasive nature and minimal risk on patients. CCTA enables accurate assessment of the entire heart, coronary artery system and thorax, displaying three-dimensional information about the spatial relations of the anomalous vessels and surrounding intraluminal and extraluminal anatomy, and thereby contributing clinically important prognostic information. Dual left anterior descending (LAD) coronary artery consists of of two LAD arteries within the anterior interventricular sulcus (AIVS). Type 4 is infrequently reported subtype and differs from the others, with a long LAD originating from the right coronary artery (Mercado, A., Johnson Jr, G., Calver, D., & Sokol, R. J. (1989). Cocaine, pregnancy, and postpartum intracerebral hemorrhage. Obstetrics & Gynecology , 73 (3, Part 2), 467-468. and the short LAD originating from the left main coronary artery. However, the radiological features between the short LAD and septal coronary arteries remain a controversy, with the latter being determined by CCTA. We present a case report based on short LAD terminating proximally in the AIVS and the long LAD originating from the RCA and terminating into the distal AIVS with the later having a long septal travelling parallel to the long LAD.

Clinical Relevance Statement: Caudocranial scan direction and contrast injection timing based on measured patient vessel dynamics can significantly improve arterial and aneurysmal opacification and reduce both contrast and radiation dose in the assessment of thoracic aortic aneurysms (TAA) using helical thoracic computed tomography angiography (CTA)., Objectives: To investigate opacification of the thoracic aorta and TAA using a caudocranial scan direction and a patient-specific contrast protocol., Materials and Methods: Thoracic aortic CTA was performed in 160 consecutive patients with suspected TAA using a 256-slice computed tomography scanner and a dual barrel contrast injector. Patients were subjected in equal numbers to one of two contrast protocols. Patient age and sex were equally distributed across both groups. Protocol A, the department's standard protocol, consisted of a craniocaudal scan direction with 100 mL of contrast, intravenously injected at a flow rate of 4.5 mL/s. Protocol B involved a caudocranial scan direction and a novel contrast formula based on patient cardiovascular dynamics, followed by 100 mL of saline at 4.5 mL/s. Each scan acquisition comprised of 120 kVp, 200 mA with modulation, temporal resolution 0.27 seconds, and pitch 0.889:1. The dose length product was measured between each protocol and data generated were compared using Mann-Whitney U nonparametric statistics. Receiver operating characteristic analysis, visual grading characteristic (VGC), and κ analyses were performed., Results: Mean opacification in the thoracic aorta and aneurysm measured was 24 % and 55%, respectively. The mean contrast volume was significantly lower in protocol B (73 ± 10 mL) compared with A (100 ± 1 mL) (P<0.001). The contrast-to-noise ratio demonstrated significant differences between the protocols (protocol A, 18.2 ± 12.9; protocol B, 29.7 ± 0.61; P < 0.003). Mean effective dose in protocol B (2.6 ± 0.4 mSv) was reduced by 19% compared with A (3.2 ± 0.8 mSv) (P < 0.004). Aneurysmal detectability demonstrated significant increases by receiver operating characteristic and visual grading characteristic analysis for protocol B compared with A (P < 0.02), and reader agreement increased from poor to excellent., Conclusions: Significant increase in the visualization of TAAs following a caudocranial scan direction during helical thoracic CTA can be achieved using low-contrast volume based on patient-specific contrast formula.

This article evaluates the most relevant state-of-the-art magnetic resonance (MR) techniques that are clinically available to investigate multiple sclerosis (MS). The presence of hypo- and hyperintense lesions on T1- and T2-weighted magnetic resonance imaging (MRI) sequences in white matter (WM) is a common finding that is occasionally a diagnostic challenge for the radiologist. The technical requirements and how they may help to understand, classify or follow-up these pathologies are briefly summarized. The gold standard for MS diagnosis is pathological correlation. Yet due to limited availability of biopsy and autopsy material, there is a high demand for imaging as a diagnostic as well as prognostic indicator. With the progress in MRI during the last decade, MRI now plays a leading role in the diagnosis and follow-up of MS. A number of correlative pathological and MR studies have helped to define pathological substrates of MS in focal lesions and normal appearing white matter (NAWM). Vascular spaces mimicking MS lesions have been minimized by the enhanced differentiation of WM and grey (GM) matter parenchyma. The aim of this article is to enhance the current understanding of histopathology and radiological characteristics of MS lesions in space and time., (© 2016 The Royal Australian and New Zealand College of Radiologists.)

Clinical Relevance: Matching contrast injection timing with vessel dynamics significantly improves vessel opacification and reduces contrast dose in the assessment of pulmonary embolism during computed tomography (CT) pulmonary angiography., Purpose: The aim of this study was to investigate opacification of the pulmonary vasculature (PV) during CT pulmonary angiography using a patient-specific contrast formula (PSCF) and exponentially decelerated contrast media (EDCM) injection rate., Materials and Methods: Institutional review board approved this retrospective study. Computed tomography pulmonary angiography was performed on 200 patients with suspected pulmonary embolism using a 64-channel CT scanner. Patient demographics were equally distributed. Patients were randomly assigned to 2 equal protocol groups: protocol A used a PSCF, and protocol B involved the use of a PSCF combined with EDCM. The mean cross-sectional opacification profile of 8 central and 11 peripheral PVs were measured for each patient, and arteriovenous contrast ratio was calculated. Protocols were compared using Mann-Whitney U nonparametric statistics. Jackknife alternative free-response receiver operating characteristic analyses were used to assess diagnostic efficacy. Interobserver variations were investigated using kappa methods., Results: A number of pulmonary arteries demonstrated increases in opacification (P < 0.02) for protocol B compared with A, whereas opacification in all veins was reduced in protocol B (P < 0.03). Subsequently, increased arteriovenous contrast ratio in protocol B compared with A was observed at all anatomic locations (P < 0.0002). An increase in jackknife alternative free-response receiver operating characteristic figure of merit (P < 0.0002) and interobserver variation was observed with protocol B compared with protocol A (κ = 0.3-0.73). Mean contrast volume was reduced in protocol B (29 [4] mL) compared with protocol A (33 [9] mL). Mean effective radiation dose in protocol B (1.2 [0.4] mSv) was reduced by 14% compared with protocol A (1.4 [0.6] mSv)., Conclusions: Significant improvements in visualization of the PV can be achieved with a low contrast volume using an EDCM and PSCF. The reduced risk of cancer induction is highlighted.

Purpose: To investigate opacification of head and neck vasculature during computed tomography (CT) of supraclavicular lymph nodes with a quadruple-phase contrast media and saline dual-injection protocol., Materials and Methods: This retrospective study was institutional review board approved. In 180 consecutive patients, routine head and neck CT was performed with one of two protocols: protocol A, craniocaudal scan direction with 100 mL of contrast material injected intravenously as a single bolus; or protocol B, 100 mL of contrast material injected in four phases (phases 1-2, 60 mL of contrast material and saline injected at 2.5 mL/sec; phases 3-4, 40 mL of contrast material and saline injected at 2.5 mL/sec); both protocols had a fixed scan delay of 70 seconds. Attenuation of supraclavicular arteries and veins was measured with arteriovenous contrast ratio (AVCR) and contrast-to-noise ratio (CNR). Effective dose was calculated. Data were compared with the two-sample t test. Receiver operating characteristic (ROC) and visual grading characteristic analyses were performed., Results: Arterial attenuation was up to 20% higher (P < .05) after protocol B (mean ± standard deviation, 234.5 HU ± 33.2) than protocol A (160.0 HU ± 29.5). Venous system attenuation was significantly lower in protocol B (164.0 HU ± 17.0) than in protocol A (664.0 HU ± 12.0), with up to a 75% reduction (P < .0001). Protocol B generated significant (P < .0001) improvements in AVCR at multiple anatomic sites. At all anatomic levels, mean CNR with protocol B (34.4 HU ± 9.0) was significantly higher than that with protocol A (14.5 HU ± 14.0) (P < .0313). Effective dose was significantly reduced with protocol B (2.6 mSv ± 0.4 vs 3.2 mSv ± 0.8 with protocol A; P < .0041). ROC analysis demonstrated significantly higher area under the ROC curve for protocol B (P < .0022), with interreader agreement increasing from poor to excellent in lymph node visualization., Conclusion: Significant improvement in lymph node visualization at the cervicothoracic junction is achieved with a quadruple-phase contrast media injection protocol., ((©) RSNA, 2015.)

Background: A patient with a history of mitral valve prolapse and regurgitation that was corrected with a mitral ring repair 15 years earlier received a diagnosis of anomalous left coronary artery arising from the pulmonary artery and underwent repair., Discussion: Coronary computed tomography angiography (CTA) was employed to image the patient before surgical intervention. Synchronizing contrast media administration to opacify the right coronary artery in the arterial phase and the left coronary artery in the venous phase required a test-bolus approach., Conclusion: Matching compromised cardiovascular dynamics with patient-specific contrast media administration protocols was improved considerably with the use of a test-bolus technique during electrocardiography-gated coronary CTA.

Over the last decade, exponential advances in computed tomography (CT) technology have resulted in improved spatial and temporal resolution. Faster image acquisition enabled renal CT angiography to become a viable and effective noninvasive alternative in diagnosing renal vascular pathologies. However, with these advances, new challenges in contrast media administration have emerged. Poor synchronization between scanner and contrast media administration have reduced the consistency in image quality with poor spatial and contrast resolution. Comprehensive understanding of contrast media dynamics is essential in the design and implementation of contrast administration and image acquisition protocols. This review includes an overview of the parameters affecting renal artery opacification and current protocol strategies to achieve optimal image quality during renal CT angiography with iodinated contrast media, with current safety issues highlighted.

Background: Urosepsis is a rare but life-threatening complication following transrectal ultrasound (TRUS) guided needle prostate biopsy. Despite the technological and pharmacological improvements, the problem of bacterial urosepsis after prostate biopsy remains. A strategy for preventing urosepsis following TRUS prostate biopsy in áreas with high prevalence of resistant strains or patients presenting risk factors is lacking., Objectives: The aim of this study was to assess the prevalence of urosepsis, as well its predictors, following TRUS guided needle biopsy of the prostate in a tertiary care medical center in Lebanon., Materials and Methods: We carried out a retrospective study on all patients who underwent TRUS prostate biopsy at the American University of Beirut Medical Center between January 1, 2011 and June 31, 2013. Patients' hospital charts were reviewed. Data collected included demographic information, pre-procedure disease specific information, as well as post-procedure information. Predictors of urosepsis following TRUS were assessed., Results: In total, 265 patients were included in this study, where the prevalence of urosepsis following TRUS prostate biopsy was found to be 9.4%. The significant independente predictors of urosepsis were found to be: age with an OR=0.93 (95% CI: 0.88-1.00, p-value=0.03), and hypertension comorbidity with an OR=3.25 (95% CI: 1.19-8.85, p-value=0.02)., Conclusion: We found a high prevalence of urosepsis among patients who have undergone TRUS prostate biopsy, and identified two significant risk factors. The results of this study highlight the importance of implementing strategies for prevention of urosepsis following TRUS prostate biopsy.

Background: The use of the Coronary Artery Calcium Score (CACS) for risk categorization instead of the Framingham Risk Score (FRS) or European Heart SCORE (EHS) to improve classification of individuals is well documented. However, the impact of reclassifying individuals using CACS on initiating lipid lowering therapy is not well understood. We aimed to determine the percentage of individuals not requiring lipid lowering therapy as per the FRS and EHS models but are found to require it using CACS and vice versa; and to determine the level of agreement between CACS, FRS and EHS based models., Methods: Data was collected for 500 consecutive patients who had already undergone CACS. However, only 242 patients met the inclusion criteria and were included in the analysis. Risk stratification comparisons were conducted according to CACS, FRS, and EHS, and the agreement (Kappa) between them was calculated., Results: In accordance with the models, 79.7% to 81.5% of high-risk individuals were down-classified by CACS, while 6.8% to 7.6% of individuals at intermediate risk were up-classified to high risk by CACS, with slight to moderate agreement. Moreover, CACS recommended treatment to 5.7% and 5.8% of subjects untreated according to European and Canadian guidelines, respectively; whereas 75.2% to 81.2% of those treated in line with the guidelines would not be treated based on CACS., Conclusion: In this simulation, using CACS for risk categorization warrants lipid lowering treatment for 5-6% and spares 70-80% from treatment in accordance with the guidelines. Current strong evidence from double randomized clinical trials is in support of guideline recommendations. Our results call for a prospective trial to explore the benefits/risks of a CACS-based approach before any recommendations can be made.

Multifocal basal ganglia T2-weighted hypointensities are believed to arise mainly from mineralization in and around penetrating arteries and perivascular spaces within gray and white matter structures. Recently, it has been proposed that these hypointensities can serve as a biomarker for small-vessel disease and aging in magnetic resonance imaging when using T2-weighted sequences. With advances in digital coil technology and parameter applications, there has been an increase in image quality and faster examination times. However, artifacts related to higher-field strengths (3.0 T) are reducing image quality. This case report demonstrates reduced focal hypointensities in the basal ganglia by using concentric rectangular blades rotated around the k-space origin to reduce artifacts at 3.0 T., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Surgical portosystemic shunting, the formation of a vascular connection between the portal and systemic venous circulation, has been used as a treatment to reduce portal venous pressure. Although the use of portosystemic shunt surgery in the management of portal hypertension has declined during the past decade in favour of alternative therapies, and subsequently surgeons and radiologists became less familiar with the procedure, it remains a well-established treatment. Knowledge of different types of surgical portosystemic shunts, their pathophysiology and complications will help radiologists improve communication with surgeons and enhance their understanding of the diagnostic and therapeutic role of radiology in the assessment and management of these shunts. Optimal assessment of the shunt is essential to determine its patency and allow timely intervention. Both non-invasive and invasive imaging modalities complement each other in the evaluation of surgical portosystemic shunts. Interventional radiology plays an important role in the management of complications, such as shunt thrombosis and stenosis. This article describes the various types of surgical portosystemic shunts, explains the anatomy and pathophysiology of these shunts, illustrates the pearls and pitfalls of different imaging modalities in the assessment of these shunts and demonstrates the role of radiologists in the interventional management of complications., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: At teaching hospitals, radiology residents give preliminary reports for imaging studies requested from the Emergency Department (ED). Discrepancy rates between preliminary and final reports represent an important performance indicator., Purpose: To present a system for feedback and follow-up of discrepancies, identify the variables associated with the rate and severity of such discrepancies, target the weaknesses, and suggest the need of a standard reference value for comparison among institutions., Material and Methods: A monitoring and communication system between the Department of Diagnostic Radiology and Emergency Department was initiated to mark and follow all studies from the ED for which the official reading was different than the preliminary interpretation. Data analysis was performed on all studies from 1 June 2011 to 31 May 2012, based on the severity of the discrepancy, imaging modality, resident training level, and organ system. The distribution of the number of discrepancies among the different resident levels and imaging modalities was determined, as well as the distribution of three severity scores in correlation with other variables., Results: The overall discrepancy rate was 1.62%. The discrepancy rate was higher for first and second year residents (1.62% and 1.96%) than for third and fourth year residents (1.35% and 1.24%). It was higher for computed tomography (2.13%) than for radiographs (1.29%) and ultrasound (0.8%) (P value < 0.01), and higher for musculoskeletal (1.61%) than non-musculoskeletal (0.99%) radiographs (P value = 0.0003). Discrepancies with severity score one constituted 35.5% of the total discrepancies, those with severity scores two and three constituted 22.9% and 41.6%, respectively., Conclusion: We have demonstrated a system for follow-up of discrepancy in interpreting emergency radiology studies, and recorded the discrepancy rate, with further analysis based on different variables. In terms of quality assurance, a periodical analysis might help to reduce the number of discrepant reports by targeted intervention., (© The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

Purpose: Cardiac magnetic resonance imaging (CMRI) is a novel non-invasive modality with many potential indications, and was recently introduced in Lebanon. We sought to assess the appropriateness and diagnostic yield of CMR studies performed at a tertiary referral center from the Middle East since the inception of the program., Methods: All patients who underwent CMR studies between January 1(st) 2013 and June 18(th) 2014 were enrolled in this study. CMR reports were retrospectively reviewed. The study indication, clinical history, and findings were extracted and analyzed. The appropriateness of the study was judged according to the 2010 updated Asian Society of Cardiac Imaging guidelines., Results: There were a total of 142 patients [mean age 42.1 (SD: 18) years, 24.6% females] that underwent CMR study. Two-thirds of studies were performed on an outpatient basis, and outside referrals constituted 16.2% of the entire cohort. The cardiologists referred 122 cases (86%) with main contribution from electrophysiology and imaging specialists. Of the 142 cases, 12 (8.4%) were not indicated and added little value. Of the remaining 130 appropriate studies (appropriateness level A8-A9), one-third had an incorrect diagnosis prior to CMR, and 8% had relevant findings that were missed on other studies but captured by CMR. Furthermore, CMR confirmed the diagnosis in 28% of the cases, provided relevant information on scar burden, shunt quantification, and ruled out infiltrative disease in the remaining patients. Also, CMR demonstrated the presence of scar in 45 of patients, among whom 20 (44%) had significant scar volume quantification (>5% of left ventricular myocardium). Finally, 9% of patients had a relevant extra-cardiac finding that needed further investigation., Conclusions: Despite the recent launch of the CMR program at our institution, the majority of studies were appropriately indicated, provided relevant data and were clinically useful. Inappropriate or uncertain studies did not provide relevant data, and should be further minimized to avoid unnecessary costs and downstream testing. Large prospective CMR database with clinical follow-up is needed to provide more insight about cardiovascular disease and outcomes in our population.

Objectives: To investigate pulmonary vasculature opacification during CTPA using an optimised patient-specific protocol for administering contrast agent., Methods: CTPA was performed on 200 patients with suspected PE. Patients were assigned to two protocol groups: protocol A, fixed 80 ml contrast agent; protocol B used a patient-specific approach. The mean cross-sectional opacification profile of 8 central and 11 peripheral pulmonary arteries and veins was measured and the arteriovenous contrast ratio (AVCR) calculated. Protocols were compared using Mann-Whitney U non-parametric statistics. Jack-knife alternative free-response receiver-operating characteristic (JAFROC) analyses assessed diagnostic efficacy. Interobserver variations were investigated using kappa methods., Results: A number of pulmonary arteries demonstrated increases in opacification (P < 0.03) for protocol B compared to A, whilst opacification in the heart and veins was reduced in protocol B (P = 0.05). Increased AVCR in protocol B compared with A was observed at all anatomic locations (P < 0.0002). Increased JAFROC (P < 0.0002) and kappa variation were observed with protocol B (κ = 0.78) compared to A (κ = 0.25). Mean contrast volume was reduced in protocol B (33 ± 9 ml) compared to A (80 ± 1 ml)., Conclusions: Significant improvements in visualisation of the pulmonary vasculature can be achieved with a low volume of contrast agent using injection timing based on a patient-specific contrast formula., Key Points: • Optimal opacification of the pulmonary arteries is essential for CT pulmonary angiography. • Matching timing with vessel dynamics significantly improves vessel opacification. • This leads to increased arterial opacification and reduced venous opacification. • This can also lead to a reduced volume of contrast agent.

Vascular anomalies are classified into vascular tumors (infantile hemangioma) and vascular malformations. Vascular malformations are divided into slow flow and high flow subtypes. Magnetic resonance imaging helps in classification and assessing extent and distribution. Conventional angiography also known as digital subtraction angiography is pivotal in assessment of fine vascular details and treatment planning. Imaging correlates well with histopathology. We review recent development in imaging techniques of various vascular anomalies most of which are affecting the peripheral system which potentially may broaden understanding of their diagnosis, classification and treatment.

Purpose: To describe a rapid T2*-weighted (T2*W), three-dimensional (3D) echo planar imaging (EPI) sequence and its application in mapping local magnetic susceptibility variations in 3 Tesla (T) prostate MRI. To compare the sensitivity of T2*W EPI with routinely used T1-weighted turbo-spin echo sequence (T1W TSE) in detecting hemorrhage and the implications on sequences sensitive to field inhomogeneities such as MR spectroscopy (MRS)., Materials and Methods: B(0) susceptibility weighted mapping was performed using a 3D EPI sequence featuring a 2D spatial excitation pulse with gradients of spiral k-space trajectory. A series of 11 subjects were imaged using 3T MRI and combination endorectal (ER) and six-channel phased array cardiac coils. T1W TSE and T2*W EPI sequences were analyzed quantitatively for hemorrhage contrast. Point resolved spectroscopy (PRESS MRS) was performed and data quality was analyzed., Results: Two types of susceptibility variation were identified: hemorrhagic and nonhemorrhagic T2*W-positive areas. Post-biopsy hemorrhage lesions showed on average five times greater contrast on the T2*W images than T1W TSE images. Six nonhemorrhage regions of severe susceptibility artifact were apparent on the T2*W images that were not seen on standard T1W or T2W images. All nonhemorrhagic susceptibility artifact regions demonstrated compromised spectral quality on 3D MRS., Conclusion: The fast T2*W EPI sequence identifies hemorrhagic and nonhemorrhagic areas of susceptibility variation that may be helpful in prostate MRI planning at 3.0T., (Copyright © 2011 Wiley-Liss, Inc.)

Creation of a transjugular intrahepatic portosystemic shunt (TIPS) can effectively treat complications of portal hypertension, but excessive shunting can cause life-threatening hepatic encephalopathy and hepatic insufficiency. The present report describes a novel technique that allows for controlled and adjustable flow reduction through the TIPS via partial closure of the shunt with a balloon-mounted covered stent. The method results in clinical improvement of hepatic encephalopathy and hepatic insufficiency and immediate increase in the portosystemic pressure gradient. However, among the four patients described herein, survival beyond 1 year was seen in only one, who underwent liver transplantation after TIPS reduction.

Objective: Transjugular intrahepatic portosystemic shunt (TIPS) creation is an effective method to control portal hypertension. TIPS creations with bare stents have shown limited and unpredictable patency. In nearly all cases of rebleeding or recurrent ascites after TIPS creation, there is shunt stenosis or occlusion. The purpose of this article is to review the biologic and technical factors that predispose to TIPS failure and how the use of an expandable polytetrafluoroethylene (PTFE)-covered-stent has significantly improved TIPS patency., Conclusion: Biologic and technical factors may predispose to shunt failure. The combination of improved technique and expandable PTFE has significantly improved TIPS patency. The need for follow-up venography and secondary interventions has been reduced significantly as a result of improved shunt patency.

The purpose of this paper is to report our experience with the endovascular treatment of crural arterial injuries using transcatheter and direct embolization techniques. A total of eight consecutive patients have been treated during a 7-year period. Six males and two females, mean age 32 years (range, 15-56 years), presented with penetrating trauma to the lower extremities. Mechanisms of injuries were stab wounds in six patients, gun shot wound in one patient, and iatrogenic injury in one patient. Five patients presented with acute trauma, while three patients presented with delayed injuries. Crural arterial injuries encountered included pseudoaneurysms with arteriovenous fistulas (n = 6), pseudoaneurysms with vessel transections (n = 2), and pseudoaneurysm (n = 1). Proximal and distal embolization with coils was used in three cases, proximal embolization with coils in three cases, percutaneous thrombin injection in one case, and liquid n-butyl cyanoacrylate in one case. Complete exclusion of the lesions was accomplished by sacrifice of one crural vessel in seven cases and of two crural vessels in one case. Two cases of delayed injuries required combined coil and liquid embolization techniques for lesion exclusion. A minor complication (groin hematoma) occurred in one patient, no distal ischemia was seen, and no amputations were required. Mean follow-up was 61 days (range, 1-180 days). One pseudoaneurysm treated with thrombin injection recurred and required surgical excision. We conclude that transcatheter embolization alone or in combination with different endovascular techniques is useful in the treatment of traumatic crural vessel injuries.