CT-based Bosniak classification of cystic renal lesions: is version 2019 an improvement on version 2005?

OBJECTIVE: To compare the diagnostic performance and inter-reader agreement of the CT-based v2019 versus v2005 Bosniak classification systems for risk stratification of cystic renal lesions (CRL). METHODS: This retrospective study included adult patients with CRL identified on CT scan between 2005 and 2018. The reference standard was histopathology or a minimum 4-year imaging follow-up. The studies were reviewed independently by five readers (three senior, two junior), blinded to pathology results and imaging follow-up, who assigned Bosniak categories based on the 2005 and 2019 versions. Diagnostic performance of v2005 and v2019 Bosniak classifications for distinguishing benign from malignant lesions was calculated by dichotomizing CRL into the potential for ablative therapy (III-IV) or conservative management (I-IIF). Inter-reader agreement was calculated using Light's Kappa. RESULTS: One hundred thirty-nine patients with 149 CRL (33 malignant) were included. v2005 and v2019 Bosniak classifications achieved similar diagnostic performance with a sensitivity of 91% vs 91% and a specificity of 89% vs 88%, respectively. Inter-reader agreement for overall Bosniak category assignment was substantial for v2005 (κ = 0.78) and v2019 (κ = 0.75) between senior readers but decreased for v2019 when the Bosniak classification was dichotomized to conservative management (I-IIF) or ablative therapy (III-IV) (0.80 vs 0.71, respectively). For v2019, wall thickness was the morphological feature with the poorest inter-reader agreement (κ = 0.43 and 0.18 for senior and junior readers, respectively). CONCLUSION: No significant improvement in diagnostic performance and inter-reader agreement was shown between v2005 and v2019. The observed decrease in inter-reader agreement in v2019 when dichotomized according to management strategy may reflect the more stringent morphological criteria. KEY POINTS: • Versions 2005 and 2019 Bosniak classifications achieved similar diagnostic performance, but the specificity of higher risk categories (III and IV) was not increased while one malignant lesion was downgraded to v2019 Bosniak category II (i.e., not subjected to further follow-up). • Inter-reader agreement was similar between v2005 and v2019 but moderately decreased for v2019 when the Bosniak classification was dichotomized according to the potential need for ablative therapies (I-II-IIF vs III-IV).

A meta-analysis comparing the risk of metastases in patients with rectal cancer and MRI-detected extramural vascular invasion (mrEMVI) vs mrEMVI-negative cases.

BACKGROUND: Pathological extramural vascular invasion (EMVI) is an independent prognostic factor in rectal cancer, but can also be identified on MRI-detected extramural vascular invasion (mrEMVI). We perform a meta-analysis to determine the risk of metastatic disease at presentation and after surgery in mrEMVI-positive patients compared with negative tumours. METHODS: Electronic databases were searched from January 1980 to March 2016. Conventional meta-analytical techniques were used to provide a summative outcome. Quality assessment of the studies was performed. RESULTS: Six articles reported on mrEMVI in 1262 patients. There were 403 patients in the mrEMVI-positive group and 859 patients in the mrEMVI-negative group. The combined prevalence of mrEMVI-positive tumours was 0.346(range=0.198-0.574). Patients with mrEMVI-positive tumours presented more frequently with metastases compared to mrEMVI-negative tumours (fixed effects model: odds ratio (OR)=5.68, 95% confidence interval (CI) (3.75, 8.61), z=8.21, df=2, P<0.001). Patients who were mrEMVI-positive developed metastases more frequently during follow-up (random effects model: OR=3.91, 95% CI (2.61, 5.86), z=6.63, df=5, P<0.001). CONCLUSIONS: MRI-detected extramural vascular invasion is prevalent in one-third of patients with rectal cancer. MRI-detected extramural vascular invasion is a poor prognostic factor as evidenced by the five-fold increased rate of synchronous metastases, and almost four-fold ongoing risk of developing metastases in follow-up after surgery.

Screening for thrombophilia does not identify patients at risk of portal or splenic vein thrombosis following laparoscopic splenectomy.

BACKGROUND: Portal and/or splenic vein thrombosis (PSVT) is a potentially lethal complication of splenectomy for hematologic disease. Known risk factors for PSVT include malignancy and splenomegaly. While these patients are believed to be hypercoagulable, the specific mechanism is unclear. The aim of this study is to evaluate whether specific acquired prothrombotic risk factors contribute to the development of PSVT following laparoscopic splenectomy (LS). METHODS: Consecutive patients undergoing LS were prospectively studied between 2005 and 2013. Preoperatively, patients were screened for prothrombotic states and surveillance duplex ultrasonography was performed between 1 week and 1 month postoperatively to assess for PSVT. The association between baseline prothrombotic disorders and PSVT was explored using descriptive statistics. RESULTS: Sixty-eight patients were included in the analysis, and 17 (25 %) of these developed PSVT. There were no differences in patients with and without PSVT with respect to age, body mass index, gender or surgical time. Preoperative spleen size, as determined by diagnostic imaging, and intraoperative blood transfusion were associated with PSVT. Seven of 9 patients (78 %) with massive splenomegaly (>20 cm) developed PSVT compared with 4 of 13 patients (31 %) with moderate splenomegaly (15-20 cm) and 6 of 45 patients (13 %) without (p < 0.001). Abnormalities in baseline prothrombotic screening tests were common, with 52 patients (75 %) demonstrating at least one; however, none were associated with the development of PSVT. CONCLUSION: In patients scheduled for LS, screening for prothrombotic states is not useful to identify patients at risk of development of PSVT. Preoperative spleen size and blood transfusion were predictive of PSVT formation.

Assessment of symptomatic women for early diagnosis of ovarian cancer: results from the prospective DOvE pilot project.

BACKGROUND: Around 90% of deaths from ovarian cancer are due to high-grade serous cancer (HGSC), which is frequently diagnosed at an advanced stage. Several cancer organisations made a joint recommendation that all women with specified symptoms of ovarian cancer should be tested with the aim of making an early diagnosis. In the Diagnosing Ovarian Cancer Early (DOvE) study we investigated whether open-access assessment would increase the rate of early-stage diagnosis. METHODS: Between May 1, 2008, and April 30, 2011, we enrolled women who were aged 50 years or older and who had symptoms of ovarian cancer. They were offered diagnostic testing with cancer antigen (CA-125) blood test and transvaginal ultrasonography (TVUS) at a central and a satellite open-access centre in Montreal, QC, Canada. We compared demographic characteristics of DOvE patients with those of women in the same age-group in the general population of the area, and compared indicators of disease burden with those in patients with ovarian cancer referred through the usual route to our gynaecological oncology clinic (clinic patients). FINDINGS: Among 1455 women assessed, 402 (27·6%) were in the highest-risk age group (≥ 65 years). 239 (16·4%) of 1455 required additional investigations. 22 gynaecological cancers were diagnosed, 11 (50%) of which were invasive ovarian cancers, including nine HGSC. The prevalence of invasive ovarian cancer, therefore, was one per 132 women (0·76%), which is ten times higher than that reported in screening studies. DOvE patients were significantly younger, more educated, and more frequently English speakers than were women in the general population. They also presented with less tumour burden than did the 75 clinic patients (median CA-125 concentration 72 U/mL, 95% CI 12-1190 vs 888 U/mL, 440-1936; p=0·010); Eight (73%) tumours were completely resectable in DOvE patients, compared with 33 (44%) in clinic patients (p=0·075). Seven (78%) of the HGSC in the DOvE group originated outside the ovaries and five were associated with only slightly raised CA-125 concentrations and minimal or no ovarian abnormalities on TVUS. INTERPRETATION: The proportion of HGSC that originated outside the ovaries in this study suggests that early diagnosis programmes should aim to identify low-volume disease rather than early-stage disease, and that diagnostic approaches should be modified accordingly. Although testing symptomatic women may result in earlier diagnosis of invasive ovarian cancer, large-scale implementation of this approach is premature. FUNDING: Canadian Institutes of Health Research, Montreal General Hospital Foundation, Royal Victoria Hospital Foundation, Cedar's Cancer Institute, and La Fondation du Cancer Monique Malenfant-Pinizzotto.

Reduction of Chest Drain Overuse Through Implementation of a Pleural Drainage Order Set.

BACKGROUND AND OBJECTIVES: Small chest drains are used in many centers as the default drainage strategy for various pleural effusions. This can lead to drain overuse, which may be harmful. This study aimed to reduce chest drain overuse. METHODS: We studied consecutive pleural procedures performed in the radiology department before (August 1, 2015, to July 31, 2016) and after intervention (September 1, 2019, to January 31, 2020). Chest drains were deemed indicated or not based on criteria established by a local interdisciplinary work group. The intervention consisted of a pleural drainage order set embedded in electronic medical records. It included indications for chest drain insertion, prespecified drain sizes for each indication, fluid analyses, and postprocedure radiography orders. Overall chest drain use and proportion of nonindicated drains were the outcomes of interest. RESULTS: We reviewed a total of 288 procedures (pre-intervention) and 155 procedures (post-intervention) (thoracentesis and drains). Order-set implementation led to a reduction in drain use (86.5% vs 54.8% of all procedures, P < .001) and reduction in drain insertions in the absence of an indication (from 45.4% to 29.4% of drains, P = .01). The need for repeat procedures did not increase after order-set implementation (22.0% pre vs 17.7% post, P = .40). Complication rates and length of hospital stay did not differ significantly after the intervention. More pleural infections were treated with drain sizes of 12Fr and greater (31 vs 70%, P < .001) after order-set deployment, and direct procedural costs were reduced by 27 CAN$ per procedure. CONCLUSION: Implementation of a pleural drainage order-set reduced chest drain use, improved procedure selection according to clinical needs, and reduced direct procedural costs. In institutions where small chest drains are used as the default drainage strategy for pleural effusions, this order set can reduce chest drain overuse.

Adverse features on rectal MRI identify a high-risk group that may benefit from more intensive preoperative staging and treatment.

BACKGROUND: Magnetic resonance imaging (MRI) is highly accurate in local staging of rectal cancer. It can identify features known to be associated with increased risk of metastatic disease. We evaluated the incidence of synchronous metastatic disease on fludeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) and contrast-enhanced multiple-row detector computed tomography (ceMDCT) in MRI-stratified high- and low-risk rectal cancers. The aim was to determine the incidence of synchronous metastatic disease according to MRI risk features. METHODS: A total of 236 patients with rectal cancer were recruited to a study evaluating FDG-PET/CT. All patients underwent MRI staging and were stratified into high and low risk (high risk: extramural venous invasion, extramural spread of >5 mm or T4, involved circumferential resection margin or intersphincteric plane involved for low rectal tumors). Confirmed metastases were those identified on FDG-PET/CT and ceMDCT. RESULTS: Imaging data were available for 230 (97.5%) of 236 patients. Incidence of confirmed distant metastases was significantly greater in the MRI high-risk group, with 28 (20.7%) of 135 (95% confidence interval [CI] 14.8-28.3), versus the low-risk group, with 4 (4.2%) of 95 (95% CI 1.7-10.3) (odds ratio 6.0, 95% CI 2.0-17.6, P<0.001). CONCLUSIONS: Adverse features found on rectal MRI identify patients at increased risk of synchronous metastatic disease. This group may benefit from additional preoperative investigation for synchronous metastases such as FDG-PET/CT or liver MRI and from alternative neoadjuvant chemotherapy regimens including induction chemotherapy.

Not Every Low-Dose Is Low-Dose: Impact of Revising Low-Dose CT Protocol on Mean Effective Radiation Exposure.

Introduction: According to the American Urological Association imaging guidelines, patients presenting with renal colic should undergo low-dose (LD) rather than standard-dose (SD) noncontrast CT. The aim of the present study was to assess how often physicians ordered LD CT scans and to calculate mean effective radiation exposure (ERE) from CT scans from dose length products, and determine mean cumulative ERE over 1-year follow-up period. Methods: After obtaining ethics approval, a retrospective chart review was conducted for patients with renal colic presenting to the emergency department between August 1, 2015 and July 31, 2016 (Phase I) and between April 1, 2019 and October 1, 2019 (Phase II). All imaging studies performed within 1-year of initial presentation were cataloged. Results: In Phase I, 146 patients, with mean age of 51 years and mean body mass index (BMI) of 28.6 kg/m2, underwent 220 CT scans. In Phase II, 225 patients, with mean age of 55 years and mean BMI of 26.7 kg/m2, underwent 273 CT scans. Urologists were the only physicians ordering LD CT scans and they ordered significantly more LD than SD CT scans (71.3% vs 28.7%, p < 0.001). In Phase II, after revision of LD CT scan protocol in March 2019, the mean ERE per LD CT significantly decreased (6.5 vs 1.6 mSv, p < 0.001). In addition, there were significant differences in mean ERE from LD CT scans between two hospitals in the same health system (1.6 vs 7.8 mSv, p < 0.001). The mean cumulative ERE in Phase II over the 1-year period was 19.3 mSv, with 6.9% of patients exceeding 50 mSv. Conclusions: Although LD CT scans are being ordered, a small percentage of patients continue to exceed the 50 mSv annual threshold. It is important to keep track of mean ERE of LD CT scans and collaborate with medical physicists and the diagnostic imaging department to further refine LD CT scan protocols since not every low-dose is low-dose.

Change in Density Not Size of Esophageal Adenocarcinoma During Neoadjuvant Chemotherapy Is Associated with Improved Survival Outcomes.

BACKGROUND: Changes in the size and density of esophageal malignancy during neoadjuvant chemotherapy (NCT) may be useful in predicting overall survival (OS). The aim of this study was to explore this relationship in patients with adenocarcinoma. METHODS: A retrospective single-centre cohort study was performed. Consecutive patients with esophageal adenocarcinoma who received NCT followed by en bloc resection with curative intent were identified. Pre- and post-NCT computed tomography scans were reviewed. The percentage difference between the greatest tumor diameter, esophageal wall thickness and tumor density was calculated. Multivariate Cox regression analysis identified variables independently associated with OS. A ROC analysis was performed on radiological markers to identify optimal cut-off points with Kaplan-Meier plots subsequently created. RESULTS: Of the 167 identified, 88 (51.5%) had disease of the gastro-esophageal junction and 149 (89.2%) were clinical T3. In total, 122 (73.1%) had node-positive disease. Increased tumor density (HR 1.01 per % change, 95% CI 1.00-1.02, p = 0.007), lymphovascular invasion (HR 3.23, 95% CI 1.34-7.52, p = 0.006) and perineural invasion (HR 2.51, 95% CI 1.03-6.08, p = 0.048) were independently associated with a decrease in OS. Patients who had a decrease in their tumor density during the time they received NCT of ≥ 20% in Hounsfield units had significantly longer OS than those who did not (75.5 months versus 34.4 months, 95% CI 38.83-105.13/18.63-35.07, p = 0.025). CONCLUSIONS: Interval changes in the density, not size, of esophageal adenocarcinoma during the time that NCT are independently associated with OS.

Recommended timing for surveillance ultrasonography to diagnose portal splenic vein thrombosis after laparoscopic splenectomy.

BACKGROUND: Symptomatic portal or splenic vein thrombosis (PSVT) is a rare but potentially lethal complication of laparoscopic splenectomy (LS). While routine postoperative duplex ultrasound surveillance can be used for early detection, the optimal timing is unknown. The aim of this study is to investigate the incidence and progression of asymptomatic PSVT 1 week and 1 month after LS. METHODS: Consecutive patients scheduled for LS for hematologic disease participated in this study. Patients underwent surveillance for PSVT using duplex ultrasonography 1 week and 1 month postoperatively. RESULTS: 43 of 48 patients planning to undergo LS in the study period were enrolled, with 3 subsequently excluded, leaving 40 for further analysis. The indications for LS were benign disease in 31 [19 had immune thrombocytopenia purpura (ITP)] and malignant disease in 9. A hand-assisted technique was used in 12 cases. PSVT was diagnosed in 9/40 patients (22.5%). Seven (77.8%) were diagnosed by 1 week with ultrasound, of whom one had mild symptoms (fever and diarrhea). After anticoagulation, subsequent ultrasounds showed resolution or improvement in all seven patients. Thirty-three patients had a normal ultrasound result at 1 week. One of these patients also had a computed tomography (CT) scan that found a PSVT not seen on ultrasound. Twenty-seven patients returned for follow-up after normal 1-week imaging: 26 patients had an ultrasound at 1 month, with no new PSVT found. One additional patient did not return for subsequent ultrasound until 2 months later, when a new distal SVT was found; ultrasound at 6 months showed complete resolution without treatment. CONCLUSION: The 1-week incidence of PSVT after LS was 8/40 (20%). The high incidence justifies ultrasonographic screening on postoperative day 7. If asymptomatic PSVT has not developed at this time, it is unlikely to develop by 1 month, and subsequent screening ultrasound at 1 month is not required.

CT of the paraumbilical and ensiform veins in patients with superior vena cava or left brachiocephalic vein obstruction.

The purpose of this study was to elaborate on the anastomoses between the paraumbilical and systemic veins, particularly the ensiform veins. The connections with the ensiform veins have received little attention in the anatomical and radiological literature, and remain incompletely described. Too small to be reliably traced in normal CT scans, the paraumbilical veins can dilate in response to increased blood flow from systemic veins in superior vena cava obstruction (SVCO), allowing a study of their arrangement and connections. Collateral paraumbilical veins were therefore analyzed retrospectively in 28 patients with SVCO using CT. We observed inferior and superior groups of collateral vessels in 23/28 (82%) and 17/28 (61%) patients, respectively. Inferior veins ascended towards the liver and drained into portal veins (19/28, 68%) or the umbilical vein (8/28, 29%); superior veins descended and drained into portal veins. The inferior veins (N = 27) could be traced to ensiform veins in almost all of the cases (26/27, 96%), and a little over half (14/27, 52%) were also traceable to subcutaneous and deep epigastric veins. They were opacified by ensiform (25/27, 93%), deep epigastric (4/27, 15%) and subcutaneous (4/27, 15%) veins. The superior veins (N = 17) were supplied by diaphragmatic (13/17, 76%) and ensiform veins (4/17, 24%); the diaphragmatic veins were branches of collateral internal thoracic, left pericardiacophrenic and anterior mediastinal veins. Collateral ensiform veins were observed in 22 patients and anastomosed with internal thoracic (19/22, 86%), superior epigastric (9/22, 41%), diaphragmatic (4/22, 18%), subcutaneous (3/22, 14%) and anterior mediastinal veins (1/22, 5%). These observations show that the paraumbilical veins communicate with ensiform, deep epigastric, subcutaneous and diaphragmatic veins, joining the liver to the properitoneal fat pad, anterior trunk, diaphragm and mediastinum. In SVCO, the most common sources of collateral flow to the paraumbilical veins are the ensiform and diaphragmatic branches of the internal thoracic veins.

Additional and repeated computed tomography in interfacility trauma transfers: Room for standardization.

BACKGROUND: Despite the recommendations of the Advanced Trauma Life Support course of the American College of Surgeons, patients undergo computed tomography (CT) in local hospitals before transfer to a trauma center. The problem of repeat CTs caused by technical and protocol issues is ongoing. The objective is to measure the importance of repeat CTs and CTs involving other body regions. METHODS: All secondary transfers to our level 1 facility with CT at the local hospital over 9 years were reviewed. Patients were considered to have had a repeat CT if the same body region or an another body region was scanned as a part of the initial assessment but not for reasons of clinical follow-up. RESULTS: Of 6,292 patients received from local hospitals, 685 (12%) had undergone 1097 CT scans at the local hospitals. Patients being scanned in local hospitals were sicker (injury severity score: 21 vs 13) and required more intensive care unit admissions (38% vs 29%) and more ventilation (32% vs 22%). Thirty-nine percent of CTs were repeated, and 55% of these patients required imaging of another body part. CONCLUSION: Repeat and additional images remain a major issue in trauma transfers. Improvement requires standardization of CT protocols and change in the approach of local hospitals from "finding and requiring need level 1 trauma center" to "not missing any injuries."

Penile metastasis from rectal cancer by PET/CT.

It is extremely rare for rectal tumors to metastasize to the penis, and when it occurs, it is associated with poor prognosis. The appearance of penile metastasis from rectal primary tumor on PET imaging has not been widely reported. We report a case of a 70-year-old man with previous history of treated stage III adenocarcinoma of the rectum 26 months ago. The restaging 18F-FDG PET/CT scan demonstrated a hypermetabolic mass at the base of his penile shaft. This lesion was confirmed on core biopsy to be a metastatic adenocarcinoma of colorectal origin consistent with the known primary rectal tumor.

Detectability of choledocholithiasis on CT: The effect of positive intraduodenal enteric contrast on portovenous contrast-enhanced studies.

BACKGROUND/AIM: To retrospectively assess the accuracy of intravenous (IV) contrast-enhanced multidetector CT (MDCT) in choledocholithiasis detectability, in the presence and absence of positive intraduodenal contrast. PATIENTS AND METHODS: Over a 3-year period, patients in whom endoscopic retrograde cholangiopancreatography (ERCP) was performed within a week from a portovenous (PV)-enhanced abdominal CT were identified. The final cohort consisted of 48 CT studies in which the entire common bile duct (CBD) length was visualized (19 males, 29 females; mean age, 68 years). We identified two groups according to the absence (n = 31) or presence (n = 17) of positive intraduodenal contrast. CT section thickness ranged from 1.25 to 5 mm. Two radiologists, blinded to clinical information and ERCP results, independently evaluated the CT images. Direct CBD stone visualization was assessed according to previously predefined criteria, correlating with original electronic CT reports and using ERCP findings as the reference standard. A third reader retrospectively reviewed all discordant results. The diagnostic performances of both observers and interobserver agreement were calculated for both groups. RESULTS: 77%-88% sensitivity, 50%-71% specificity, and 71%-74% accuracy were obtained in the group without positive intraduodenal contrast, versus 50%-80% sensitivity, 57%-71% specificity, and 59%-71% accuracy in the group with positive intraduodenal contrast. With the exception of the positive predictive value (PPV), all diagnostic performance parameters decreased in the positive intraduodenal contrast group, mostly affecting the negative predictive value (NPV) (71%-78% vs 50%-67%). CONCLUSION: PV-enhanced MDCT has moderate diagnostic performance in choledocholithiasis detection. A trend of decreasing accuracy was noted in the presence of positive intraduodenal contrast.

Transmural colonic ischemia: clinical features and computed tomography findings.

Our purpose was to describe the computed tomography features of transmural colonic ischemia in correlation with clinical, laboratory and histopathological findings of 14 patients who underwent colectomy (9 female and 5 male; mean age, 68 years). Seven patients died (50%). Transmural necrosis involved the right colon in 10 patients (10/14, or 72%). Eleven patients showed thickened colonic wall (11/14, or 79%), 10 pneumatosis (10/14, or 71%), 5 gas in the portal venous system (5/14, or 36%), and 14 fat stranding (14/14, or 100%).

Development and impact evaluation of an e-learning radiation oncology module.

PURPOSE: Radiation oncologists are faced with the challenge of irradiating tumors to a curative dose while limiting toxicity to healthy surrounding tissues. This can be achieved only with superior knowledge of radiologic anatomy and treatment planning. Educational resources designed to meet these specific needs are lacking. A web-based interactive module designed to improve residents' knowledge and application of key anatomy concepts pertinent to radiotherapy treatment planning was developed, and its effectiveness was assessed. METHODS AND MATERIALS: The module, based on gynecologic malignancies, was developed in collaboration with a multidisciplinary team of subject matter experts. Subsequently, a multi-centre randomized controlled study was conducted to test the module's effectiveness. Thirty-six radiation oncology residents participated in the study; 1920 were granted access to the module (intervention group), and 17 in the control group relied on traditional methods to acquire their knowledge. Pretests and posttests were administered to all participants. Statistical analysis was carried out using paired t test, analysis of variance, and post hoc tests. RESULTS: The randomized control study revealed that the intervention group's pretest and posttest mean scores were 35% and 52%, respectively, and those of the control group were 37% and 42%, respectively. The mean improvement in test scores was 17% (p < 0.05) for the intervention group and 5% (p = not significant) for the control group. Retrospective pretest and posttest surveys showed a statistically significant change on all measured module objectives. CONCLUSIONS: The use of an interactive e-learning teaching module for radiation oncology is an effective method to improve the radiologic anatomy knowledge and treatment planning skills of radiation oncology residents.

[A fractured kidney, an unexpected sequela of a remote lumbar trauma]. / Un rein fracturé, séquelle inattendue d'un ancien traumatisme lombaire.

A 40-year old man is evaluated for arterial hypertension of one's year duration, which responded well to salt restriction and mild antihypertensive medication. The standard investigation for possible secondary hypertension is negative. In view of a remote history of left renal trauma, it is decided to do an angiogram, which reveals the presence of a fractured left kidney. This unusual image is considered to be secondary to the combination of an arterial supply provided by two polar arteries and of scarring in the mid-portion of the renal parenchyma secondary to the remote trauma.

Imaging of Small Bowel Obstruction following Gastric Bypass Surgery for Morbid Obesity: A retrospective review.

OBJECTIVES: This study is a single institution retrospective evaluation of imaging findings of small bowel obstruction (SBO) after retrocolic antegastric Roux-en-Y gastric bypass surgery for morbid obesity. METHODS: The radiological database of 490 patients who underwent gastric bypass surgery for morbid obesity from January 2001-2005 at the Royal Victoria Hospital McGill University Health Center was searched for SBO complications related to the procedure. There were 22 cases of small bowel obstruction related to the procedure. Ten patients had abdominal and pelvic computed tomography (CT) scans, 12 patients had upper gastrointestinal (UGI) and small bowel follow through (SBFT). RESULTS: Among 22 cases of SBO, 14 cases were due to anastomotic stenosis or adhesion, 7 due to internal hernia and one to jejuno-jejunal intussusception. Among the 14 patients with SBO related to adhesion and anastomotic narrowing, 11 patients were managed medically and 3 cases managed surgically. CT scans correctly diagnosed 4 out of 5 cases including the 3 patients managed surgically and UGI and SBFT examinations diagnosed the remaining 9 cases that were managed medically. Among the 7 patients with internal hernias, CT scans correctly diagnosed 2 out of 4 cases, while UGI and SBFT examinations correctly diagnosed 1 out of 3. The jejuno-jejunal intussusception was correctly diagnosed by CT scan. CONCLUSION: The most frequent cause of SBO is anastomotic narrowing or adhesion. CT scan remains the most appropriate imaging modality in diagnosing acute presentation of SBO caused by internal hernia or adhesion/anastomotic narrowing. UGI and SBFT appear more appropriate for diagnosing the subacute insidious presentation of adhesive partial SBO.