Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography.

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

Evaluation of a multiparametric renal CT algorithm for diagnosis of clear-cell renal cell carcinoma among small (≤ 4 cm) solid renal masses.

OBJECTIVE: To evaluate a recently proposed CT-based algorithm for diagnosis of clear-cell renal cell carcinoma (ccRCC) among small (≤ 4 cm) solid renal masses diagnosed by renal mass biopsy. METHODS: This retrospective study included 51 small renal masses in 51 patients with renal-mass CT and biopsy between 2014 and 2021. Three radiologists independently evaluated corticomedullary phase CT for the following: heterogeneity and attenuation ratio (mass:renal cortex), which were used to inform the CT score (1-5). CT score ≥ 4 was considered positive for ccRCC. Diagnostic accuracy was calculated for each reader and overall using fixed effects logistic regression modelling. RESULTS: There were 51% (26/51) ccRCC and 49% (25/51) other masses. For diagnosis of ccRCC, area under curve (AUC), sensitivity, specificity, and positive predictive value (PPV) were 0.69 (95% confidence interval 0.61-0.76), 78% (68-86%), 59% (46-71%), and 67% (54-79%), respectively. CT score ≤ 2 had a negative predictive value 97% (92-99%) to exclude diagnosis of ccRCC. For diagnosis of papillary renal cell carcinoma (pRCC), CT score ≤ 2, AUC, sensitivity, specificity, and PPV were 0.89 (0.81-0.98), 81% (58-94%), 98% (93-99%), and 85% (62-97%), respectively. Pooled inter-observer agreement for CT scoring was moderate (Fleiss weighted kappa = 0.52). CONCLUSION: The CT scoring system for prediction of ccRCC was sensitive with a high negative predictive value and moderate agreement. The CT score is highly specific for diagnosis of pRCC. CLINICAL RELEVANCE STATEMENT: The CT score algorithm may help guide renal mass biopsy decisions in clinical practice, with high sensitivity to identify clear-cell tumors for biopsy to establish diagnosis and grade and high specificity to avoid biopsy in papillary tumors. KEY POINTS: • A CT score ≥ 4 had high sensitivity and negative predictive value for diagnosis of clear-cell renal cell carcinoma (RCC) among solid ≤ 4-cm renal masses. • A CT score ≤ 2 was highly specific for diagnosis of papillary RCC among solid ≤ 4-cm renal masses. • Inter-observer agreement for CT score was moderate.

Disparities in Radiologist Fee-For-Service Payments by Gender in Canada.

Objective: To examine differences in fee-for-service (FFS) payments to men and women radiologists in Canada and evaluate potential contributors. Methods: Publicly available FFS radiology billing data was analyzed from British Columbia (BC), Ontario (ON), Prince-Edward Island (PEI) and Nova Scotia (NS) between 2017 and 2021. Data was analyzed by gender on a per-province and national level. Variables evaluated included year, province, procedure billings, and days worked (BC and ON only). The gender pay gap was expressed as the difference in mean billing payments between men and women divided by mean payments to men. Results: Data points from 8478 radiologist years were included (2474 [29%] women and 6004 [71%] men). The unadjusted difference in annual FFS billings between men and women was $126,657. Overall, payments to women were 81% of payments to men with a 19% gender pay gap. The difference in billings between men and women did not change significantly between 2017 and 2021 (range in gender pay gap, 17-21%) but did vary by province (highest gap NS). Compared to men, women worked fewer days per year (weighted mean 218 ± 29 vs 236 ± 25 days/year, P < .001, 8% difference). Conclusion: In an analysis of fee-for-service payments to radiologists in 4 Canadian provinces between 2017 and 2021, payments to women were 81% of payments to men with a 19% gender pay gap. Payments were lower to women across all years evaluated. Women worked 8% fewer days per year on average than men, which did not fully account for the difference in FFS billing payments between men and women. Summary Statement: In an analysis of fee-for-service payments to Canadian radiologists between 2017 and 2021, payments to women were 81% of payments to men with a 19% gender pay gap which is not fully accounted for by time spent working.

Standardized Reporting on the Preoperative CT Assessment of Potential Living Renal Transplant Donors: Can We Create a Universal Report Standard to Meet the Needs of Transplant Urologists?

Purpose: Determine whether standardized template reporting for the preoperative assessment of potential living renal transplant donors improves the comprehensiveness of radiology reports to meet the needs of urologists performing renal transplants. Methods: Urologist and radiologist stakeholders from renal transplant centres in our province ratified a standardized reporting template for evaluation of potential renal donors. Three centres (A, B, and C) were designated "intervention" groups. Centre D was the control group, given employment of a site-specific standardized template prior to study commencement. Up to 100 consecutive CT scan reports per centre, pre- and post-implementation of standardized reporting, were evaluated for reporting specific outcome measures. Results: At baseline, all intervention groups demonstrated poor reporting of urologist-desired outcome measures. Centre A discussed 5/13 variables (38%), Centre B discussed 6/13 variables (46%), and Centre C only discussed 1/13 variables (8%) with ≥90% reliability. The control group exhibited consistent reporting, with 11/13 variables (85%) reported at ≥90% reliability. All institutions in the intervention group exhibited excellent compliance to structured reporting post-template implementation (Centres A = 95%, B = 100%, and C = 77%, respectively). Additionally, all intervention centres demonstrated a significant improvement in the comprehensiveness of reports post-template implementation, with statistically significant increases in the reporting of all variables under-reported at baseline (P > .01). Conclusion: Standardized templates across our province for CT scans of potential renal donors promote completeness of reports. Radiologists can reliably provide our surgical colleagues with needed preoperative anatomy and incidental findings, helping to determine suitable transplant donors and reduce potential complications associated with organ retrieval.

Multicenter Evaluation of Multiparametric MRI Clear Cell Likelihood Scores in Solid Indeterminate Small Renal Masses.

Background Solid small renal masses (SRMs) (≤4 cm) represent benign and malignant tumors. Among SRMs, clear cell renal cell carcinoma (ccRCC) is frequently aggressive. When compared with invasive percutaneous biopsies, the objective of the proposed clear cell likelihood score (ccLS) is to classify ccRCC noninvasively by using multiparametric MRI, but it lacks external validation. Purpose To evaluate the performance of and interobserver agreement for ccLS to diagnose ccRCC among solid SRMs. Materials and Methods This retrospective multicenter cross-sectional study included patients with consecutive solid (≥25% approximate volume enhancement) SRMs undergoing multiparametric MRI between December 2012 and December 2019 at five academic medical centers with histologic confirmation of diagnosis. Masses with macroscopic fat were excluded. After a 1.5-hour training session, two abdominal radiologists per center independently rendered a ccLS for 50 masses. The diagnostic performance for ccRCC was calculated using random-effects logistic regression modeling. The distribution of ccRCC by ccLS was tabulated. Interobserver agreement for ccLS was evaluated with the Fleiss κ statistic. Results A total of 241 patients (mean age, 60 years ± 13 [SD]; 174 men) with 250 solid SRMs were evaluated. The mean size was 25 mm ± 8 (range, 10-39 mm). Of the 250 SRMs, 119 (48%) were ccRCC. The sensitivity, specificity, and positive predictive value for the diagnosis of ccRCC when ccLS was 4 or higher were 75% (95% CI: 68, 81), 78% (72, 84), and 76% (69, 81), respectively. The negative predictive value of a ccLS of 2 or lower was 88% (95% CI: 81, 93). The percentages of ccRCC according to the ccLS were 6% (range, 0%-18%), 38% (range, 0%-100%), 32% (range, 60%-83%), 72% (range, 40%-88%), and 81% (range, 73%-100%) for ccLSs of 1-5, respectively. The mean interobserver agreement was moderate (κ = 0.58; 95% CI: 0.42, 0.75). Conclusion The clear cell likelihood score applied to multiparametric MRI had moderate interobserver agreement and differentiated clear cell renal cell carcinoma from other solid renal masses, with a negative predictive value of 88%. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Mileto and Potretzke in this issue.

Progression Rates of LR-2 and LR-3 Observations on MRI to Higher LI-RADS Categories in Patients at High Risk of Hepatocellular Carcinoma: A Retrospective Study.

BACKGROUND. Reported rates of hepatocellular carcinoma (HCC) for LR-2 and LR-3 observations are generally greater than those expected on the basis of clinical experience, possibly reflecting some studies' requirement for pathologic reference. OBJECTIVE. The purpose of this study was to determine rates of progression to higher LI-RADS categories of LR-2 and LR-3 observations in patients at high risk of HCC. METHODS. This retrospective study included 91 patients (64 men, 27 women; mean age, 62 years) at high risk of HCC who had clinically reported LR-2 (n = 55) or LR-3 (n = 36) observations on MRI who also underwent follow-up CT or MRI at least 12 months after the observation was made. A study coordinator annotated the location of a single LR-2 or LR-3 observation per patient on the basis of the clinical reports. Using LI-RADS version 2018 criteria, two radiologists independently assigned LI-RADS categories on the follow-up examinations. Progression rates from LR-2 or LR-3 to higher categories were determined. A post hoc consensus review was performed of observations that progressed to LR-4 or LR-5. Subgroup analyses were performed with respect to presence of prior HCC (n = 34) or a separate baseline LR-5 observation (n = 12). RESULTS. For LR-2 observations, the rate of progression to LR-4 was 0.0% (95% CI, 0.0-6.7%) and to LR-5 was 3.6% (95% CI, 0.4-13.1%) for both readers. For LR-3 observations, the rate of progression to LR-4 was 22.2% (95% CI, 9.6-43.8%) and to LR-5 was 11.1% (95% CI, 3.0-28.4%) for both readers. Fourteen observations progressed to LR-4 or LR-5 for both readers. Post hoc analysis revealed no instances of progression from LR-2 to LR-4; two, from LR-2 to LR-5; eight, from LR-3 to LR-4; and four, from LR-3 to LR-5. The progression rate from LR-3 to LR-5 was higher (p < .001) among patients with (100.0%) than those without (3.0%) a separate baseline LR-5 observation for both readers. The progression rate from LR-2 to LR-5 was not associated with a separate baseline LR-5 observation for either reader (p = .30). Progression rates were not different (p > .05) between patients with versus those without prior HCC. CONCLUSION. On the basis of progression to LR-4 or LR-5, LR-2 and LR-3 observations had lower progression rates than reported in studies incorporating pathology results in determining progression. CLINICAL IMPACT. The findings refine understanding of the clinical significance of LR-2 and LR-3 observations.

Diagnostic and surgical dilemma of cholecystitis that mimics cancer - A case report of xanthogranulomatous cholecystitis.

INTRODUCTION: Xanthogranulomatous cholecystitis (XGC) is a rare and benign chronic inflammatory disease of the gallbladder that can mimic carcinoma on presentation, imaging, and gross pathology. The aim of this case report is to describe the considerations involved in navigating the diagnostic and surgical dilemma of managing XGC in a patient with findings equivocal to gallbladder cancer. PRESENTATION OF CASE: A 64-year-old female patient presented with an incidental, suspicious gallbladder mass on imaging. Due to her asymptomatic presentation and high risk features for carcinoma on imaging, an oncologic, en-bloc resection of the mass involving the gallbladder, liver, wall of duodenum, and hepatic flexure of the colon was performed. On pathological examination, the gallbladder specimen showed marked lymphohistiocytic inflammatory infiltrate of XGC that extended into adjacent structures without dysplasia. The patient had an uncomplicated postoperative course. DISCUSSION: Considerations around management of XGC must include the potential consequences associated with overtreating a benign entity or undertreating a potentially curable malignancy. Imaging findings that may be more suggestive of XGC include continuous mucosal lines and the presence of pericholecystic infiltration or fat stranding. Pitfalls of biopsy include potential tumour spillage and false negative results, especially when both XGC and cancer are present. Intraoperatively, macroscopic examination of the mass can also be misleading. CONCLUSION: Surgeons must ensure that preoperative counselling includes the possibility of both XGC and gallbladder carcinoma, especially when findings are uncharacteristic. XGC must be managed with careful consideration of all findings and multidisciplinary input from a team of surgeons, radiologists, and pathologists.

Editorial on "Diagnostic Efficacy of Contrast-Enhanced MRI in Detecting Residual or Recurrent Hepatocellular Carcinoma After Transarterial Chemoembolization: A Systematic Review and Meta-analysis".

LEVEL OF EVIDENCE: 5 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;52:1029-1030.

Can We Use Administrative Data to Accurately Identify Patients Who Receive a Prostate Biopsy?

PURPOSE: Administrative health data can be a valuable resource for health research. Because these data are not collected for research purposes, it is imperative that the accuracy of codes used to identify patients, exposures, and outcomes is measured. PATIENTS AND METHODS: Code sensitivity was determined by identifying a cohort of men with histologically confirmed prostate cancer in the Ontario Cancer Registry and linking them to the Ontario Health Insurance Plan (OHIP) to determine whether a prostate biopsy code had been claimed. Code specificity was estimated using a random sample of patients at The Ottawa Hospital for whom a prostate biopsy code was submitted to OHIP. A simulation model, which varied the code false-positive rate, true-negative rate, and proportion of code positives in the population, was created to determine specificity under a range of combinations of these parameters. RESULTS: Between 1991 and 2012, 97,369 of 148,669 men with histologically confirmed prostate cancer in the Ontario Cancer Registry had a prostate biopsy code in OHIP within 1 week of their diagnosis (code sensitivity, 86.0%). This increased significantly over time (63.8% in 1991 to 87.9% in 2012). The false-positive rate of the code for index prostate biopsies was 1.9%. The simulation model found that the code specificity exceeded 95% for first prostate biopsy but was lower for secondary biopsies because of more false positives. False positives primarily were related to placement of fiducial markers for patients who received radiotherapy. CONCLUSION: Administrative data in Ontario can accurately identify men who receive a prostate biopsy. The code is less accurate for secondary biopsy procedures and their sequelae.

Internal Hernia after Laparoscopic Roux-en-Y Gastric Bypass: Optimal CT Signs for Diagnosis and Clinical Decision Making.

Purpose To evaluate the accuracy of computed tomography (CT) for diagnosis of internal hernia (IH) in patients who have undergone laparoscopic Roux-en-Y gastric bypass and to develop decision tree models to optimize diagnostic accuracy. Materials and Methods This was a retrospective, ethics-approved study of patients who had undergone laparoscopic Roux-en-Y gastric bypass with surgically confirmed IH (n = 76) and without IH (n = 78). Two radiologists independently reviewed each examination for the following previously established CT signs of IH: mesenteric swirl, small-bowel obstruction (SBO), mushroom sign, clustered loops, hurricane eye, small bowel behind the superior mesenteric artery, and right-sided anastomosis. Radiologists also evaluated images for two new signs, superior mesenteric vein (SMV) "beaking" and "criss-cross" of the mesenteric vessels. Overall impressions for diagnosis of IH were recorded. Diagnostic accuracy and interobserver agreement were calculated, and multivariate recursive partitioning was performed to evaluate various decision tree models by using the CT signs. Results Accuracy and interobserver agreement regarding the nine CT signs of IH showed considerable variation. The best signs were mesenteric swirl (sensitivity and specificity, 86%-89% and 86%-90%, respectively; κ = 0.74) and SMV beaking (sensitivity and specificity, 80%-88% and 94%-95%, respectively; κ = 0.83). Overall reader impression yielded the highest sensitivity and specificity (96%-99% and 90%-99%, respectively; κ = 0.79). The decision tree model with the highest overall accuracy and sensitivity included mesenteric swirl and SBO, with a diagnostic odds ratio of 154 (95% confidence interval [CI]: 146, 161), sensitivity of 96% (95% CI: 87%, 99%), and specificity of 87% (95% CI: 75%, 93%). The decision tree with the highest specificity included SMV beaking and SBO, with a diagnostic odds ratio of 105 (95% CI: 101, 109), sensitivity of 90% (95% CI: 79%, 95%), and specificity of 92% (95% CI: 83%, 97%). Conclusion The decision tree with the highest accuracy and sensitivity for diagnosis of IH included mesenteric swirl and SBO, the model with the highest specificity included SMV beaking and SBO, and the remaining signs showed lower accuracy and/or poor to fair interobserver agreement. Overall reader impression yielded the highest accuracy for diagnosis of IH, likely because alternate diagnoses not incorporated in the models were considered. © RSNA, 2016 Online supplemental material is available for this article.

Pictorial review. Magnetic resonance for radiotherapy management and treatment planning in prostatic carcinoma.

MRI has an important role for radiotherapy (RT) treatment planning in prostate cancer (PCa) providing accurate visualization of the dominant intraprostatic lesion (DIL) and locoregional anatomy, assessment of local staging and depiction of implanted devices. MRI enables the radiation oncologist to optimize RT planning by better defining target tumour volumes (thereby increasing local tumour control), as well as decreasing morbidity (by minimizing the dose to adjacent normal structures). Using MRI, radiation oncologists can define the DIL for delivery of boost doses of RT using a variety of techniques including: stereotactic body radiotherapy, intensity-modulated radiotherapy, proton RT or brachytherapy to improve tumour control. Radiologists require a familiarity with the different RT methods used to treat PCa, as well as an understanding of the advantages and disadvantages of the various MR pulse sequences available for RT planning in order to provide an optimal multidisciplinary RT treatment approach to PCa. Understanding the expected post-RT appearance of the prostate and typical characteristics of local tumour recurrence is also important because MRI is rapidly becoming an integral component for diagnosis, image-guided histological sampling and treatment planning in the setting of biochemical failure after RT or surgery.

The mysterious organ. Spectrum of focal lesions within the splenic parenchyma: cross-sectional imaging with emphasis on magnetic resonance imaging.

Incidental splenic lesions are frequently encountered at imaging performed for unrelated causes. Splenic cysts, hemangiomas, and lymphomatous involvement are the most frequently encountered entities. Computed tomography and sonography are commonly used for initial evaluation with magnetic resonance imaging reserved as a useful problem-solving tool for characterizing atypical and uncommon lesions. The value of magnetic resonance imaging lies in classifying these lesions as either benign or malignant by virtue of their signal-intensity characteristics on T1- and T2-weighted imaging and optimal depiction of internal hemorrhage. Dynamic contrast-enhanced sequences may improve the evaluation of focal splenic lesions and allow characterization of cysts, smaller hemangiomas, and hamartomas. Any atypical or unexplained imaging feature related to an incidental splenic lesion requires additional evaluation and/or follow-up. Occasionally, biopsy or splenectomy may be required for definitive assessment given that some of tumours may demonstrate uncertain biologic behavior.

Mucinous neoplasms of the appendix: a current comprehensive clinicopathologic and imaging review.

Mucinous neoplasms of the appendix are a heterogeneous group of neoplasms ranging from simple mucoceles to complex pseudomyxoma peritonei. Considerable controversy exists on their pathologic classification and nomenclature. Clear understanding of the histopathologic diversity of these neoplasms helps in establishing proper communication between the radiologist, the pathologist and the surgeon. In this article, we present a brief discussion of the current taxonomy and nomenclature of mucinous neoplasms of the appendix followed by a review of their imaging features. Important points including the significance of identifying extra-appendiceal mucin at imaging, the new classification of pseudomyxoma peritonei into low- and high-grade varieties and the significance of simultaneous ovarian and appendiceal neoplasms are highlighted.

Improving safety and operational efficiency in residential care settings with WiFi-based localization.

OBJECTIVES: To assess the effectiveness of a wireless network (WiFi-based) localization system (devices mounted on resident wheelchairs) in decreasing caretaker time spent searching for residents and providing alerts of residents going outdoors in a skilled nursing facility. DESIGN: A controlled study over two 2-month periods approved by the institutional review board. SETTING: A long-term skilled nursing facility in Massachusetts specializing in multiple sclerosis previously instrumented with wireless network infrastructure. PARTICIPANTS: Nineteen residents and 9 staff members at the facility for the first 2-month period; 9 residents and 3 staff members at the facility for the second 2-month period. INTERVENTION: Software was installed on 4 staff computers to display the locations of residents enrolled in the study. This software was made available to enrolled staff for the second half of the first 2-month period and the entirety of the second 2-month study. In the second 2-month study, the software was modified to provide alerts if any 1 of 9 participating "high-risk"' residents went outdoors, and the accuracy of the alert system was evaluated. MEASUREMENTS: In the first 2-month study, 9 staff members recorded the amount of time it took them to locate participating residents (as and when needed during the course of their daily activities). In the second 2-month study, 3 staff members recorded whether outdoor-alerts correctly identified a resident leaving the building or if it was a false alarm. RESULTS: In both phases, participating staff members made frequent use of the system (44 searches and 215 outdoor alerts). Overall, the localization information decreased the average time needed to find residents by about two-thirds (from 311.1 seconds to 110.9 seconds). For outdoor alerts, the system had a false-alarm rate of 9.1% (under normal facility operations); systematic tests of the outdoor-alert system carried out by the authors had a false-negative, or missed-alarm, rate of 1.7%. CONCLUSION: Using timely resident location information can provide significant gains for both operational efficiency (finding residents) and enhanced resident safety (outdoor alerts). This approach may provide an inexpensive alternative for facilities that have sufficient wireless infrastructure; future work should assess its effectiveness in additional settings.

A 20-year experience with urgent percutaneous cardiopulmonary bypass for salvage of potential survivors of refractory cardiovascular collapse.

OBJECTIVE: In-hospital cardiac arrest or refractory shock carries a high mortality despite the use of advanced resuscitative measures. We have implemented an in-hospital, nurse-based, continuously available, percutaneous, venoarterial cardiopulmonary bypass system, also known as extracorporeal life support (ECLS), as an adjunct to resuscitation when initial measures are ineffective. METHODS: In 1986, a system for the rapid initiation of ECLS, was created in which trained critical care nurses primed an ECLS circuit and in-house physicians percutaneously placed required cannulas. From a prospective registry, we assessed long-term survival (LTS) (> or =30 days, cardiopulmonary support weaned), short-term survival (<30 days, CPS weaned), or death on CPS. RESULTS: One hundred fifty patients (age, 57 +/- 17 years) were urgently started on CPS for cardiac arrest (n = 127; witnessed, n = 124; unwitnessed, n = 3) and refractory shock (n = 23). Sixty-nine patients were weaned from CPS, and 81 could not be weaned. Overall, 39 (26.0%) patients achieved LTS with a subsequent Kaplan-Meier median survival of 9.5 years. Duration of CPS was 32 +/- 38 hours for LTS and 21 +/- 38 hours for non-LTS. LTS occurred in 29 (23.4%) of 124 patients started on CPS for witnessed cardiac arrest and 11 (47.8%) of 23 for refractory shock (P < .05). Among patients with CPS initiated in the cardiac catheterization laboratory, LTS was seen in 24 (50.0%) of 48 versus 15 (14.7%) of 102 in patients with CPS initiated in other locations (P < .001). Cardiopulmonary resuscitation times greater than or equal to 30 minutes were associated with lower LTS (P < .05). The most common cause of death during CPS was refractory cardiac dysfunction (39.5%), and the most common cause associated with short-term survival was neurologic/pulmonary dysfunction (53.6%). Seven patients were bridged to a left ventricular assist device, and 1 subsequently underwent heart transplantation. Multivariate analysis revealed only cardiac catheterization laboratory site of initiation as a significant independent predictor of LTS (P < .01). When dividing the 20-year experience in tertiles, recent recipients have had more common prearrest insertion. Rates of long-term survival have not changed. CONCLUSION: Of patients started on CPS, 46% were weaned, and 26.0% were long-time survivors. Rapid initiation of CPS permits LTS for some inpatients with cardiovascular collapse when initial advanced resuscitation fails. Strategies to improve end-organ function associated with use of CPS should lead to greater LTS. This practical application of inexpensive available technology should be more widely used.