Update on Percutaneous Ablation for Sarcoma.

PURPOSE OF REVIEW: To provide an update on the current state of percutaneous thermal ablation in the treatment of sarcoma. RECENT FINDINGS: Data continue to accrue in support of ablation for local control and palliation of specific sarcoma subtypes such as extra-abdominal desmoid fibromatosis and for broader indications such as the treatment of oligometastatic disease. The synergistic possibilities of various combination therapies such as cryoablation and immunotherapy represent intriguing areas of active investigation. Histotripsy is an emerging non-invasive, non-thermal ablative modality that may further expand the therapeutic arsenal for sarcoma treatment. Percutaneous thermal ablation is a valuable tool in the multidisciplinary management of sarcoma, offering a minimally invasive adjunct to surgery and radiation therapy. Although there remains a paucity of high-level evidence specific to sarcomas, ablation techniques are demonstrably safe and effective for achieving local tumor control and providing pain relief in select patients and are of particular benefit in those with metastatic disease or requiring palliative care.

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.

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.

Imaging considerations for thermal and radiotherapy ablation of primary and metastatic renal cell carcinoma.

Ablative (percutaneous and stereotactic) thermal and radiotherapy procedures for management of both primary and metastatic renal cell carcinoma are increasing in popularity in clinical practice. Data suggest comparable efficacy with lower cost and morbidity compared to nephrectomy. Ablative therapies may be used alone or in conjunction with surgery or chemotherapy for treatment of primary tumor and metastatic disease. Imaging plays a crucial role in pre-treatment selection and planning of ablation, intra-procedural guidance, evaluation for complications, short- and long-term post-procedural surveillance of disease, and treatment response. Treatment response and disease recurrence may differ considerably after ablation, particularly for stereotactic radiotherapy, when compared to conventional surgical and chemotherapies. This article reviews the current and emerging role of imaging for ablative therapy of renal cell carcinoma.

Diagnostic Radiology Residency Assessment Tools: A Scoping Review.

PURPOSE: The multifaceted nature of learning in diagnostic radiology residency requires a variety of assessment methods. However, the scope and quality of assessment tools has not been formally examined. A scoping review was performed to identify assessment tools available for radiology resident training and to evaluate the validity of these tools. METHODS: A literature search was conducted through multiple databases and on-line resources. Inclusion criteria were defined as any tool used in assessment of radiology resident competence. Data regarding residents, evaluators and specifics of each tool was extracted. Each tool was subjected through a validation process with a customized rating scale using the 5 categories of validity: content, response process, internal structure, relations to other variables, and consequences. RESULTS: The initial search returned 447 articles; 35 were included. The most evaluated competency being overall knowledge (31%), most common published journal was Academic Radiology (24%); evaluations were most commonly set in the United States (57%). In terms of validation, we found low adherence to modern integrated validity, with 34% of studies including a definition of validity. When specifically examining the 5 domains of validation evidence presented, most were either absent or of low rigor (70%). Only one study presented a modern definition of validation (3%, 1/35). CONCLUSION: We identified 35 evaluation tools covering a variety of competency areas. However, few of these tools have been validated. Development of new validated assessment tools or validation of existing tools is essential for the ongoing transition to a competency-based curriculum.

Delivering CaRMS Transparency: Applicant Review and Selection Process of a Single-Center Diagnostic Radiology Residency Training Program.

PURPOSE: To report the current application review and selection process in our Canadian diagnostic radiology program at the University of Ottawa for both Canadian and international medical graduates. APPLICATION REVIEW AND SELECTION PROCESS: Submitted applications fulfilling institutional requirements were selected for a detailed file review after preliminary screening. A diverse group of file reviewers and interviewers was selected. Interviews were offered based on file review score sheet outcomes. Each interviewer generated a postinterview rank list. Applicants were reviewed and discussed from highest to lowest rank based on a preliminary compiled rank list generated from the average of the postinterview rank lists. Group discussion and a consensus model were used to create a final applicant rank list. CONCLUSIONS: We outlined our systematic, consistent selection process which aligns with current best practices. This description may inform other programs wishing to adopt or optimize strategies to improve candidate assessments and selection processes.

Cadaveric Simulation Training Improves Residents' Knowledge and Confidence in Performing Fluoroscopic Guided Joint Injections.

RATIONALE AND OBJECTIVE: Simulation training has been strongly encouraged to enhance radiology trainees' procedural competency. We aimed to assess whether a cadaveric simulation training session was effective in improving radiology residents' subjective technical ability, knowledge and confidence in performing fluoroscopic-guided joint injections. METHODS: As part of the residency program's procedural training curriculum, first year radiology resident participated in a cadaveric, musculoskeletal injection training session including a didactic lecture followed by a practical hands-on component. Trainees performed fluoroscopic guided hip and shoulder injections on fresh cadavers, supervised by two fellowship-trained musculoskeletal radiologists. Trainees' knowledge on indications, contraindications, preprocedural care, complications, and technical ability in performing the procedures, as well as their rating of overall session experience were evaluated with pre- and post-session questionnaires (5 point Likert-scale). The mean residents' scores for pre- and post-session questionnaire items were calculated and compared using paired t-test. The magnitude of difference between mean pre- and post-session scores was compared between the items using analysis of variance. RESULTS: Results Over a 5-year period, 27 trainees participated in the joint injection simulation session. The mean pre- and post-session scores were significantly higher in the post session questionnaire for all five items pertaining to knowledge of indications, contraindications, preprocedural care, complications, and technical ability (all p < 0.0001). The magnitude of improvement was not different between the items (p = 0.45). Most of the participants rated the training facilities, contents, hands-on experience, teaching quality, and session organization as very good or excellent. CONCLUSIONS: Cadaveric joint injection simulation training significantly improved trainees' subjective knowledge, confidence, and technical ability in performing joint injections.

Gender Disparity Among Leaders of Canadian Academic Radiology Departments.

OBJECTIVE. Underrepresentation of women in the top hierarchy of academic medicine exists despite women comprising more than half of the medical school graduates and residency positions. The purpose of this study is to analyze and quantify the relationship of gender, research productivity, and career advancement in Canadian academic radiology departments. MATERIALS AND METHODS. Seventeen academic radiology departments with affiliated residency programs in Canada were searched for publicly available data on faculty to generate a database for gender and academic profiles of the radiologists. Bibliometric data were collected using Scopus archives. The associations of gender, academic ranks, and leadership positions were assessed, and a p value of ≤ 0.05 was defined as significant. Significant variables were analyzed using a multivariate linear regression model. RESULTS. Of 1266 faculty members, gender information and academic rank were available for 932 faculty members: 597 (64.05%) were men and 335 (35.95%) were women (χ2 = 21.82; p < 0.0001). Of a total of 563 assistant professors, 331 (58.79%) were men and 232 (41.21%) were women; of 258 associate professors, 177 (68.60%) were men and 81 (31.40%) were women; and of 111 professors, 89 (80.18%) were men and 22 (19.82%) were women. The gender gap widens at higher academic ranks, displaying a threefold drop in the ratio of women holding the rank of full professor (6.57%) compared with 14.91% male professors; 29.55% of women radiologists have first-in-command leadership positions compared with 70.45% of men. A comparable or higher h-index is noted for women Canadian radiologists after adjusting for number of citations, number of publications, and years of active research. CONCLUSION. Canadian academic radiology departments have fewer women radiologists in senior faculty and leadership positions. Our study results show that Canadian female radiologists at the professor level have more publications than their male counterparts.

Utility of T1-weighted MRI as a predictor of liver lesion visibility on ultrasound: A clinical tool to determine feasibility of ultrasound-guided percutaneous interventions.

PURPOSE: To determine the utility of fat-suppressed T1-weighted gradient recalled echo (FS-T1W-GRE) MRI to predict visibility of focal liver lesions (FLL) on abdominal ultrasound (US). MATERIALS AND METHODS: With IRB approval, between 2010 and 2013, 109 patients (28.4% females, age 66.9±10.9years) with 177 FLL (hepatocellular carcinoma=132, metastases=44, other=1) underwent MRI and prospective, radiologist-performed treatment-planning US (to determine eligibility for US-guided ablation). MRI examinations were reviewed by a blinded radiologist who assessed: a) size and location of FLL, b) presence of hepatic steatosis on dual-echo T1W-GRE, and c) quantitative signal intensity of FLL relative to liver on FS-T1W-GRE. Associations between MR imaging findings and visibility on US were assessed using independent t-tests and the chi-squares test. RESULTS: 69.5% (123/177) FLL were identified with US and 30.5% (54/177) were not visible. Size of FLL on MRI was associated with visibility on US (p<0.0001) with no association between FLL visibility on US and segmental or subcapsular location (p=0.29 and p=0.25, respectively). 20.2% (22/109) patients had hepatic steatosis on MRI, which was not associated with non-visibility of FLL on US (p=0.67). 38.4% (68/177) FLL were isointense to liver on FS-T1W-GRE which was associated with non-visibility on US (p=0.036) particularly in non-steatotic livers (p=0.014). CONCLUSION: FLL size and isointensity of FLL to liver parenchyma on FS-T1W-GRE MRI are associated with non-visibility on US, particularly in non-steatotic livers. These results have implications when planning US-guided percutaneous interventions of FLL detected with MRI.

Development of RAD-Score: A Tool to Assess the Procedural Competence of Diagnostic Radiology Residents.

OBJECTIVE: The purpose of this study is to develop a tool to assess the procedural competence of radiology trainees, with sources of evidence gathered from five categories to support the construct validity of tool: content, response process, internal structure, relations to other variables, and consequences. SUBJECTS AND METHODS: A pilot form for assessing procedural competence among radiology residents, known as the RAD-Score tool, was developed by evaluating published literature and using a modified Delphi procedure involving a group of local content experts. The pilot version of the tool was tested by seven radiology department faculty members who evaluated procedures performed by 25 residents at one institution between October 2014 and June 2015. Residents were evaluated while performing multiple procedures in both clinical and simulation settings. The main outcome measure was the percentage of residents who were considered ready to perform procedures independently, with testing conducted to determine differences between levels of training. RESULTS: A total of 105 forms (for 52 procedures performed in a clinical setting and 53 procedures performed in a simulation setting) were collected for a variety of procedures (eight vascular or interventional, 42 body, 12 musculoskeletal, 23 chest, and 20 breast procedures). A statistically significant difference was noted in the percentage of trainees who were rated as being ready to perform a procedure independently (in postgraduate year [PGY] 2, 12% of residents; in PGY3, 61%; in PGY4, 85%; and in PGY5, 88%; p < 0.05); this difference persisted in the clinical and simulation settings. User feedback and psychometric analysis were used to create a final version of the form. CONCLUSION: This prospective study describes the successful development of a tool for assessing the procedural competence of radiology trainees with high levels of construct validity in multiple domains. Implementation of the tool in the radiology residency curriculum is planned and can play an instrumental role in the transition to competency-based radiology training.

Local tumor progression patterns after radiofrequency ablation of colorectal cancer liver metastases.

PURPOSE: We aimed to evaluate patterns of local tumor progression (LTP) after radiofrequency ablation (RF ablation) of colorectal cancer liver metastases (CRCLM) and to highlight the percentage of LTP not attributable to lesion size or RF ablation procedure-related factors (heat sink or insufficient ablation margin). METHODS: CRCLM treated by RF ablation at a single tertiary care center from 2004-2012, with a minimum of six months of postprocedure follow-up, were included in this retrospective study. LTP morphology was classified as focal nodular (<90° of ablation margin), circumferential (>270°), or crescentic (90°-270°). Initial metastasis size, minimum ablation margin size, morphology of LTP, presence of a heat sink, and time to progression were recorded independently by two radiologists. RESULTS: Thirty-two of 127 RF ablation treated metastases (25%) with a mean size of 23 mm (standard deviation 12 mm) exhibited LTP. Fifteen of 32 LTPs (47%) were classified as focal nodular, with seven having no procedure-related factor to explain recurrence. Ten of 32 LTPs (31%) were circumferential, with four having no procedure-related factor to explain recurrence. Seven of 32 LTPs (22%) were crescentic, with two having no procedure-related factor to explain recurrence. Of the 13 lesions without any obvious procedure-related reason for LTP, six (46%) were <3 cm in size. CONCLUSION: Although LTP in RF ablation treated CRCLM can often be explained by procedure-related factors or size of the lesion, in this study up to six (5%) of the CRCLM we treated showed LTP without any reasonable cause.

How Competitive Is the Canadian Diagnostic Radiology Residency Match? Application and Matching Trends From 1991-2014.

PURPOSE: The study sought to evaluate application trends in Canadian diagnostic radiology residency programs and to assess the relative competitiveness of radiology as a specialty. METHODS: The Canadian Residency Matching Service Reports from 1991-2014 for Canadian graduates were used to extract the total residency positions and radiology residency positions, number of applicants to all specialties and to radiology, number of first-choice radiology applicants, number of unmatched radiology positions, and number of positions and applicants to each specialty. Ratios were calculated: radiology positions to applicants and first-choice applicants, first-choice radiology applicants to applicants for all specialties, and training positions to applicants in each specialty. Data trends and correlation coefficients were analysed. RESULTS: The number of radiology residency positions offered increased, with strong positive correlation (r = 0.91, P < .001), while the number of applicants increased with only a moderate positive correlation (r = 0.49, P = .03). Radiology was the most competitive in 1997, with a ratio of 0.32 positions/applicant. There was an increase of positions/applicant over time (decreasing competitiveness; r = 0.76, P < .001) but no change in positions/first-choice applicant (r = 0.11, P = .65). The highest percentage of applicants who ranked radiology as their first choice was in 2003 at 6.5% with a decrease in this percentage over time (r = -0.36, P = .13). Radiology is moderately competitive for positions/overall applicants and very competitive for positions/first-choice applicants compared to other specialties. CONCLUSIONS: The number of radiology residency positions has increased while the number of applicants has not grown commensurately. The match was most competitive in 1997, and decreased in subsequent years. Possible reasons include job market, reimbursement, and work environment.

Focal Nodular Hyperplasia and Hepatocellular Adenoma: Accuracy of Gadoxetic Acid-enhanced MR Imaging--A Systematic Review.

PURPOSE: To perform a systematic review to evaluate the diagnostic accuracy of hepatobiliary (HPB) phase gadoxetic acid-enhanced MR imaging of the liver in the diagnosis of focal nodular hyperplasia (FNH) versus hepatocellular adenoma (HCA) and to identify the rate of (a) reported HCAs that are iso- or hyperintense to liver and (b) reported FNHs that are hypointense to liver on HPB phase MR images. MATERIALS AND METHODS: The institutional review board granted a waiver for this study type, and multiple databases were searched for studies in which researchers distinguished between FNH and HCA with gadoxetic acid-enhanced MR imaging. Studies to evaluate diagnostic accuracy were included; case reports and series were included to analyze the rate of iso- or hyperintense HCAs on HPB phase MR images. Risk of bias was assessed by using the Quality Assessment Tool for Diagnostic Accuracy Studies-2. Sensitivity and specificity were plotted with a forest plot; pooling was not performed because a small number of heterogeneous studies were included. Rate of iso- or hyperintense HCA on HPB phase gadoxetic acid-enhanced MR images was evaluated. RESULTS: Six studies (309 patients; 164 with HCA, 233 with FNH) were included for diagnostic accuracy assessment. Twelve case series (129 patients; 81 with HCA, 70 with FNH) were included (studies with insufficient 2 × 2 table data for diagnostic accuracy assessment). Sensitivity was high (range, 0.91-1.00; lower margin of the 95% confidence interval: 0.77). Specificity was high (range, 0.87-1.00; lower margin of the 95% confidence interval: 0.54). Specificity was lowest among studies in which molecular subtyping of HCA was performed. Rate of iso-or hyperintensity of HCA on HPB phase MR images was variable (range, 0%-67%) and occurred more frequently in the inflammatory subtype. High risk of bias was identified in the domains of patient selection and reference standard. CONCLUSION: The reported diagnostic accuracy of HPB phase gadoxetic acid-enhanced MR imaging in the diagnosis of HCA versus FNH is high; however, studies are few, heterogeneous, and at high risk for bias, indicating that diagnostic accuracy may be overestimated.

Duplicate publication in radiology journals.

OBJECTIVE: The purpose of this study is to evaluate the rate of duplicate publication in radiology journals. The secondary objective is to evaluate the sensitivity of iThenticate. MATERIALS AND METHODS: From January 1993 to December 2013, Déjà Vu (a database of highly similar citations) and PubMed were used to search for similar citations in 53 radiology journals. Citations were screened independently by two reviewers and verified by a third using predefined criteria to determine true cases of duplicate publication. The overall rate of duplicate publication was calculated; analysis of rate by journal, impact factor, and publication year was performed. The sensitivity of iThenticate was evaluated by analyzing all identified duplicate publications. RESULTS: From 128,818 citations in the included journals, 1786 (Déjà Vu) and 104 (PubMed) were flagged as potential duplicates. Of these, 248 (226 from Déjà Vu and 22 from PubMed) were classified as true duplicate publications after application of our criteria. The overall rate was 1.92/1000 citations; it varied widely across journals from zero to over 10/1000 citations, showed no correlation with impact factor (R(2) = 0.06; p = 0.093), and no change over time (R(2) = 0.28; p = 0.515). iThenticate flagged 153 of 248 (61.9%) duplicates as "possible duplicates" (defined as overall percentage match > 30%) and identified the corresponding duplicate citation pair in 140 of 248 (56.7%) cases; in 98 of these, the duplicate citation pair was the highest percentage similarity match. CONCLUSION: Duplicate publications in radiology journals are uncommon. The rate varies widely between journals, but was not associated with journal impact factor and did not change over time. iThenticate shows promise for identification of duplicate publications; however, refinements may be necessary to maximize its effectiveness.

Myocardial metastases from renal cell carcinoma mimicking ischemia on myocardial perfusion scintigraphy.

A 60-year-old man with history of metastatic renal cell carcinoma and atypical chest pain was referred for dipyridamole Tc-tetrofosmin perfusion scintigraphy (MPS). Two years earlier, the patient was noted to have myocardial metastases on cardiac MRI. On the MPS, perfusion defects were present at stress in multiple vascular territories; resting myocardial uptake was homogeneous. These findings suggested multivessel atherosclerotic heart disease. In fact, retrospective rigid fusion with prior chest CT and cardiac MRI demonstrated that the reversible perfusion defects corresponded to metastatic deposits in the myocardium. This unusual case illustrates how myocardial metastases can mimic ischemia on MPS.