Clinical indications, safety, and effectiveness of percutaneous image-guided adrenal mass biopsy: an 8-year retrospective analysis in 160 patients

PURPOSE

To assess indications, safety, and effectiveness of percutaneous adrenal mass biopsy in contemporary practice.

METHODS

This institutional review board-approved, retrospective study included all patients undergoing percutaneous image-guided adrenal mass biopsies at an academic health system from January 6, 2015, to January 6, 2023. Patient demographics, biopsy indications, mass size, laboratory data, pathology results, and complications were recorded. Final diagnoses were based on pathology or ≥ 1 year of imaging follow-up when biopsy specimens did not yield malignant tissue. Test performance calculations excluded repeat biopsies. Continuous variables were compared with Student's t test, dichotomous variables with chi-squared test.

RESULTS

A total of 160 patients underwent 186 biopsies. Biopsies were indicated to diagnose metastatic disease (139/186; 74.7%), for oncologic research only (27/186; 14.5%), diagnose metastatic disease and oncologic research (15/186; 8%), and diagnose an incidental adrenal mass (5/186; 2.7%). Biopsy specimens were diagnostic in 154 patients (96.3%) and non-diagnostic in 6 (3.8%). Diagnostic biopsies yielded malignant tissue (n = 136), benign adrenal tissue (n = 12), and benign adrenal neoplasms (n = 6) with sensitivity = 98.6% (136/138), specificity = 100% (16/16), positive predictive value = 100% (136/136), and negative predictive value = 88.9% (16/18). Adverse events followed 11/186 procedures (5.9%) and most minor (7/11, 63.6%). The adverse event rate was similar whether tissue was obtained for clinical or research purposes (10/144; 6.9% vs. 1/42; 2.4%, p = 0.27), despite more specimens obtained for research (5.8 vs. 3.7, p < 0.001).

CONCLUSION

Percutaneous adrenal mass biopsy is safe, accurate, and utilized almost exclusively to diagnose metastatic disease or for oncologic research. The negative predictive value is high when diagnostic tissue samples are obtained. Obtaining specimens for research does not increase adverse event risk.

Transitioning from interventional radiology: ideas for the inevitable

BACKGROUND

Interventional Radiology (IR) is a highly rewarding specialty, both for its salutary effects for patients, as will as the satisfaction it provides for the operating radiologists. Nonetheless, arduous work and long hours have led to numerous reports of burnout amongst interventional radiologists (IRs).

MATERIALS AND METHODS

Six long-term academic radiologists in leadership positions briefly chronicle their becoming IRs, their type of transitioning from IR, and the pros and cons of those respective transitions.

RESULTS

The specific transitions include reduced time in IR, switching to diagnostic radiology, becoming involved in medical school education, ceasing IR leadership, and retirement. Pros and cons of the various transition strategies are highlighted.

CONCLUSION

As the taxing work and long hours are so ubiquitous for IRs, and as burnout is so common, transitioning from IR is highly likely eventually for IRs. The varied transition experiences highlighted in this report hopefully will be helpful for current and aspiring IRs.

Performance of VI-RADS in predicting muscle-invasive bladder cancer after transurethral resection: a single center retrospective analysis

PURPOSE

To assess VIRADS performance and inter-reader agreement for detecting muscle-invasive bladder cancer (MIBC) following transurethral resection of bladder tumor (TURBT).

METHODS

An IRB-approved, HIPAA-compliant, retrospective study from 2016 to 2020 included patients with bladder urothelial carcinoma who underwent MRI after TURBT, and cystectomy within 3 months without post-MRI treatments. Three radiologists blinded to pathology results independently reviewed MR images and assigned a VI-RADS score. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of VI-RADS were assessed for diagnosing MIBC using VI-RADS scores ≥ 3 and ≥ 4. Inter-reader agreement was assessed using Gwet's agreement coefficient (AC) and percent agreement.

RESULTS

The cohort consisted of 70 patients (mean age, 68 years ± 11 [SD]; range 39-85; 58 men) and included 32/70 (46%) with MIBC at cystectomy. ROC analysis revealed an AUC ranging from 0.67 to 0.77 and no pairwise statistical difference between readers (p-values, 0.06, 0.08, 0.97). Percent sensitivity, specificity, PPV, NPV and accuracy for diagnosing MIBC for the three readers ranged from 81.3-93.8, 36.8-55.3, 55.6-60.5, 77.3-87.5, and 62.9-67.1 respectively for VI-RADS score ≥ 3, and 78.1-81.3, 47.4-68.4, 55.6-67.6, 72.0-78.8 and 61.4-72.9 respectively for VI-RADS score ≥ 4. Gwet's AC was 0.63 [95% confidence interval (CI): 0.49,0.78] for VI-RADS score ≥ 3 with 79% agreement [95% CI 72,87] and 0.54 [95%CI 0.38,0.70] for VI-RADS score ≥ 4 with 76% agreement [95% CI 69,84]. VIRADS performance was not statistically different among 31/70 (44%) patients who received treatments prior to MRI (p ≥ 0.16).

CONCLUSION

VI-RADS had moderate sensitivity and accuracy but low specificity for detection of MIBC following TURBT, with moderate inter-reader agreement.

Low-grade oncocytic tumor: a review of radiologic and clinical features

PURPOSE

The 2022 World Health Organization classification of renal neoplasia expanded the spectrum of oncocytic neoplasms to encompass newly established and emerging entities; one of the latter is the low-grade oncocytic tumor (LOT). This study reports the radiologic appearance and clinical behavior of LOT.

METHODS

In this IRB-approved, HIPPA-compliant retrospective study, our institution's pathology database was searched for low-grade oncocytic tumors or neoplasms. Patient age, gender, and comorbidities were obtained from a review of electronic medical records, and imaging characteristics of the tumors were assessed through an imaging platform.

RESULTS

The pathology database search yielded 14 tumors in 14 patients. Four patients were excluded, as radiologic images were not available in three, and one did not fulfill diagnostic criteria after pathology re-review. The resulting cohort consisted of 10 tumors (median diameter 2.3 cm, range 0.7-5.1) in 10 patients (median age 68 years, range 53-91, six women). All tumors presented as a solitary, well-circumscribed, mass with solid components. All enhanced as much or almost as much as adjacent renal parenchyma; all but one enhanced heterogeneously. None had lymphadenopathy, venous invasion, or metastatic disease at presentation or at clinical follow-up (median, 22.2 months, range 3.4-71.6). Among five tumors undergoing active surveillance, mean increase in size was 0.4 cm/year at imaging follow-up (median 16.7 months, range 8.9-25.4).

CONCLUSION

LOT, a recently described pathologic entity in the kidney, can be considered in the differential diagnosis of an avidly and typically heterogeneously enhancing solid renal mass in an adult patient.

Feasibility and safety of bipolar radiofrequency track cautery during percutaneous image-guided abdominal biopsy procedures

PURPOSE

The purpose of this study was to assess the feasibility and safety of using a bipolar radiofrequency track cautery device during percutaneous image-guided abdominal biopsy procedures in at-risk patients.

METHODS

Forty-two patients (26-79 years old; female 44%) with at least one bleeding risk factor who underwent an abdominal image-guided (CT or US) biopsy and intended bipolar radiofrequency track cautery (BRTC) were retrospectively studied. An 18G radiofrequency electrode was inserted through a 17G biopsy introducer needle immediately following coaxial 18G core biopsy, to cauterize the biopsy track using temperature control. Bleeding risk factors, technical success, and adverse events were recorded.

RESULTS

BRTC was technically successful in 41/42 (98%) of procedures; in one patient, the introducer needle retracted from the liver due to respiratory motion prior to BRTC. BRTC following percutaneous biopsy was applied during 41 abdominal biopsy procedures (renal mass = 12, renal parenchyma = 10, liver mass = 9, liver parenchyma = 5, splenic mass or parenchyma = 4, gastrohepatic mass = 1). All patients had one or more of the following risk factors: high-risk organ (spleen or renal parenchyma), hypervascular mass, elevated prothrombin time, renal insufficiency, thrombocytopenia, recent anticoagulation or anticoagulation not withheld for recommended interval, cirrhosis, intraprocedural hypertension, brisk back bleeding observed from the introducer needle, or subcapsular tumor location. No severe adverse events (grade 3 or higher) occurred. Two (2/41, 5%) mild (grade 1) bleeding events did not cause symptoms or require intervention.

CONCLUSION

Bipolar radiofrequency track cautery was feasible and safe during percutaneous image-guided abdominal biopsy procedures. IRB approval: MBG 2022P002277.

Development, Implementation, and Assessment of a Quality, Research, Education, and Wellness (QREW) Professional Development Lecture Series for Radiology Faculty

RATIONALE AND OBJECTIVES

Professional development is important to academic radiologists. We developed, implemented, and assessed an internal professional development lecture series focusing on the non-interpretative themes of Quality, Research, Education, and Wellness (QREW).

MATERIALS AND METHODS

The faculty of a 29-member abdominal radiology division at an academic hospital were invited to deliver 1-hour virtual lectures on noninterpretative topics to division colleagues. Topics were curated by division leadership based on the perceived needs of faculty. Anonymous feedback was collected from attendees for quality improvement purposes and analyzed using descriptive statistics and Fisher's exact test.

RESULTS

Over 17 months, 13 QREW lectures were delivered. In total, 91 feedback forms were completed by faculty (mean 7 forms, range 2-12 per session). Of these, 57 responses (63%) were by those <7 years post training ("junior faculty"), 34 responses (37%) by those ≥ 7 years from training ("senior faculty"). Most respondents reported low levels of prior instruction (80/90, 89%) and personal knowledge (49/91, 54%) on topics. Compared to senior faculty, a greater proportion of junior faculty reported less prior instruction (73% vs 98%, P < 0.001) and less personal knowledge (32% vs 65%, P < 0.01). Most respondents agreed or strongly agreed that the topics were important to their clinical practice (87/90, 97%), professional development (86/90, 96%), and personal well-being (82/91, 90%). Faculty identified the QREW program as a major contributor to their professional development.

CONCLUSION

A noninterpretative professional development lecture series delivered by radiology faculty in a virtual, interactive format is feasible and effective, particularly for junior faculty.

Risk of persistent air leaks following percutaneous cryoablation and microwave ablation of peripheral lung tumors

OBJECTIVES

To compare the incidence of persistent air leak (PAL) following cryoablation vs MWA of lung tumors when the ablation zone includes the pleura.

METHODS

This bi-institutional retrospective cohort study evaluated consecutive peripheral lung tumors treated with cryoablation or MWA from 2006 to 2021. PAL was defined as an air leak for more than 24 h after chest tube placement or an enlarging postprocedural pneumothorax requiring chest tube placement. The pleural area included by the ablation zone was quantified on CT using semi-automated segmentation. PAL incidence was compared between ablation modalities and a parsimonious multivariable model was developed to assess the odds of PAL using generalized estimating equations and purposeful selection of predefined covariates. Time-to-local tumor progression (LTP) was compared between ablation modalities using Fine-Gray models, with death as a competing risk.

RESULTS

In total, 260 tumors (mean diameter, 13.1 mm ± 7.4; mean distance to pleura, 3.6 mm ± 5.2) in 116 patients (mean age, 61.1 years ± 15.3; 60 women) and 173 sessions (112 cryoablations, 61 MWA) were included. PAL occurred after 25/173 (15%) sessions. The incidence was significantly lower following cryoablation compared to MWA (10 [9%] vs 15 [25%]; p = .006). The odds of PAL adjusted for the number of treated tumors per session were 67% lower following cryoablation (odds ratio = 0.33 [95% CI, 0.14-0.82]; p = .02) vs MWA. There was no significant difference in time-to-LTP between ablation modalities (p = .36).

CONCLUSIONS

Cryoablation of peripheral lung tumors bears a lower risk of PAL compared to MWA when the ablation zone includes the pleura, without adversely affecting time-to-LTP.

KEY POINTS

• The incidence of persistent air leaks after percutaneous ablation of peripheral lung tumors was lower following cryoablation compared to microwave ablation (9% vs 25%; p = .006). • The mean chest tube dwell time was 54% shorter following cryoablation compared to MWA (p = .04). • Local tumor progression did not differ between lung tumors treated with percutaneous cryoablation compared to microwave ablation (p = .36).

Risk of malignancy in T1-hyperintense Bosniak version 2019 class II and IIF cystic renal masses

BACKGROUND

Bosniak classification version 2019 includes cystic masses in class II and IIF based partly on their hyperintense appearance at T1-weighted MRI. The prevalence of malignancy in non-enhancing heterogeneously T1-hyperintense masses is unknown, nor whether the pattern of T1 hyperintensity affects malignancy likelihood.

PURPOSE

To determine the malignancy proportion among six patterns of T1 hyperintensity within non-enhancing cystic renal masses.

METHODS

This retrospective, single-institution study included 72 Bosniak class II and IIF, non-enhancing, T1-hyperintense cystic renal masses. Diagnosis was confirmed by histopathology or by follow-up imaging demonstrating 5-year size and morphologic stability, decreased in size by ≥ 30%, resolution, or Bosniak down-classification. Six patterns of T1 hyperintensity were pre-defined: homogeneous (pattern A), fluid-fluid level (pattern B), peripherally markedly T1-hyperintense (pattern C), containing a T1-hyperintense non-enhancing nodule (pattern D), peripherally T1-hypointense (pattern E), and heterogeneously T1-hyperintense without a distinct pattern (pattern F). Three readers independently assigned each mass to a pattern. Individual and mean malignancy proportion were determined. Mann-Whitney test and Fischer's exact test compared the likelihood of malignancy between patterns. Inter-reader agreement was analyzed with Gwet's agreement coefficient (AC).

RESULTS

Among 72 masses, the mean number of masses assigned was 11 (15%) to pattern A, 21 (29%) to pattern B, 6 (8%) to pattern C, 7 (10%) to pattern D, 5 (7%) to pattern E, and 22 (31%) to pattern F. Five of 72 masses (7%) were malignant; none was assigned pattern A, B, or D. Mean malignancy proportion was 5% (0/9, 1/6, and 0/4) for pattern C, 13% (0/4, 1/3, and 1/7) for pattern E, and 18% (5/20, 3/21, and 4/25) for pattern F. Malignant masses were more likely assigned to pattern E or F (p = 0.003-0.039). Inter-reader agreement was substantial (Gwet's AC: 0.68).

CONCLUSION

Bosniak version 2019 class IIF masses that are non-enhancing and heterogeneously T1-hyperintense with a fluid-fluid level are likely benign. Those that are non-enhancing and heterogeneously T1-hyperintense without a distinct pattern have a malignancy proportion up to 25% (5/20).

Perineural Invasion and Spread in Common Abdominopelvic Diseases: Imaging Diagnosis and Clinical Significance

Malignancies and other diseases may spread by multiple pathways, including direct extension, hematogenous spread, or via lymphatic vessels. A less-well-understood route is the peripheral nervous system, which is known as perineural spread (PNS). In addition to accounting for pain and other neurologic symptoms, PNS affects both disease prognosis and management. Although PNS is commonly discussed in relation to head and neck tumors, there is emerging data regarding PNS in abdominopelvic malignancies and other conditions such as endometriosis. Due to improved contrast and spatial resolution, perineural invasion, a finding heretofore diagnosed only at pathologic examination, can be detected at CT, MRI, and PET/CT. PNS most commonly manifests as abnormal soft-tissue attenuation extending along neural structures, and diagnosis of it is aided by optimizing imaging parameters, understanding pertinent anatomy, and becoming familiar with the typical neural pathways of spread that largely depend on the disease type and location. In the abdomen, the celiac plexus is a central structure that innervates the major abdominal organs and is the principal route of PNS in patients with pancreatic and biliary carcinomas. In the pelvis, the lumbosacral plexus and inferior hypogastric plexus are the central structures and principal routes of PNS in patients with pelvic malignancies. Although the imaging findings of PNS may be subtle, a radiologic diagnosis can have a substantial effect on patient care. Knowledge of anatomy and known routes of PNS and optimizing imaging parameters is of utmost importance in providing key information for prognosis and treatment planning. © RSNA, 2023 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

Factors Associated with Hospital Length of Stay and Adverse Events following Percutaneous Ablation of Lung Tumors

PURPOSE

To explore the association between risk factors established in the surgical literature and hospital length of stay (HLOS), adverse events, and hospital readmission within 30 days after percutaneous image-guided thermal ablation of lung tumors.

MATERIALS AND METHODS

This bi-institutional retrospective cohort study included 131 consecutive adult patients (67 men [51%]; median age, 65 years) with 180 primary or metastatic lung tumors treated in 131 sessions (74 cryoablation and 57 microwave ablation) from 2006 to 2019. Age-adjusted Charlson Comorbidity Index, sex, performance status, smoking status, chronic obstructive pulmonary disease (COPD), primary lung cancer versus pulmonary metastases, number of tumors treated per session, maximum axial tumor diameter, ablation modality, number of pleural punctures, anesthesia type, pulmonary artery-to-aorta ratio, lung densitometry, sarcopenia, and adipopenia were evaluated. Associations between risk factors and outcomes were assessed using univariable and multivariable generalized linear models.

RESULTS

In univariable analysis, HLOS was associated with current smoking (incidence rate ratio [IRR], 4.54 [1.23-16.8]; P = .02), COPD (IRR, 3.56 [1.40-9.04]; P = .01), cryoablations with ≥3 pleural punctures (IRR, 3.13 [1.07-9.14]; P = .04), general anesthesia (IRR, 10.8 [4.18-27.8]; P < .001), and sarcopenia (IRR, 2.66 [1.10-6.44]; P = .03). After multivariable adjustment, COPD (IRR, 3.56 [1.57-8.11]; P = .003) and general anesthesia (IRR, 12.1 [4.39-33.5]; P < .001) were the only risk factors associated with longer HLOS. No associations were observed between risk factors and adverse events in multivariable analysis. Tumors treated per session were associated with risk of hospital readmission (P = .03).

CONCLUSIONS

Identified preprocedural risk factors from the surgical literature may aid in risk stratification for HLOS after percutaneous ablation of lung tumors, but were not associated with adverse events.

Safety and Effectiveness of Percutaneous Image-Guided Thermal Ablation of Juxtacardiac Lung Tumors

PURPOSE

To evaluate the safety and effectiveness of percutaneous image-guided thermal ablation (IGTA) for juxtacardiac lung tumors.

MATERIALS AND METHODS

This bi-institutional retrospective cohort study included 23 consecutive patients (13 [57%] male; mean age, 55 years ± 18) with 30 juxtacardiac lung tumors located ≤10 mm from the pericardium treated in 28 IGTA sessions (25 sessions of cryoablation and 3 sessions of microwave ablation) between April 2008 and August 2022. The primary outcome was any adverse cardiac event within 90 days after ablation. Secondary outcomes included noncardiac adverse events, local tumor progression-free survival (LT-PFS), and the cumulative incidence of local tumor progression with death as a competing risk. Two tumors treated without curative intent or follow-up imaging were considered in the safety analysis but not in the progression analysis.

RESULTS

The median imaging follow-up duration was 22 months (interquartile range [IQR], 10-53 months). Primary technical success was achieved in 25 (89%) ablations. No adverse cardiac events attributable to IGTA occurred. One patient experienced a phrenic nerve injury. The median LT-PFS duration was 59 months (IQR, 32-73 months). At 1, 3, and 5 years, LT-PFS was 90% (95% CI, 78%-100%), 74% (CI, 53%-100%), and 45% (CI, 20%-97%), respectively, and the cumulative incidence of local tumor progression was 4.3% (CI, 0.29%-19%), 11% (CI, 1.6%-30%), and 26% (CI, 3.3%-58%), respectively.

CONCLUSIONS

IGTA is safe and effective for lung tumors located ≤10 mm from the pericardium. No adverse cardiac events were not observed within 90 days after ablation.

Reliability and Management Outcomes Following a Percutaneous Biopsy Diagnosis of Oncocytoma: A 15-year Retrospective Analysis

Background There is uncertainty in the management of renal masses diagnosed as oncocytomas with image-guided percutaneous biopsy. Purpose To assess the reliability of a diagnosis of oncocytoma based on image-guided percutaneous renal mass biopsy and evaluate patient outcomes following different management strategies. Materials and Methods In this retrospective study, image-guided percutaneous biopsy pathology reports from April 2004 to April 2019 were searched for keywords "oncocytoma" and "oncocytic neoplasm" and compared with surgical pathology or repeat biopsy results. Patients with at least 12 months of clinical follow-up and known cause of death were grouped according to management strategies, and disease-specific survival and metastatic renal cell carcinoma (RCC)-free survival were compared. Mass growth rates were calculated with use of a normal linear mixed model. Results The database yielded 160 biopsy reports of 149 renal masses in 139 patients; 149 masses were categorized as oncocytoma (n = 107), likely oncocytoma (n = 12), oncocytic neoplasm (n = 28), and indeterminate with oncocytoma in differential (n = 2). Biopsied masses categorized as oncocytoma or likely oncocytoma were oncocytomas in 16 of 17 masses (94%) based on surgical pathology or repeat biopsy; four of eight masses (50%) categorized as oncocytic neoplasms were low-grade RCCs. Outcome analysis included 121 patients (mean age ± SD, 68 years ± 9.1; 82 men); 80 patients initially underwent active surveillance (11 were later treated), 33 underwent ablation, and eight underwent surgery. Disease-specific survival and metastatic-free survival were 100% after each management strategy (median follow-up, 86.6 months; range, 14.2-207.9 months). Mass growth rate (mean, 1.7 mm per year) showed no evidence of a significant difference among biopsy result categories (P = .37) or initial (P = .84) or final management strategies (P = .11). Conclusion Image-guided percutaneous biopsy diagnosis of renal oncocytoma was reliable. Although some masses diagnosed as oncocytic neoplasms were low-grade renal cell carcinomas (RCCs) at final diagnosis, no patients died of RCC, including those managed with active surveillance. © RSNA, 2023 See also the editorial by Lockhart in this issue.

Learning From Experience- Confronting Challenges and Adapting to Change in a Large Academic Abdominal Radiology Practice: Insights From a Faculty Retreat

RATIONALE

Substantial organizational changes, increasing clinical volumes, and the COVID-19 pandemic presented compound stressors to faculty radiologists in our large academic abdominal radiology division and necessitated multiple changes in our practice.

METHODS

To address the challenges and establish group consensus, we conducted a virtual divisional faculty retreat centered on themes of team building, clinical work, trainee education, and faculty mentorship. A pre-retreat survey evaluated satisfaction with aspects of professional life and clinical work practices and invited personal reflections. Survey data were presented in the retreat segments focused on each theme, and subsequent discussion was facilitated in small group breakouts.

RESULTS

Responses to the team-building survey revealed common values and sources of gratitude, including health, family and meaningful work and relationships. Faculty reported a strong sense of personal accomplishment, but with varied emotional exhaustion scores. Faculty were satisfied with remote work assignments but identified opportunities to improve the clinical work schedule including reversion of some remote assignments to in-person and increased interventional radiology shift staggering. Compared to pre-COVID practice, faculty respondents perceived giving lower quality and less frequent feedback to trainees; evolving educational resource needs were identified. A more formal approach to faculty mentoring was sought. A post-retreat survey revealed high participant satisfaction.

OUTCOMES

In the future, we plan to continue divisional retreat activities to respond to evolving challenges and further improve team building, clinical workflow, trainee education, and faculty mentorship.

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.

Rapid Quality Assessment of Nonrigid Image Registration Based on Supervised Learning

When preprocedural images are overlaid on intraprocedural images, interventional procedures benefit in that more structures are revealed in intraprocedural imaging. However, image artifacts, respiratory motion, and challenging scenarios could limit the accuracy of multimodality image registration necessary before image overlay. Ensuring the accuracy of registration during interventional procedures is therefore critically important. The goal of this study was to develop a novel framework that has the ability to assess the quality (i.e., accuracy) of nonrigid multimodality image registration accurately in near real time. We constructed a solution using registration quality metrics that can be computed rapidly and combined to form a single binary assessment of image registration quality as either successful or poor. Based on expert-generated quality metrics as ground truth, we used a supervised learning method to train and test this system on existing clinical data. Using the trained quality classifier, the proposed framework identified successful image registration cases with an accuracy of 81.5%. The current implementation produced the classification result in 5.5 s, fast enough for typical interventional radiology procedures. Using supervised learning, we have shown that the described framework could enable a clinician to obtain confirmation or caution of registration results during clinical procedures.

Active Surveillance of Renal Masses: The Role of Radiology

Active surveillance of renal masses, which includes serial imaging with the possibility of delayed treatment, has emerged as a viable alternative to immediate therapeutic intervention in selected patients. Active surveillance is supported by evidence that many benign masses are resected unnecessarily, and treatment of small cancers has not substantially reduced cancer-specific mortality. These data are a call to radiologists to improve the diagnosis of benign renal masses and differentiate cancers that are biologically aggressive (prompting treatment) from those that are indolent (allowing treatment deferral). Current evidence suggests that active surveillance results in comparable cancer-specific survival with a low risk of developing metastasis. Radiology is central in this. Imaging is used at the outset to estimate the probability of malignancy and degree of aggressiveness in malignant masses and to follow up masses for growth and morphologic change. Percutaneous biopsy is used to provide a more definitive histologic diagnosis and to guide treatment decisions, including whether active surveillance is appropriate. Emerging applications that may improve imaging assessment of renal masses include standardized assessment of cystic and solid masses and radiomic analysis. This article reviews the current and future role of radiology in the care of patients with renal masses undergoing active surveillance.

Rectal MRI after neoadjuvant chemoradiation therapy: a pictorial guide to interpretation

Magnetic resonance imaging (MRI) is the current reference standard imaging modality for restaging rectal cancer after neoadjuvant chemoradiation and is used to guide clinical management decisions. This pictorial essay provides an illustrative atlas of the key MRI features used to assess rectal cancer after treatment. MRI findings of residual tumor including non-mucinous, mucinous, and signet-ring cell adenocarcinoma subtypes are correlated with histopathology. Imaging appearances of treatment changes that mimic residual tumor in the setting of confirmed pathological complete response at resection are illustrated. Treatment complications are also shown. Knowledge of these imaging findings and their importance may help radiologists comply with all elements of the structured reporting templates proposed by the Rectal Cancer Disease Focused Panel of the Society of Abdominal Radiology and by the European Society of Gastrointestinal and Abdominal Radiology.

Bosniak classification of cystic renal masses, version 2019: interpretation pitfalls and recommendations to avoid misclassification

The purpose of this review is to describe the potential sources of variability or discrepancy in interpretation of cystic renal masses under the Bosniak v2019 classification system. Strategies to avoid these pitfalls and clinical examples of diagnostic approaches are also presented. Potential pitfalls in the application of Bosniak v2019 are divided into three categories: interpretative, technical, and mass related. An organized, comprehensive review of possible discrepancies in interpreting Bosniak v2019 cystic masses is presented with pictorial examples of difficult clinical cases and proposed solutions. The scheme provided can guide readers to consistent, precise application of the classification system. Radiologists should be aware of the possible sources of misinterpretation of cystic renal masses when applying Bosniak v2019. Knowing which features and types of cystic masses are prone to interpretive errors, in addition to the inherent trade-offs between the CT and MR techniques used to characterize them, can help radiologists avoid these pitfalls.

Bosniak Classification of Cystic Renal Masses, Version 2019: A Pictorial Guide to Clinical Use

Cystic renal masses are commonly encountered in clinical practice. In 2019, the Bosniak classification of cystic renal masses, originally developed for CT, underwent a major revision to incorporate MRI and is referred to as the Bosniak Classification, version 2019. The proposed changes attempt to (a) define renal masses (ie, cystic tumors with less than 25% enhancing tissue) to which the classification should be applied; (b) emphasize specificity for diagnosis of cystic renal cancers, thereby decreasing the number of benign and indolent cystic masses that are unnecessarily treated or imaged further; (c) improve interobserver agreement by defining imaging features, terms, and classes of cystic renal masses; (d) reduce variation in reported malignancy rates for each of the Bosniak classes; (e) incorporate MRI and to some extent US; and (f) be applicable to all cystic renal masses encountered in clinical practice, including those that had been considered indeterminate with the original classification. The authors instruct how, using CT, MRI, and to some extent US, the revised classification can be applied, with representative clinical examples and images. Practical tips, pitfalls to avoid, and decision tree rules are included to help radiologists and other physicians apply the Bosniak Classification, version 2019 and better manage cystic renal masses. An online resource and mobile application are also available for clinical assistance. An invited commentary by Siegel and Cohan is available online. ^©RSNA, 2021.

Outcomes Following Percutaneous Microwave and Cryoablation of Lung Metastases from Adenoid Cystic Carcinoma of the Head and Neck: A Bi-Institutional Retrospective Cohort Study

OBECTIVE

The aim of this study was to report outcomes following percutaneous microwave and cryoablation of lung metastases from adenoid cystic carcinoma (ACC) of the head and neck.

MATERIAL AND METHODS

This bi-institutional retrospective cohort study included 10 patients (6 females, median age 59 years [range 28-81]) who underwent 32 percutaneous ablation sessions (21 cryoablation, 11 microwave) of 60 lung metastases (median 3.5 tumors per patient [range 1-16]) from 2007 to 2019. Median tumor diameter was 16 mm [range 7-40], significantly larger for cryoablation (22 mm, p = 0.002). A median of two tumors were treated per session [range 1-7]. Technical success, local control, complications, and overall survival were assessed.

RESULTS

Primary technical success was achieved for 55/60 tumors (91.7%). Median follow-up was 40.6 months (clinical) and 32.5 months (imaging, per tumor). Local control at 1, 2, and 3 years was 94.7%, 80.8%, and 76.4%, respectively, and did not differ between ablation modalities. Five of fifteen recurrent tumors underwent repeat ablation, and secondary technical success was achieved in four (80%). Assisted local tumor control at 1, 2, and 3 years was 96.2%, 89.8%, and 84.9%, respectively. Complications occurred following 24/32 sessions (75.0%) and 57.2% Common Terminology Criteria for Adverse Events (CTCAE) lower than grade 3. Of 13 pneumothoraces, 7 required chest tube placements. Hemoptysis occurred after 7/21 cryoablation sessions, and bronchopleural fistula developed more frequently with microwave (p = 0.037). Median length of hospital stay was 1 day [range 0-10], and median overall survival was 81.5 months (IQR 40.4-93.1).

CONCLUSION

Percutaneous computed tomography-guided microwave and cryoablation can treat lung metastases from ACC of the head and neck. Complications are common but manageable, with full recovery expected.

Lexicon for renal mass terms at CT and MRI: a consensus of the society of abdominal radiology disease-focused panel on renal cell carcinoma

PURPOSE

There is substantial variation in the radiologic terms used to characterize renal masses, leading to ambiguity and inconsistency in clinical radiology reports and research studies. The purpose of this study was to develop a standardized lexicon to describe renal masses at CT and MRI.

MATERIALS AND METHODS

This multi-institutional, prospective, quality improvement project was exempt from IRB oversight. Thirteen radiologists belonging to the Society of Abdominal Radiology (SAR) disease-focused panel on renal cell carcinoma representing nine academic institutions participated in a modified Delphi process to create a lexicon of terms used to describe imaging features of renal masses at CT and MRI. In the first round, members voted on terms to be included and proposed definitions; subsequent voting rounds and a teleconference established consensus. One non-voting member developed the questionnaire and consolidated responses. Consensus was defined as ≥ 80% agreement.

RESULTS

Of 37 proposed terms, 6 had consensus to be excluded. Consensus for inclusion was reached for 30 of 31 terms (13/14 basic imaging terms, 8/8 CT terms, 6/6 MRI terms and 3/3 miscellaneous terms). Despite substantial initial disagreement about definitions of 'renal mass,' 'necrosis,' 'fat,' and 'restricted diffusion' in the first round, consensus for all was eventually reached. Disagreement remained for the definition of 'solid mass.'

CONCLUSIONS

A modified Delphi method produced a lexicon of preferred terms and definitions to be used in the description of renal masses at CT and MRI. This lexicon should improve clarity and consistency of radiology reports and research related to renal masses.

Perceptions of patients with early stage breast cancer toward research biopsies

Background

The objective of this study was to describe the perspective of patients with early breast cancer toward research biopsies. The authors hypothesized that more patients at academic sites than at community‐based sites would be willing to consider these procedures.

Methods

In total, 198 patients with early stage breast cancer were recruited from 3 academic centers (n = 102) and from 1 community oncology practice (n = 96). The primary objective was to compare the proportion of patients willing to consider donating excess tissue biospecimens from surgery, from a clinically indicated breast biopsy, or from a research purposes‐only biopsy (RPOB) between practice types.

Results

Most patients (93% at academic sites, 94% at the community oncology site) said they would consider donating excess tissue from surgery for research. One‐half of patients from academic or community sites would consider donating tissue from a clinically indicated breast biopsy. On univariate analysis, significantly fewer patients from academic sites would consider an RPOB (22% at academic sites, 42% at the community site; P = .003); however, this difference was no longer significant on multivariate analysis (P = .96). Longer transportation times and unfavorable prior experiences were associated with less willingness to consider an RPOB on multivariate analysis. Significantly fewer patients from academic sites (14%) than from the community site (35%) would consider a research biopsy in a clinical trial (P = .04). Contributing to scientific knowledge, return of results, and a personal request by their physician were the strongest factors influencing patients' willingness to undergo research biopsies.

Conclusions

The current results rejected the hypothesis that more patients with early breast cancer at academic sites would be willing to donate tissue biospecimens for research compared with those at community oncology sites. These findings identify modifiable factors to consider in biobanking studies and clinical trials.

In this study of the willingness of patients with early stage breast cancer to consider biospecimen collection procedures for the purposes of research, most patients were willing to provide blood samples for research but were less likely to consider percutaneous breast biopsies. Longer travel time to the clinic and adverse experiences with prior biopsies, but not treatment center type (academic versus community‐based center), were associated with less willingness to consider research biopsies.

Update on MRI of Cystic Renal Masses Including Bosniak Version 2019

Incidental cystic renal masses are common, usually benign, and almost always indolent. Since 1986, the Bosniak classification has been used to express the risk of malignancy in a cystic renal mass detected at imaging. Historically, magnetic resonance imaging (MRI) was not included in that classification. The proposed Bosniak v.2019 update has formally incorporated MRI, included definitions of imaging terms designed to improve interobserver agreement and specificity for malignancy, and incorporated a variety of masses that were incompletely defined or not included in the original classification. For example, at unenhanced MRI, homogeneous masses markedly hyperintense at T₂ -weighted imaging (similar to cerebrospinal fluid) and homogeneous masses markedly hyperintense at fat suppressed T₁ -weighted imaging (approximately ≥2.5 times more intense than adjacent renal parenchyma) are classified as Bosniak II and may be safely ignored, even when they have not been imaged with a complete renal mass MRI protocol. MRI has specific advantages and is recommended to evaluate masses that at computed tomography (CT) 1) have abundant thick or nodular calcifications; 2) are homogeneous, hyperattenuating, ≥3 cm, and nonenhancing; or 3) are heterogeneous and nonenhancing. Although MRI is generally excellent for characterizing cystic renal masses, there are unique weaknesses of MRI that bear consideration. These details and others related to MRI of cystic renal masses are described in this review, with an emphasis on Bosniak v.2019. A website (https://bosniak-calculator.herokuapp.com/) and mobile phone apps named "Bosniak Calculator" have been developed for ease of assignment of Bosniak classes. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

Contemporary trends in percutaneous renal mass biopsy utilization in the United States

INTRODUCTION

Patients with a renal mass traditionally proceed directly to surgery without a preoperative tissue diagnosis confirming malignancy. Many surgically treated renal masses represent benign tumors or indolent malignancies on final pathology. This has led to a growing body of literature supporting an expanded role for percutaneous renal mass biopsy (RMB). This study aims to characterize national trends in RMB utilization.

METHODS

Patients undergoing renal biopsy during a 12-year period (2006-2017) in the Premier Hospital Database were captured using International Classification of Diseases, Ninth Revision and Tenth Revision codes. We restricted our analysis to patients with a concurrent diagnosis of a renal mass. We determined utilization rate, subsequent interventions within 90 days of biopsy, predictors of RMB, and 30-day RMB complication rates. We applied sampling weights and adjusted for hospital clustering to achieve a nationally representative analysis.

RESULTS

Among 115,511 patients who met the inclusion criteria, the annual number of RMB rose from 7,196 in 2006 to 11,528 in 2017; during this period, more than 3 times as many patients proceeded directly to surgery without a prior RMB. After RMB, 85,848 (74.32%) patients were not treated within 90 days. Of those treated, thermal ablation was more common than surgery (17,269 vs. 12,394). Trend analysis showed that patients with metastatic disease represented a decreasing proportion of patients receiving RMB (27.0%-21.8%; P < 0.001). Compared to patients who proceeded directly to surgery, RMB was more commonly performed in patients in the highest age group (80 years and older, 15.9% vs. 9.2%), unmarried (50% vs. 45.9%), with more medical comorbidities (Charlson comorbidity index ≥4, 30.9% vs. 17.4%), or with metastatic disease (24.5% vs. 10.4%). Multivariable regression analysis determined the primary predictor of RMB was the presence of metastatic disease. Hematuria was the most common complication present in 5.18% of patients followed by pneumothorax in 1.75%. All other complications were rare (<0.4%).

CONCLUSION

Although there has been progressive adoption of RMB for the management of renal masses in the United States, utilization remains relatively limited and differentially employed across the population based on both clinical and nonclinical patient factors. More research is needed to understand which factors are considered when determining whether to utilize RMB in the evaluation of a renal mass.

Trainee and Attending Perspectives on Remote Radiology Readouts in the Era of the COVID-19 Pandemic

Rationale and Objectives

Social distancing mandates due to COVID-19 have necessitated adaptations to radiology trainee workflow and educational practices, including the radiology “readout.” We describe how a large academic radiology department achieved socially distant “remote readouts,” provide trainee and attending perspectives on this early experience, and propose ways by which “remote readouts” can be used effectively by training programs beyond COVID-19.

Materials and Methods

Beginning March 2020, radiologists were relocated to workspaces outside of conventional reading rooms. Information technologies were employed to allow for “remote readouts” between trainees and attendings. An optional anonymous open-ended survey regarding remote readouts was administered to radiology trainees and attendings as a quality improvement initiative. From the responses, response themes were abstracted using thematic analysis. Descriptive statistics of the qualitative data were calculated.

Results

Radiologist workstations from 14 traditional reading rooms were relocated to 36 workspaces across the hospital system. Two models of remote readouts, synchronous and asynchronous, were developed, facilitated by commercially available information technologies. Thirty-nine of 105 (37%) trainees and 42 of 90 (47%) attendings responded to the survey. Main response themes included: social distancing, technology, autonomy/competency, efficiency, education/feedback and atmosphere/professional relationship. One hundred and forty-eight positive versus 97 negative comments were reported. Social distancing, technology, and autonomy/competency were most positively rated. Trainees and attending perspectives differed regarding the efficiency of remote readouts.

Conclusion

“Remote readouts,” compliant with social distancing measures, are feasible in academic radiology practice settings. Perspectives from our initial experience provide insight into how this can be accomplished, opportunities for improvement and future application, beyond the COVID-19 pandemic.

Percutaneous CT- and MRI-guided Cryoablation of cT1 Renal Cell Carcinoma: Intermediate- to Long-term Outcomes in 307 Patients

Background Percutaneous ablation for cT1 renal cell carcinoma (RCC) remains underused, partially because of heterogeneous and limited long-term outcomes data assessing recent cryoablation methods. Purpose To report intermediate- to long-term outcomes of image-guided percutaneous cryoablation of cT1 RCC and to compare outcomes for CT versus MRI guidance. Materials and Methods This HIPAA-compliant retrospective single-institution study assessed patients who underwent percutaneous cryoablation for solitary pathology-proven cT1 RCC between August 2000 and July 2017. Tumors (cT1a, n = 282; cT1b, n = 25; size range, 0.6-6.5 cm; median size, 2.5 cm) underwent cryoablation with CT (n = 155) or MRI (n = 152) guidance. Primary end points of overall survival (OS), disease-specific survival (DSS), imaging-confirmed disease-free survival (DFS), and local progression-free survival (LPFS) were calculated by using Kaplan-Meier analysis. Secondary end points of technique efficacy and adverse event rate were also calculated. Primary and secondary end points for CT and MRI guidance were compared by using univariable regression analysis. Results A total of 307 patients (mean age, 68 years ± 11 [standard deviation]; 192 men) were evaluated. Median clinical follow-up lasted 95 months (range, 8-219 months), and median imaging follow-up lasted 41 months (range, 0-189 months). Survival metrics at 3, 5, 10, and 15 years, respectively, included OS of 91% (95% confidence interval [CI]: 88%, 94%), 86% (95% CI: 82%, 90%), 78% (95% CI: 73%, 84%), and 76% (95% CI: 69%, 83%); DSS of 99.6% (95% CI: 99%, 100%), 99% (95% CI: 98%, 100%), 99% (95% CI: 98%, 100%), and 99% (95% CI: 98%, 100%); DFS of 94% (95% CI: 92%, 97%), 91% (95% CI: 88%, 96%), 88% (95% CI: 83%, 93%), and 88% (95% CI: 83%, 93%); and LPFS of 97% (95% CI: 94%, 99%), 95% (95% CI: 93%, 98%), 95% (95% CI: 93%, 98%), and 95% (95% CI: 93%, 98%). Survival did not significantly differ between CT and MRI guidance, with univariable Cox regression analysis hazard ratios of 0.97 (95% CI: 0.57, 1.67; P = .92) for OS, 0.63 (95% CI: 0.26, 1.52; P = .30) for DFS, and 0.83 (95% CI: 0.26, 2.74; P = .77) for LPFS. Primary and secondary technique efficacy were 96% and 99%, respectively. Overall adverse event rate was 14% (43 of 307), including 11 grade 3 events and three grade 4 events according to the Common Terminology Criteria for Adverse Events. Conclusion Percutaneous CT- and MRI-guided cryoablation of cT1 renal cell carcinoma had similar excellent intermediate- and long-term outcomes. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Georgiades in this issue.

Muscle-invasive Urothelial Cancer: Association of Mutational Status with Metastatic Pattern and Survival

Background Muscle-invasive urothelial cancer (MIUC) is characterized by substantial genetic heterogeneity and high mutational frequency. Correlation between frequently mutated genes with clinical behavior has been recently demonstrated. Nonetheless, correlation between mutational status of MIUC and metastatic pattern is unknown. Purpose To investigate the association of mutational status of MIUC with metastatic pattern, metastasis-free survival (MFS), and overall survival (OS). Materials and Methods This single-center retrospective study evaluated consecutive patients with biopsy-proven MIUC who underwent serial cross-sectional imaging (CT, MRI, or fluorine 18 fluorodeoxyglucose PET/CT) between April 2010 and December 2018. Mutational status was correlated with location of metastases using the χ² or Fisher exact test. Mutational status and metastatic pattern were correlated with MFS and OS using univariable Cox proportional hazard models. High-risk (presence of TP53, RB1, or KDM6A mutation) and low-risk (presence of ARID1A, FGFR3, PIK3CA, STAG2, and/or TSC1 mutation and absence of TP53, RB1, or KDM6A mutation) groups were determined according to existing literature and were correlated with MFS and OS by using multivariable Cox proportional hazard models. Results One hundred three patients (mean age, 72 years ± 11 [standard deviation]; 81 men) were evaluated. Seventeen of 103 (16%) patients had metastatic disease at diagnosis; 38 of 103 (37%) developed metastatic disease at a median of 5.9 months (interquartile range, 0.8-28 months). TP53 mutation (seen in 58 of 103 patients, 56%) was associated with lymphadenopathy (relative risk [RR]: 1.7; 95% confidence interval [CI]: 1.2, 2.4; P = .002) and osseous metastases (RR: 1.9; 95% CI: 1.6, 2.3; P = .02); RB1 mutation (seen in 19 of 103 patients, 18.4%) was associated with peritoneal carcinomatosis (RR: 5.9; 95% CI: 3.8, 9.2; P = .03). ARID1A mutation was associated with greater OS (hazard ratio [HR]: 3.1; 95% CI: 1.2, 10; P = .01). At multivariable Cox analysis, the high-risk group (TP53, RB1, and/or KDM6A mutations) was independently associated with shorter MFS (HR: 3.5, 95% CI: 1.3, 12; P = .009) and shorter OS (HR: 3.1; 95% CI: 1.2, 10; P = .02). Conclusion Mutational status of muscle-invasive urothelial cancer has implications on metastatic pattern, metastasis-free survival, and overall survival. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Choyke in this issue.

Preoperative imaging for locoregional staging of bladder cancer

Bladder cancer is the ninth most common cancer, expected to lead to an estimated 17,670 deaths in the United States in 2019. Clinical management and prognosis of bladder cancer mainly depend on the extent of locoregional disease, particularly whether bladder muscle is involved. Therefore, bladder cancer is often divided into superficial, non-muscle-invasive bladder cancer and muscle-invasive bladder cancer; the latter often prompts consideration for cystectomy. While precise staging prior to cystectomy is crucial, the optimal preoperative imaging modality used to stage the disease remains controversial. Transurethral resection of bladder tumor (TURBT) followed by computed tomography (CT) urography is the current recommended approach for staging bladder cancer but suffers from a high rate of understaging. We review the recent literature and compare different imaging modalities for assessing the presence of muscle invasion and lymph node involvement prior to cystectomy and highlight the advantages of each modality.

An interventional image-guided microdevice implantation and retrieval method for in-vivo drug response assessment

PURPOSE

Recently developed implantable microdevices can perform multi-drug response assessment of cancer drugs in-vivo, with potential to develop highly optimized personalized cancer treatment strategies. However, minimally invasive/interventional image-guided methods of in-vivo microdevice implantation, securement, and retrieval are needed for broad clinical translation. Here we demonstrate proof-of-concept of an interventional microdevice implantation and retrieval method for personalized drug response assessment, using ex-vivo phantom, ex-vivo tissue, and in-vivo murine models.

METHODS

A method for minimally-invasive microdevice implantation and retrieval was developed, by which a custom-prototyped 6 mm retrievable microdevice can be implanted into a live tumor, deliver drugs into 10 discrete regions of adjacent tissue, and retrieved along with the adjacent drug-exposed tissue with a custom-prototyped retrieval needle device to allow in-vivo multi-drug response assessment. Computed tomography (CT) and ultrasound (US)-guided minimally invasive microdevice implantation and retrieval were tested in ex-vivo phantom and tissue models. Successful retrieval was defined as retrieval of the microdevice and adjacent core phantom/tissue sample containing at least 4/10 drug delivery sites. Subsequently, 10 implantation and retrieval trials in phantom models were performed using bi-axial and tri-axial retrieval needles; success rates were calculated and compared using a two-proportion z-test and the number of successfully retrieved drug release sites per microdevice was calculated and compared using a one-tailed independent t-test. Finally, five microdevices, each containing ten reservoirs preloaded with chemotherapy agent Doxorubicin, were implanted into mouse tumors in-vivo, secured for 24-h during drug release, and microdevice/tissue retrieval was performed under ultrasound guidance. Fluorescence microscopy of the retrieved tissue was used to confirm drug delivery and apoptosis staining assessed in-vivo tissue response; correlation of drug release and apoptosis staining were used to assess in-vivo drug efficacy.

RESULTS

Image-guided microdevice implantation and retrieval were successful in ex-vivo phantom and tissue models with both US and CT guidance. Bi-axial retrieval success rate was significantly higher than triaxial retrieval in ex-vivo phantom trials (90% vs 50%, z = 1.95, P = 0.026), and had nonsignificantly higher number of retrieved drug-release sites per microdevice (8.3 vs 7.0, t = 1.37, P = 0.097). Bi-axial retrieval was successful in all five in-vivo mouse tumor models, and allowed in-vivo drug response assessment at up to ten discrete drug delivery sites per microdevice. An average of 6.8/10 discrete tumor sites containing micro-doses of delivered drug were retrieved per in-vivo attempt (min 5, max 10, std 1.93). Tissue regions of drug delivery, as assessed with fluorescent Doxorubicin drug signal, correlated with regions of apoptosis staining in all in-vivo models, indicating drug efficacy. No bleeding, microdevice migration, or other complications were noted during implantation, 24-h observation, or retrieval.

CONCLUSIONS

The demonstrated image-guided minimally invasive microdevice implantation and retrieval method is similar to routine outpatient biopsy procedures, obviates the need for surgery, and can be performed at varying depths under CT and/or US guidance. There is potential for this method to enable clinical translation of in-vivo personalized drug response assessment/prediction in a much larger number of patients than currently possible.

Bosniak Classification of Cystic Renal Masses, Version 2019: An Update Proposal and Needs Assessment

Cystic renal cell carcinoma (RCC) is almost certainly overdiagnosed and overtreated. Efforts to diagnose and treat RCC at a curable stage result in many benign neoplasms and indolent cancers being resected without clear benefit. This is especially true for cystic masses, which compared with solid masses are more likely to be benign and, when malignant, less aggressive. For more than 30 years, the Bosniak classification has been used to stratify the risk of malignancy in cystic renal masses. Although it is widely used and still effective, the classification does not formally incorporate masses identified at MRI or US or masses that are incompletely characterized but are highly likely to be benign, and it is affected by interreader variability and variable reported malignancy rates. The Bosniak classification system cannot fully differentiate aggressive from indolent cancers and results in many benign masses being resected. This proposed update to the Bosniak classification addresses some of these shortcomings. The primary modifications incorporate MRI, establish definitions for previously vague imaging terms, and enable a greater proportion of masses to enter lower-risk classes. Although the update will require validation, it aims to expand the number of cystic masses to which the Bosniak classification can be applied while improving its precision and accuracy for the likelihood of cancer in each class.

Standardized report template for indeterminate renal masses at CT and MRI: a collaborative product of the SAR Disease-Focused Panel on Renal Cell Carcinoma

PURPOSE

To create a succinct yet comprehensive evidence-based structured report template for indeterminate renal masses characterized at CT and MRI.

METHODS

This IRB-exempt, iterative, multi-institutional quality improvement project was informed by published data derived from a multi-institutional survey and a multi-institutional review of CT and MRI radiology reports. A two-stage blinded Delphi process by the 16-member 12-institution Society of Abdominal Radiology Disease-Focused Panel on Renal Cell Carcinoma was conducted to create a structured report template for indeterminate renal masses evaluated at CT and MRI. Individual reporting characteristics were scored by members as 'core,' 'optional,' or 'exclude.' Threshold for inclusion was ≥ 80% support. If < 80% members considered a characteristic a 'core' feature, but ≥ 80% considered it either 'core' or 'optional,' it was considered an 'optional' feature. If neither was the case, the characteristic was excluded. Free-text comments were permitted. Characteristics considered 'core' by 50-99% of respondents in Round 1 (i.e., nonunanimous support) and uninvestigated free-text comments were assessed in Round 2. Core and optional structured reporting templates were derived.

RESULTS

The response rate was 100% in Round 1 (16/16) and Round 2 (16/16). In Round 1, 5 characteristics had unanimous support as 'core' features. Following Round 2, 13 characteristics had ≥ 80% support as 'core' features, and 10 characteristics had ≥ 80% support as 'optional' features. Structured report templates were derived.

DISCUSSION

Structured 'core' and 'optional' templates for indeterminate renal masses at CT and MRI were derived, which may improve compliance with reporting preferred and essential imaging characteristics.

Renal and adrenal masses containing fat at MRI: Proposed nomenclature by the society of abdominal radiology disease-focused panel on renal cell carcinoma

This article proposes a consensus nomenclature for fat-containing renal and adrenal masses at MRI to reduce variability, improve understanding, and enhance communication when describing imaging findings. The MRI appearance of "macroscopic fat" occurs due to a sufficient number of aggregated adipocytes and results in one or more of: 1) intratumoral signal intensity (SI) loss using fat-suppression techniques, or 2) chemical shift artifact of the second kind causing linear or curvilinear India-ink (etching) artifact within or at the periphery of a mass at macroscopic fat-water interfaces. "Macroscopic fat" is most commonly observed in adrenal myelolipoma and renal angiomyolipoma (AML) and only rarely encountered in other adrenal cortical tumors and renal cell carcinomas (RCC). Nonlinear noncurvilinear signal intensity loss on opposed-phase (OP) compared with in-phase (IP) chemical shift MRI (CSI) may be referred to as "microscopic fat" and is due to: a) an insufficient amount of adipocytes, or b) the presence of fat within tumor cells. Determining whether the signal intensity loss observed on CSI is due to insufficient adipocytes or fat within tumor cells cannot be accomplished using CSI alone; however, it can be inferred when other imaging features strongly suggest a particular diagnosis. Fat-poor AML are homogeneously hypointense on T₂ -weighted (T₂ W) imaging and avidly enhancing; signal intensity loss at OP CSI is uncommon, but when present is usually focal and is caused by an insufficient number of adipocytes within adjacent voxels. Conversely, clear-cell RCC are heterogeneously hyperintense on T₂ W imaging and avidly enhancing, with the signal intensity loss observed on OP CSI being typically diffuse and due to fat within tumor cells. Adrenal adenomas, adrenal cortical carcinoma, and adrenal metastases from fat-containing primary malignancies also show signal intensity loss on OP CSI due to fat within tumor cells and not from intratumoral adipocytes. Level of Evidence: 5 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;49:917-926.

Multi-institutional analysis of CT and MRI reports evaluating indeterminate renal masses: comparison to a national survey investigating desired report elements

PURPOSE

To determine the need for a standardized renal mass reporting template by analyzing reports of indeterminate renal masses and comparing their contents to stated preferences of radiologists and urologists.

METHODS

The host IRB waived regulatory oversight for this multi-institutional HIPAA-compliant quality improvement effort. CT and MRI reports created to characterize an indeterminate renal mass were analyzed from 6 community (median: 17 reports/site) and 6 academic (median: 23 reports/site) United States practices. Report contents were compared to a published national survey of stated preferences by academic radiologists and urologists from 9 institutions. Descriptive statistics and Chi-square tests were calculated.

RESULTS

Of 319 reports, 85% (271; 192 CT, 79 MRI) reported a possibly malignant mass (236 solid, 35 cystic). Some essential elements were commonly described: size (99% [269/271]), mass type (solid vs. cystic; 99% [268/271]), enhancement (presence vs. absence; 92% [248/271]). Other essential elements had incomplete penetrance: the presence or absence of fat in solid masses (14% [34/236]), size comparisons when available (79% [111/140]), Bosniak classification for cystic masses (54% [19/35]). Preferred but non-essential elements generally were described in less than half of reports. Nephrometry scores usually were not included for local therapy candidates (12% [30/257]). Academic practices were significantly more likely than community practices to include mass characterization details, probability of malignancy, and staging. Community practices were significantly more likely to include management recommendations.

CONCLUSIONS

Renal mass reporting elements considered essential or preferred often are omitted in radiology reports. Variation exists across radiologists and practice settings. A standardized template may mitigate these inconsistencies.

Correction to: Multi-institutional analysis of CT and MRI reports evaluating indeterminate renal masses: comparison to a national survey investigating desired report elements

The original version of this article contained an error in author name. The co-author's name was published as Ivan M. Pedrosa, instead it should be Ivan Pedrosa. The original article has been corrected.

Bladder cancer local staging: multiparametric MRI performance following transurethral resection

PURPOSE

To evaluate the performance of multiparametric MRI (mpMRI) for the local staging of bladder cancer following transurethral resection of bladder tumor.

METHODS

This Institutional Review Board-approved, retrospective study identified 45 patients with pathology-proven bladder cancer who underwent transurethral resection followed by mpMRI between August 2011 and October 2016. Two radiologists reviewed each MRI independently and assigned T and N stage. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for the presence of muscle invasion (T2 or higher), peri-vesical invasion (T3 or higher), and regional nodal disease compared to findings at cystectomy as the reference standard. Inter-observer agreement was measured using Cohen's κ coefficient.

RESULTS

Of 45 patients, 13% were stage T2, 27% T3, 16% T4; of 40 patients, 28% had regional nodal disease. Sensitivity, specificity, PPV, NPV, and accuracy of mpMRI for readers 1 and 2, respectively, were muscle invasion, 92% and 88%, 74% and 84%, 81% and 88%, 88% and 84%, 84% and 86%; peri-vesical invasion, 72% and 67%, 92% and 92%, 87% and 86%, 81% and 79%, 83% and 81%; regional nodal disease, 45% and 45%, 93% and 90%, 71% and 63%, 82% and 81%, 80% and 78%. Inter-observer agreement was good using all sequences.

CONCLUSIONS

mpMRI was both sensitive and specific in the detection of muscle invasive bladder cancer, and was specific but not sensitive for both peri-vesical invasion and nodal involvement. mpMRI may have a role at locally staging bladder cancer following transurethral resection.

Society of Abdominal Radiology disease-focused panel on renal cell carcinoma: update on past, current, and future goals

The disease-focused panel (DFP) program was created by the Society of Abdominal Radiology (SAR) as a mechanism to "improve patient care, education, and research" in a "particular disease or a particular aspect of a disease". The DFP on renal cell carcinoma (RCC) was proposed in 2014 and has been functional for 4 years. Although nominally focused on RCC, the scope of the DFP has included indeterminate renal masses because many cannot be assigned a specific diagnosis when detected. Since its founding, the DFP has been active in a variety of clinical, research, and educational projects to optimize the care of patients with known or suspected RCC. The DFP is utilizing multi-institutional and cross-disciplinary collaboration to differentiate benign from malignant disease, optimize the management of early stage RCC, and ultimately to differentiate indolent from aggressive cancers. Several additional projects have worked to develop a quantitative biomarker that predicts metastatic RCC response to anti-angiogenic therapy. While disease focus is the premise by which all DFPs are created, it is likely that in the future the RCC DFP will need to expand or create new panels that will focus on other specific aspects of RCC-a result that the program's founders envisioned. New knowledge creates a need for more focus.

Abstract 1611: High quality next generation sequencing results for breast cancer using dual-mode biopsy tissue preservation

Introduction: Formalin-fixed paraffin-embedded (FFPE) tissue is commonly used for molecular analysis, including for next generation sequencing (NGS). In an effort to improve the quality of molecular results in small tissue samples, we developed a novel biopsy transport device that splits the biopsy sample longitudinally for dual-mode preservation by freezing (for biomolecular analysis) and formalin (for the evaluation of histologic features without freezing artifact). In this feasibility study we compared NGS results from samples acquired by the new device with those obtained using standard biopsy handling procedures.

Methods: Following informed consent, biopsy samples were obtained ex-vivo by a breast imaging radiologist under ultrasound guidance from invasive cancers in two mastectomy specimens using a standard biopsy needle (Mission 14G, CR Bard). A reference sample (REF) was placed directly into 10% neutral buffered formalin. An experimental sample (EXP) was placed in the new device, ink marked on one end for orientation and sectioned longitudinally. After sectioning, one half-sample was formalin fixed and one half was frozen and then stored at -80 degrees until further processing. The REF samples and one half of the EXP samples were fixed for 24 hours then processed routinely into FFPE blocks. DNA was extracted from the REF sample and the frozen EXP half-sample and evaluated using NGS Oncopanel (targeted exome sequencing, Illumina) at 25ng, 50ng and 100ng input template.

Results: The formalin-fixed EXP halves maintained high quality of tissue histology with minimal artifacts. The number of unique, aligned, high-quality reads was on average 1.85-fold greater in the EXP specimens relative to the paired REF samples for all three template amounts in both tumors that were analyzed (range 1.58-fold to 2.29-fold; p=0.0016). More than twice as many high-quality reads were present in the EXP specimens for Tier 2 and Tier 3 mutations (TP53, PIK3CA and GATA3) at the lowest template amounts (average 2.40-fold at 25ng). Copy number reads showed lower cutoff scores (a measure of signal variability across segments) in EXP samples than in REF samples (p=0.0052).

Conclusions: Dual-mode preservation of core biopsy samples by freezing and formalin can be done with the new device and it provides equivalent quality of histology sections. Preservation of biopsy samples by freezing rather than formalin improved the quality of NGS evaluation in all samples down to 25ng input template, both for single variant analysis and for copy number detection. Longitudinal sectioning of the tissue samples allows for assessment of tumor purity and for macrodissection of the oriented frozen half-sample as needed. These improvements allow for greater confidence in variant and copy number calls with lower input template amounts.

Citation Format: Deborah A. Dillon, Elizabeth P. Garcia, Michele Baltay, Krishan Taneja, Teri Bowman, Eva C. Gombos, Tom Gal, Stuart G. Silverman, Erez Nevo, Shoshan Nevo. High quality next generation sequencing results for breast cancer using dual-mode biopsy tissue preservation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1611.

Renal cancer at unenhanced CT: imaging features, detection rates, and outcomes

PURPOSE

To describe and quantify the rate of detection of renal cancer on unenhanced CT.

METHODS

This retrospective, HIPAA-compliant study was approved by the Institutional Review Board. Electronic health records for all patients who underwent unenhanced abdominal CT at our institution between 2000 and 2005 were reviewed to identify patients subsequently diagnosed with renal cancer during a follow-up period of up to 12 years. Images were reviewed to determine if the cancer was visible at index (first) unenhanced CT and their findings recorded. Original radiology reports were reviewed to determine whether the renal cancer was reported; Fisher's Exact Test compared imaging features of detected and missed cancers. Clinical outcomes including time until diagnosis and stage at diagnosis were used to assess the potential impact of missed cancers.

RESULTS

Of 15,695 patients, 82 (0.52%) were diagnosed with renal cancer. Of these, 43/82 (52%) cancers were retrospectively detectable on index unenhanced CT. Among retrospectively detectable cancers, 63% (27/43) were originally detected and reported on index CT and 37% (16/43) were missed. Size was the only feature associated with detection; 83% (20/24) of cancers > 3.0 cm were detected versus 37% (7/19) of cancers ≤ 3.0 cm (p = 0.0036). Although none of the 16 missed renal cancers developed metastases between index CT and time of diagnosis (median 33.5 months), 4 (25%) progressed in stage.

CONCLUSIONS

Renal cancer was rare in patients undergoing unenhanced abdominal CT. Over one-third of potentially detectable cancers were missed prospectively. However, missed cancers did not metastasize and infrequently progressed in stage before being diagnosed.

Real-time Genomic Characterization of Advanced Pancreatic Cancer to Enable Precision Medicine

Clinically relevant subtypes exist for pancreatic ductal adenocarcinoma (PDAC), but molecular characterization is not yet standard in clinical care. We implemented a biopsy protocol to perform time-sensitive whole-exome sequencing and RNA sequencing for patients with advanced PDAC. Therapeutically relevant genomic alterations were identified in 48% (34/71) and pathogenic/likely pathogenic germline alterations in 18% (13/71) of patients. Overall, 30% (21/71) of enrolled patients experienced a change in clinical management as a result of genomic data. Twenty-six patients had germline and/or somatic alterations in DNA-damage repair genes, and 5 additional patients had mutational signatures of homologous recombination deficiency but no identified causal genomic alteration. Two patients had oncogenic in-frame BRAF deletions, and we report the first clinical evidence that this alteration confers sensitivity to MAPK pathway inhibition. Moreover, we identified tumor/stroma gene expression signatures with clinical relevance. Collectively, these data demonstrate the feasibility and value of real-time genomic characterization of advanced PDAC.Significance: Molecular analyses of metastatic PDAC tumors are challenging due to the heterogeneous cellular composition of biopsy specimens and rapid progression of the disease. Using an integrated multidisciplinary biopsy program, we demonstrate that real-time genomic characterization of advanced PDAC can identify clinically relevant alterations that inform management of this difficult disease. Cancer Discov; 8(9); 1096-111. ©2018 AACR.See related commentary by Collisson, p. 1062This article is highlighted in the In This Issue feature, p. 1047.

Bladder cancer diagnosis with CT urography: test characteristics and reasons for false-positive and false-negative results

PURPOSE

To determine test characteristics of CT urography for detecting bladder cancer in patients with hematuria and those undergoing surveillance, and to analyze reasons for false-positive and false-negative results.

METHODS

A HIPAA-compliant, IRB-approved retrospective review of reports from 1623 CT urograms between 10/2010 and 12/31/2013 was performed. 710 examinations for hematuria or bladder cancer history were compared to cystoscopy performed within 6 months. Reference standard was surgical pathology or 1-year minimum clinical follow-up. False-positive and false-negative examinations were reviewed to determine reasons for errors.

RESULTS

Ninety-five bladder cancers were detected. CT urography accuracy: was 91.5% (650/710), sensitivity 86.3% (82/95), specificity 92.4% (568/615), positive predictive value 63.6% (82/129), and negative predictive value was 97.8% (568/581). Of 43 false positives, the majority of interpretation errors were due to benign prostatic hyperplasia (n = 12), trabeculated bladder (n = 9), and treatment changes (n = 8). Other causes include blood clots, mistaken normal anatomy, infectious/inflammatory changes, or had no cystoscopic correlate. Of 13 false negatives, 11 were due to technique, one to a large urinary residual, one to artifact. There were no errors in perception.

CONCLUSION

CT urography is an accurate test for diagnosing bladder cancer; however, in protocols relying predominantly on excretory phase images, overall sensitivity remains insufficient to obviate cystoscopy. Awareness of bladder cancer mimics may reduce false-positive results. Improvements in CTU technique may reduce false-negative results.

Expanding the Definition of a Benign Renal Cyst on Contrast-enhanced CT: Can Incidental Homogeneous Renal Masses Measuring 21-39 HU be Safely Ignored?

RATIONALE AND OBJECTIVE

We aimed to determine the frequency and clinical significance of homogeneous renal masses measuring 21-39 Hounsfield units on contrast-enhanced computed tomography (CT).

METHODS

Subjects 40-69 years old undergoing portal-venous-phase contrast-enhanced abdominal CT from January 1, 2006 to December 31, 2010 with slice thickness ≤5 mm and no prior CT or magnetic resonance imaging were identified (n = 1387) for this institutional review board-approved retrospective cohort study. Images were manually reviewed by three radiologists in consensus to identify all circumscribed homogeneous renal masses (maximum of three per subject) ≥10 mm with a measured attenuation of 21-39 Hounsfield units. Exclusion criteria were known renal cancer or imaging performed for a renal indication. The primary outcome was retrospective characterization as a clinically significant mass, defined as a solid mass, a Bosniak IIF/III/IV mass, or extirpative therapy or metastatic renal cancer within 5 years' follow-up.

RESULTS

Eligible masses (n = 74) were found in 5% (63/1387) of subjects. Of those with a reference standard (n = 42), none (0% [95% CI: 0.0%-8.4%]) were determined to be clinically significant.

CONCLUSION

Incidental renal masses on contrast-enhanced CT that are homogeneous and display an attenuation of 21-39 Hounsfield units are uncommon in patients 40-69 years of age, unlikely to be clinically significant, and may not need further imaging evaluation. If these results can be replicated in an independent and larger population, the practical definition of a benign cyst on imaging may be able to be expanded.

Using needle orientation sensing as surrogate signal for respiratory motion estimation in percutaneous interventions

PURPOSE

To develop and evaluate an approach to estimate the respiratory-induced motion of lesions in the chest and abdomen.

MATERIALS AND METHODS

The proposed approach uses the motion of an initial reference needle inserted into a moving organ to estimate the lesion (target) displacement that is caused by respiration. The needles position is measured using an inertial measurement unit (IMU) sensor externally attached to the hub of an initially placed reference needle. Data obtained from the IMU sensor and the target motion are used to train a learning-based approach to estimate the position of the moving target. An experimental platform was designed to mimic respiratory motion of the liver. Liver motion profiles of human subjects provided inputs to the experimental platform. Variables including the insertion angle, target depth, target motion velocity and target proximity to the reference needle were evaluated by measuring the error of the estimated target position and processing time.

RESULTS

The mean error of estimation of the target position ranged between 0.86 and 1.29 mm. The processing maximum training and testing time was 5 ms which is suitable for real-time target motion estimation using the needle position sensor.

CONCLUSION

The external motion of an initially placed reference needle inserted into a moving organ can be used as a surrogate, measurable and accessible signal to estimate in real-time the position of a moving target caused by respiration; this technique could then be used to guide the placement of subsequently inserted needles directly into the target.

Bending percutaneous drainage catheters to facilitate CT-guided insertion using curved trocar technique

PURPOSE

To assess the safety and efficacy of placing thoraco-abdominal drainage catheters under CT-guidance using a curved trocar technique.

METHODS

A retrospective study of 182 CT/CT-fluoroscopy-guided thoraco-abdominal catheter drainages was conducted; half were performed by residents or fellows under the supervision of one radiologist (Group 1) and the other half under the supervision of 10 other radiologists (Group 2). Group 1 procedures employed a curved catheter assembly placed using trocar technique (n = 44) or straight catheters placed with Seldinger technique (n = 47). Group 2 procedures employed a straight catheter placed using trocar technique (n = 16) or straight catheters placed with Seldinger technique (n = 75). Technical success, procedure time, radiation dose (CT Dose Index CTDI_vol), and adverse events (Common Terminology Criteria for Adverse Events, 4.0) were compared between techniques and groups using Student's t test, Fisher's exact test or Chi-square analysis.

RESULTS

All procedures in groups 1 and 2 were technically successful. Mean procedure time for Group 1 curved trocar technique (28 ± 8 min) was shorter than groups 1 and 2 Seldinger technique (37 ± 11 min, p = .00002). Mean CTDI_vol for Group 1 curved trocar technique (107.8 ± 54.2 mGy) was lower than groups 1 and 2 Seldinger technique (136.1 ± 99.7 mGy, p = 0.032). Adverse event rates for curved trocar, straight trocar, and Seldinger techniques were 2.3% (1/44), 0% (0/16), and 3.3% (4/122), respectively (p = 1); all were grade 1 or 2, and no catheter malfunctions occurred.

CONCLUSIONS

The curved catheter trocar technique is a safe and effective modification of the standard trocar technique that may facilitate CT-guided procedures impeded by CT gantry size limitations.