A Multi-Institutional Study of Magnetic Resonance/Ultrasound Fusion-Guided Nanoparticle-Directed Focal Therapy for Prostate Ablation.

PURPOSE: Focal therapy aims to provide a durable oncologic treatment option for men with prostate cancer (PCa), while preserving their quality of life. Most focal therapy modalities rely on the direct tissue effect, resulting in a possible nontargeted approach to ablation. Here, we report the results of the first human feasibility trial utilizing nanoparticle-directed focal photothermal ablation for PCa. MATERIALS AND METHODS: A prospective, open-label, single-arm, multicenter study of men with localized PCa in Gleason Grade Group 1 to 3 was conducted. Men received a single infusion of gold nanoparticles (AuroShells), followed by magnetic resonance (MR)/ultrasound (US) fusion-guided laser excitation of the target tissue to induce photothermal ablation. MRI was used to assess the effectiveness of prostate tissue ablation at 48 to 96 hours, 3 months, and 12 months post treatment. At 3 months, a targeted fusion biopsy of the lesion(s) was conducted. At 12 months, a targeted fusion biopsy and standard templated biopsy were performed. Treatment success was determined based on a negative MR/US fusion biopsy outcome within the treated area. RESULTS: Forty-six men were enrolled in the study, and 44 men with 45 lesions completed nanoparticle infusion and laser treatment. The mean PSA level at baseline was 9.5 ng/mL, which decreased to 5.9 ng/mL at 3 months and to 4.7 ng/mL at 12 months (P < .0001). The oncologic success rates at 3 and 12 months resulted in 29 (66%) and 32 (73%) of 44 patients, respectively, being successfully treated, confirmed with negative MR/US fusion biopsies within the ablation zone. Among Gleason Grade Group, maximum lesion diameter on MRI, prostate volume, and Prostate Imaging Reporting and Data System scoring, the maximum lesion diameter was significantly associated with the odds of treatment failure at 12 months (P = .046). CONCLUSIONS: Nanoparticle-directed focal laser ablation of neoplastic prostate tissue resulted in 73% of patients with successful treatment at 12 months post treatment, confirmed by negative MR/US fusion biopsy of the treated lesion and a systematic biopsy. CLINICAL TRIAL REGISTRATION NO.: 02680535.

Opportunity and Opportunism in Artificial-Intelligence-Powered Data Extraction: A Value-Centered Approach.

Radiologists' traditional role in the diagnostic process is to respond to specific clinical questions and reduce uncertainty enough to permit treatment decisions. This charge is rapidly evolving due to forces such as artificial intelligence [AI], big data [opportunistic imaging, imaging prognostication], and advanced diagnostic technologies. A new "modernistic" paradigm is emerging whereby radiologists, in conjunction with computer algorithms, will be tasked with extracting as much information from imaging data as possible, often without a specific clinical question being posed and independent of any stated clinical need. In addition, AI algorithms are increasingly able to predict long-term outcomes using data from seemingly normal examinations, enabling AI-assisted prognostication. As these algorithms become a standard component of radiology practice, the sheer amount of information they demand will increase the need for streamlined workflows, communication, and data management techniques. In addition, the provision of such information raises reimbursement, liability, and access issues. Guidelines will be needed to ensure all patients have access to the benefits of this new technology and guarantee mined data do not inadvertently create harm. In this article, we discuss challenges and opportunities relevant to radiologists in this changing landscape, with an emphasis on ensuring that radiologists provide high-value care.

Anal sphincter function in rectal intussusception and high and low "take-off" external rectal prolapse-A prospective observational study.

AIM: Rectal intussusception (RI) and external rectal prolapse (ERP) are associated with anal sphincter dysfunction. The aim of this study was to examine sphincter function with anal acoustic reflectometry (AAR) in RI and two distinct phenotypes of ERP termed high and low "take-off". METHODS: A prospective study of patients with RI and ERP attending a tertiary pelvic floor unit. Clinical data, AAR, and conventional anal manometry were analysed according to the Oxford prolapse grade. RESULTS: A total of 108 (102 [94%] female, median age 62 years [range: 26-95]) patients were recruited into three groups according to prolapse grade: Oxford grades I and II (intrarectal RI, n = 34), Oxford grades III and IV (intra-anal RI, n = 35) and Oxford grade V (ERP, n = 39). As the grade of prolapse increased, resting AAR measurements of opening pressure, opening elastance, closing pressure, and closing elastance decreased (p < 0.001). Maximum resting pressure with manometry was reduced in ERP and intra-anal RI compared to intrarectal RI (p < 0.001). However, incremental squeeze function was not different between the three groups with either AAR or manometry (p > 0.05). There were no differences in AAR or manometry variables between grade IV RI (n = 18) and high take-off ERP (n = 20) (p > 0.05). By contrast, opening pressure (p = 0.010), closing pressure (p = 0.019) and elastance (p = 0.022) were reduced in low take-off ERP (n = 19). CONCLUSION: Increasing rectal prolapse grade is associated with reduced anal sphincter function at rest indicating internal anal sphincter dysfunction. Physiological differences exist between high and low take-off ERP with sphincter function in the former similar to that seen in grade IV RI.

Nociceptive and Transcriptomic Responses in a Swine Diabetic Wound Model Treated With a Topical Angiotensin 1 Receptor Antagonist.

BACKGROUND: Painful, treatment-resistant wounds are prevalent among diabetic patients and significantly affect health-related quality of life (HRQOL). Topical treatments may help alleviate pain without risk of dependence or side effects. However, there is a lack of topical wound compounds targeting pain-specific receptors. One possible target is proinflammatory angiotensin 1 receptor (AT1R), which is upregulated in diabetic skin and has been implicated in nociception. OBJECTIVES: We investigated the effects of topical valsartan, an AT1R antagonist, on pain (nociceptive thresholds) and gene expression changes (transcriptomics) in a swine model of diabetic wounds. METHODS: Eight wounds were surgically induced in diabetic, hyperglycemic Yucatan miniature swine ( n = 4). Topical AT1R antagonist was applied to wounds on one side and vehicle on the other side. Nocifensive testing was conducted at baseline and then weekly, beginning 7 days after wound induction. Mechanical and thermal stimuli were applied to the wound margins until a nocifensive reaction was elicited or a predetermined cutoff was reached. After 7 weeks of testing, tissue from the dorsal horn, dorsal root ganglion, and wounds were sequenced and analyzed with DESeq2. Unbiased pathway analyses using Metascape were conducted on differentially expressed genes. RESULTS: There was no significant difference in mechanical tolerance threshold between AT1R antagonist-treated and vehicle-treated wounds ( p = .106). Thermal tolerance was significantly higher in AT1R antagonist-treated wounds compared to vehicle-treated ( p = .015). Analysis of differentially expressed genes revealed enriched pathways of interest: interleukin-18 signaling in dorsal horn laminae IV-V and sensory perception of mechanical stimulus in wound tissue. DISCUSSION: In this study, wounds modeling diabetic ulcers were created in hyperglycemic swine and treated with a topical AT1R antagonist. AT1R-antagonist-treated wounds had a higher tolerance threshold than vehicle-treated wounds for thermal hyperalgesia, but not mechanical allodynia. Pathway analyses of differentially expressed genes revealed several pathways of interest for future pain research. Although further studies are needed to confirm the findings, this study can improve nursing care by providing information about a potential future treatment that may be used to decrease pain and improve HRQOL in patients with diabetic wounds.

Multicenter Validation of Abbreviated MRI for Detecting Early-Stage Hepatocellular Carcinoma.

Background Abbreviated MRI is a proposed paradigm shift for hepatocellular carcinoma (HCC) surveillance, but data on its performance are lacking for histopathologically confirmed early-stage HCC. Purpose To evaluate the sensitivity and specificity of dynamic contrast-enhanced abbreviated MRI for early-stage HCC detection, using surgical pathologic findings as the reference standard. Materials and Methods This retrospective study was conducted at three U.S. liver transplant centers in patients with cirrhosis who underwent liver resection or transplant between January 2009 and December 2019 and standard "full" liver MRI with and without contrast enhancement within 3 months before surgery. Patients who had HCC-directed treatment before surgery were excluded. Dynamic abbreviated MRI examinations were simulated from the presurgical full MRI by selecting the coronal T2-weighted and axial three-dimensional fat-suppressed T1-weighted dynamic contrast-enhanced sequences at precontrast, late arterial, portal venous, and delayed phases. Two abdominal radiologists at each center independently interpreted the simulated abbreviated examinations with use of the Liver Imaging Reporting and Data System version 2018. Patients with any high-risk liver observations (>LR-3) were classified as positive; otherwise, they were classified as negative. With liver pathologic findings as the reference standard for the presence versus absence of early-stage HCC, the sensitivity, specificity, and their 95% CIs were calculated. Logistic regression was used to identify factors associated with correct classification. Results A total of 161 patients with early-stage HCC (median age, 62 years [IQR, 58-67 years]; 123 men) and 138 patients without HCC (median age, 55 years [IQR, 47-63 years]; 85 men) were confirmed with surgical pathologic findings. The sensitivity and specificity of abbreviated MRI were 88.2% (142 of 161 patients) (95% CI: 83.5, 92.5) and 89.1% (123 of 138 patients) (95% CI: 84.4, 93.8), respectively. Sensitivity was lower for Child-Pugh class B or C versus Child-Pugh class A cirrhosis (64.1% vs 94.2%; P < .001). Conclusion With surgical pathologic findings as the reference standard, dynamic abbreviated MRI had high sensitivity and specificity for early-stage hepatocellular carcinoma detection in patients with compensated cirrhosis but lower sensitivity in those with decompensated cirrhosis. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Kim in this issue.

A Multicenter Assessment of Interreader Reliability of LI-RADS Version 2018 for MRI and CT.

Background Various limitations have impacted research evaluating reader agreement for Liver Imaging Reporting and Data System (LI-RADS). Purpose To assess reader agreement of LI-RADS in an international multicenter multireader setting using scrollable images. Materials and Methods This retrospective study used deidentified clinical multiphase CT and MRI and reports with at least one untreated observation from six institutions and three countries; only qualifying examinations were submitted. Examination dates were October 2017 to August 2018 at the coordinating center. One untreated observation per examination was randomly selected using observation identifiers, and its clinically assigned features were extracted from the report. The corresponding LI-RADS version 2018 category was computed as a rescored clinical read. Each examination was randomly assigned to two of 43 research readers who independently scored the observation. Agreement for an ordinal modified four-category LI-RADS scale (LR-1, definitely benign; LR-2, probably benign; LR-3, intermediate probability of malignancy; LR-4, probably hepatocellular carcinoma [HCC]; LR-5, definitely HCC; LR-M, probably malignant but not HCC specific; and LR-TIV, tumor in vein) was computed using intraclass correlation coefficients (ICCs). Agreement was also computed for dichotomized malignancy (LR-4, LR-5, LR-M, and LR-TIV), LR-5, and LR-M. Agreement was compared between research-versus-research reads and research-versus-clinical reads. Results The study population consisted of 484 patients (mean age, 62 years ± 10 [SD]; 156 women; 93 CT examinations, 391 MRI examinations). ICCs for ordinal LI-RADS, dichotomized malignancy, LR-5, and LR-M were 0.68 (95% CI: 0.61, 0.73), 0.63 (95% CI: 0.55, 0.70), 0.58 (95% CI: 0.50, 0.66), and 0.46 (95% CI: 0.31, 0.61) respectively. Research-versus-research reader agreement was higher than research-versus-clinical agreement for modified four-category LI-RADS (ICC, 0.68 vs 0.62, respectively; P = .03) and for dichotomized malignancy (ICC, 0.63 vs 0.53, respectively; P = .005), but not for LR-5 (P = .14) or LR-M (P = .94). Conclusion There was moderate agreement for LI-RADS version 2018 overall. For some comparisons, research-versus-research reader agreement was higher than research-versus-clinical reader agreement, indicating differences between the clinical and research environments that warrant further study. © RSNA, 2023 Supplemental material is available for this article. See also the editorials by Johnson and Galgano and Smith in this issue.

Adverse Events Associated with Intra-Arterial Administration of Gadolinium-Based Contrast Agents: A Systematic Review and Meta-Analysis.

PURPOSE: To determine the risk of immediate hypersensitivity reactions (HRs), contrast-associated acute kidney injury (CA-AKI), nephrogenic systemic fibrosis (NSF), and gadolinium retention associated with use of intra-arterial gadolinium-based contrast agents (GBCAs). MATERIALS AND METHODS: MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched from 1988 (GBCAs approved for clinical use) to March 2021 for studies reporting adverse events associated with intra-arterial administration of GBCAs. The number of adverse events and GBCA administrations were used to calculate incidence in individual studies, and results across studies were pooled using random-effects meta-analysis. RESULTS: There were 72 studies (patients = 1,221) that reported on HR, 59 studies (patients = 1,142) that reported on CA-AKI, and 6 studies (patients = 291) that reported on NSF. No studies reported gadolinium retention as an outcome. Based on 5 events and 1,451 GBCA administrations, the incidence of HR per 100 administrations was 0.95 (95% CI, 0.52-1.51). Based on 90 events and 1,318 GBCA administrations, the incidence of CA-AKI per 100 administrations was 5.94 (95% CI, 3.92-8.34). Based on 7 events and 361 GBCA administrations, the incidence of NSF per 100 Group I GBCA administrations was 4.72 (95% CI, 0.35-13.70). There were no unconfounded NSF events after Group II GBCA administration. CONCLUSIONS: HRs to intra-arterial administration of GBCAs are rare, with no serious reactions. Limited data demonstrate a higher-than-expected rate of CA-AKI; however, multiple confounding factors were noted. Thus, any causative link of CA-AKI to GBCA remains controversial. Also, severe physiologic reactions (including life-threatening arrhythmias) during coronary angiography have been reported.

Diagnostic yield of whole-body 18F-FDG PET/CT in patients with suspected cardiac sarcoidosis.

BACKGROUND: Whole-body F-18 FDG PET has been included in the 2014 Heart Rhythm Society guidelines for cardiac sarcoidosis evaluation to identify alternate sites of biopsy prior to endomyocardial biopsy. The purpose of this study was to evaluate the diagnostic yield of whole-body F-18 FDG PET/CT. METHODS: All adult patients with suspected cardiac sarcoidosis undergoing same-day cardiac F-18 FDG PET/CT and whole-body F-18 FDG PET/CT between 10/1/2016 and 6/14/2021 to assess potential biopsy sites were retrospectively identified. Clinical indications, findings, recommendations, and outcomes were assessed. RESULTS: Eighty-eight patients were included. Extracardiac PET findings suggestive of sarcoidosis were present in 30 patients (34%), 27 of which had thoracic findings (90%). Sarcoidosis was diagnosed in 11% of patients. Only 1% (1/88) was diagnosed by extrathoracic biopsy of a whole-body PET finding. Incidental findings were common (31%), resulting in 11 additional tests or interventions. Recommendations from extrathoracic findings affected treatment in one case: a drainage catheter placement into an unsuspected pelvic abscess. CONCLUSION: Addition of whole-body F-18 FDG PET/CT to cardiac F-18 FDG PET/CT for the identification of extrathoracic sites of biopsy in patients with suspected cardiac sarcoidosis has marginal diagnostic yield but commonly results in incidental findings that rarely affect patient outcome.

Incidental Findings and Low-Value Care.

Incidental imaging findings are common and analogous to the results of screening tests when screening is performed of unselected, low-risk patients. Approximately 15-30% of all diagnostic imaging and 20-40% of CT examinations contain at least one incidental finding. Patients with incidental findings but low risk for disease are likely to experience length bias, lead-time bias, overdiagnosis, and overtreatment that create an illusion of benefit while conferring harm. This includes incidental detection of many types of cancers that, although malignant, would have been unlikely to affect a patient's health had the cancer not been detected. Detection of some incidental findings can improve health, but most do not. Greater patient- and disease-related risk increase the likelihood an incidental finding is important. Clinical guidelines for incidental findings should more deeply integrate patient risk factors and disease aggressiveness to inform management. Lack of outcome and cost-effectiveness data has led to reflexive management strategies for incidental findings that promote low-value and sometimes harmful care.

Patient Preferences for Hepatocellular Carcinoma Surveillance Parameters.

BACKGROUND AND AIMS: Professional societies recommend abdominal ultrasound (US) with or without alpha fetoprotein (AFP) for hepatocellular cancer (HCC) surveillance; however, there are several emerging surveillance modalities, including abbreviated MRI and blood-based biomarker panels. Most studies have focused on provider perspectives for surveillance logistics, but few have assessed patient preferences. We aimed to measure preferences among patients with cirrhosis regarding HCC surveillance modalities. METHODS: We conducted a choice-based conjoint survey to patients with cirrhosis at four institutions. Participants were provided 15 scenarios in which they were asked to choose surveillance modalities based on five test attributes: benefits, i.e. sensitivity for early HCC (range: 35-95%), physical harm, i.e. false positives requiring additional testing (range: 10-40%), financial harm, i.e. out-of-pocket costs (range: $10-100), test logistics and convenience, i.e. duration of testing (range: 10-60 min). Hierarchical Bayes discrete choice conjoint analysis was used to derive attribute importance, and preference shares were determined by simulation. RESULTS: In total 91% (182/199) of approached patients consented to participate in the study and 98% (n=179) successfully completed the survey. Surveillance benefits (importance: 51.3%, 95%CI: 49.0-53.4%) were valued more than risk of physical harm (importance: 7.6%, 95%CI 7.0-8.2%), financial harm (importance: 15.2%, 95%CI 14.0-16.3%), convenience (importance: 9.3%, 95%CI 8.5-10.1%) and test logistics (importance: 16.7%, 95%CI 15.4-18.1%). Based on simulations including all possible tests, patients preferred abbreviated MRI (29.0%), MRI (23.3%), or novel blood-based biomarkers (20.9%) to ultrasound alone (3.4%) or with AFP (8.8%). CONCLUSIONS: Patients with cirrhosis prioritize early HCC detection over potential surveillance-related harms or inconvenience.

Symptoms Associated with Gadolinium Exposure (SAGE): A Suggested Term.

In this article, members of the American College of Radiology Committee on Drugs and Contrast Media propose a new term for symptoms reported after intravascular exposure to gadolinium-based contrast agents-Symptoms Associated with Gadolinium Exposure, or SAGE. This term is advocated in lieu of other proposed nomenclature that presumes a causal relationship that has not yet been scientifically verified. The purpose of this new term, SAGE, is to assist researchers and clinical providers in describing such symptoms without prematurely causally attributing them to a disease and to standardize reporting of these symptoms to allow for coherent interpretation of related studies.

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.

Preoperative Prostate MRI Predictors of Urinary Continence Following Radical Prostatectomy.

Background Urinary continence after radical prostatectomy (RP) is an important determinant of patient quality of life. Anatomic measures at prostate MRI have been previously associated with continence outcomes, but their predictive ability and interrater agreement are unclear in comprehensive clinical models. Purpose To evaluate the predictive ability and interrater agreement of MRI-based anatomic measurements of post-RP continence when combined with clinical multivariable models. Materials and Methods In this retrospective cohort study, continence outcomes were evaluated in men who underwent RP from August 2015 to October 2019. Preoperative MRI-based anatomic measures were obtained retrospectively by four abdominal radiologists. Before participation, these radiologists completed measure-specific training. Logistic regression models were developed with clinical variables alone, MRI variables alone, and combined variables for predicting continence at 3, 6, and 12 months after RP; some patient data were missing at each time point. Interrater agreement of MRI variables was assessed by using intraclass correlation coefficients (ICCs). Results A total of 586 men were included (mean age ± standard deviation: 63 years ± 7). The proportion of patients with incontinence was 0.2% (one of 589) at baseline, 27% (145 of 529) at 3 months, 14% (63 of 465) at 6 months, and 9% (37 of 425) at 12 months. Longer coronal membranous urethra length (MUL) improved the odds of post-RP continence at all time points (odds ratio per 1 mm: 0.86 [95% CI: 0.80, 0.93], P < .001; 0.86 [95% CI: 0.78, 0.95], P = .003; and 0.79 [95% CI: 0.67, 0.91], P = .002, respectively) in models that incorporated both clinical and MRI predictors. No other MRI variables were predictive. Age and baseline urinary function score were the only other predictive clinical variables at every time point. Interrater agreement was moderate (ICC, 0.62) for MUL among readers with measure-specific prostate MRI training and poor among those without the training (ICC, 0.38). Conclusion Preoperative MRI-measured coronal membranous urethra length was an independent predictor of urinary continence after prostatectomy. © RSNA, 2022 Online supplemental material is available for this article.

Iodinated Contrast Media Substitution to Prevent Recurrent Hypersensitivity Reactions: A Systematic Review and Meta-Analysis.

Background Changing iodinated contrast media (ICM) may reduce the risk of recurrent ICM-induced hypersensitivity reactions in patients with a prior reaction. Purpose To perform a systematic review on the effectiveness of ICM change in comparison with no change to prevent recurrent ICM immediate hypersensitivity reactions. Materials and methods Multiple data bases were searched without language restriction between January 1990 and August 2021 to identify comparative studies of any design that included patients with a prior ICM hypersensitivity reaction to low-osmolality ICM and re-exposure to intravascular ICM. The methods used included a duplicate assessment of eligibility, double extraction of quantitative data, validity assessment, and random-effects meta-analysis. The primary outcome was the incidence of all-grade immediate recurrent hypersensitivity reactions. Secondary outcomes were the incidence of severe immediate recurrent hypersensitivity reactions and other adverse events associated with ICM change. Results Six retrospective observational studies at moderate to severe risk of bias assessed 7155 adult patients (4329 in the ICM change group and 2826 in the no-change group). Studies adopted nonstandardized switching methods, and the proportions of the ICM change group ranged between 19% (five of 27 examinations) and 80% (3104 of 3880 examinations). A Bayesian meta-analysis revealed that changing ICM was associated with a reduced risk of recurrent hypersensitivity reaction by 61% (risk ratio = 0.39; 95% credible interval [CrI]: 0.24, 0.58). The wide-ranging estimates of risk reduction were not explained by the risk of bias ratings, the event rates in the no-change group, the index-reaction severity, or the co-administered nonstandard premedication. Rare severe recurrent reactions (five studies with five events) precluded a conclusion (risk ratio = 0.34, favoring ICM change; CrI: 0.01, 3.74). Adverse events associated with ICM change were not reported. Conclusion In observational evidence of limited quality, iodinated contrast media (ICM)-change was associated with a reduced risk of recurrent immediate hypersensitivity reaction in patients with a prior ICM-induced hypersensitivity reaction. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by McDonald in this issue.

Interrater Agreement of Bosniak Classification Version 2019 and Version 2005 for Cystic Renal Masses at CT and MRI.

Background The Bosniak classification system for cystic renal masses was updated in 2019 in part to improve agreement compared with the 2005 version. Purpose To compare and investigate interrater agreement of Bosniak version 2019 and Bosniak version 2005 at CT and MRI. Materials and Methods In this retrospective single-center study, a blinded eight-reader assessment was performed in which 195 renal masses prospectively considered Bosniak IIF-IV (95 at CT, 100 at MRI, from 2006 to 2019 with version 2005) were re-evaluated with Bosniak versions 2019 and 2005. Radiologists (four faculty members, four residents) who were blinded to the initial clinical reading and histopathologic findings assessed all feature components and reported the overall Bosniak class for each system independently. Agreement was assessed with Gwet agreement coefficients. Uni- and multivariable linear regression models were developed to identify predictors of dispersion in the final Bosniak class assignment that could inform system refinement. Results A total of 185 patients were included (mean age, 63 years ± 13 [standard deviation]; 118 men). Overall interrater agreement was similar between Bosniak version 2019 and version 2005 (Gwet agreement coefficient: 0.51 [95% CI: 0.45, 0.57] vs 0.46 [95% CI: 0.42, 0.51]). This was true for experts (0.54 vs 0.49) and novices (0.50 vs 0.47) and at CT (0.56 vs 0.51) and MRI (0.52 vs 0.43). Nine percent of masses prospectively considered cystic using Bosniak version 2005 criteria were considered solid using version 2019 criteria. In general, masses were more commonly classified in lower categories when radiologists used Bosniak version 2019 criteria compared with version 2005 criteria. The sole predictor of dispersion in Bosniak version 2019 class assignment was dispersion in septa or wall quality (ie, smooth vs irregular thickening vs nodule; 72% [MRI] and 60% [CT] overall model variance explained; multivariable P < .001). Conclusion Overall interrater agreement was similar between Bosniak version 2019 and version 2005; disagreements in septa or wall quality were common and strongly predictive of variation in Bosniak class assignment. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Eberhardt in this issue.

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.

Repeatability and Reproducibility Assessment of the Apparent Diffusion Coefficient in the Prostate: A Trial of the ECOG-ACRIN Research Group (ACRIN 6701).

BACKGROUND: Uncertainty regarding the reproducibility of the apparent diffusion coefficient (ADC) hampers the use of quantitative diffusion-weighted imaging (DWI) in evaluation of the prostate with magnetic resonance imaging MRI. The quantitative imaging biomarkers alliance (QIBA) profile for quantitative DWI claims a within-subject coefficient of variation (wCV) for prostate lesion ADC of 0.17. Improved understanding of ADC reproducibility would aid the use of quantitative diffusion in prostate MRI evaluation. PURPOSE: Evaluation of the repeatability (same-day) and reproducibility (multi-day) of whole-prostate and focal-lesion ADC assessment in a multi-site setting. STUDY TYPE: Prospective multi-institutional. SUBJECTS: Twenty-nine males, ages 53 to 80 (median 63) years, following diagnosis of prostate cancer, 10 with focal lesions. FIELD STRENGTH/SEQUENCE: 3T, single-shot spin-echo diffusion-weighted echo-planar sequence with four b-values. ASSESSMENT: Sites qualified for the study using an ice-water phantom with known ADC. Readers performed DWI analyses at visit 1 ("V1") and visit 2 ("V2," 2-14 days after V1), where V2 comprised scans before ("V2pre") and after ("V2post") a "coffee-break" interval with subject removal and repositioning. A single reader segmented the whole prostate. Two readers separately placed region-of-interests for focal lesions. STATISTICAL TESTS: Reproducibility and repeatability coefficients for whole prostate and focal lesions derived from median pixel ADC. We estimated the wCV and 95% confidence interval using a variance stabilizing transformation and assessed interreader reliability of focal lesion ADC using the intraclass correlation coefficient (ICC). RESULTS: The ADC biases from b0 -b600 and b0 -b800 phantom scans averaged 1.32% and 1.44%, respectively; mean b-value dependence was 0.188%. Repeatability and reproducibility of whole prostate median pixel ADC both yielded wCVs of 0.033 (N = 29). In 10 subjects with an evaluable focal lesion, the individual reader wCVs were 0.148 and 0.074 (repeatability) and 0.137 and 0.078 (reproducibility). All time points demonstrated good to excellent interreader reliability for focal lesion ADC (ICCV1  = 0.89; ICCV2pre  = 0.76; ICCV2post  = 0.94). DATA CONCLUSION: This study met the QIBA claim for prostate ADC. Test-retest repeatability and multi-day reproducibility were largely equivalent. Interreader reliability for focal lesion ADC was high across time points. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 2 TOC CATEGORY: Pelvis.

What Is It We Do Here?

We argue radiologists generate most of their value by serving as translators and communicators-linguists skilled in the languages of imaging. The disconnect between these core functions and how radiology practices are paid impedes our efforts to maximize value. We believe more investigation is needed to optimize the fidelity of our translations and the coherence, visibility, and actionability of our communications.

Effect of Prostate MRI Interpretation Experience on PPV Using PI-RADS Version 2: A 6-Year Assessment Among Eight Fellowship-Trained Radiologists.

BACKGROUND. Understanding the effect of specific experience in prostate MRI interpretation on diagnostic performance would help inform the minimum interpretation volume to establish proficiency. OBJECTIVE. The purpose of this article is to assess for an association between increasing experience in prostate MRI interpretation and change in radiologist-level PPVs for PI-RADS version 2 (v2) categories 3, 4, and 5. METHODS. This retrospective study included prostate MRI examinations performed between July 1, 2015, and August 13, 2021, that were assigned a PI-RADS v2 category of 3, 4, or 5 and with an MRI-ultrasound fusion biopsy available as the reference standard. All examinations were among the first 100-200 prostate MRI examinations interpreted using PI-RADS v2 by fellowship-trained abdominal radiologists. Radiologists received feedback through a quality assurance program. Radiologists' experience levels were classified using progressive subsets of 50 interpreted examinations. Change with increasing experience in distribution of individual radiologists' whole-gland PPVs for Gleason sum score 7 or greater prostate cancer, stratified by PI-RADS category, was assessed by hierarchic linear mixed models. RESULTS. The study included 1300 prostate MRI examinations in 1037 patients (mean age, 66 ± 7 [SD] years), interpreted by eight radiologists (median, 13 years of postfellow-ship experience; range, 5-22 years). Aggregate PPVs were 20% (68/340) for PI-RADS category 3, 49% (318/652) for category 4, and 71% (220/308) for category 5. Interquartile ranges (IQRs) of PPVs overlapped for category 4 (51%; IQR, 42-60%) and category 5 (70%; IQR, 54-75%) for radiologists' first 50 examinations. IQRs of PPVs did not overlap between categories of greater experience; for example, at the 101-150 examination level, PPV for category 3 was 24% (IQR, 20-29%), category 4 was 55% (IQR, 54-63%), and category 5 was 81% (IQR, 77-82%). Hierarchic modeling showed no change in radiologists' absolute PPV with increasing experience (category 3, p = .27; category 4, p = .71; category 5, p = .38). CONCLUSION. Absolute PPVs at specific PI-RADS categories did not change during radiologists' first 200 included examinations. However, resolution of initial overlap in IQRs indicates improved precision of PPVs after the first 50 examinations. CLINICAL IMPACT. If implementing a minimum training threshold for fellowship-trained abdominal radiologists, 50 prostate MRI examinations may be sufficient in the context of a quality assurance program with feedback.

Use of Intravenous Gadolinium-based Contrast Media in Patients with Kidney Disease and the Risk of Nephrogenic Systemic Fibrosis: Radiology In Training.

A 66-year-old male patient with end-stage chronic kidney disease undergoing maintenance dialysis and with a history of group I intravenous gadolinium-based contrast media (GBCM) administration presented with clinical and pathologic findings consistent with nephrogenic systemic fibrosis. A summary of the evidence and recommendations for use of intravenous GBCM in patients with kidney disease is presented. © RSNA, 2021.