Comparison of Positive Predictive Values of Biparametric MRI and Multiparametric MRI-directed Transrectal US-guided Targeted Prostate Biopsy.

Background Biparametric MRI (bpMRI) of the prostate is an alternative to multiparametric MRI (mpMRI), with lower cost and increased accessibility. Studies investigating the positive predictive value (PPV) of bpMRI-directed compared with mpMRI-directed targeted biopsy are lacking in the literature. Purpose To compare the PPVs of bpMRI-directed and mpMRI-directed targeted prostate biopsies. Materials and Methods This retrospective cross-sectional study evaluated men who underwent bpMRI-directed or mpMRI-directed transrectal US (TRUS)-guided targeted prostate biopsy at a single institution from January 2015 to December 2022. The PPVs for any prostate cancer (PCa) and clinically significant PCa (International Society of Urological Pathology grade ≥2) were calculated for bpMRI and mpMRI using mixed-effects logistic regression modeling. Results A total of 1538 patients (mean age, 67 years ± 8 [SD]) with 1860 lesions underwent bpMRI-directed (55%, 849 of 1538) or mpMRI-directed (45%, 689 of 1538) prostate biopsy. When adjusted for the number of lesions and Prostate Imaging Reporting and Data System (PI-RADS) score, there was no difference in PPVs for any PCa or clinically significant PCa (P = .61 and .97, respectively) with bpMRI-directed (55% [95% CI: 51, 59] and 34% [95% CI: 30, 38], respectively) or mpMRI-directed (56% [95% CI: 52, 61] and 34% [95% CI: 30, 39], respectively) TRUS-guided targeted biopsy. PPVs for any PCa and clinically significant PCa stratified according to clinical indication were as follows: biopsy-naive men, 64% (95% CI: 59, 69) and 43% (95% CI: 39, 48) for bpMRI, 67% (95% CI: 59, 75) and 51% (95% CI: 43, 59) for mpMRI (P = .65 and .26, respectively); and active surveillance, 59% (95% CI: 49, 69) and 30% (95% CI: 22, 39) for bpMRI, 73% (95% CI: 65, 89) and 38% (95% CI: 31, 47) for mpMRI (P = .04 and .23, respectively). Conclusion There was no evidence of a difference in PPV for clinically significant PCa between bpMRI- and mpMRI-directed TRUS-guided targeted biopsy. © RSNA, 2024 Supplemental material is available for this article.

Adrenal Mass Biopsy in Patients Without Extraadrenal Primary Malignancy: A Multicenter Study.

BACKGROUND. Adrenal washout CT is not useful for evaluating incidental adrenal masses in patients without known or suspected primary extraadrenal malignancy. OBJECTIVE. The purpose of our study was to evaluate the diagnostic utility of adrenal mass biopsy in patients without known or suspected extraadrenal primary malignancy. METHODS. This retrospective six-center study included 69 patients (mean age, 56 years; 32 men, 37 women) without known or suspected extraadrenal primary malignancy who underwent image-guided core needle biopsy between January 2004 and June 2021 of a mass suspected to be arising from the adrenal gland. Biopsy results were classified as diagnostic or nondiagnostic. For masses resected after biopsy, histopathologic concordance was assessed between diagnoses from biopsy and resection. Masses were classified as benign or malignant by resection or imaging follow-up, and all nondi-agnostic biopsies were classified as false results. RESULTS. The median mass size was 7.4 cm (range, 1.9-19.2 cm). Adrenal mass biopsy had a diagnostic yield of 64% (44/69; 95% CI, 51-75%). After biopsy, 25 masses were resected, and 44 had imaging follow-up. Of the masses that were resected after diagnostic biopsy, diagnosis was concordant between biopsy and resection in 100% (12/12). Of the 13 masses that were resected after nondiagnostic biopsy, the diagnosis from re-section was benign in eight masses and malignant in five masses. The 44 masses with imaging follow-up included one mass with diagnostic biopsy yielding benign adenoma and two masses with nondiagnostic biopsy results that were classified as malignant by imaging follow-up. Biopsy had overall sensitivity and specificity for malignancy of 73% (22/30) and 54% (21/39), respectively; diagnostic biopsies had sensitivity and specificity for malignancy of 96% (22/23) and 100% (21/21), respectively. Among nine nondi-agnostic biopsies reported as adrenocortical neoplasm, six were classified as malignant by the reference standard (resection showing adrenocortical carcinoma in four, resection showing adrenocortical neoplasm of uncertain malignant potential in one, imaging follow-up consistent with malignancy in one). CONCLUSION. Adrenal mass biopsy had low diagnostic yield, with low sensitivity and low specificity for malignancy. A biopsy result of adrenocortical neoplasm did not reliably differentiate benign and malignant adrenal masses. CLINICAL IMPACT. Biopsy appears to have limited utility for the evaluation of incidental adrenal masses in patients without primary extraadrenal malignancy.

Prevalence of 'Fat-Poor' Adrenal Adenomas at Chemical-Shift MRI.

OBJECTIVE: : To determine the prevalence of 'fat-poor' adrenal adenomas at chemical-shift-MRI. MATERIALS AND METHODS: : This prospective IRB approved study identified 104 consecutive patients with 127 indeterminate adrenal masses that underwent 1.5-T chemical-shift-MRI between 2021-2023. Two blinded radiologists independently measured: 1) 2-Dimensionsal (2D) chemical-shift signal intensity (SI)-index on 2D Chemical-shift-MRI (SI-index >16.5% diagnosed presence of microscopic fat), 2) unenhanced CT attenuation (in cases where unenhanced CT was available). RESULTS: : From 127 adrenal masses, there were 94% (119/127) adenomas and 6% (8/127) other masses (2 pheochromocytoma, 5 metastases, 1 lymphoma). 98% (117/119) adenomas had SI-Index >16.5%, only 2% (2/119) adenomas were 'fat-poor' by MRI. SI-Index >16.5% was 100% specific for adenoma, all other masses had SI-Index <16.5%. Unenhanced CT was available in 43% (55/127) lesions (50 adenomas, 5 other masses). 34% (17/50) adenomas were lipid-poor (>10 HU). Percentage of adenomas with SI-Index >16.5% were: 1) ≤10 HU, 100% (33/33), 2) 11-29 HU, 100% (12/12), 3) ≥30 HU, 60% (3/5). No other masses had attenuation ≤10 HU (0/5). CONCLUSION: : Fat-poor adrenal adenomas are uncommon using 2D chemical-shift signal intensity index >16.5% at 1.5-T, occurring in approximately 2% of adenomas in this large prospective series.

Diagnosis, Management, and Follow-Up of the Incidentally Discovered Adrenal Mass: CUA Guideline Endorsed by the AUA.

PURPOSE: Incidental adrenal masses are common and require a multidisciplinary approach to evaluation and management that includes family physicians, urologists, endocrinologists, and radiologists. The purpose of this guideline is to provide an updated approach to the diagnosis, management, and follow-up of adrenal incidentalomas, with a special focus on the areas of discrepancy/controversy existing among the published guidelines from other associations. MATERIALS AND METHODS: This guideline was developed by the Canadian Urological Association (CUA) through a working group comprised of urologists, endocrinologists, and radiologists and subsequently endorsed by the American Urological Association (AUA). A systematic review utilizing the GRADE approach served as the basis for evidence-based recommendations with consensus statements provided in the absence of evidence. For each guideline statement, the strength of recommendation was reported as weak or strong, and the quality of evidence was evaluated as low, medium, or high. RESULTS: The CUA working group provided evidence- and consensus-based recommendations based on an updated systematic review and subject matter expertise. Important updates on evidence-based radiological evaluation and hormonal testing are included in the recommendations. This guideline clarifies which patients may benefit from surgery and highlights where short term surveillance is appropriate. CONCLUSION: Incidentally detected adrenal masses require a comprehensive assessment of hormonal function and oncologic risk. This guideline provides a contemporary approach to the appropriate clinical, radiographic, and endocrine assessments required for the evaluation, management, and follow-up of patients with such lesions.

Diagnostic Accuracy of MRI for Solid Renal Masses: A Systematic Review and Meta-analysis.

BACKGROUND: Biparametric (bp)-MRI and multiparametric (mp)-MRI may improve the diagnostic accuracy of renal mass histology. PURPOSE: To evaluate the available evidence on the diagnostic accuracy of bp-MRI and mp-MRI for solid renal masses in differentiating malignant from benign, aggressive from indolent, and clear cell renal cell carcinoma (ccRCC) from other histology. STUDY TYPE: Systematic review. POPULATION: MEDLINE, EMBASE, and CENTRAL up to January 11, 2022 were searched. FIELD STRENGTH/SEQUENCE: 1.5 or 3 Tesla. ASSESSMENT: Eligible studies evaluated the accuracy of MRI (with at least two sequences: T2, T1, dynamic contrast and diffusion-weighted imaging) for diagnosis of solid renal masses in adult patients, using histology as reference standard. Risk of bias and applicability were assessed using QUADAS-2. STATISTICAL TESTS: Meta-analysis using a bivariate logitnormal random effects model. RESULTS: We included 10 studies (1239 masses from approximately 1200 patients). The risk of bias was high in three studies, unclear in five studies and low in two studies. The diagnostic accuracy of malignant (vs. benign) masses was assessed in five studies (64% [179/281] malignant). The summary estimate of sensitivity was 95% (95% confidence interval [CI]: 77%-99%), and specificity was 63% (95% CI: 46%-77%). No study assessed aggressive (vs. indolent) masses. The diagnostic accuracy of ccRCC (vs. other subtypes) was evaluated in six studies (47% [455/971] ccRCC): the summary estimate of sensitivity was 85% (95% CI: 77%-90%) and specificity was 77% (95% CI: 73%-81%). DATA CONCLUSION: Our study reveals deficits in the available evidence on MRI for diagnosis of renal mass histology. The number of studies was limited, at unclear/high risk of bias, with heterogeneous definitions of solid masses, imaging techniques, diagnostic criteria, and outcome measures. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

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

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

Proportion of malignancy in Bosniak classification of cystic renal masses version 2019 (v2019) classes: systematic review and meta-analysis.

OBJECTIVES: Determine the proportion of malignancy within Bosniak v2019 classes. METHODS: MEDLINE and EMBASE were searched. Eligible studies contained patients with cystic renal masses undergoing CT or MRI renal protocol examinations with pathology confirmation, applying Bosniak v2019. Proportion of malignancy was estimated within Bosniak v2019 class. Risk of bias was assessed using QUADAS-2. RESULTS: We included 471 patients with 480 cystic renal masses. No class I malignant masses were observed. Pooled proportion of malignancy were class II, 12% (6/51, 95% CI 5-24%); class IIF, 46% (37/85, 95% CI 28-66%); class III, 79% (138/173, 95% CI 68-88%); and class IV, 84% (114/135, 95% CI 77-90%). Proportion of malignancy differed between Bosniak v2019 II-IV classes (p = 0.004). Four studies reported the proportion of malignancy by wall/septa feature. The pooled proportion of malignancy with 95% CI were class III thick smooth wall/septa, 77% (41/56, 95% CI 53-91%); class III obtuse protrusion ≤ 3 mm (irregularity), 83% (97/117, 95% CI 75-89%); and class IV nodule with acute angulation, 86% (50/58, 95% CI 75-93%) or obtuse angulation ≥ 4 mm, 83%, (64/77, 95% CI 73-90%). Subgroup analysis by wall/septa feature was limited by sample size; however, no differences were found comparing class III masses with irregularity to class IV masses (p = 0.74) or between class IV masses by acute versus obtuse angles (p = 0.62). CONCLUSION: Preliminary data suggest Bosniak v2019 class IIF masses have higher proportion of malignancy compared to the original classification, controlling for pathologic reference standard. There are no differences in proportion of malignancy comparing class III masses with irregularities to class IV masses with acute or obtuse nodules. KEY POINTS: • The proportion of malignancy in Bosniak v2019 class IIF cystic masses is 46% (37 malignant/85 total IIF masses, 95% confidence intervals (CI) 28-66%). • The proportion of malignancy in Bosniak v2019 class III cystic masses is 79% (138/173, 95% CI 68-88%) and in Bosniak v2019 class IV cystic masses is 84% (114/135, 95% CI 77-90%). • Class III cystic masses with irregularities had similar proportion of malignancy (83%, 97/117, 95% CI 75-89%) compared to Bosniak class IV masses (84%, 114/135, 95% CI 77-90%) overall (p = 0.74) with no difference within class IV masses by acute versus obtuse angulation (p = 0.62).

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.

Prevalence of Malignancy in Adrenal Nodules With Heterogeneous Microscopic Fat on Chemical-Shift MRI: A Multiinstitutional Study.

BACKGROUND. Homogeneous microscopic fat within adrenal nodules on chemical-shift MRI (CS-MRI) is diagnostic of benign adrenal adenoma, but the clinical relevance of heterogeneous microscopic fat is not well established. OBJECTIVE. This study sought to determine the prevalence of malignancy in adrenal nodules with heterogeneous microscopic fat on dual-echo T1-weighted CS-MRI. METHODS. We performed a retrospective study of adult patients with adrenal nodules detected on MRI performed between August 2007 and November 2020 at seven institutions. Eligible nodules had a short-axis diameter of 10 mm or larger with heterogeneous microscopic fat (defined by an area of signal loss of < 80% on opposed-phase CS-MRI). Two radiologists from each center, blinded to reference standard results, determined the signal loss pattern (diffuse, two distinct parts, speckling pattern, central loss, or peripheral loss) within the nodules. The reference standard used was available for 283 nodules (pathology for 21 nodules, ≥ 1 year of imaging follow-up for 245, and ≥ 5 years of clinical follow-up for 17) in 282 patients (171 women and 111 men; mean age, 60 ± 12 [SD] years); 30% (86/282) patients had prior malignancy. RESULTS. The mean long-axis diameter was 18.7 ± 7.9 mm (range, 10-80 mm). No malignant nodules were found in patients without prior cancer (0/197; 95% CI, 0-1.5%). Four of the 86 patients with prior malignancy (hepatocellular carcinoma [HCC], renal cell carcinoma [RCC], lung cancer, or both colon cancer and RCC) (4.7%; 95% CI, 1.3-11.5%) had metastatic nodules. Detected patterns were diffuse heterogeneous signal loss (40% [114/283]), speckling (28% [80/283]), two distinct parts (18% [51/283]), central loss (9% [26/283]), and peripheral loss (4% [12/283]). Two metastases from HCC and RCC showed diffuse heterogeneous signal loss. Lung cancer metastasis manifested as two distinct parts, and the metastasis in the patient with both colon cancer and RCC showed peripheral signal loss. CONCLUSION. Presence of heterogeneous microscopic fat in adrenal nodules on CS-MRI indicates a high likelihood of benignancy, particularly in patients without prior cancer. This finding is also commonly benign in patients with cancer; however, caution is warranted when primary malignancies may contain fat or if the morphologic pattern of signal loss may indicate a collision tumor. CLINICAL IMPACT. In the absence of prior cancer, adrenal nodules with heterogeneous microscopic fat do not require additional imaging evaluation.

Autosomal Dominant Polycystic Kidney Disease: Role of Imaging in Diagnosis and Management.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic kidney disorder with progressive renal function decline, and disease severity is determined based on the type of genetic mutation. The diagnosis is usually established at imaging, primarily at US, and is based on age-dependent criteria and the number of visible cysts. ADPKD is classified into class 1 (typical) and class 2 (atypical) according to the Mayo Clinic Imaging Classification (MCIC) system. Height-adjusted total kidney volume (TKV) has emerged as a predictor of future renal function decline and renal failure in ADPKD, and several methods can be used for estimation. MCIC class 1 ADPKD is further subdivided into five types based on height-adjusted TKV (A, B, C, D, and E). Patients with a larger height-adjusted TKV (ie, MCIC 1C-E) are at high risk for progression to end-stage renal disease and will potentially benefit from vasopressin receptor antagonists, which have been shown to reduce the rate of cyst growth and slow renal function decline. Other renal complications primarily relate to hemorrhage within cysts or cyst infections. Subtraction images are key for assessment of complex cysts when malignancy is suspected, as the presence of protein and blood can limit the assessment for an enhancing component. The radiologist has a central role in establishing a diagnosis, excluding mimics, identifying complications, assessing severity, and predicting future renal failure. Interventional radiologists play a therapeutic role in management of complications by cyst drainage, sclerotherapy, or embolization. © RSNA, 2022 Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.