Micro-ultrasound for the detection of clinically significant prostate cancer in biopsy-naive men with negative MRI.

INTRODUCTION: Despite a negative magnetic resonance imaging (MRI), some patients may still harbor clinically significant prostate cancer (csPCa, Gleason grade group ≥2). High-resolution micro-ultrasound (microUS) is a novel imaging technology that could visualize csPCa that is missed by MRI. METHODS: This retrospective review included 1011 consecutive patients biopsied between September 2021 and July 2023 in Alberta, Canada. Among them were 103 biopsy-naive patients with negative MRI (Prostate Imaging Reporting & Data System [PI-RADS] ≤2) undergoing microUS-informed prostate biopsy (n=56) scored using Prostate Risk Identification Using Micro-ultrasound (PRI-MUS) or standard transrectal ultrasound prostate biopsy (n=47). The primary outcome was detection rate of csPCa stratified by biopsy technique and PRI-MUS score. RESULTS: MicroUS biopsy identified csPCa in 14/56 (25%) compared to standard biopsy in 8/47 (17%) (p=0.33). Patients with lesions PRI-MUS ≥3 had csPCa detected at a higher rate compared to patients with PRI-MUS ≤2 (42% vs. 16%, p=0.03). The csPCa detection rate was significantly different comparing patients with PSA density <0.15 and PRI-MUS ≤2 compared to patients with PSA density ≥0.15 and PRI-MUS ≥3 (14% vs. 60%, p=0.02). CONCLUSIONS: MicroUS may aid in the detection of csPCa for patients with negative MRI.

Value of Incremental Biopsy Cores for Microultrasound Targeted Prostate Biopsies.

OBJECTIVE: To determine the optimal number of cores needed during microultrasound-informed prostate biopsy for the detection of clinically significant prostate cancer (csPCa, defined as Gleason Grade Group ≥2). METHODS: A retrospective review of 1011 consecutive patients between September 2021 and July 2023 at our institution were identified; 536 underwent microultrasound biopsy and 475 underwent magnetic resonance imaging (MRI)/ultrasound (US) targeted biopsy. Lesions were given a Prostate Risk Identification using Microultrasound (PRI-MUS) score, with lesions PRI-MUS ≥3 targeted. MRI lesions were scored with Prostate Imaging-Reporting and Data System (PI-RADS) and lesions PI-RADS ≥3 were targeted. The primary outcome is the detection of csPCa stratified by number of cores. RESULTS: One hundred thirty-eight patients underwent targeted biopsies for microultrasound only lesions, 182 for microultrasound and MRI lesions and 426 underwent MRI/US for MRI lesions. The first targeted core detected 78.0% (46/59), 77.8% (63/81), and 78.8% (216/274) of csPCa for microultrasound, microultrasound+MRI, and MRI/US, respectively. Comparing first to third core, there was not a significant difference in overall detection of csPCa by microultrasound, though MRI/US was significantly different (28.4% vs 36.4% P = .12, 32.5% vs 41.8% P = .06, 42.5% vs 53.9% P < .001 for microultrasound, microultrasound+MRI, and MRI/US, respectively). PI-RADS 3 and PRI-MUS 3 lesions had lower first core detection rates compared to PI-RADS 5 and PRI-MUS 5 lesions (44.4% vs 85.4% P = .01, 65.2% vs 81.4% P = .14, 60% vs 83.1% P = .07 for microultrasound, microultrasound+MRI, and MRI/US, respectively). CONCLUSION: A three-core targeted biopsy per microultrasound lesion improves detection rate of csPCa and should be considered to improve diagnostic accuracy.

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.

Smooth Muscle Tumors of the Uterus at MRI: Focus on Leiomyomas and FIGO Classification.

Leiomyomas are smooth muscle tumors of the uterus and are the most common uterine neoplasm. Although leiomyomas are usually asymptomatic, they can manifest with symptoms such as pain or uterine bleeding. Leiomyomas are classified on the basis of their anatomic location and morphology. Localization of leiomyomas relative to the endometrium, myometrium, and uterine serosa with use of the International Federation of Gynecology and Obstetrics (FIGO) classification system is helpful for guiding management in symptomatic patients. The FIGO system is a practical and universally accepted approach for classifying leiomyomas to guide radiologists and clinicians in deciding management. The MRI appearance of conventional leiomyomas is related to their tissue contents of smooth muscle and fibrous tissue and is well established. The MRI features of some leiomyoma subtypes and forms of degeneration also have been described. Other smooth muscle tumors of the uterus recognized in the 2020 World Health Organization classification system include intravenous leiomyomatosis, smooth muscle tumors of uncertain malignant potential, and metastasizing leiomyoma. At the far end of the spectrum are leiomyosarcomas, which are frankly malignant and therefore must be managed accordingly. Although MRI features that suggest a diagnosis of leiomyosarcoma have been proposed, these features overlap with those of some leiomyoma subtypes and degeneration. © RSNA, 2023 See the invited commentary by Fennessy and Gargiulo in this issue. Online 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.

Adrenal Neoplasms: Lessons from Adrenal Multidisciplinary Tumor Boards.

The radiologic diagnosis of adrenal disease can be challenging in settings of atypical presentations, mimics of benign and malignant adrenal masses, and rare adrenal anomalies. Misdiagnosis may lead to suboptimal management and adverse outcomes. Adrenal adenoma is the most common benign adrenal tumor that arises from the cortex, whereas adrenocortical carcinoma (ACC) is a rare malignant tumor of the cortex. Adrenal cyst and myelolipoma are other benign adrenal lesions and are characterized by their fluid and fat content, respectively. Pheochromocytoma is a rare neuroendocrine tumor of the adrenal medulla. Metastases to the adrenal glands are the most common malignant adrenal tumors. While many of these masses have classic imaging appearances, considerable overlap exists between benign and malignant lesions and can pose a diagnostic challenge. Atypical adrenal adenomas include those that are lipid poor; contain macroscopic fat, hemorrhage, and/or iron; are heterogeneous and/or large; and demonstrate growth. Heterogeneous adrenal adenomas may mimic ACC, metastasis, or pheochromocytoma, particularly when they are 4 cm or larger, whereas smaller versions of ACC, metastasis, and pheochromocytoma and those with washout greater than 60% may mimic adenoma. Because of its nonenhanced CT attenuation of less than or equal to 10 HU, a lipid-rich adrenal adenoma may be mimicked by a benign adrenal cyst, or it may be mimicked by a tumor with central cystic and/or necrotic change such as ACC, pheochromocytoma, or metastasis. Rare adrenal tumors such as hemangioma, ganglioneuroma, and oncocytoma also may mimic adrenal adenoma, ACC, metastasis, and pheochromocytoma. The authors describe cases of adrenal neoplasms that they have encountered in clinical practice and presented to adrenal multidisciplinary tumor boards. Key lessons to aid in diagnosis and further guide appropriate management are provided. © RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Multiparametric MR assessment of liver fat, iron, and fibrosis: a concise overview of the liver "Triple Screen".

Chronic liver disease (CLD) is a common source of morbidity and mortality worldwide. Non-alcoholic fatty liver disease (NAFLD) serves as a major cause of CLD with a rising annual prevalence. Additionally, iron overload can be both a cause and effect of CLD with a negative synergistic effect when combined with NAFLD. The development of state-of-the-art multiparametric MR solutions has led to a change in the diagnostic paradigm in CLD, shifting from traditional liver biopsy to innovative non-invasive methods for providing accurate and reliable detection and quantification of the disease burden. Novel imaging biomarkers such as MRI-PDFF for fat, R2 and R2* for iron, and liver stiffness for fibrosis provide important information for diagnosis, surveillance, risk stratification, and treatment. In this article, we provide a concise overview of the MR concepts and techniques involved in the detection and quantification of liver fat, iron, and fibrosis including their relative strengths and limitations and discuss a practical abbreviated MR protocol for clinical use that integrates these three MR biomarkers into a single simplified MR assessment. Multiparametric MR techniques provide accurate and reliable non-invasive detection and quantification of liver fat, iron, and fibrosis. These techniques can be combined in a single abbreviated MR "Triple Screen" assessment to offer a more complete metabolic imaging profile of CLD.

Evaluation of the T2-weighted (T2W) adrenal MRI calculator to differentiate adrenal pheochromocytoma from lipid-poor adrenal adenoma.

OBJECTIVES: To evaluate the T2-weighted (T2W) MRI calculator to differentiate adrenal pheochromocytoma from lipid-poor adrenal adenoma. METHODS: Twenty-nine consecutive pheochromocytomas resected between 2010 and 2019 were compared to 23 consecutive lipid-poor adrenal adenomas. Three blinded radiologists (R1, R2, R3) subjectively evaluated T2W signal intensity and heterogeneity and extracted T2W signal intensity ratio (SIR) and entropy. These values were imputed into a quantitative and qualitative T2W adrenal MRI calculator (logistic regression model encompassing T2W SIR + entropy and subjective SI [relative to renal cortex] and heterogeneity) using a predefined threshold to differentiate metastases from adenoma and accuracy derived by a 2 × 2 table analysis. RESULTS: Subjectively, pheochromocytomas were brighter (p < 0.001) and more heterogeneous (p < 0.001) for all three radiologists. Inter-observer agreement was fair-to-moderate for T2W signal intensity (K = 0.37-0.46) and fair for heterogeneity (K = 0.24-0.32). Pheochromocytoma had higher T2W-SI-ratio (p < 0.001) and entropy (p < 0.001) for all three readers. The quantitative calculator differentiated pheochromocytoma from adenoma with high sensitivity, specificity, and accuracy (100% [95% confidence intervals 88-100%], 87% [66-97%], and 94% [86-100%] R1; 93% [77-99%], 96% [78-100%], and 94% [88-100%] R2; 97% [82-100%], 96% [78-100%], and 96% [91-100% R3]). The qualitative calculator was specific with lower sensitivity and overall accuracy (48% [29-68%], 100% [85-100%], and 74% [65-83%] R1; 45% [26-64%], 100% [85-100%], and 72% [63-82%] R2; 59% [39-77%], 100% [85-100%], and 79% [70-88% R3]). CONCLUSIONS: T2W signal intensity and heterogeneity differ, subjectively and quantitatively, in pheochromocytoma compared to adenoma. Use of a quantitative T2W adrenal calculator which combines T2W signal intensity ratio and entropy was highly accurate to diagnose pheochromocytoma outperforming subjective analysis. KEY POINTS: • Pheochromocytomas have higher T2-weighted signal intensity and are more heterogeneous compared to lipid-poor adrenal adenomas evaluated subjectively and quantitatively. • The quantitative T2-weighted adrenal MRI calculator, a logistic regression model combining T2-weighted signal intensity ratio and entropy, is highly accurate for diagnosis of pheochromocytoma. • The qualitative T2-weighed adrenal MRI calculator had high specificity but lower sensitivity and overall accuracy compared to quantitative assessment and agreement was only fair-to-moderate.

Comparison of MRI features in lipid-rich and lipid-poor adrenal adenomas using subjective and quantitative analysis.

OBJECTIVE: To compare MR-imaging features in benign lipid-rich and lipid-poor adrenal adenomas. MATERIALS AND METHODS: With institutional review board approval, we compared 23 consecutive lipid-poor adenomas (chemical shift [CS] signal intensity [SI] index < 16.5%) imaged with MRI to 29 consecutive lipid-rich adenomas (CS-SI index ≥ 16.5%) imaged during the same time period. A blinded radiologist measured T2-weighted (T2W) SI ratio (adrenal adenoma/psoas muscle), dynamic enhancement wash-in (WI) and wash-out (WO) indices, and T2W texture features. Two blinded Radiologists (R1/R2) assessed T2W-SI (relative to renal cortex) and T2W heterogeneity (using 5-Point Likert scales). Comparisons were performed between groups using independent t tests and Chi-square with Holm-Bonferroni correction. RESULTS: There was no difference in age or gender between groups (p = 0.594, 0.051 respectively). Subjectively, all lipid-rich and lipid-poor adenomas were rated hypointense or isointense compared to renal cortex and T2W-SI did not differ between groups (p = 0.129, 0.124 for R1, R2). Agreement was substantial (Kappa = 0.67). There was no difference in T2W SI ratio (1.8 ± 0.9 [0.5-4.3] lipid rich versus 2.2 ± 1.0 [0.6-4.3] lipid poor, p = 0.139). Enhancement WI and WO did not differ comparing lipid-rich and lipid-poor adenomas (p = 0.759, 0.422 respectively). There was no difference comparing lipid-rich and lipid-poor adenomas T2W heterogeneity judged subjectively (p = 0.695, 0.139 for R1, R2; Kappa = 0.19) or by texture analysis (entropy, kurtosis, skewness; p = 0.134-0.191) with all adenomas except for one rated as mostly or completely homogeneous. CONCLUSIONS: There is no difference in T2W signal intensity, enhancement pattern or T2W heterogeneity judged subjectively or by quantitative texture analysis comparing lipid-poor and lipid-rich adrenal adenomas.

Utility of T2-weighted MRI to Differentiate Adrenal Metastases from Lipid-Poor Adrenal Adenomas.

Purpose: To evaluate T2-weighted MRI features to differentiate adrenal metastases from lipid-poor adenomas. Materials and Methods: With institutional review board approval, this study retrospectively compared 40 consecutive patients (mean age, 66 years ± 10 [standard deviation]) with metastases to 23 patients (mean age, 60 years ± 15) with lipid-poor adenomas at 1.5- and 3-T MRI between June 2016 and March 2019. A blinded radiologist measured T2-weighted signal intensity (SI) ratio (SInodule/SIpsoas muscle), T2-weighted histogram features, and chemical shift SI index. Two blinded radiologists (radiologist 1 and radiologist 2) assessed T2-weighted SI and T2-weighted heterogeneity using five-point Likert scales. Results: Subjectively, T2-weighted SI (P < .001 for radiologist 1 and radiologist 2) and T2-weighted heterogeneity (P < .001, for radiologist 1 and radiologist 2) were higher in metastases compared with adenomas when assessed by both radiologists. Agreement between the radiologists was substantial for T2-weighted SI (Cohen κ = 0.67) and T2-weighted heterogeneity (κ = 0.62). Metastases had higher T2-weighted SI ratio than adenomas (3.6 ± 1.7 [95% confidence interval {CI}: 0.2, 8.2] vs 2.2 ± 1.0 [95% CI: 0.6, 4.3], P < .001) and higher T2-weighted entropy (6.6 ± 0.6 [95% CI: 4.9, 7.5] vs 5.0 ± 0.8 [95% CI: 3.5, 6.6], P < .001). At multivariate analysis, T2-weighted entropy was the best differentiating feature (P < .001). Chemical shift SI index did not differ between metastases and adenomas (P = .748). Area under the receiver operating characteristic curve (AUC) for T2-weighted SI ratio and T2-weighted entropy were 0.76 (95% CI: 0.64, 0.88) and 0.94 (95% CI: 0.88, 0.99). The logistic regression model combining T2-weighted SI ratio with T2-weighted entropy yielded AUC of 0.95 (95% CI: 0.91, 0.99) and did not differ compared with T2-weighted entropy alone (P = .268). There was no difference in logistic regression model accuracy comparing the data by either field strength, 1.5- or 3-T MRI (P > .05). Conclusion: Logistic regression models combining T2-weighted SI and T2-weighted heterogeneity can differentiate metastases from lipid-poor adenomas. Validation of these preliminary results is required.Keywords: Adrenal, MR-Imaging, UrinarySupplemental material is available for this article.© RSNA, 2020.

Update on MR Imaging of cystic retroperitoneal masses.

OBJECTIVE: This article reviews the MRI appearance of cystic retroperitoneal (RP) masses. CONCLUSION: Lymphangiomas are the most common RP cystic masses and typically appear simple; microscopic fat is a specific but insensitive finding. Location, internal complexity, and enhancement pattern suggest alternative diagnoses which range from normal anatomic variants to congenital abnormalities and importantly include benign, neurogenic, and malignant neoplasms. An approach to the MR imaging of cystic RP masses is presented.

Assessing Patient Preferences for Intestinal Failure Management Using the Time Trade-Off Methodology.

BACKGROUND: There are limited management options available for people with Type III intestinal failure (IF), with home parenteral nutrition (HPN) being the main treatment option. The aim of this research is to compare patient preferences in managing Type III IF using time trade-off (TTO) methodology and to determine which factors have the greatest impact on health-related quality of life (HRQoL). METHODS: An interviewer-administered telephone survey was conducted on a cross-sectional cohort of 19 HPN participants. The survey was designed to measure HRQoL using a TTO methodology. Four different treatment options were presented, and participants decided how many years of life they would trade to have access to the treatment and hence a different health state. The 4 scenarios included reduction in line infections, optimization of care, small bowel growth (teduglutide), and intestinal transplantation. Health state utility scores were calculated. RESULTS: The median health utility score for optimization of care and small bowel growth (teduglutide) were lowest (0.5; range 0-1) meaning a greater desire for this treatment. Intestinal transplant had the highest median utility score (1.0; range 0-1) indicating less willingness for this treatment option. CONCLUSIONS: This is the first known study to use TTO methodology assessing treatment options in people with IF requiring HPN. Results indicate people requiring HPN make careful decisions when considering treatment options. Facilities providing HPN services should focus on optimization of current care, which is highly valued by their patients.

Evaluation of a free-breathing respiratory-triggered (Navigator) 3-D T1-weighted (T1W) gradient recalled echo sequence (LAVA) for detection of enhancement in cystic and solid renal masses.

OBJECTIVES: To evaluate free-breathing Navigator-triggered 3-D T1-weighted MRI (NAV-LAVA) compared to breath-hold (BH)-LAVA among cystic and solid renal masses. MATERIALS AND METHODS: With an IRB waiver, 44 patients with 105 renal masses (71 non-enhancing cysts and 14 cystic and 20 solid renal masses) underwent MRI between 2016 and 2017 where BH-LAVA and NAV-LAVA were performed. Subtraction images were generated for BH-LAVA and NAV-LAVA using pre- and 3-min post-gadolinium-enhanced images and were evaluated by two blinded radiologists for overall image quality, image sharpness, motion artifact, and quality of subtraction (using 5-point Likert scales) and presence/absence of enhancement. Percentage signal intensity change (Δ%SI) = ([SI.post-gadolinium-SI.pre-gadolinium]/SI.pre-gadolinium)*100, was measured on BH-LAVA and NAV-LAVA. Likert scores were compared using Wilcoxon's sign-rank test and accuracy for detection of enhancement compared using receiver operator characteristic (ROC) analysis. RESULTS: Overall image quality (p = 0.002-0.141), image sharpness (p = 0.002-0.031), and motion artifact were better (p = 0.002) comparing BH-LAVA to NAV-LAVA for both radiologists; however, quality of image subtraction did not differ between groups (p = 0.09-0.14). Sensitivity/specificity/area under ROC curve for enhancement in cystic and solid renal masses using subtraction and %SIΔ were (1) BH-LAVA: 64.7%/98.6%/0.82 (radiologist 1), 61.8%/95.8%/0.79 (radiologist 2), and 70.6%/81.7%/0.76 (%SIΔ) versus 2) NAV-LAVA: 58.8%/95.8%/0.79 (radiologist 1, p = 0.16), 58.8%/88.7%/0.73 (radiologist 2, p = 0.37), and 73.5%/76.1%/0.75 (%SIΔ, p = 0.74). CONCLUSIONS: NAV-LAVA showed similar quality of subtraction and ability to detect enhancement compared to BH-LAVA in renal masses albeit with lower image quality, image sharpness, and increased motion artifact. NAV-LAVA may be considered in renal MRI for patients where BH is suboptimal. KEY POINTS: • Free-breathing Navigator (NAV) 3-D subtraction MRI is comparable to breath-hold (BH) images. • Accuracy for subjective and quantitative diagnosis of enhancement in renal masses on NAV 3-D T1W is comparable to BH MRI. • NAV 3-D T1W renal MRI is useful in patients who may not be able to adequately BH.

Update on multiparametric MRI of urinary bladder cancer.

While many institutions perform MRI during the work-up of urinary bladder cancer, others use MRI rarely if at all, possibly due to a variation in the reported staging accuracy and unfamiliarity with the potential benefits of performing MRI. Through increased application of functional imaging techniques including diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) imaging, there has been a resurgence of interest regarding evaluation of bladder cancer with MRI. Several recent meta-analyses have shown that MRI is accurate at differentiating between ≤T1 and T2 disease (with pooled sensitivity/specificity of ∼90/80%) and differentiating between T2 and ≥T3 disease. DWI and DCE, in combination with high-resolution T2 -weighted images, improves detection and possibly local staging accuracy of bladder cancer. High b value echo-planar DWI is particularly valuable for tumor detection. Zoomed field of view and segmented readout DWI techniques improve image quality by reducing susceptibility artifact, while methods to extract calculated high b value images save time and improve the contrast-to-noise ratio. DCE traditionally required imaging of the pelvis with high temporal but lower spatial resolution; however, advances in parallel and keyhole imaging techniques can preserve spatial resolution. The use of compressed sensing reconstruction may improve utilization of DCE of the bladder, especially when imaging the abdomen simultaneously, as in MR urography. Quantitative imaging analysis of bladder cancer using pharmacokinetic modeling of DCE, apparent diffusion coefficient values, and texture analysis may enable radiomic assessment of bladder cancer grade and stage. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:882-896.

Can Adrenal Adenomas Be Differentiated From Adrenal Metastases at Single-Phase Contrast-Enhanced CT?

OBJECTIVE: The purpose of this study is to evaluate whether adrenal metastases can be reliably differentiated from adenomas at single-phase contrast-enhanced CT. MATERIALS AND METHODS: Sixty-one consecutive patients from a single-institution lung cancer registry (40 metastases and 36 adenomas) who underwent single-phase contrast-enhanced CT at baseline diagnosis were retrospectively studied by two radiologists (blinded to the diagnoses) who independently evaluated four features previously described in adenomas: smooth margin, rim enhancement, central vein sign (preserved adrenal vein), and homogeneity (using a 5-point Likert scale). A third radiologist measured size and attenuation and performed quantitative texture analysis. Comparisons were performed using chi-square, logistic regression, and ROC analysis. RESULTS: Metastases were larger than adenomas (mean [± SD] 24 ± 11 mm [range, 11-66 mm] vs 19 ± 5 mm [range, 11-34 mm]; p = 0.012), with overlap between groups. Attenuation of metastases and adenomas did not differ significantly (58.2 ± 21.0 HU [range, 21.0-108.0] vs 55.5 ± 21.5 HU [range, 14.0-105.0]; p = 0.582). Skewness and kurtosis did not differ between groups (p = 0.612 and 0.978, respectively), whereas entropy was higher in metastases (p = 0.013). The AUC for entropy to diagnose metastases was 0.65 (95% CI, 0.52-0.77). Tumor margin, rim enhancement, and the central vein sign did not differ between groups (p > 0.05). Metastases were considered more heterogeneous by both radiologists (p = 0.001 and 0.011, respectively), and agreement was satisfactory (κ = 0.51). Likert scores of 4 or 5 (mostly or completely heterogeneous) yielded sensitivity and specificity for diagnosis of metastases of 32.5% and 97.2%, respectively, for radiologist 1 and 22.5% and 97.2%, respectively, for radiologist 2. CONCLUSION: Adrenal metastases cannot be reliably differentiated from adenomas at single-phase contrast-enhanced CT. Increased tumor size and heterogeneity were specific findings but showed unacceptably low sensitivity.