O-RADS MRI Risk Stratification System: Guide for Assessing Adnexal Lesions from the ACR O-RADS Committee.

MRI plays an important role as a secondary test or problem-solving modality in the evaluation of adnexal lesions depicted at US. MRI has increased specificity compared with US, decreasing the number of false-positive diagnoses for malignancy and thereby avoiding unnecessary or over-extensive surgery in patients with benign lesions or borderline tumors, while women with possible malignancies can be expeditiously referred for oncologic surgical evaluation. The Ovarian-Adnexal Reporting and Data System (O-RADS) MRI Committee is an international collaborative effort formed under the direction of the American College of Radiology and includes a diverse group of experts on adnexal imaging and management who developed the O-RADS MRI risk stratification system. This scoring system assigns a probability of malignancy based on the MRI features of an adnexal lesion and provides information to facilitate optimal patient management. The widespread implementation of a codified reporting system will lead to improved interpretation agreement and standardized communication between radiologists and referring physicians. In addition, it will allow for high-quality multi-institutional collaborations-an important unmet need that has hampered the performance of high-quality research in this area in the past. This article provides guidelines on using the O-RADS MRI risk stratification system in clinical practice, as well as in the educational and research settings.

Evaluation of the Viability of Untreated Leiomyomas Using Computed Tomography-Detected Calcification Patterns.

OBJECTIVE: To evaluate the relationship between computed tomography (CT)-detected calcification patterns and Magnetic Resonance Imaging (MRI) enhancement as a surrogate for viability in untreated uterine leiomyomas. METHODS: We queried 2 university hospital databases to identify patients with: (1) at least 1 calcified leiomyoma on CT greater than 1 cm (2) contrast-enhanced MRI of the pelvis performed within 5 years of the CT, and (3) no prior history of uterine fibroid embolization (UFE). Computed tomography was used to analyze calcification pattern and contrast-enhanced MRI to analyze size and viability. RESULTS: There were 12,862 reports that fit the criteria. After exclusion, 50 patients with 74 calcified untreated leiomyomas were analyzed. Three calcification patterns were identified: rim (n = 22), diffuse (n = 9), and coarse either less than or greater than 50% (n = 43). Four of 22 (18%) of leiomyomas with rim calcification were viable. Three of 9 (33%) of leiomyomas with diffuse calcification were viable. All leiomyomas with coarse calcifications were viable, 43 of 43 (100%). CONCLUSIONS: Leiomyomas with coarse calcifications are viable, whereas the majority with rim or diffuse calcification are not. This information may be helpful when triaging symptomatic women to treatment.

Occult Hepatocellular Carcinoma Associated With Transjugular Intrahepatic Portosystemic Shunts in Liver Transplant Recipients.

Transplant eligibility for hepatocellular carcinoma (HCC) is determined by the imaging identification of tumor burden within the Milan criteria. Transjugular intrahepatic portosystemic shunt(s) (TIPS) reduce portal hypertension but may impact HCC visualization. It was hypothesized that the presence of pretransplant TIPS would correlate with occult HCC and reduced survival. A single-center, retrospective, case control study was performed among liver transplant recipients with HCC (2000-2017). The primary endpoint was occult disease on explant pathology. Backward stepwise logistic regression was performed. The secondary endpoints disease-free survival (DFS) and overall survival (OS) were evaluated with Kaplan-Meier curves and Cox regression analysis. Of 640 patients, 40 had TIPS and more frequently exhibited occult disease (80.0% versus 43.1%; P < 0.001; odds ratio [OR], 4.16; P < 0.001). Portal vein thrombosis (PVT) similarly correlated with occult disease (OR, 1.97; P = 0.02). Explant tumor burden was equivalent between TIPS subgroups; accordingly, TIPS status was not independently associated with reduced DFS or OS. However, exceeding the Milan criteria was associated with reduced DFS (hazard ratio, 3.21; P = 0.001), and TIPS status in patients with a single suspected lesion (n = 316) independently correlated with explant tumor burdens beyond these criteria (OR, 13.47; P = 0.001). TIPS on pretransplant imaging are associated with occult HCC on explant pathology. Comparable occult disease findings in patients with PVT suggest that the mechanism may involve altered hepatic perfusion, obscuring imaging diagnosis. TIPS are not independently associated with reduced DFS or OS but are associated with exceeding the Milan criteria for patients with a single suspected lesion. The presence of TIPS may necessitate a higher index of suspicion for occult HCC.

Platinum response characteristics of patients with pancreatic ductal adenocarcinoma and a germline BRCA1, BRCA2 or PALB2 mutation.

BACKGROUND: Retrospective studies suggest a survival benefit when platinum-based chemotherapy is administered to patients with pancreatic cancer harbouring a germline mutation in BRCA1, BRCA2 or PALB2 (mut-positive PDAC). However, the objective response rate (ORR) and real-world progression free survival (rwPFS) achieved with such treatment remain ill-defined. METHODS: Twenty-six patients with advanced-stage mut-positive PDAC who had been treated with platinum-based therapy were matched by age, race and sex to 52 platinum-treated control PDAC patients. Responses to therapy were determined by RECIST v1.1, performed by blinded radiology review. Measured outcomes included ORR and rwPFS. RESULTS: The ORR in mut-positive patients was 58% compared to 21% in the control group (p = 0.0022). There was no significant difference in ORR between platinum regimens in mut-positive patients (p = 0.814), whereas in control patients, the only observed responses were to FOLFIRINOX. rwPFS was 10.1 mo. for mut-positive patients and 6.9 mo. for controls (HR 0.43; 95% CI 0.25-0.74; 0.0068). CONCLUSION: Mut-positive PDAC has a high ORR and prolonged rwPFS to platinum-based chemotherapy. These findings may have implications particularly in the neoadjuvant setting, and for future clinical trial design, and highlight the importance of early germline testing in patients with PDAC.

Pancreatic schwannoma, an extremely rare and challenging entity: Report of two cases and review of literature.

Pancreatic schwannoma is a rare benign tumor, for which the preoperative and intraoperative definitive diagnosis is quite challenging. We present the clinical, radiological and pathologic features of two primary pancreatic schwannomas identified in our pathology database over a period of 30 years at our tertiary care hospital. To better understand the clinico-pathological and radiological features of this entity, we provide a comprehensive review of 73 cases described in the English literature, along with our two cases. This review will especially focus on preoperative and intraoperative diagnosis to assess their accuracy for pancreatic schwannoma. The three most common preoperative diagnoses based on imaging for pancreatic schwannomas were cystic neoplasm (56%), pancreatic neuroendocrine tumor (29%) and mucinous cystic neoplasm (26%). Imaging could not definitely diagnose pancreatic schwannoma in any of the reported cases. To obtain a definite diagnosis before surgery, 25 cases underwent imaging-guided fine-needle aspiration (FNA)/biopsy, of which 60% were correctly reported as benign with definite diagnosis of pancreatic schwannoma in 48%. A higher diagnostic accuracy was observed in biopsies (71%) than FNA (37%). In addition, an intraoperative frozen section was carried out in 15 cases, and 47% were correctly diagnosed. Despite relatively low accuracy, preoperative histological assessment can be helpful in surgical managment. A core tissue specimen is recommended to improve the diagnostic accuracy in this setting.

Characterizing and eliminating errors in enhancement and subtraction artifacts in dynamic contrast-enhanced breast MRI: Chemical shift artifact of the third kind.

PURPOSE: To characterize errors in enhancement in breast dynamic contrast-enhanced (DCE) MRI studies as a function of echo time and determine the source of dark band artifacts in clinical subtraction images. METHODS: Computer simulations, oil and water substitute (methylene chloride), as well as an American College of Radiology quality control phantom were tested. Routine clinical DCE breast MRI study was bracketed with (accelerated) in-phase DCE acquisitions in five patients. RESULTS: Simulation results demonstrated up to -160% suppression of the expected enhancement caused by differential enhancement of fat and water. Two-dimensional gradient-recalled echo and fat-suppressed 3D GRE phantom imaging confirmed the simulation results and showed that fat suppression does not eliminate the artifact. In vivo in-phase DCE images showed increased enhancement consistent with predictions and also confirmed increased spatial blurring on in-phase 3D gradient-recalled echo images. Combined multi-dimensional partial Fourier and parallel imaging provided a time-equivalent in-phase DCE MRI acquisition. CONCLUSION: Errors in expected enhancement occur in DCE breast MRI subtraction images because of differential enhancement of fat and water and incomplete fat signal suppression. These errors can lead to artificial suppression of enhancement as well as dark band artifacts on subtraction images. These artifacts can be eliminated with a time-equivalent in-phase fat-suppressed 3D gradient-recalled echo sequence. Understanding chemical shift artifact of the third kind, a unique artifact of artificial enhancement suppression in the presence of intravoxel fat and water signal, will aid DCE breast MRI image interpretation. In-phase acquisitions (combined with simultaneous minimum echo time or opposed-phase echoes) may facilitate qualitative, quantitative and longitudinal analysis of contrast enhancement. Magn Reson Med 79:2277-2289, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

CT and MR Imaging Features of Artificial Urinary Sphincters, Penile Prostheses, and Other Devices in the Male Lower Genitourinary Tract.

Urinary incontinence and erectile dysfunction are relatively common conditions in the aging male population. Surgical interventions for urinary incontinence include placement of an artificial urinary sphincter (AUS), perineal sling, or sacral nerve stimulator and injections of periurethral bulking agents. Erectile dysfunction can be treated surgically with placement of a penile prosthesis. The complications of these devices can be broadly categorized as device component malposition, malfunction, and infection. This article focuses on AUSs, penile prostheses, and their complications. Familiarity with these devices and their complications allows the radiologist to effectively describe these implants in radiologic reports and to recognize complications when they occur. This article reviews the normal cross-sectional radiologic appearance of the most common implants used to surgically treat male urinary incontinence and erectile dysfunction, as well as the potential complications associated with these devices. ©RSNA, 2018.

Update on CT and MRI of Adrenal Nodules.

OBJECTIVE: The objective of this article is to review the current role of CT and MRI for the characterization of adrenal nodules. CONCLUSION: Unenhanced CT and chemical-shift MRI have high specificity for lipid-rich adenomas. Dual-energy CT provides comparable to slightly lower sensitivity for the diagnosis of lipid-rich adenomas but may improve characterization of lipid-poor adenomas. Nonadenomas containing intracellular lipid pose an imaging challenge; however, nonadenomas that contain lipid may be potentially diagnosed using other imaging features. Multiphase adrenal washout CT can be used to differentiate lipid-poor adenomas from metastases but is limited for the diagnosis of hypervascular malignancies and pheochromocytoma.

Utility of MRI to Differentiate Clear Cell Renal Cell Carcinoma Adrenal Metastases From Adrenal Adenomas.

OBJECTIVE: The purpose of this study is to compare MRI features of clear cell renal cell carcinoma (RCC) adrenal metastases and adenomas. MATERIALS AND METHODS: Fifteen clear cell RCC adrenal metastases imaged with MRI were compared to 29 consecutive adenomas between 2006 and 2015. Two blinded radiologists assessed homogeneity (homogeneous vs heterogeneous), signal intensity (SI) decrease on chemical-shift MRI, and T2-weighted SI (isointense, mildly hyperintense, or markedly hyperintense) relative to muscle. A third blinded radiologist measured the chemical-shift SI index, adrenal-to-spleen SI ratio, T2-weighted SI ratio, AUC for contrast-enhanced MRI, and histogram analysis. Analyses were performed using chi-square, linear regression, ROC, and logistic regression modeling. RESULTS: Clear cell RCC metastases were larger than adenomas (mean [± SD], 5.0 ± 4.2 cm [range, 1.1-15 cm] vs 2.0 ± 0.7 cm [range, 1.2-3.7 cm]; p < 0.0001). Subjectively, 33.3% (5/15) of metastases and 68.9% (20/29) of adenomas showed an SI decrease on chemical-shift MRI (p = 0.0421; κ = 0.76). Chemical-shift SI index (mean, 9.2% ± 20.6%; range, -30.0% to 57.9%) and adrenal-to-spleen SI ratio (0.94 ± 0.23 [range, 0.44-1.33]) for metastases differed significantly from those for adenomas (47.3% ± 27.8% [range, -9.4% to 86%] and 0.52 ± 0.28 [range, 0.13-1.11], respectively) (p < 0.0001). Twenty percent (3/15) of metastases had chemical-shift SI index in the adenoma range (> 16.5%). Metastases had higher T2-weighted SI than did adenomas, both quantitatively (5.1 ± 3.0 [range, 1.5-10.6] vs 1.8 ± 0.8 [range, 0.5-3.8]; p < 0.0001) and subjectively (p < 0.0001; κ = 0.89). Metastases had higher entropy than did adenomas (6.76 ± 0.61 vs 6.1 ± 0.74; p = 0.0051) and were subjectively more heterogeneous (p < 0.0001; κ = 0.86). The contrast-enhanced MRI AUC, skewness, and kurtosis did not differ between groups (p > 0.05). The ROC AUCs were 0.91 (95% CI, 0.79-1.0) for T2-weighted SI ratio and 0.85 (95% CI, 0.68-1.0) for entropy. The logistic regression model of T2-weighted SI ratio plus entropy improved accuracy (ROC AUC, 0.97; 95% CI, 0.93-1.0]) compared with either feature alone (p = 0.0215). CONCLUSION: Increased T2-weighted SI and heterogeneity are features that can differentiate clear cell RCC adrenal metastases from adenomas using quantitative and subjective analysis.

MRI Evaluation of the Urothelial Tract: Pitfalls and Solutions.

OBJECTIVE: MR urography (MRU) can be an alternative to CT urography (CTU) for imaging of the kidneys, urinary bladder, and collecting systems. MRU can be a challenging examination to perform and interpret, which may result in technical and interpretive errors being made. This article highlights the pitfalls associated with MRU and discusses how to recognize and avoid them. CONCLUSION: When performed properly, MRU may provide imaging quality generally comparable to that of CTU, and it enables comprehensive evaluation of the entire urinary tract.

Sendai and Fukuoka Consensus Guidelines Identify Advanced Neoplasia in Patients With Suspected Mucinous Cystic Neoplasms of the Pancreas.

BACKGROUND & AIMS: Little is known about whether the 2006 Sendai guidelines or 2012 Fukuoka guidelines are being used to determine the level of risk posed by suspected pancreatic mucinous cystic neoplasms (PCNs). We evaluated whether the guidelines accurately predicted which patients with suspected PCNs, which was based on cross-sectional imaging findings, would be found to have advanced neoplasia in surgery. METHODS: We performed a retrospective study of data collected from 194 patients with cystic lesions of the pancreas, which were assessed by cross-sectional imaging analyses, who underwent surgery for suspected PCNs at the Hospital at the University of Pennsylvania from 2000 through 2008. Imaging data were used to classify patients according to the Sendai guidelines as high risk or low risk and according to the Fukuoka guidelines as high risk, worrisome, or low risk. Pathology analyses of samples collected during surgery were used as the reference. A logistic regression model was created to identify factors associated with advanced neoplasia. The Sendai and Fukuoka guideline criteria were analyzed by univariate and multivariable logistic regression analyses. RESULTS: Advanced neoplasias were found in 36 patients (18.5%; 22 invasive cancers and 14 high-grade dysplasias). The median size of cysts was 33 mm. All patients found to have invasive cancers were accurately assigned to the Sendai guidelines high risk or Fukuoka guidelines high risk groups. However, 3 patients in the Sendai guidelines low risk and 2 patients in the Fukuoka guidelines low risk groups were found to have high-grade dysplasia. The Sendai guidelines identified patients with advanced neoplasia with 91.7% sensitivity, 21.5% specificity, 21% positive predictive value, and 91.9% negative predictive value. A designation of Fukuoka guidelines high risk identified patients with advanced neoplasia with 55.6% sensitivity, 73% specificity, 32% positive predictive value, and 87.9% negative predictive value. Overall, there was no statistically significant difference between the guidelines in predicting which patients had advanced neoplasia. On multivariate analysis, the presence of a mural nodule (odds ratio [OR], 2.88; 95% confidence interval [CI], 1.33-6.27; P = .008), dilated main pancreatic duct >10 mm (OR, 7.44; 95% CI, 2.36-23.52; P = .001), or enhancing solid component (OR, 2.92; 95% CI, 1.16-7.64; P = .02) were associated with detection of advanced neoplasia in pancreatic cysts. CONCLUSION: On the basis of a retrospective analysis, the Sendai and Fukuoka guidelines accurately determine which patients with pancreatic cysts have advanced neoplasia. The guidelines accurately recommended surgical resection for all patients found to have invasive cancer, although some patients with high-grade dysplasia were missed. The updated Fukuoka guidelines are not superior to the Sendai guidelines in identifying neoplasias. Cyst size was not associated with advanced neoplasia.

Magnetic resonance imaging of acute appendicitis in pregnancy: a 5-year multiinstitutional study.

OBJECTIVE: The purpose of this study was to determine the diagnostic performance of magnetic resonance imaging (MRI) in the diagnosis of acute appendicitis during pregnancy in a multiinstitutional study. STUDY DESIGN: In this multicenter retrospective study, the cases of pregnant women who underwent MRI evaluation of abdominal or pelvic pain and who had clinical suspicion of acute appendicitis between June 1, 2009, and July 31, 2014, were reviewed. All MRI examinations with positive findings for acute appendicitis were confirmed with surgical pathologic information. Sensitivity, specificity, negative predictive values, and positive predictive values were calculated. Receiver operating characteristic curves were generated, and area under the curve analysis was performed for each participating institution. RESULTS: Of the cases that were evaluated, 9.3% (66/709) had MRI findings of acute appendicitis. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive values were 96.8%, 99.2%, 99.0%, 92.4%, and 99.7%, respectively. There was no statistically significant difference between centers that were included in the study (pair-wise probability values ranged from 0.12-0.99). CONCLUSION: MRI is useful and reproducible in the diagnosis of suspected acute appendicitis during pregnancy.

Suburothelial and extrinsic lesions of the urinary bladder: radiologic and pathologic features with emphasis on MR imaging.

OBJECTIVE: The purpose of this article is to present a contemporary review of the imaging appearance of diseases which affect the deeper layers of the urinary bladder, including both suburothelial and extrinsic pathologies, using radiologic-pathologic correlation. CONCLUSION: Compared to the more common urothelial lesions, at cystoscopy, suburothelial and extrinsic diseases of the urinary bladder wall often have a non-specific appearance or may be occult. Cross-sectional imaging, in particular MRI, plays an integral role in diagnosis. Mesenchymal tumors have distinct imaging features on MRI. Leiomyomas are characteristically low signal intensity on T2-weighted (T2W) imaging and progressively enhance. Lipomas and lipomatous hypertrophy are diagnosed by the presence of macroscopic fat. Neurofibromas, hemangiomas, and paragangliomas are hyperintense on T2W sequences and hypervascular. Reactive lesions occur in the setting of chronic inflammation and include: nephrogenic adenoma, cystitis cystica, and cystitis glandularis. Imaging findings are commonly non-specific; however, a mass with internal cystic spaces in association with pelvic lipomatosis is suggestive of cystitis glandularis. Urachal anomalies may be complicated by infection or malignancy. Urachal mucinous adenocarcinoma has a poor prognosis and may present as a T2-hyperintense suburothelial/extrinsic mass centered in the bladder dome. Other diseases may extrinsically involve the urinary bladder by hematogenous and peritoneal spread, including infection, endometriosis, and malignancy. A familiarity with suburothelial and extrinsic pathologies of the urinary bladder is critical for the radiologist, who may be the first to suggest these diagnoses.

Physical examination of the female internal and external genitalia with and without pelvic organ prolapse: A review.

Pelvic organ prolapse, a herniation of pelvic organs through the vagina, is a common condition in older women. Pelvic organ prolapse distorts vaginal anatomy making pelvic examination difficult. A clinician must accurately identify anatomic landmarks both in women presenting with symptoms of prolapse and in women noted to have coincidental prolapse during routine gynecologic examination. We present a systematic approach to the female pelvic examination including anatomic landmarks of the external genitalia, vagina, and uterus in women with normal support as well as changes that occur with pelvic organ prolapse. Knowledge and awareness of normal anatomic landmarks will improve a clinician's ability to identify defects in pelvic support and allow for better diagnosis and treatment of pelvic organ prolapse.

Correlation of pelvic magnetic resonance imaging diagnosis with pathology for indeterminate adnexal masses.

OBJECTIVES: The aim of this study was to determine the accuracy of pelvic magnetic resonance imaging (MRI) diagnoses compared with the final pathology diagnoses for a series of women with indeterminate adnexal masses. MATERIALS AND METHODS: We performed a retrospective cohort study of women who underwent pelvic MRI with a diagnosis of an adnexal mass between June 2009 and 2010 after indeterminate ultrasound at our tertiary care institution. Chart abstraction was performed for demographic information and radiologic interpretations (benign or malignant) and favored a specific histologic subtype on MRI reports. The radiologic diagnoses were compared with the diagnoses by surgical pathology. RESULTS: Data from 237 female patients who underwent pelvic MRI were included, and 41.35% underwent surgical intervention for the adnexal mass. Pelvic MRI (n = 88) was determined to have a sensitivity of 95.0% and specificity of 94.1%. The predicted specific histologic subtype by MRI (n = 84) was accurate in 56 (98.25%) of 57 women with an anticipated benign diagnosis and in 23 (85.19%) of 27 women with an anticipated malignancy. The agreement between a benign diagnosis from MRI and benign final surgical pathology was 0.85 (95% confidence interval, 0.716-0.976). CONCLUSIONS: In our tertiary care center, MRI is used to further characterize indeterminate adnexal masses and can accurately differentiate benign versus malignant adnexal masses. The diagnosis on MRI was highly correlative with the final histopathology. The majority of the cohort (59%) were able to be managed expectantly based on reassuring results of the MRI. Magnetic resonance imaging offered diagnostic value, more detailed patient counseling, appropriate subspecialty referral, and surgical planning, as well as reassurance to pursue conservative management of benign masses by MRI.

MRI assessment of early tumor response in metastatic renal cell carcinoma patients treated with sorafenib.

OBJECTIVE: The purpose of this study was to examine early MRI changes in renal cell carcinoma (RCC) treated with the antiangiogenic agent sorafenib and to identify MRI biomarkers of RCC response to sorafenib. MATERIALS AND METHODS: Sixteen patients with RCC were evaluated by MRI before and 3-12 weeks after commencing treatment with sorafenib. Two experienced MR radiologists, blinded to treatment status, independently graded tumor appearance on T1-weighted, T2-weighted, and gadolinium-enhanced images. The proportional odds mixed model was used to compare qualitative appearance of tumors before and after therapy. Time-to-progression was correlated with Response Evaluation Criteria in Solid Tumors (RECIST) 1.0 and MR-modified Choi criteria, incorporating changes in both tumor enhancement and size. RESULTS: After sorafenib therapy, there was a significant increase in T1 signal intensity of tumors (p < 0.0001) and a significant decrease in degree of tumor enhancement (p < 0.0001). The sum of unidimensional tumor diameters decreased significantly after therapy (p = 0.005). However, the average decrease in size at early follow-up was 13%, and all patients except one had stable disease by RECIST 1.0. Early responders defined by MR-modified Choi criteria had increased time-to-progression compared with nonresponders, whereas early RECIST evaluation did not predict clinical outcome. CONCLUSION: Decreased enhancement and T1 shortening of tumors on MRI may be useful biomarkers of RCC response to angiogenesis inhibitors. Response criteria combining early changes in size and enhancement lead to better correlation with clinical outcome compared with size decrease alone.

MR Imaging of Müllerian Anomalies.

Constituting a broad spectrum of developmental abnormalities of the female genital tract, Müllerian duct anomalies (MDAs) are present in up to 7% of the general population and in up to 25% of women who present with infertility and a history of miscarriage. Imaging plays an important role in narrowing the diagnostic considerations in these patients. In this article, we review the normal embryologic development of the female genital tract followed by the MR imaging techniques and protocol recommendations to evaluate such patients. The differential diagnoses and the MR imaging features of MDAs are also reviewed.

MR Imaging of Germ Cell and Sex Cord Stromal Tumors.

MR imaging is useful in the detection and characterization of adnexal lesions. This review discusses the clinical findings and MR imaging appearances of two types of ovarian neoplasms: germ cell and sex cord stromal tumors. The most common of these lesions, mature cystic teratomas, is characterized by the presence of bulk fat on MR imaging. Some of the other germ cell neoplasms and sex cord stromal tumors may have suggestive clinical, laboratory, or MR imaging features (eg, lipid and fibrosis) to establish a diagnosis. The ability to differentiate benign tumors from possible malignancy can aid in patient management.

Adrenal MRI: techniques and clinical applications.

The article reviews current magnetic resonance imaging (MRI) techniques and illustrates the MRI features of the commonly encountered lesions of the adrenal gland. MR may not always be able to characterize an adrenal mass. In these instances, reviewing the patient's clinical history and prior imaging can usually differentiate benign from malignant lesions, even if you cannot establishing an exact tissue diagnosis. The reader is referred to other reviews of adrenal imaging that emphasizes the use of CT and imaging-management algorithms that are beyond the purview of this focused review (1-6).