Clinical characteristics and outcomes of splenic infarction in cancer patients: a retrospective, single center report of 206 cases.

Cancer patients have a high risk of thromboembolic events including splenic infarct (SI). However, risk factors for SI in cancer patients are poorly understood, and the utility of systemic anticoagulation in such patients is uncertain. We performed a retrospective cohort study of all cancer patients with SI treated at Yale New Haven Hospital from 2008 to 2017. Central review of radiology imaging was performed to confirm the diagnosis of SI. Baseline differences in variables among patients with and without recurrent SI were compared using Fisher's exact test, Pearson's χ2 test, and t-test. Multivariable regression models were conducted to identify factors associated with recurrent SI. Of 206 patients with cancer and SI, 42 had a prior venous thromboembolic event, while 29 had atrial fibrillation/flutter. At a median follow-up of 11.4 months (range: 0-142.3 months), 152 patients underwent follow-up imaging, with only 6 having recurrent SI. The use of anticoagulation after initial SI was associated with a nonsignificant increase in recurrent SI (p = 0.054) and was not associated with development of venous thromboembolism after SI (p = 0.414). In bivariate analyses, the risk of recurrent SI showed a significant association with lower platelet counts (p < 0.001) and with atrial fibrillation/flutter (p = 0.036). In a multivariable logistic regression model, no variables were identified that were associated with a higher risk of recurrent SI. SI in cancer patients is typically an isolated event with low recurrence risk. Anticoagulation use should be guided by other thromboembolic risk factors.

Magnetic Resonance Imaging Features of Endometrial Polyps: Frequency of Occurrence and Interobserver Reliability.

OBJECTIVE: This study aimed to evaluate magnetic resonance imaging (MRI) features and interobserver agreement of endometrial polyps. METHODS: After institutional review board approval, our database was searched for women older than 18 years who underwent MRI pelvis and pelvic surgical intervention from 2012 to 2016. Seventy-two patients with polyps and 75 controls composed the study cohort. Two radiologists evaluated the MRIs retrospectively for polyps. Polyp characteristics and enhancement were assessed. RESULTS: Sensitivity and specificity of readers 1 and 2 were 59.7% and 88.0%, and 44.4 and 96.0%, respectively. There was moderate agreement for presence of polyps (κ = 0.556, P ≤ 0001), T2 fibrous core, and intratumoral cysts, with slight agreement for T2 signal and enhancement. Polyp size moderately correlated with pathology (κ = 0.465 [P = 0.025] for reader 1, κ = 0.562 [P = 0.029] for reader 2). The most common enhancement was same as myometrium. CONCLUSION: Magnetic resonance imaging is moderately sensitive for detecting endometrial polyps, demonstrating features that are not sensitive but can be specific, with moderate interobserver agreement.

Differentiating Renal Neoplasms From Simple Cysts on Contrast-Enhanced CT on the Basis of Attenuation and Homogeneity.

OBJECTIVE: The purpose of this study is to compare the attenuation and homogeneity of renal neoplasms with those of cysts on contrast-enhanced CT. MATERIALS AND METHODS: A total of 129 renal neoplasms and 24 simple cysts were evaluated. Two readers determined whether each mass was qualitatively heterogeneous or homogeneous. Mean, minimum, and maximum attenuation values were measured. Statistical analysis was performed. RESULTS: A total of 116 heterogeneous renal cell carcinomas (RCCs) (99 clear cell, four papillary, four oncocytic, seven chromophobe, and two unclassified RCCs), 13 homogeneous RCCs (10 papillary, two oncocytic, and one chromophobe RCC), and 24 cysts (all of which were homogeneous) were evaluated. All homogeneous RCCs had mean attenuation values of more than 42 HU, whereas renal cysts had mean attenuation values of up to 30 HU (p < 0.001). Two readers qualitatively and identically categorized all RCCs as homogeneous or heterogeneous (κ = 1.0; p < 0.001). CONCLUSION: Homogeneous simple renal cysts can have mean attenuation values of up to 30 HU, as determined by contrast-enhanced CT, whereas homogeneous RCCs have mean attenuation values as low as 42 HU, with no overlap occurring between the two groups. These data suggest that further evaluation of a homogeneous renal mass with a mean attenuation value of 30 HU or less on a contrast-enhanced CT scan likely is unwarranted.

Role of MRI in the Use of an Absorbable Hydrogel Spacer in Men Undergoing Radiation Therapy for Prostate Cancer: What the Radiologist Needs to Know.

OBJECTIVE: Hydrogel spacers have a novel role in the treatment of low- and intermediate-risk prostate cancer with dose-escalated radiation therapy. Given the growing number of patients undergoing treatment with radiation therapy, the use of hydrogel spacers is expected to increase. The purpose of this article is to review what a radiologist needs to know about the imaging of hydrogel spacers, including MRI technique and appearance on CT and MRI. CONCLUSION: MRI has a critical role in the evaluation of hydrogel spacer placement and is used to facilitate contouring by the radiation oncologist. The radiologist should be familiar with the imaging appearance of hydrogel spacers on CT and MRI to avoid interpretation pitfalls and errors.

Homogeneous T1 Hyperintense Renal Lesions with Smooth Borders: Is Contrast-enhanced MR Imaging Needed?

Purpose To retrospectively determine if homogeneous high T1 signal intensity (SI) masses with smooth borders on unenhanced magnetic resonance (MR) images can be characterized as benign. Materials and Methods Institutional review board approval was obtained for this HIPAA-compliant retrospective study, with waiver of informed consent. MR images in 84 patients with hemorrhagic or proteinaceous cysts and 50 patients with renal cell carcinoma (RCC) were evaluated. Sixty-three cysts and 49 RCCs underwent unenhanced computed tomography (CT). SI ratio and CT attenuation were determined. Two radiologists evaluated lesions as follows: score 1, homogeneous with smooth borders; score 2, mildly heterogeneous with mildly lobulated borders; score 3, moderately heterogeneous and irregular borders; and score 4, markedly heterogeneous with markedly irregular borders. Statistical analysis was performed by using multivariable logistic regression, Welch t test, Z test, Fisher-exact test, Shapiro-Wilk test, and receiver operating characteristic curve analysis. A diagnostic criterion was formulated by using classification and regression tree analysis. Results SI ratio and attenuation of hemorrhagic or proteinaceous cysts were significantly higher than those of RCCs (SI ratio: cyst 2.4 ± 0.8, RCC 1.5 ± 0.3; attenuation: cyst 51.9 ± 21.5, RCC: 34.8 ± 10.0). Reader 1 scored morphology of 68 (81%) hemorrhagic or proteinaceous cysts as score 1 on MR images and as score 45 (71%) on CT scans. Reader 2 scored morphology of 59 (70%) hemorrhagic or proteinaceous cysts as score 1 on MR images and as score 43 (68%) on CT scans. Two-step classification tree suggested that homogeneous high T1 SI lesions with smooth borders and SI ratio of greater than 1.6 predict the lesion as benign cysts. Similar algorithm for CT suggested threshold of 51 HU. Increasing threshold to 2.5 for SI ratio and 66 for Hounsfield units resulted in 99.9% confidence for characterizing benign cysts. Conclusion The retrospective assessment shows that morphologic assessment and SI quantification on unenhanced T1-weighted MR images can be used to differentiate benign hemorrhagic or proteinaceous cysts from RCC, although prospective assessment will be needed to confirm these results. (©) RSNA, 2016.

US of the Inguinal Canal: Comprehensive Review of Pathologic Processes with CT and MR Imaging Correlation.

Ultrasonography (US) has a fundamental role in the initial examination of patients who present with symptoms indicating abnormalities of the inguinal canal (IC), an area known for its complex anatomy. A thorough understanding of the embryologic and imaging characteristics of the contents of the IC is essential for any general radiologist. Moreover, an awareness of the various pathologic conditions that can affect IC structures is crucial to preventing misdiagnoses and ensuring optimal patient care. Early detection of IC abnormalities can reduce the risk of morbidity and mortality and facilitate proper treatment. Abnormalities may be related to increased intra-abdominal pressure, which can result in development of direct inguinal hernias and varicoceles, or to congenital anomalies of the processus vaginalis, which can result in development of indirect hernias and hydroceles. US is also helpful in assessing postoperative complications of hernia repair, such as hematoma, seroma, abscess, and hernia recurrence. In addition, it is often the modality initially used to detect neoplasms arising from or invading the IC. US is an important tool in the examination of patients suspected of having undescended testes or posttraumatic testicular retraction and is essential for the examination of patients suspected of having torsion or infectious inflammatory conditions of the spermatic cord. Online supplemental material is available for this article. ©RSNA, 2016.

Incompletely characterized incidental renal masses: emerging data support conservative management.

With imaging, most incidental renal masses can be diagnosed promptly and with confidence as being either benign or malignant. For those that cannot, management recommendations can be devised on the basis of a thorough evaluation of imaging features. However, most renal masses are either too small to characterize completely or are detected initially in imaging examinations that are not designed for full evaluation of them. These masses constitute a group of masses that are considered incompletely characterized. On the basis of current published guidelines, many masses warrant additional imaging. However, while the diagnosis of renal cancer at a curable stage remains the first priority, there is the additional need to reduce unnecessary healthcare costs and radiation exposure. As such, emerging data now support foregoing additional imaging for many incompletely characterized renal masses. These data include the low risk of progression to metastases or death for small renal masses that have undergone active surveillance (including biopsy-proven cancers) and a better understanding of how specific imaging features can be used to diagnose their origins. These developments support (a) avoidance of imaging entirely for those incompletely characterized renal masses that are highly likely to be benign cysts and (b) delay of further imaging of small solid masses in selected patients. Although more evidence-based data are needed and comprehensive management algorithms have yet to be defined, these recommendations are medically appropriate and practical, while limiting the imaging of many incompletely characterized incidental renal masses.

The gallbladder: uncommon gallbladder conditions and unusual presentations of the common gallbladder pathological processes.

This article reviews a spectrum of gallbladder conditions that are either uncommon or represent unusual manifestations of common diseases. These conditions are divided into four major categories: (a) congenital anomalies and normal variants including duplication, ectopia, and lymphangioma; (b) inflammatory processes and stone-related diseases and complications including adenomyomatosis, emphysematous cholecystitis, xanthogranulomatous cholecystitis, gangrenous and hemorrhagic cholecystitis, perforation, gallstone ileus, and Bouveret and Mirizzi syndromes; (c) gallbladder neoplasms including adenocarcinoma with associated porcelain gallbladder, squamous cell carcinoma, lymphoma, melanoma, and neurofibroma. A thorough understanding of the imaging characteristics of each condition can help the radiologist to make a timely and accurate diagnosis, thus avoiding potentially harmful delays in patient management and decreasing morbidity and mortality rates.

CT urography for the diagnosis of medullary sponge kidney.

BACKGROUND: Medullary sponge kidney (MSK) is characterized by malformation of the terminal collecting ducts and is associated with an increased risk of nephrolithiasis, nephrocalcinosis, urinary tract infections, renal acidification defects, and reduced bone density. It has been historically diagnosed with intravenous pyelography (IVP), which is falling out of favor as an imaging modality. CT urography (CTU) performed with multidetector CT (MDCT) has been shown to create images of the renal collecting system with similar detail as IVP; however, its utility in diagnosing MSK has not been defined. CASE REPORT: We present the first 15 patients with recurrent symptomatic nephrolithiasis who were evaluated in our renal stone clinic with CTU. Four patients were diagnosed with MSK after visualization of the characteristic radiologic findings. DISCUSSION: CTU effectively demonstrates the characteristic radiologic findings of MSK including collecting tubule dilatation, medullary nephrocalcinosis, nephrolithiasis, and medullary cysts. Dose reduction protocols can reduce radiation exposure below that associated with conventional IVP. We propose CTU be considered for the diagnosis of MSK.

Radiographic features of potential donor livers that precluded donation.

OBJECTIVE: The objective of our study was to catalog the anatomic features shown on preoperative CT that precluded living-donor liver donation. MATERIALS AND METHODS: We retrospectively reviewed the records of 159 consecutive candidates who were evaluated for potential right or left lobe liver donation from November 2007 to January 2012 using MDCT angiography and cholangiography. For the potential donors who were excluded secondary to findings depicted on preoperative imaging, we determined which findings precluded donation. RESULTS: In two (1%) patients who had no prohibitive preoperative imaging findings, anatomic abnormalities were detected intraoperatively that precluded transplantation. Sixty-one (38%) candidates were excluded from liver donation on the basis of imaging findings. Of these patients, 40 (66%) had inadequate liver volume, 14 (23%) had vascular or biliary variants, five (8%) had steatosis, and two (3%) were found to have renal cell carcinoma. Arterial and biliary variants were the most common reason for exclusion based on anatomic findings. CONCLUSION: Inadequate liver volume was the most common reason for exclusion based on preoperative imaging. Arterial and biliary anatomic variants precluded both right and left lobe transplantation in a number of cases.

Cystic kidney disease in a patient with systemic toxicity from long-term D-penicillamine use.

D-penicillamine, used to treat cystinuria, is known to cause impaired collagen deposition and dysfunction in elastic fibers. D-penicillamine also has been associated with glomerular abnormalities, typically membranous glomerulonephritis. We describe a patient with severe bilateral cystic kidney disease that developed after long-term D-penicillamine use for treatment of cystinuria. The cysts in the kidneys were noted during an evaluation for acute kidney injury. The patient had no evidence of cysts on prior renal imaging at a time when his kidney function was normal. Simultaneously, he presented with multiorgan manifestations of D-penicillamine toxicity, including the skin findings of cutix laxa and elastosis perforans serpiginosa. Consequently, D-penicillamine treatment was discontinued, after which the progression of cystic kidney disease gradually ceased, along with the other systemic manifestations of toxicity. To our knowledge, this is the first report of cystic kidney disease associated with and perhaps caused by long-term d-penicillamine therapy. The proposed mechanism of cyst formation is the malfunction of the extracellular matrix of the kidney by d-penicillamine that leads to an impaired repair process after kidney injury.

CT angiography in potential living kidney donors: 80 kVp versus 120 kVp.

OBJECTIVE: The purpose of this article is to retrospectively investigate the diagnostic accuracy, image quality, and radiation dose of renal artery CT angiography (CTA), at 80 kVp compared with 120 kVp, in adult kidney donors. MATERIALS AND METHODS: CTA examinations of 258 consecutive potential kidney donors were retrospectively evaluated; 189 patients were scanned using 64-MDCT scanners (higher maximal tube current), and 69 patients were scanned using 16-MDCT scanners (lower maximal tube current). On the basis of the tube potential and scanners, the study population was divided into four groups. Qualitative and quantitative analysis include vascular attenuation measurements, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Volume CT dose index (CTDIvol) was recorded, and size-specific dose estimate was also estimated. RESULTS: Using 80 kVp for the 16-MDCT scanner, there was a 64.9% reduction in size-specific dose estimate (66.1% reduction in CTDIvol), increased noise, and tube current saturation in all cases. Axial image quality was significantly lower compared with that obtained at 120 kVp (p = 0.02), but image quality and visibility of renal artery branch order were comparable. Using 80 kVp for the 64-MDCT scanner, there was a 40.5% reduction in size-specific dose estimate (43.6% reduction in CTDIvol) and increased SNR and CNR (p < 0.001). No significant differences in 3D image quality and branch order visibility were observed. Tube current saturation was reached in 31% of cases. One hundred fifty-one patients (86 imaged at 80 kVp and 65 imaged at 120 kVp) underwent donor nephrectomy; CTA diagnostic accuracy was 100%. CONCLUSION: Renal artery CTA using 80 kVp combined with limiting the tube current results in a significant reduction in radiation dose and improved SNR and CNR, without deterioration of image quality.

Comparison of multidetector computed tomography angiography and cholangiography performed at 80 and 120 kVp in live liver donors.

OBJECTIVE: The objective of this study was to compare the radiation exposure and image quality of contrast-enhanced multidetector computed tomography angiography (CTA) and computed tomography cholangiography (CTC) performed for living liver donor evaluation using 80 and 120 kVp. METHODS: Ninety-three potential liver donors who underwent preoperative contrast-enhanced 64 multidetector CTA and CTC were retrospectively divided into 2 groups: at 80 and at 120 kVp. An institutional review board waiver was obtained. Signal-to-noise ratio and contrast-to-noise ratio of the hepatic artery and common bile duct were obtained. The dose-length product was recorded. Image quality and visibility of hepatic artery and biliary tract anatomy were evaluated. Mann-Whitney U test was used for statistical evaluation. RESULTS: Mean hepatic artery/common bile duct signal-to-noise ratio was 28.9/28.6 (SD, 14.2/10.0) at 80 kVp and 27.6/25.8 (SD, 8.0/6.2) at 120 kVp (P = 0.61/0.099). Mean hepatic artery/common bile duct contrast-to-noise ratio was 24.8/23.3 (SD, 12.9/8.6) at 80 kVp and 22.2/19.3 (SD, 7.7/5.0) at 120 kVp (P = 0.76/0.005). Mean CTA/CTC dose-length product was 279/281 (SD, 42/52) mGy-cm at 80 kVp and 407/451 (SD, 208/243) mGy-cm at 120 kVp (P = 0.026/0.002). Computed tomography cholangiography image quality and visibility of biliary tract anatomy were not significantly different at 80 versus 120 kVp (all P > 0.13). Computed tomography angiography image quality was significantly lower (P < 0.01), and the noise scores significantly higher (P < 0.01) at 80 versus 120 kVp, but diagnostic. CONCLUSIONS: Contrast-enhanced CTA and CTC performed at 80 kVp result in comparable image quality and anatomical evaluation with reduced radiation exposure when compared with 120 kVp.

Detection of hepatic steatosis on contrast-enhanced CT images: diagnostic accuracy of identification of areas of presumed focal fatty sparing.

OBJECTIVE: The purpose of this article is to determine the diagnostic accuracy of identifying focal areas of increased density along the gallbladder fossa or in the periphery of segment IV for diagnosing hepatic steatosis. MATERIALS AND METHODS: Five hundred consecutive three-phase CT examinations were retrospectively evaluated. Two reference standards for hepatic steatosis were determined using the unenhanced CT examination: a liver-spleen attenuation difference of greater than 10 HU and the absolute attenuation of the liver less than 40 HU. The portal venous phase was independently analyzed by two radiologists. Hepatic steatosis was diagnosed on the contrast-enhanced images if there was increased attenuation in the liver, either at the gallbladder fossa or in the posterior medial aspect of segment IV, when compared with background liver parenchyma. RESULTS: The criterion of relative liver-spleen attenuation difference diagnosed 38 cases. The criterion of absolute liver attenuation less than 40 HU diagnosed 44 cases. Of these cases, hepatic steatosis was diagnosed on the portal venous phase in 23 cases (κ = 1.0), with no false-positive cases. The criterion of relative liver-spleen attenuation difference yielded sensitivity, specificity, positive predictive value, and negative predictive value of 60.5%, 100%, 100%, and 96.9%, respectively. The criterion of absolute liver attenuation less than 40 HU yielded sensitivity, specificity, positive predictive value, and negative predictive value of 52.5%, 100%, 100%, and 95.7%, respectively. CONCLUSION: Qualitative evaluation of the liver on a portal venous phase contrast-enhanced CT is highly specific for the diagnosis of hepatic steatosis; the sensitivity of the method, however, is rather low.

Patient size and radiation exposure in thoracic, pelvic, and abdominal CT examinations performed with automatic exposure control.

OBJECTIVE: The purpose of this study was to investigate the effect of patient size on the amount of radiation used to perform CT examinations of the chest, abdomen, and pelvis with automatic exposure control and on the corresponding patient doses. MATERIALS AND METHODS: Ninety-one patients underwent CT of the chest, abdomen, and pelvis with a 64-MDCT scanner with automatic exposure control in the x, y, and z planes (noise index, 11.5; tube rotation speed, 1 second; maximal x-ray tube capacity, 800 mA; slice thickness, 5 mm; slice interval, 5 mm; table speed, 40 mm/rotation; pitch, 1; tube voltage, 120 kVp). Volume CT dose index was obtained from the scanner console at the completion of each examination. The volume CT dose index and a dosimetry calculator were used to determine the organ dose in a 70-kg patient. Patient organ doses were obtained by correction of the calculator organ doses by factors that accounted for size variations in the lung and abdomen among patients and the corresponding regions in the phantom. RESULTS: The average volume CT dose index for a 60-kg patient was approximately 11 mGy, which increased to approximately 22 mGy for an 80-kg patient and to approximately 33 mGy for a 100-kg patient. The corresponding average liver doses for 60-kg patients was approximately 16 mGy, which increased to approximately 25 mGy for 80-kg patients and to approximately 34 mGy for 100-kg patients. For this patient cohort, the median doses to the colon, stomach, and liver were approximately 25 mGy; to the bladder, 31 mGy; and to the red bone marrow, 16 mGy. The 90th percentile organ doses were generally three to four times that of the corresponding 10th percentile organ doses. CONCLUSION: For body CT examinations performed with automatic exposure control, the radiation used to perform examinations of 100-kg patients is approximately three times that for a 60-kg patient and results in organ doses that are generally twice as high as those in a 60-kg patient.

Comparison of four embolic materials at uterine artery embolization by using postprocedural MR imaging enhancement.

PURPOSE: To test the hypothesis that not all embolic materials are equivalent by using postprocedural magnetic resonance (MR) imaging enhancement of uterine fibroids in patients treated with uterine artery embolization (UAE). MATERIALS AND METHODS: Approval and a waiver of consent from the institutional human investigations committee was received for this study. The study was HIPAA compliant. A total of 84 women who underwent 6-month MR imaging follow-up constituted this retrospective study. Within this group, 25 women were treated with Contour polyvinyl alcohol (PVA) particles, 23 were treated with Contour SE particles, 19 were treated with Embosphere microspheres, and 17 were treated with Bead Block microspheres. Pre- and postprocedural MR imaging results were analyzed for the total number of fibroids present in the uterus of each patient and for the percentage of individual fibroid enhancement. Enhancement of individual fibroids was measured with quartile intervals. Greater than 25% residual enhancement of a fibroid after embolization was considered an incomplete infarction. The overall percentage change in enhancement was calculated for each patient. Bivariate analysis by using generalized linear modeling and one-way analysis of variance was used to assess differences in infarction with different embolic materials. RESULTS: Among patients treated with Contour and Embosphere, there was a mean reduction in enhancement by 76.60% and 83.07%, respectively, compared with a mean reduction of 52.53% and 49.78% in patients treated with Bead Block and Contour SE, respectively. There was a significant difference in postembolization enhancement between Bead Block and Embosphere, Bead Block and Contour, Contour SE and Embosphere, and Contour SE and Contour. CONCLUSION: Patients treated with Bead Block or Contour SE demonstrated a reduced degree of infarction at follow-up MR imaging compared with patients treated with Contour or Embosphere.

Renal lesions: characterization with diffusion-weighted imaging versus contrast-enhanced MR imaging.

PURPOSE: To compare the diagnostic performance of diffusion-weighted (DW) magnetic resonance (MR) imaging with that of contrast material-enhanced (CE) MR imaging and to assess the performance of these examinations combined for the characterization of renal lesions, with MR follow-up and histopathologic analysis as the reference standards. MATERIALS AND METHODS: The institutional review board waived the requirement of informed patient consent for this retrospective HIPAA-compliant study. One hundred nine renal lesions in 64 patients (46 men, 18 women; mean age, 60.7 years) were evaluated with CE MR imaging and breath-hold DW imaging performed with various b values. Renal lesions were characterized with use of CE MR criteria, and apparent diffusion coefficients (ADCs) were measured. The ADCs of benign and malignant lesions were compared at Mann-Whitney testing. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of DW imaging and CE MR imaging in the diagnosis of renal cell carcinoma (RCC). RESULTS: The 109 renal lesions--81 benign lesions and 28 RCCs--had a mean diameter of 4.2 cm +/- 2.5 (standard deviation). The mean ADC for RCCs (1.41 x 10(-3) mm(2)/sec +/- 0.61) was significantly lower (P < .0001) than that for benign lesions (2.23 x 10(-3) mm(2)/sec +/- 0.87) at DW imaging performed with b values of 0, 400, and 800 sec/mm(2). At a cutoff ADC of less than or equal to 1.92 x 10(-3) mm(2)/sec, the area under the ROC curve (AUC), sensitivity, and specificity of DW imaging for the diagnosis of RCCs (excluding angiomyolipomas) were 0.856, 86%, and 80%, respectively. The corresponding AUC, sensitivity, and specificity of CE MR imaging were 0.944, 100%, and 89%, respectively. Combined DW and CE MR imaging had 96% specificity. The AUC for the DW imaging-based diagnosis of solid RCC versus oncocytoma was 0.854. Papillary RCCs had lower ADCs than nonpapillary RCCs. CONCLUSION: DW imaging can be used to characterize renal lesions; however, compared with CE MR imaging, it is less accurate. DW imaging can be used to differentiate solid RCCs from oncocytomas and characterize the histologic subtypes of RCC.

Annular pancreas in a 24-year-old woman with persistent abdominal pain.

Annular pancreas (AP) is a rare diagnosis in the adult population but can cause significant morbidity if not correctly identified. In adults, the most common symptoms are abdominal pain, nausea and vomiting. While these are not specific to AP, they are important clues to this diagnosis in the right clinical context. We present the case of a 24-year-old woman presenting with a 6-year history of progressive abdominal pain and dyspepsia in the context of an extensive negative workup. Upper gastrointestinal (GI) series and MRI revealed partial duodenal obstruction, concerning for AP. While patients with chronic abdominal pain and vague GI complaints may be diagnosed with functional bowel disorders, it is important to appropriately address the possibility of an underlying structural lesion such as AP. This strategy is not only cost-effective but also saves the patient discomfort associated with unnecessary procedures and allows a timely intervention.