Multimodality pictorial review of IgG4-related disease in the abdomen and pelvis.

BACKGROUND: Immunoglobulin G4-related disease (IgG4-RD) is a systemic, immune-mediated disease that can affect multiple organs, including the orbits, salivary glands, thyroid gland, lungs, aorta, pancreas, bile ducts, lymph nodes, and retroperitoneum. While timely diagnosis is particularly important given the efficacy of glucocorticoid treatment for IgG4-RD, accurate recognition can prove a challenge given the overlap between the imaging features of this disease and other entities. PURPOSE: After a review of the epidemiology, pathophysiology, and clinical considerations (including treatment) associated with IgG4-RD, this pictorial review will showcase the variable imaging manifestations of this disease in the abdomen and pelvis. Post-treatment imaging appearance of these entities will be reviewed and mimickers of this disease in the abdomen and pelvis will be presented. CONCLUSION: The presence of mass-like soft tissue with radiographic characteristics of fibrosis affecting multiple organs should raise suspicion for IgG4-RD, although definite diagnosis can only be made with appropriate clinical, serological, and pathologic data.

Polyethylene glycol-based gels for treatment of prostate cancer: pictorial review of normal placement and complications.

Rectal spacers are commonly used in the radiotherapy for prostate cancers, serving as a means to protect the rectum and surrounding structures from radiation toxicity. Polyethylene Glycol-Based Gels (SpaceOAR ™ and Space-OAR Vue™, Boston Scientific) are the most commonly used rectal spacers. Given their increasingly widespread use and the relative paucity of radiology literature on this topic, it is imperative for the radiologist to recognize both the normal and abnormal placement of these polyethylene glycol-based rectal spacers, particularly as the latter may be associated with suboptimal therapy and/or complications.

Wunderlich Syndrome: Wonder What It Is.

Wunderlich syndrome (WS) refers to spontaneous renal or perinephric hemorrhage occurring in the absence of known trauma. WS is much less common than hemorrhage occurring after iatrogenic or traumatic conditions. Lenk's triad of acute onset flank pain, flank mass, and hypovolemic shock is a classic presentation of WS but seen in less than a quarter of patients. The majority of patients present only with isolated flank pain and often imaged with an unenhanced CT in the emergency department. The underlying etiology is varied with most cases attributed to neoplasms, vascular disease, cystic renal disease and anticoagulation induced; the etiology is often occult on the initial exam and further evaluation is necessary. Urologists are familiar with this unique entity but radiologists, who are more likely to be the first to diagnose WS, may not be familiar with the imaging work up and management options. In the last decade or so, there has been a conspicuous shift in the approach to WS and thus it will be worthwhile to revisit WS in detail. In our review, we will review the multimodality imaging approach to WS, describe optimal follow up and elaborate on management.

Endoscopic Retrograde Cholangiopancreatography: Deciphering the Black and White.

Endoscopic Retrograde Cholangiopancreatography (ERCP) remains the conventional method of imaging the pancreatic and biliary tree and is performed by direct injection of iodinated contrast material via the major papilla. This diagnostic procedure gained popularity in the 1970s and subsequently paved way for ERCP guided interventions such as sphincterotomy, stone retrieval and stent placement. Currently, therapeutic ERCP is more widespread than diagnostic ERCP primarily due to the availability of noninvasive imaging. Nevertheless, more than half a million ERCPs are performed annually in the United States and radiologists need to be comfortable interpreting them. The following review will familiarize the reader with the imaging appearances of biliary and pancreatic disorders on conventional ERCP, and elaborate on therapeutic ERCP with illustrative examples.

Multimodality Imaging Approach to Ovarian Neoplasms with Pathologic Correlation.

Ovarian neoplasms can be categorized on the basis of histopathologic features into epithelial surface cell tumors, germ cell tumors, sex cord-stromal tumors, and metastases. While their imaging appearance is often nonspecific, it closely parallels the gross pathologic appearance, and radiologic-pathologic correlation is helpful to aid in a deeper understanding of the subtypes. Epithelial cell neoplasms are the most common category, and they can be benign, borderline, or malignant. Specific subtypes include serous (most common), mucinous, seromucinous, endometrioid, clear cell, Brenner, and undifferentiated. High-grade serous cystadenocarcinoma accounts for the majority of malignant ovarian tumors and the most ovarian cancer deaths. While serous neoplasms are often unilocular and bilateral, mucinous neoplasms are larger, unilateral, and multilocular. Solid components, thickened septa, and papillary projections, particularly with vascularity, indicate borderline or malignant varieties. Endometrioid and clear cell carcinomas can arise within endometriomas. Fibrous tumors (cystadenofibroma, adenofibroma, fibroma or fibrothecoma, and Brenner tumors) demonstrate low T2-weighted signal intensity of their solid components, while teratomas contain lipid. The nonspecific imaging appearance of additional malignant ovarian germ cell tumors can be narrowed with tumor marker profiles. Sex cord-stromal tumors are often solid, and secondary signs from their hormonal secretion can be a clue to their diagnosis. The authors review the anatomy of the ovary and distal fallopian tube, the proposed origins of the histologic subtypes of tumors, the clinical features and epidemiology of ovarian neoplasms, and the applications of US, CT, and MRI in imaging ovarian neoplasms. The main focus is on the radiologic and pathologic features of the multiple ovarian neoplasm subtypes. An algorithmic approach to the diagnosis of ovarian neoplasms is presented. Online supplemental material is available for this article. ©RSNA, 2020.

Radiologic-Pathologic Correlation of Primary Retroperitoneal Neoplasms.

An earlier incorrect version of this article appeared in print. The online version is correct.

MRI of the Penis: Indications, Anatomy, and Pathology.

The purpose of this review is to discuss the role of magnetic resonance imaging (MRI) in the evaluation of penile pathology. Normal penile anatomy as well as the appearance of neoplastic and non-neoplastic entities on MRI will be reviewed. While ultrasound remains the first line imaging modality in evaluating most penile pathology, MR imaging has specific advantages owing to improved soft tissue resolution, ability to evaluate less accessible or complex anatomy (such as at the base of the penis), and the ability to detect subtle enhancement. Therefore, MRI is useful for when ultrasound and/or clinical findings are equivocal or incongruent. In addition, MR imaging is essential for preoperative surgical planning and is the imaging modality of choice in evaluating penile prostheses. The added value of MRI in these settings makes it an integral component to the management of many pathological entities affecting the penis.

Gadolinium Deposition and Nephrogenic Systemic Fibrosis: A Radiologist's Primer.

Gadolinium-based contrast agents (GBCAs) have an excellent safety profile. However, over the last 2 decades, two specific concerns have surfaced. GBCAs are associated with nephrogenic systemic fibrosis (NSF) and tissue retention of gadolinium. NSF is a rare fibrosing disorder with a poor prognosis, which is characterized by skin and subcutaneous thickening as well as systemic manifestations. The disease has been reported exclusively in patients with advanced renal disease, and it is associated with higher doses and specific types of GBCAs. The number of new cases of NSF has fallen over the past decade, presumably because of adherence by health care providers to regulatory guidelines, which continue to evolve. While gadolinium retention has been known to occur in the liver and bones, the relatively recent findings of deposition and retention in the brain have reignited the debate concerning the safety profile of GBCAs. Despite these concerns, there have been no proven health effects related to gadolinium deposition and retention other than NSF. The authors review the different categories of GBCAs available for commercial use, discuss NSF and gadolinium retention in the brain, and provide updates on the latest U.S. and European regulatory guidelines regarding use of these agents. Given the frequency with which GBCAs are used in clinical practice, it is imperative for all radiologists to learn the current guidelines to provide the safest and highest quality of patient care. ©RSNA, 2019.

Nongynecologic Causes of Pelvic Pain: Ultrasound First.

Ultrasonography (US) is often the first-line imaging study used to evaluate women who present with acute or chronic pelvic pain. Detection of nongynecologic causes of pelvic pain is critical, because delay in diagnosis can cause significant morbidity and mortality. Evaluation of these entities requires a variety of transducers to achieve optimal imaging depth and changes in patient positioning. Specific imaging techniques (such as graded compression) may be required if bowel pathology is suspected. Contrast-enhanced ultrasonography is increasingly used to improve detection of certain entities. The US appearance of common gastrointestinal and urinary tract-related causes of pelvic pain is reviewed.

Automated Test-Item Generation System for Retrieval Practice in Radiology Education.

OBJECTIVE: To develop and disseminate an automated item generation (AIG) system for retrieval practice (self-testing) in radiology and to obtain trainee feedback on its educational utility. MATERIALS AND METHODS: An AIG software program (Radmatic) that is capable of generating large numbers of distinct multiple-choice self-testing items from a given "item-model" was created. Instead of writing multiple individual self-testing items, an educator creates an "item-model" for one of two distinct item styles: true/false knowledge based items and image-based items. The software program then uses the item model to generate self-testing items upon trainee request. This internet-based system was made available to all radiology residents at our institution in conjunction with our didactic conferences. After obtaining institutional review board approval and informed consent, a written survey was conducted to obtain trainee feedback. RESULTS: Two faculty members with no computer programming experience were able to create item-models using a standard template. Twenty five of 54 (46%) radiology residents at our institution participated in the study. Twelve of these 25 (48%) study participants reported using the self-testing items regularly, which correlated well with the anonymous website usage statistics. The residents' overall impression and satisfaction with the self-testing items was quite positive, with a score of 7.89 ± 1.91 (mean ± SD) out of 10. Lack of time and email overload were the main reasons provided by residents for not using self-testing items. CONCLUSION: AIG enabled self-testing is technically feasible, and is perceived positively by radiology residents as useful to their education.

MR Imaging of the Testicular and Extratesticular Tumors: When Do We Need?

Testicular ultrasound is typically the first-line imaging examination in evaluating scrotal pathology. However, MR imaging can often provide valuable additional information, especially when ultrasound and/or clinical examinations are inconclusive. This is particularly evident when encountering testicular or paratesticular lesions, where accurate localization and characterization are paramount for management and prognosis. After reviewing normal scrotal anatomy as seen on MR imaging and offering a sample imaging protocol, the article describes specific indications for scrotal MR imaging and highlights imaging findings unique to various benign and malignant causes.

Does MR enterography offer added value after a recent CT in the evaluation of abdominal pain in Crohn's disease patients?

PURPOSE: To determine if there is added value in performing MR enterography shortly after a contrast-enhanced CT of the abdomen and pelvis in patients with Crohn's disease presenting with acute abdominal pain. MATERIALS AND METHODS: A total of 45 consecutive patients who underwent MRE examination <7 days after a CT met our strict inclusion criteria. Independent and blinded review of both MRE and CT exams was performed by two abdominal radiologists. RESULTS: There were no significant differences in detection of various findings associated with Crohn's disease between modalities. These findings included abscess, fistula, bowel wall thickening, free fluid, stricture, and bowel obstruction. There was moderate interobserver agreement with CT (Kappa: 0.52, 95% CI: [0.4-0.6]) and fair with MRE (Kappa: 0.36, 95% CI:[0.3 = 0.5]). CONCLUSION: The routine use of MRE after a diagnostic CT should be avoided, as it provides no additional valuable information, at the expense of extra patient risks, discomfort, and higher health care costs.

MRI-Ultrasound Fusion Targeted Biopsy of Prostate Imaging Reporting and Data System Version 2 Category 5 Lesions Found False-Positive at Multiparametric Prostate MRI.

OBJECTIVE: The purpose of this study was to determine imaging and clinical features associated with Prostate Imaging Reporting and Data System (PI-RADS) category 5 lesions identified prospectively at multiparametric MRI (mpMRI) that were found benign at MRI-ultrasound fusion targeted biopsy. MATERIALS AND METHODS: Between January 2015 and July 2016, 325 men underwent prostate mpMRI followed by MRI-ultrasound fusion targeted biopsy of 420 lesions prospectively identified and assessed with PI-RADS version 2. The frequency of clinically significant prostate cancer (defined as Gleason score ≥ 7) among PI-RADS 5 lesions was determined. Lesions with benign pathologic results were retrospectively reassessed by three abdominal radiologists and categorized as concordant or discordant between mpMRI and biopsy results. Multivariate logistic regression was used to identify factors associated with benign disease. Bonferroni correction was used. RESULTS: Of the 98 PI-RADS 5 lesions identified in 89 patients, 18% (18/98) were benign, 10% (10/98) were Gleason 6 disease, and 71% (70/98) were clinically significant prostate cancer. Factors associated with benign disease at multivariate analysis were lower prostate-specific antigen density (odds ratio [OR], 0.88; p < 0.001) and apex (OR, 3.54; p = 0.001) or base (OR, 7.11; p = 0.012) location. On secondary review of the 18 lesions with benign pathologic results, 39% (7/18) were scored as benign prostatic hyperplasia nodules, 28% (5/18) as inflammatory changes, 5% (1/18) as normal anatomic structures, and 28% (5/18) as discordant with imaging findings. CONCLUSION: PI-RADS 5 lesions identified during routine clinical interpretation are associated with a high risk of clinically significant prostate cancer. A benign pathologic result was significantly correlated with lower prostate-specific antigen density and apex or base location and most commonly attributed to a benign prostatic hyperplasia nodule. Integration of these clinical features may improve the interpretation of high-risk lesions identified with mpMRI.

Diagnosis of gastrogastric fistula on computed tomography: a quantitative approach.

OBJECTIVE: To determine if the attenuation of contrast material in the excluded stomach compared with the gastric pouch is helpful in diagnosing gastrogastric (GG) fistula. MATERIALS AND METHODS: In a retrospective study, 13 CT scans in 12 patients (age 43.2 ± 9.2, 10 females) who had undergone Roux-en-Y gastric bypass and who had oral contrast in both the gastric pouch and excluded stomach were qualitatively and quantitatively evaluated for GG fistula by two radiologists, using upper GI series (UGI) as the gold standard. Quantitative analysis was performed by computing the relative attenuation (RA) ratio (HU in excluded stomach/HU in gastric pouch). Statistical analysis was performed to determine if the RA ratio values correlated with the UGI findings of GG fistula. RESULTS: 46.2% (6/13) of UGI studies demonstrated a GG fistula. Statistical analysis demonstrated a significant difference in RA ratio (P < 0.05) between the fistula group (1.12 ± 0.29) and the reflux group (0.56 ± 0.19). A receiver operating characteristic analysis identified an RA ratio of 0.8 that maximized sensitivity (100%), at the expense of specificity (78.6%), for diagnosing GG fistula. In contrast, the initial qualitative evaluation for GG fistula yielded a lower sensitivity (45.8%) and a higher specificity (89.2%). After taking RA ratios into account, radiologists' final conclusions achieved higher sensitivity (58.3%) and specificity (100%). CONCLUSION: The relative attenuation ratio of oral contrast in the excluded stomach versus the gastric pouch can be a reliable tool in differentiating GG fistula from oral contrast reflux up the biliopancreatic limb on CT.

Standards for MRI reporting-the evolution to PI-RADS v 2.0.

Prostate cancer (PCa) remains a leading cause of death in the United States, but the vast majority of men diagnosed with PCa will die from other causes. While historically the capability of assessing the risk of life-threatening versus indolent PCa has relied heavily on serum prostate-specific antigen (PSA) and transrectal ultrasound (TRUS), multiparametric magnetic resonance imaging (mpMRI) has emerged as the leading tool for detection and characterization of clinically significant PCa. However, wide variations and lack of standardization of mpMRI data acquisition, interpretation, and reporting have hampered its progress. The development of a set of consensus guidelines, initially called Prostate Imaging and Reporting and Data System (PI-RADS) and eventually updated to a document called PI-RADS v2 has attempted to solve these shortcomings. As it stands, PI-RADS v2 currently represents the most up-to-date information on how to acquire, interpret, and report mpMRI of the prostate.

Magnetic resonance imaging of the scrotum: pictorial review with ultrasound correlation.

The purpose of this review is to showcase the added value of scrotal magnetic resonance imaging (MRI) in the workup of neoplastic and non-neoplastic entities. While ultrasound (US) remains the first-line imaging modality for evaluating scrotal pathology, MRI may add valuable information, particularly when US findings are equivocal. The inherent soft tissue resolution characteristics of MRI, as well as the ability to detect subtle enhancement and provide wider field-of-view imaging, can prove useful in evaluating inconclusive US findings. The added value of MR in these instances is critical as it may have a significant impact on patient management.

BILATERAL DIFFUSE UVEAL MELANOCYTIC PROLIFERATION: A CASE REPORT.

PURPOSE: To report a case of bilateral diffuse uveal melanocytic proliferation (BDUMP) in the setting of metastatic ovarian cancer. METHODS: In this observational case report, a 59-year-old woman presented with bilateral worsening vision and photophobia. She had been diagnosed with metastatic ovarian cancer 5 years prior for which she received Tamoxifen. Ophthalmic examination was completed followed by fluorescein angiography and optical coherence tomography (Spectralis OCT; Heidelberg Engineering). RESULTS: The visual acuity was 20/150 in both eyes. Exam demonstrated an iris pigmented lesion in the right eye, bilateral nuclear sclerotic cataracts, multiple orange lesions in the fundus, elevated pigmented uveal melanocytic tumors with diffuse choroidal thickening and multifocal early hyperfluorescence of these lesions (giraffe-like pattern) on fluorescein angiography, and exudative retinal detachment on OCT. The patient was diagnosed with BDUMP in the setting of metastatic ovarian carcinoma. Further metastatic workup demonstrated enlarged lymphadenopathy in the right axilla and inguinal regions. The patient declined chemotherapy and was initiated on plasmapheresis. CONCLUSIONS: BDUMP is a peculiar paraneoplastic syndrome in the setting of metastatic ovarian cancer, where antigens from the retinal pigment epithelium, iris and choroidal melanocytes cross-react with ovarian tumor cell antibodies that are circulating in the serum. Plasmapheresis can decrease the concentrations of the antibodies, maintain reasonable functional vision and improve the quality of life.

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.

Pelvic Inflammatory Disease: Multimodality Imaging Approach with Clinical-Pathologic Correlation.

Pelvic inflammatory disease (PID) is a common medical problem, with almost 1 million cases diagnosed annually. Historically, PID has been a clinical diagnosis supplemented with the findings from ultrasonography (US) or magnetic resonance (MR) imaging. However, the diagnosis of PID can be challenging because the clinical manifestations may mimic those of other pelvic and abdominal processes. Given the nonspecific clinical manifestations, computed tomography (CT) is commonly the first imaging examination performed. General CT findings of early- and late-stage PID include thickening of the uterosacral ligaments, pelvic fat stranding with obscuration of fascial planes, reactive lymphadenopathy, and pelvic free fluid. Recognition of these findings, as well as those seen with cervicitis, endometritis, acute salpingitis, oophoritis, pyosalpinx, hydrosalpinx, tubo-ovarian abscess, and pyometra, is crucial in allowing prompt and accurate diagnosis. Late complications of PID include tubal damage resulting in infertility and ectopic pregnancy, peritonitis caused by uterine and/or tubo-ovarian abscess rupture, development of peritoneal adhesions resulting in bowel obstruction and/or hydroureteronephrosis, right upper abdominal inflammation (Fitz-Hugh-Curtis syndrome), and septic thrombophlebitis. Recognition of these late manifestations at CT can also aid in proper patient management. At CT, careful assessment of common PID mimics, such as endometriosis, adnexal torsion, ruptured hemorrhagic ovarian cyst, adnexal neoplasms, appendicitis, and diverticulitis, is important to avoid misinterpretation, delay in management, and unnecessary surgery. Correlation with the findings from complementary imaging examinations, such as US and MR imaging, is useful for establishing a definitive diagnosis. (©)RSNA, 2016.