Imaging of Small-Bowel Neuroendocrine Neoplasms: AJR Expert Panel Narrative Review.

Neuroendocrine neoplasms (NENs) of the small bowel are typically slow-growing lesions that remain asymptomatic until reaching an advanced stage. Imaging modalities for lesion detection, staging, and follow-up in patients with known or suspected NEN include CT enterography, MR enterography, and PET/CT using a somatostatin receptor analog. FDG PET/CT may have a role in the evaluation of poorly differentiated NENs. Liver MRI, ideally with a hepatocyte-specific contrast agent, should be used in the evaluation of hepatic metastases. Imaging informs decisions regarding both surgical approaches and systematic therapy (specifically, peptide receptor radionuclide therapy). This AJR Expert Panel Narrative Review describes the multimodality imaging features of small-bowel NENs; explores the optimal imaging modalities for their diagnosis, staging, and follow-up; and discusses how imaging may be used to guide therapy.

Modest agreement between magnetic resonance and pathological tumor regression after neoadjuvant therapy for rectal cancer in the real world.

Magnetic resonance imaging (MRI) is routinely used for preoperative tumor staging and to assess response to therapy in rectal cancer patients. The aim of our study was to evaluate the accuracy of MRI based restaging after neoadjuvant chemoradiotherapy (CRT) in predicting pathologic response. This multicenter cohort study included adult patients with histologically confirmed locally advanced rectal adenocarcinoma treated with neoadjuvant CRT followed by curative intent elective surgery between January 2014 and December 2019 at four academic high-volume institutions. Magnetic resonance tumor regression grade (mrTRG) and pathologic tumor regression grade (pTRG) were reviewed and compared for all the patients. The agreement between radiologist and pathologist was assessed with the weighted k test. Risk factors for poor agreement were investigated using logistic regression. A total of 309 patients were included. Modest agreement was found between mrTRG and pTRG when regression was classified according to standard five-tier systems (k = 0.386). When only two categories were considered for each regression system, (pTRG 0-3 vs pTRG 4; mrTRG 2-5 vs mrTRG 1) an accuracy of 78% (95% confidence interval [CI] 0.73-0.83) was found between radiologic and pathologic assessment with a k value of 0.185. The logistic regression model revealed that "T3 greater than 5 mm extent" was the only variable significantly impacting on disagreement (OR 0.33, 95% CI 0.15-0.68, P = .0034). Modest agreement exists between mrTRG and pTRG. The chances of appropriate assessment of the regression grade after neoadjuvant CRT appear to be higher in case of a T3 tumor with at least 5 mm extension in the mesorectal fat at the pretreatment MRI.

Early Cholangiocarcinoma Detection With Magnetic Resonance Imaging Versus Ultrasound in Primary Sclerosing Cholangitis.

BACKGROUND AND AIMS: Early detection of perihilar cholangiocarcinoma (CCA) among patients with primary sclerosing cholangitis (PSC) is important to identify more people eligible for curative therapy. While many recommend CCA screening, there are divergent opinions and limited data regarding the use of ultrasound or magnetic resonance imaging (MRI) for early CCA detection, and it is unknown whether there is benefit in testing asymptomatic individuals. Our aims were to assess the diagnostic performances and prognostic implications of ultrasound and MRI-based CCA detection. APPROACH AND RESULTS: This is a multicenter review of 266 adults with PSC (CCA, n = 120) who underwent both an ultrasound and MRI within 3 months. Images were re-examined by radiologists who were blinded to the clinical information. Respectively, MRI had a higher area under the curve compared with ultrasound for CCA detection: 0.87 versus 0.70 for the entire cohort; 0.81 versus 0.59 for asymptomatic individuals; and 0.88 versus 0.71 for those listed for CCA transplant protocol. The absence of symptoms at CCA diagnosis was associated with improved 5-year outcomes including overall survival (82% vs. 46%, log-rank P < 0.01) and recurrence-free survival following liver transplant (89% vs. 65%, log-rank P = 0.04). Among those with asymptomatic CCA, MRI detection (compared with ultrasound) was associated with reduction in both mortality (hazard ratio, 0.10; 95% confidence interval, 0.01-0.96) and CCA progression after transplant listing (hazard ratio, 0.10; 95% confidence interval, 0.01-0.90). These benefits continued among patients who had annual monitoring and PSC for more than 1 year before CCA was diagnosed. CONCLUSIONS: MRI is superior to ultrasound for the detection of early-stage CCA in patients with PSC. Identification of CCA before the onset of symptoms with MRI is associated with improved outcomes.

Into the future: A pilot study combining imaging with molecular profiling to predict resectability in ovarian cancer.

OBJECTIVE: We sought to determine the predictive value of combining tumor molecular subtype and computerized tomography (CT) imaging for surgical outcomes after primary cytoreductive surgery in advanced stage high-grade serous ovarian cancer (HGSOC) patients. METHODS: We identified 129 HGSOC patients who underwent pre-operative CT imaging and post-operative tumor mRNA profiling. A continuous CT-score indicative of overall disease burden was defined based on six imaging measurements of anatomic involvement. Molecular subtypes were derived from mRNA profiling of chemo-naïve tumors and classified as mesenchymal (MES) subtype (36%) or non-MES subtype (64%). Fischer exact tests and multivariate logistic regression examined residual disease and surgical complexity. RESULTS: Women with higher CT-scores were more likely to have MES subtype tumors (p = 0.014). MES subtypes and a high CT-score were independently predictive of macroscopic disease and high surgical complexity. In multivariate models adjusting for age, stage and American Society of Anesthesiologists (ASA) score, patients with a MES subtype and high CT-score had significantly elevated risk of macroscopic disease (OR = 26.7, 95% CI = [6.42, 187]) and were more likely to undergo high complexity surgery (OR = 9.53, 95% CI = [2.76, 40.6], compared to patients with non-MES tumor and low CT-score. CONCLUSION: Preoperative CT imaging combined with tumor molecular subtyping can identify a subset of women unlikely to have resectable disease and likely to require high complexity surgery. Along with other clinical factors, these may refine predictive scores for resection and assist treatment planning. Investigating methods for pre-surgical molecular subtyping is an important next step.

Eosinophilic Disorders of the Gastrointestinal Tract and Associated Abdominal Viscera: Imaging Findings and Diagnosis.

Eosinophilic gastrointestinal disorders (EGIDs) are inflammatory conditions of the gastrointestinal tract that are characterized by tissue eosinophilia and end-organ dysfunction or damage. Primary EGIDs are associated with atopy and other allergic conditions, whereas secondary EGIDs are associated with underlying systemic diseases or hypereosinophilic syndrome. Within the spectrum of EGIDs, eosinophilic esophagitis is the most prevalent. Eosinophilic gastroenteritis and eosinophilic colitis are relatively uncommon. Eosinophilic infiltration of the liver, biliary tree, and/or pancreas also can occur and mimic other inflammatory and malignant conditions. Although endoscopic evaluation is the method of choice for eosinophilic esophagitis, radiologic evaluation of the esophagus plays an important role in the assessment of disease severity. CT and MR enterography are the modalities of choice for demonstrating specific forms of eosinophilic gastroenteritis. CT and MRI are important in the detection of abdominal visceral involvement in EGIDs. Diagnosis is often challenging and relies on symptoms, imaging findings, histologic confirmation of tissue eosinophilia, and correlation with peripheral eosinophilia. Imaging is crucial for identifying characteristic organ-specific findings, although imaging findings are not specific. When promptly treated, EGIDs usually have a benign clinical course. However, a delayed diagnosis and associated surgical interventions have been associated with morbidity. Therefore, a radiologist's knowledge of the imaging findings of EGIDs in the appropriate clinical settings may aid in early diagnosis and thereby improve patient care. An overview of the clinical features and imaging findings of EGIDs and the eosinophilic disorders of associated abdominal viscera is provided. Online supplemental material is available for this article. ©RSNA, 2022.

Imaging Review of Gastrointestinal Motility Disorders.

The motor function of the gastrointestinal tract relies on the enteric nervous system, which includes neurons spanning from the esophagus to the internal anal sphincter. Disorders of gastrointestinal motility arise as a result of disease within the affected portion of the enteric nervous system and may be caused by a wide array of underlying diseases. The etiology of motility disorders may be primary or due to secondary causes related to infection or inflammation, congenital abnormalities, metabolic disturbances, systemic illness, or medication-related side effects. The symptoms of gastrointestinal dysmotility tend to be nonspecific and may cause diagnostic difficulty. Therefore, evaluation of motility disorders requires a combination of clinical, radiologic, and endoscopic or manometric testing. Radiologic studies including fluoroscopy, CT, MRI, and nuclear scintigraphy allow exclusion of alternative pathologic conditions and serve as adjuncts to endoscopy and manometry to determine the appropriate diagnosis. Additionally, radiologist understanding of clinical evaluation of motility disorders is necessary for guiding referring clinicians and appropriately imaging patients. New developments and advances in imaging techniques have allowed improved assessment and diagnosis of motility disorders, which will continue to improve patient treatment options. Online supplemental material is available for this article. ©RSNA, 2022.

Hepatic Mucinous Cystic Neoplasm Versus Simple Biliary Cyst: Assessment of Distinguishing Imaging Features Using CT and MRI.

OBJECTIVE. The purpose of our study was to identify the imaging features that differentiate a hepatic mucinous cystic neoplasm (MCN) from a simple biliary cyst. MATERIALS AND METHODS. Surgically resected hepatic MCNs and simple biliary cysts over a 20-year period (October 29, 1997-January 23, 2018) with preoperative CT, MRI, or both were retrospectively identified. Included cases underwent histopathologic confirmation of diagnosis based on the 2010 World Health Organization criteria and blinded imaging review. Various imaging features, including cyst shape and septal enhancement, were assessed for performance. For septate cysts, the relationship of the septation to the cyst wall-that is, arising from the wall without an indentation versus arising from an external macrolobulation-was recorded. Statistical analysis was performed for the imaging features with the chi-square test. RESULTS. The study group comprised 22 hepatic MCNs and 56 simple biliary cysts. A unilocular hepatic cystic lesion was highly predictive of a simple biliary cyst (positive predictive value = 95.2%). The imaging feature of septations arising only from macro-lobulations was 100% specific for a simple biliary cyst on CT (p = 0.001). The presence of septations arising from the cyst wall without indentation was 100% sensitive for hepatic MCN but was only 56.3% specific on CT. Septal enhancement reached 100% sensitivity for hepatic MCN on MRI (p = 0.018). CONCLUSION. The presence of septations, relationship of the septations to the cyst wall, and septal enhancement were sensitive imaging features in the detection of hepatic MCN. The imaging feature of septations arising only from macrolobulations in the cyst wall was specific for simple biliary cysts on CT and helped differentiate simple biliary cysts from hepatic MCNs.

Computerized tomography scan in pre-diagnostic pancreatic ductal adenocarcinoma: Stages of progression and potential benefits of early intervention: A retrospective study.

BACKGROUND: The frequency, nature and timeline of changes on thin-slice (≤3 mm) multi-detector computerized tomography (CT) scans in the pre-diagnostic phase of pancreatic ductal adenocarcinoma (PDAC) are unknown. It is unclear if identifying imaging changes in this phase will improve PDAC survival beyond lead time. METHODS: From a cohort of 128 subjects (Cohort A) with CT scans done 3-36 months before diagnosis of PDAC we developed a CTgram defining CT Stages (CTS) I through IV in the radiological progression of pre-diagnostic PDAC. We constructed Cohort B of PDAC resected at CTS I and II and compared survival in CTS I and II in Cohort A (n = 22 each; control natural history cohort) vs Cohort B (n = 33 and 72, respectively; early interception cohort). RESULTS: CTs were abnormal in 16% and 85% at 24-36 and 3-6 months respectively, before PDAC diagnosis. The PDAC CTgram stages, findings and median lead times (months) to clinical diagnosis were: CTS I: Abrupt duct cut-off/duct dilatation (-12.8); CTS II: Low density mass confined to pancreas (-9.5), CTS III: Peri-pancreatic infiltration (-5.8), CTS IV: Distant metastases (only at diagnosis). PDAC survival was better in cohort B than in cohort A despite inclusion of lead time in Cohort A: CTS I (36 vs 17.2 months, p = 0.03), CTS II (35.2 vs 15.3 months, p = 0.04). CONCLUSION: Starting 12-18 months before PDAC diagnosis, progressive and increasingly frequent changes occur on CT scans. Resection of PDAC at the time of pre-diagnostic CT changes is likely to provide survival benefit beyond lead time.

Recurrence patterns in patients with abnormal cardiophrenic lymph nodes at ovarian cancer diagnosis.

OBJECTIVES: Metastases in cardiophrenic lymph nodes noted at diagnosis of epithelial ovarian cancer confer a poor prognosis. It is unclear if cardiophrenic nodal metastases portend an atypical pattern of recurrence. We report on patients with radiographically involved cardiophrenic lymph nodes who underwent optimal primary debulking surgery to describe patterns of recurrence and response to chemotherapy. METHODS: Patients undergoing primary debulking surgery for stage IIIC/IV epithelial ovarian carcinoma with residual disease ≤1.0 cm at our institution from 2003 to 2011 with a pre-operative computed tomography (CT) scan were identified. Scans were reviewed by blinded radiologists, who identified abnormal cardiophrenic lymph nodes via a qualitative assessment scale based on size, heterogeneity, and architecture. RESULTS: Of the 250 patients identified, a recurrence site was documented in 22/27 (81.5%) with abnormal pre-operative cardiophrenic lymph nodes (defined by an elevated Qualitative Assessment Scale (QAS) score of ≥4), and in 128/223 (57.4%) without abnormal pre-operative cardiophrenic lymph nodes. Median short axis and long axis lymph node diameters for these patients was 9 (range 6-15) mm and 15 (range 11-22) mm, respectively. Cardiophrenic lymph nodes were resected in one patient. Patients with abnormal cardiophrenic nodes are more likely to have synchronous recurrence in thorax/pelvis and abdomen (50.0% (11/22) vs 25.0% (32/128), p=0.02) and less likely to have isolated recurrence in pelvis or abdomen (40.9% (9/22) vs 68.0% (87/128)). All patients who had a CT scan after six cycles of chemotherapy had improvement (defined as reduction of QAS score) in cardiophrenic lymphadenopathy. CONCLUSIONS: Despite cardiophrenic adenopathy demonstrating a complete radiographic response to chemotherapy, their presence pre-operatively is associated with an increased risk of recurrence in the thorax. Knowledge of this propensity to recur in the thorax is important to ensure all extra-abdominal recurrence sites are diagnosed and managed appropriately.

Quantitative Inflammation Assessment for Crohn Disease Using Ultrasensitive Ultrasound Microvessel Imaging: A Pilot Study.

OBJECTIVES: Crohn disease (CD) is a chronic inflammation in the digestive tract that affects millions of Americans. Bowel vascularity has important diagnostic information because inflammation is associated with blood flow changes. We recently developed an ultrasensitive ultrasound microvessel imaging (UMI) technique with high vessel sensitivity. This study aimed to evaluate the feasibility of UMI to assist CD detection and staging. METHODS: Ultrasound microvessel imaging was performed on 76 bowel wall segments from 48 symptomatic patients with CD. Clinically indicated computed tomographic/magnetic resonance enterography was used as the reference standard. The vessel-length ratio (VLR, the number of vessel pixels in the bowel wall segment normalized to the segment length) was derived in both conventional color flow imaging (CFI) and UMI to quantitatively stage disease activity. Receiver operating characteristic curves were then analyzed between different disease groups. RESULTS: The VLR-CFI and VLR-UMI detected similar correlations between vascularization and disease activity: severe inflammation had a higher VLR than normal/mildly inflamed bowels (P < .05). No significant difference was found between quiescent and mild CD due to the small sample size. The VLR-CFI had more difficulties in distinguishing quiescent versus mild CD compared to the VLR-UMI. After combining the VLR-UMI with thickness, in the receiver operating characteristic curve analysis, the areas under the curves (AUCs) improved to AUC1 = 0.996 for active versus quiescent CD, AUC2 = 0.978 for quiescent versus mild CD, and AUC3 = 0.931 for mild versus severe CD, respectively, compared to those using thickness alone (AUC1 = 0.968; P = .04; AUC2 = 0.919; P = .16; AUC3 = 0.857; P = .01). CONCLUSIONS: Ultrasound microvessel imaging offers a safe and cost-effective tool for CD diagnosis and staging, which may potentially assist disease activity classification and therapy efficacy evaluation.

Models to predict outcomes after primary debulking surgery: Independent validation of models to predict suboptimal cytoreduction and gross residual disease.

OBJECTIVE: Treatment planning requires accurate estimation of surgical complexity (SC) and residual disease (RD) at primary debulking surgery (PDS) for advanced ovarian cancer (OC). We sought to independently validate two published computed tomography (CT) prediction models. METHODS: We included stage IIIC/IV OC patients who underwent PDS from 2003 to 2011. Two prediction models which included imaging and clinical variables to predict RD > 1 and any gross RD, respectively, were applied to our cohort. Two radiologists scored CTs. Discrimination was estimated using the c-index and calibration were assessed by comparing the observed and predicted estimates. RESULTS: The validation cohort consisted of 276 patients; median age of the cohort was 64 years old and majority had serous histology. The validation and model development cohorts were similar in terms of baseline characteristics, however the RD rates differed between cohorts (9.4% vs 25.4% had RD >1 cm; 50.7% vs. 66.6% had gross RD). Model 1, the model to predict RD >1 cm, did not validate well. The c-index of 0.653 for the validation cohort was lower than reported in the development cohort (0.758) and the model over-predicted the proportion with RD >1 cm. The second model to predict gross RD had excellent discrimination with a c-index of 0.762. CONCLUSIONS: We are able to validate a CT model to predict presence of gross RD in an independent center; the separate model to predict RD >1 cm did not validate. Application of the model to predict gross RD can help with clinical decision making in advanced ovarian cancer.

Procedure-Related Pain During Image-Guided Percutaneous Biopsies: A Retrospective Study of Prevalence and Predictive Factors.

OBJECTIVE. The purpose of this study was to evaluate the prevalence and severity of pain reported during image-guided percutaneous biopsies and to identify factors associated with increased reported pain. MATERIALS AND METHODS. In this retrospective study, a database of adult patients who underwent CT- or ultrasound-guided percutaneous core needle biopsy between July 22, 2013, and February 1, 2018, was reviewed. Data collected included patient age and sex, biopsy site, biopsy type (lesion or parenchymal), needle gauge, number of passes, use of sedation, and whether it was the patient's first recorded biopsy. The maximum procedure-related pain reported on a 0-10 numeric rating scale was recorded. Multivariable logistic regression with generalized estimating equations was used to assess the association between covariates and patient-reported pain. RESULTS. A total of 13,344 biopsy procedures were performed in 10,474 patients. Patients reported no pain (0 of 10 scale) during 9765 (73.2%) procedures. Female sex, younger age at biopsy, undergoing IV sedation, and larger needle diameter were all associated with increases in patient-reported pain. Biopsies of renal allografts were the least likely to be painful, followed by hepatic allografts. CONCLUSION. Patients typically report mild or no pain from image-guided biopsy performed by radiologists. Younger patients and women report greater pain. This information can assist preprocedural counseling and reassurance of patients and may help them predict procedure-related patient needs.

MRI review of female pelvic fistulizing disease.

A wide variety of fistulae occur in the female pelvis, most of which cause significant morbidity. Diagnosis, characterization, and treatment planning may be difficult using traditional imaging modalities such as fluoroscopy and computed tomography. To date, there is no comprehensive literature review of the radiologic findings associated with various types of female pelvic fistulae, and furthermore, none dedicated to magnetic resonance imaging (MRI). In this article, we seek to provide a broad overview of the MRI characteristics of female pelvic fistulizing disease in combination with epidemiologic and clinical characteristics. MRI is often considered the imaging modality of choice for evaluation of fistulae owing to its superior soft-tissue contrast and ability to provide surgeons with the highest quality information derived from just one study, including anatomic location of fistulae and associated pelvic pathology. In other instances, MRI can be complementary to the more traditional imaging techniques. This review will describe the etiology, anatomy, MRI findings, and treatment pearls for several of the more common pelvic fistulae found in female patients, including anovaginal, rectovaginal, colovaginal, vesicovaginal, colovesical, and other complex fistulae. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1172-1184.

Clinical significance of enlarged cardiophrenic lymph nodes in advanced ovarian cancer: Implications for survival.

OBJECTIVE: Advanced ovarian cancer (OC) commonly spreads to cardiophrenic lymph nodes (CPLNs), and is often visible on preoperative imaging. We investigated the prognostic significance of abnormal CPLNs in OC detected by preoperative CT scans using three different definitions. METHODS: Patients undergoing primary debulking surgery for stage IIIC/IV with residual disease (RD) ≤1.0cm and a preoperative abdominopelvic CT scan available were included. Scans were reviewed by two blinded radiologists. We characterized abnormal CPLNs using three different definitions: i) qualitative assessment score (QAS); ii) nodes >7mm on the short axis; or, iii) nodes ≥10mm on the short axis. We compared overall survival (OS) using the log-rank test. RESULTS: Of the 253 patients (mean age 64.0years), 136 had no gross residual disease (NGR) and 117 had RD. By the QAS definition, CPLNs were abnormal in 28 (11.1%) patients and removed in one case. Among patients with NGR, presence of abnormal CPLNs was associated with worse OS (median OS, 38.4 vs. 69.6months, p=0.08). We observed no association between abnormal CPLNs and OS among patients with RD (median OS, 37.5 vs. 28.5months, p=0.49). OS was significantly better in NGR group without abnormal CPLNs (median OS for NGR vs. RD, 69.6 vs. 28.5months, p<0.001); however, there was no difference in OS between patients with NGR versus RD when abnormal CPLNs were present (median OS, 38.4 vs. 37.5months, p=0.99). Lack of benefit from NGR when abnormal CPLNs were present was observed for all three definitions tested. CONCLUSION: Abnormal CPLNs are an important predictor of survival in advanced stage OC. Management of abnormal CPLNs should be considered in treatment planning when the goal is NGR.

Imaging and Surgical Management of Anorectal Vaginal Fistulas.

Anorectal vaginal fistulas (ARVFs) can result in substantial morbidity and potentially embarrassing symptoms in adult women of all ages. Despite having what may be obvious clinical manifestations, the fistulas themselves can be difficult to identify with imaging. MRI is the modality of choice for the diagnosis and characterization of ARVFs. A dedicated protocol involving the use of vaginal gel and optimized imaging planes with respect to the vagina, as well as an understanding of the MRI pelvic floor anatomy, is crucial for reporting surgically relevant details. Ancillary findings such as postsurgical changes, inflammation, abscess, sphincter destruction, and neoplasm are well evaluated. Vaginography, contrast enema, endoscopic US, and CT can be highly useful complementary diagnostic examinations. The entities that result in ARVFs may be obstetric, inflammatory (eg, Crohn disease and diverticulitis), neoplastic, iatrogenic, and/or radiation induced. Surgical management is heavily dependent on the cause and complexity of the fistulizing disease, which are related to the location of the fistula in the vagina, the type and extent of fistula branching, the number of fistulas, sphincter tears, inflammation, and abscess. ©RSNA, 2018.

J Pouch: Imaging Findings, Surgical Variations, Natural History, and Common Complications.

Ileal pouch-anal anastomosis, or J pouch, surgery has become the procedure of choice for treatment of medically refractory ulcerative colitis and familial adenomatous polyposis. Overall, this operation is associated with a low rate of postoperative morbidity and good long-term function. However, when complications develop, there is a heavy reliance on imaging to facilitate an accurate diagnosis. Reported postoperative complication rates range from 5% to 35%. Complications generally can be categorized as structural, inflammatory, or neoplastic conditions. Structural complications include leaks, strictures, afferent and efferent limb syndromes, and pouch prolapse. Inflammatory conditions include cuffitis, pouchitis, and Crohn disease of the pouch. In addition, a variety of neoplastic conditions can develop in the pouch. Overall, pouchitis and leaks are the most common complications, occurring in up to 50% and 20% of individuals, respectively. Many imaging modalities are used to evaluate the J pouch and associated postoperative complications. The indications and various surgical techniques for J pouch surgery, normal postoperative appearance of the pouch, and most common associated complications are reviewed. In addition, the various imaging findings associated with J pouch surgery are described and illustrated. The radiologist's familiarity with the potential complications of the pouch can facilitate appropriate imaging, hasten an accurate diagnosis, and aid in rendering proper management. ©RSNA, 2018.

MR Imaging of Perianal Crohn Disease.

Pelvic magnetic resonance (MR) imaging is currently the standard for imaging perianal Crohn disease. Perianal fistulas are a leading cause of patient morbidity because closure often requires multimodality treatments over a prolonged period of time. This review summarizes clinically relevant anal sphincter anatomy, imaging methods, classification systems, and treatment objectives. In addition, the MR appearance of healing perianal fistulas and fistula complications is described. Difficult imaging tasks including the assessment of rectovaginal fistulas and ileoanal anastomoses are highlighted, along with illustrative cases. Emerging innovative treatments for perianal Crohn disease are now available and have the promise to better control sepsis and maintain fecal continence. Different treatment modalities are selected based on fistula anatomy, patient factors, and management goals (closure versus sepsis control). Radiologists can help maximize patient care by being familiar with MR imaging features of perianal Crohn disease and knowledgeable about what features may influence therapy decisions. © RSNA, 2017 Online supplemental material is available for this article.

Radiological Response Is Associated With Better Long-Term Outcomes and Is a Potential Treatment Target in Patients With Small Bowel Crohn's Disease.

OBJECTIVES: Crohn's disease (CD) management targets mucosal healing on ileocolonoscopy as a treatment goal. We hypothesized that radiologic response is also associated with better long-term outcomes. METHODS: Small bowel CD patients between 1 January 2002 and 31 October 2014 were identified. All patients had pre-therapy computed tomography enterography (CTE)/magnetic resonance enterography (MRE) with follow-up CTE or MRE after 6 months, or 2 CTE/MREs≥6 months apart while on maintenance therapy. Radiologists characterized inflammation in up to five small bowel lesions per patient. At second CTE/MRE, complete responders had all improved lesions, non-responders had worsening or new lesions, and partial responders had other scenarios. CD-related outcomes of corticosteroid usage, hospitalization, and surgery were assessed using Kaplan-Meier survival analysis and multivariable Cox models. RESULTS: CD patients (n=150), with a median disease duration of 9 years, had 223 inflamed small bowel segments (76 with strictures and 62 with penetrating, non-perianal disease), 49% having ileal distribution. Fifty-five patients (37%) were complete radiologic responders, 39 partial (26%), and 56 non-responders (37%). In multivariable Cox models, complete and partial response decreased risk for steroid usage by over 50% (hazard ratio (HR)s: 0.37 (95% confidence interval (CI), 0.21-0.64); 0.45 (95% CI, 0.26-0.79)), and complete response decreased the risk of subsequent hospitalizations and surgery by over two-thirds (HRs: HR, 0.28 (95% CI, 0.15-0.50); HR, 0.34 (95% CI, 0.18-0.63)). CONCLUSIONS: Radiological response to medical therapy is associated with significant reductions in long-term risk of hospitalization, surgery, or corticosteroid usage among small bowel CD patients. These findings suggest the significance of radiological response as a treatment target.

Evaluation of Patient Tolerance and Small-Bowel Distention With a New Small-Bowel Distending Agent for Enterography.

OBJECTIVE: The objective of our study was to compare a flavored beverage containing a thickening agent for enterography with a low-Hounsfield-value barium suspension for side effects, taste, subjects' willingness to repeat the drinking protocol, and small-bowel distention. SUBJECTS AND METHODS: The following five drinking protocols were administered to 10 volunteers: 1000 mL of flavored beverage followed by 350 mL of water, 1500 mL of flavored beverage, 900 mL of low-Hounsfield-value barium suspension followed by 450 mL of water, 1350 mL of low-Hounsfield-value barium suspension followed by 150 mL of water, and 1500 mL of water. MR images were obtained 50 and 60 minutes after initiation of drinking. Subjects completed a questionnaire evaluating the side effects, the taste of the drink, and their willingness to repeat the drinking protocol. Reviewers assigned scores evaluating small-bowel distention and ranked the examinations in order of preference. RESULTS: There was no significant difference in nausea or vomiting among the protocols (p = 0.20 and 0.42, respectively), but larger volumes of flavored beverage and low-Hounsfield-value barium suspension resulted in more cramping and diarrhea (p = 0.001 and 0.002, respectively). The taste of the low-Hounsfield-value barium suspension was rated the worst (p < 0.0001). The subjects' willingness to repeat the drinking protocol was highest for the 1000 mL of flavored beverage or water alone (p < 0.05). There were no significant differences in subjective small-bowel distention except that water was rated the worst by two of the three readers (p < 0.02). There was no significant difference in the diameter of the most dis-tended small bowel for any segment or reader (p > 0.23). CONCLUSION: A flavored beverage containing a thickening agent has a similar side effect profile and results in equivalent small-bowel distention compared with a low-Hounsfield-value barium suspension, but subjects rate taste and their willingness to repeat the drinking protocol higher for this new agent.