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This selection from the NCCN Guidelines for Rectal Cancer focuses on management of malignant polyps and resectable nonmetastatic rectal cancer because important updates have been made to these guidelines. These recent updates include redrawing the algorithms for stage II and III disease to reflect new data supporting the increasingly prominent role of total neoadjuvant therapy, expanded recommendations for short-course radiation therapy techniques, and new recommendations for a “watch-and-wait” nonoperative management technique for patients with cancer that shows a complete response to neoadjuvant therapy. The complete version of the NCCN Guidelines for Rectal Cancer, available online at NCCN.org, covers additional topics including risk assessment, pathology and staging, management of metastatic disease, posttreatment surveillance, treatment of recurrent disease, and survivorship.

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colon Cancer focuses on systemic therapy options for the treatment of metastatic colorectal cancer (mCRC), because important updates have recently been made to this section. These updates include recommendations for first-line use of checkpoint inhibitors for mCRC, that is deficient mismatch repair/microsatellite instability-high, recommendations related to the use of biosimilars, and expanded recommendations for biomarker testing. The systemic therapy recommendations now include targeted therapy options for patients with mCRC that is HER2-amplified, or BRAF V600E mutation–positive. Treatment and management of nonmetastatic or resectable/ablatable metastatic disease are discussed in the complete version of the NCCN Guidelines for Colon Cancer available at NCCN.org. Additional topics covered in the complete version include risk assessment, staging, pathology, posttreatment surveillance, and survivorship.

Magnetic resonance imaging (MRI) has emerged as the imaging method of choice for evaluation of perianal fistulizing disease. As treatment of Crohn disease and associated perianal fistulas has evolved to include a combination of systemic treatments and surgical interventions, perianal MRI provides critical information to guide treatment selection and timing. Radiologists need to be familiar with the normal regional anatomy to accurately describe perianal fistulas and any associated complications which can then be used to classify fistulas based on several available classification systems. Following treatment, MRI can provide information that suggests treatment success or failure. We propose a perianal fistula reporting template that includes the necessary information to convey fistula complexity, guide treatment, and evaluate treatment response. This review article will also discuss the postoperative appearance of many treatments currently used for management of perianal fistulizing disease and some associated complications.

Background and Aims It is unclear whether the common practice of postoperative day (POD) 1 esophagram impacts clinical care or reliably identifies significant adverse events (AEs) related to peroral endoscopic myotomy (POEM). Therefore, we aimed to correlate the most clinically relevant esophagram findings with postoperative outcomes after POEM. Methods Patients were retrospectively reviewed and included if they underwent POEM at 1 of the 3 study institutions between 2014 and 2018. Patient outcomes were assessed in relation to relevant POD 1 esophagram findings such as esophageal dissection or leak. Results One hundred seventy post-POEM contrast esophagrams (139 fluoroscopy-based vs 31 CT-based) performed on POD 1 were included. Most esophagrams (n = 98) contained abnormal findings but only 5 showed esophageal leak or dissection. Confirmed postoperative AEs of leak or dissection occurred in 4 patients. In 2 patients, POD 1 esophagram appropriately identified the leak or dissection, but in the other 2 patients the initial esophagram was negative, and the AEs were not recognized before clinical deterioration. One patient had a false-positive leak and dissection noted on esophagram leading to an unremarkable endoscopy. Conclusions Despite the low AE rate after POEM, follow-up esophagram on POD 1 frequently shows expected, unremarkable postprocedural findings and occasionally fails to diagnose serious AEs. This results in pitfalls in accuracy regarding agreement between esophagram versus clinical and endoscopic findings. Relying exclusively on esophagram for post-POEM clinical decision-making can lead to unnecessary additional testing or missed AEs.

The NCCN Guidelines for Rectal Cancer provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with rectal cancer. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines. These updates include clarifying the definition of rectum and differentiating the rectum from the sigmoid colon; the total neoadjuvant therapy approach for localized rectal cancer; and biomarker-targeted therapy for metastatic colorectal cancer, with a focus on new treatment options for patients with BRAF V600E– or HER2 amplification–positive disease.

Representatives from the Society of Abdominal Radiology Crohn's Disease-Focused Panel, the Society for Pediatric Radiology, the American Gastroenterological Association, and other international experts recently reported consensus recommendations for standardized nomenclature for the interpretation and reporting of CT enterography and MR enterography findings of small bowel Crohn disease. The consensus recommendations included CT enterography and MR enterography bowel wall findings that are associated with Crohn disease, findings that occur with penetrating Crohn disease, and changes that occur in the mesentery related to Crohn disease. Also included were recommended radiology report impression statements that summarize the findings of small bowel Crohn disease at CT enterography and MR enterography. This article, authored by the Society of Abdominal Radiology Crohn's Disease-Focused Panel, illustrates the imaging findings and recommended radiology report impression statements described in the consensus recommendations with examples of CT enterography and MR enterography images. Additional interpretation guidelines for reporting CT enterography and MR enterography examinations are also presented. The recommended standardized nomenclature can be used to generate radiology report dictations that will help guide medical and surgical management for patients with small bowel Crohn disease.

Despite important innovations in the treatment of pancreatic ductal adenocarcinoma (PDAC), PDAC remains a disease with poor prognosis and high mortality. A key area for potential improvement in the management of PDAC, aside from earlier detection in patients with treatable disease, is the improved ability of imaging techniques to differentiate treatment response after neoadjuvant therapy (NAT) from worsening disease. It is well established that current imaging techniques cannot reliably make this distinction. This narrative review provides an update on the imaging assessment of pancreatic cancer resectability after NAT. Current definitions of borderline resectable PDAC, as well as implications for determining likely patient benefit from NAT, are described. Challenges associated with PDAC pathologic evaluation and surgical decision making that are of relevance to radiologists are discussed. Also explored are the specific limitations of imaging in differentiating the response after NAT from stable or worsening disease, including issues relating to protocol optimization, tumor size assessment, vascular assessment, and liver metastasis detection. The roles of MRI as well as PET and/or hybrid imaging are considered. Finally, a short PDAC reporting template is provided for use after NAT. The highlighted methods seek to improve radiologists' assessment of PDAC treatment response after NAT.

Background: Objective radiographic assessment is crucial for accurately evaluating therapeutic efficacy and patient outcomes in oncology clinical trials. Imaging assessment workflow can be complex; can vary with institution; may burden medical oncologists, who are often inadequately trained in radiology and response criteria; and can lead to high interobserver variability and investigator bias. This article reviews the development of a tumor response assessment core (TRAC) at a comprehensive cancer center with the goal of providing standardized, objective, unbiased tumor imaging assessments, and highlights the web-based platform and overall workflow. In addition, quantitative response assessments by the medical oncologists, radiologist, and TRAC are compared in a retrospective cohort of patients to determine concordance. Patients and Methods: The TRAC workflow includes an image analyst who pre-reviews scans before review with a board-certified radiologist and then manually uploads annotated data on the proprietary TRAC web portal. Patients previously enrolled in 10 lung cancer clinical trials between January 2005 and December 2015 were identified, and the prospectively collected quantitative response assessments by the medical oncologists were compared with retrospective analysis of the same dataset by a radiologist and TRAC. Results: This study enlisted 49 consecutive patients (53% female) with a median age of 60 years (range, 29–78 years); 2 patients did not meet study criteria and were excluded. A linearly weighted kappa test for concordance for TRAC versus radiologist was substantial at 0.65 (95% CI, 0.46–0.85; standard error [SE], 0.10). The kappa value was moderate at 0.42 (95% CI, 0.20–0.64; SE, 0.11) for TRAC versus oncologists and only fair at 0.34 (95% CI, 0.12–0.55; SE, 0.11) for oncologists versus radiologist. Conclusions: Medical oncologists burdened with the task of tumor measurements in patients on clinical trials may introduce significant variability and investigator bias, with the potential to affect therapeutic response and clinical trial outcomes. Institutional imaging cores may help bridge the gap by providing unbiased and reproducible measurements and enable a leaner workflow.

Small bowel adenocarcinoma (SBA) is a rare malignancy of the gastrointestinal tract that has increased in incidence across recent years. Often diagnosed at an advanced stage, outcomes for SBA are worse on average than for other related malignancies, including colorectal cancer. Due to the rarity of this disease, few studies have been done to direct optimal treatment, although recent data have shown that SBA responds to treatment differently than colorectal cancer, necessitating a separate approach to treatment. The NCCN Guidelines for Small Bowel Adenocarcinoma were created to establish an evidence-based standard of care for patients with SBA. These guidelines provide recommendations on the workup of suspected SBA, primary treatment options, adjuvant treatment, surveillance, and systemic therapy for metastatic disease. Additionally, principles of imaging and endoscopy, pathologic review, surgery, radiation therapy, and survivorship are described.

Pancreatic cancer is the fourth leading cause of cancer-related death among men and women in the United States. A major challenge in treatment remains patients’ advanced disease at diagnosis. The NCCN Guidelines for Pancreatic Adenocarcinoma provides recommendations for the diagnosis, evaluation, treatment, and follow-up for patients with pancreatic cancer. Although survival rates remain relatively unchanged, newer modalities of treatment, including targeted therapies, provide hope for improving patient outcomes. Sections of the manuscript have been updated to be concordant with the most recent update to the guidelines. This manuscript focuses on the available systemic therapy approaches, specifically the treatment options for locally advanced and metastatic disease.

The NCCN Guidelines for Rectal Cancer provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with rectal cancer. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines. These updates include clarifying the definition of rectum and differentiating the rectum from the sigmoid colon; the total neoadjuvant therapy approach for localized rectal cancer; and biomarker-targeted therapy for metastatic colorectal cancer, with a focus on new treatment options for patients with BRAF V600E- or HER2 amplification-positive disease.

Topical tissue sealants and hemostatic agents, seen on postoperative imaging in a variety of intraabdominal and pelvic locations, have the potential to be mistaken for abdominal abnormalities, especially if the radiologist is not aware of the patient's surgical history. The normal appearance of these agents may mimic abscesses, tumors, enlarged lymph nodes, or retained foreign bodies. Therefore, it is important to be familiar with their typical imaging appearances and to review the surgical records when needed to avoid misdiagnoses. The purpose of this article is to increase the radiologist's familiarity with various types of topical tissue sealants and hemostatic agents used during surgical and percutaneous procedures in the abdomen and pelvis along with their radiologic appearances.Various types of hemostatic agents are now commonly used during surgery and percutaneous procedures in the abdomen and pelvis, and it is important to recognize the various appearances of these agents. Although there are suggestive features outlined in this article, the most important factor for the radiologist is to be aware of the patient's history and the possibility that a hemostatic agent may be present. On postoperative imaging, hemostatic agents may mimic abscesses, tumors, enlarged lymph nodes, or retained foreign bodies, and accurate diagnosis can save a patient unnecessary treatment. It is therefore crucial to incorporate knowledge of the patient's surgical history with recognition of the typical imaging appearances of hemostatic agents and other pseudolesions to avoid misdiagnoses.

The NCCN Guidelines for Colon Cancer provide recommendations regarding diagnosis, pathologic staging, surgical management, perioperative treatment, surveillance, management of recurrent and metastatic disease, and survivorship. These NCCN Guidelines Insights summarize the NCCN Colon Cancer Panel discussions for the 2018 update of the guidelines regarding risk stratification and adjuvant treatment for patients with stage III colon cancer, and treatment of BRAF V600E mutation-positive metastatic colorectal cancer with regimens containing vemurafenib.

Computed tomography and magnetic resonance enterography have become routine small bowel imaging tests to evaluate patients with established or suspected Crohn's disease, but the interpretation and use of these imaging modalities can vary widely. A shared understanding of imaging findings, nomenclature, and utilization will improve the utility of these imaging techniques to guide treatment options, as well as assess for treatment response and complications. Representatives from the Society of Abdominal Radiology Crohn's Disease-Focused Panel, the Society of Pediatric Radiology, the American Gastroenterological Association, and other experts, systematically evaluated evidence for imaging findings associated with small bowel Crohn's disease enteric inflammation and established recommendations for the evaluation, interpretation, and use of computed tomography and magnetic resonance enterography in small bowel Crohn's disease. This work makes recommendations for imaging findings that indicate small bowel Crohn's disease, how inflammatory small bowel Crohn's disease and its complications should be described, elucidates potential extra-enteric findings that may be seen at imaging, and recommends that cross-sectional enterography should be performed at diagnosis of Crohn's disease and considered for small bowel Crohn's disease monitoring paradigms. A useful morphologic construct describing how imaging findings evolve with disease progression and response is described, and standard impressions for radiologic reports that convey meaningful information to gastroenterologists and surgeons are presented.

This review article focuses on gastroduodenal and pancreatic surgeries with the goal of identifying radiologic findings that translate to important surgical considerations. The topics covered include partial gastrectomy with reconstruction techniques, total gastrectomy, pancreaticoduodenectomy, and pancreaticojejunostomy. Indications, contraindications, surgical techniques, and postoperative imaging are described within each of these topics. Knowledge of these surgical techniques is extremely helpful for the interpreting radiologists to identify expected postoperative anatomy and related complications that would remain clinically relevant to our surgical colleagues and direct timely patient management.

Background Imaging is essential in the assessment of Crohn’s disease (CD) severity, phenotype, and therapeutic response. However, qualitative findings can be limited by interobserver variation and ambiguous feature definitions. Our aim was to evaluate computational approaches for identifying qualitative disease features using CT-enterography (CTE). Methods CD subjects with ileal CD and CTE imaging between 2009 and 2017 were retrospective identified at a single tertiary care centre. CTE scans were reviewed by two fellowship-trained abdominal radiologists who labelled diseased and normal bowel transitions agreeing on definitions of qualitative findings prior to labelling. Computed intestinal features were used by machine learning methods (k-nearest neighbour, support vector machines, random forest) to model regions of diseased bowel and predict qualitative findings with 5-fold cross validation. Cohen’s kappa with quadratic weighting was used to assess agreement between radiologists and model predictions. Results In 206 unique patients, 548 small bowel segments underwent paired radiologist review for qualitative imaging findings. Automated localisation of diseased vs. normal bowel segments had excellent performance, with an AUC, PPV, and NPV of 0.922, 0.924, and 0.918, respectively (Figure 1). Radiologist-to-Radiologist and Radiologist-to-automated prediction agreement on qualitative findings are shown in Table 1. Agreement on the degree of mural enhancement between radiologists was very good (k = 0.75,95% CI 0.68–0.82), with nearly identical agreement (k = 0.75, 95% CI 0.72–0.79) between radiologists and automated grading models. Conclusion Computer vision methods have excellent performance for automatically distinguishing diseased from normal ileum and show potential for qualitative disease assessments of Crohn’s disease on CTEs.

To formulate consensus recommendations for CT angiography technical parameters used to evaluate overt gastrointestinal (GI) bleeding. An electronic questionnaire consisting of 17 questions was sent to a panel of 16 radiologists with expertise on the imaging of GI bleeding from the Society of Abdominal Radiology GI Bleeding disease-focused panel to obtain consensus agreement on issues related to CTA technical parameters for imaging overt GI bleeding. A multi-round Delphi method of voting was performed to obtain consensus which was defined as ≥ 80% agreement. Consensus agreement was reached in 15/17 (89%) of the questions including the technique for the administration of IV contrast, the number of phases, scan timing, and image reconstruction. A panel of experts on the imaging of GI bleeding from the Society of Abdominal Radiology was able to reach consensus on the majority of technical parameters used for CTA of overt GI bleeding. These recommendations should improve the quality of patient care by adopting these minimal technical requirements for optimal exam performance and lead to less variation in the performance of these exams which will facilitate collecting and comparing published data from different centers. These recommendations will need revisions as additional scientific data become available.

Background Evaluating structural damage using imaging is essential for the evaluation of small intestinal Crohn’s disease (CD), but it is limited by potential interobserver variation. We compared the agreement of enterography-based bowel damage measurements collected by experienced radiologists and a semi-automated image analysis system. Methods Patients with small bowel CD undergoing a CT-enterography (CTE) between 2011 and 2017 in a tertiary care setting were retrospectively reviewed. CT-enterography studies were reviewed by 2 experienced radiologists and separately underwent automated computer image analysis using bowel measurement software. Measurements included maximum bowel wall thickness (BWT-max), maximum bowel dilation (DIL-max), minimum lumen diameter (LUM-min), and the presence of a stricture. Measurement correlation coefficients and paired t tests were used to compare individual operator measurements. Multivariate regression was used to model identification of strictures using semi-automated measures. Results In 138 studies, the correlation between radiologists and semi-automated measures were similar for BWT-max (r = 0.724, 0.702), DIL-max (r = 0.812, 0.748), and LUM-min (r = 0.428, 0.381), respectively. Mean absolute measurement difference between semi-automated and radiologist measures were no different from the mean difference between paired radiologists for BWT-max (1.26 mm vs 1.12 mm, P = 0.857), DIL-max (2.78 mm vs 2.67 mm, P = 0.557), and LUM-min (0.54 mm vs 0.41 mm, P = 0.596). Finally, models of radiologist-defined intestinal strictures using automatically acquired measurements had an accuracy of 87.6%. Conclusion Structural bowel damage measurements collected by semi-automated approaches are comparable to those of experienced radiologists. Radiomic measures of CD will become an important new data source powering clinical decision-making, patient-phenotyping, and assisting radiologists in reporting objective measures of disease status.

Imaging plays a central role in the management of patients with suspected or known periampullary masses, including the initial diagnosis, staging, and follow-up to assess treatment response or recurrence. Use of appropriate imaging tools, application of optimal imaging protocols, and knowledge about imaging findings are essential for the diagnosis and accurate staging of these masses. Structured reporting of the imaging studies offers several advantages over freestyle dictations ensuring completeness of the relevant imaging findings, which would in turn help in deciding the best individual treatment strategy for each patient.

Computed tomography enterography and magnetic resonance enterography are essential in the evaluation and treatment of patients with Crohn's disease. As such, examination reporting must use standardized nomenclature for effective communication. This report documents an interdisciplinary consensus of the Society of Abdominal Radiology, the Society of Pediatric Radiology, and the American Gastroenterology Association on the computed tomography enterography/magnetic resonance enterography imaging findings and imaging-based morphologic phenotypes.

The NCCN Guidelines for Anal Carcinoma provide recommendations for the management of patients with squamous cell carcinoma of the anal canal or perianal region. Primary treatment of anal cancer usually includes chemoradiation, although certain lesions can be treated with margin-negative local excision alone. Disease surveillance is recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is essential for optimal patient care.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Rectal Cancer address diagnosis, staging, surgical management, perioperative treatment, management of recurrent and metastatic disease, disease surveillance, and survivorship in patients with rectal cancer. This portion of the guidelines focuses on the management of localized disease, which involves careful patient selection for curative-intent treatment options that sequence multimodality therapy usually comprised of chemotherapy, radiation, and surgical resection.

Purpose To assess the impact of clinical history on the maximum Prostate Imaging Recording and Data System (PI-RADS) version 2 (v2) score assigned to multiparametric magnetic resonance (MR) imaging of the prostate. Materials and Methods This retrospective cohort study included 120 consecutively selected multiparametric prostate MR imaging studies performed between November 1, 2016, and December 31, 2016. Sham clinical data in four domains (digital rectal examination, prostate-specific antigen level, plan for biopsy, prior prostate cancer history) were randomly assigned to each case by using a balanced orthogonal design. Six fellowship-trained abdominal radiologists independently reviewed the sham data, actual patient age, and each examination while they were blinded to interreader scoring, true clinical data, and histologic findings. Readers were told the constant sham histories were true, believed the study to be primarily investigating interrater agreement, and were asked to assign a maximum PI-RADS v2 score to each case. Linear regression was performed to assess the association between clinical variables and maximum PI-RADS v2 score designation. Intraclass correlation coefficients (ICCs) were obtained to compare interreader scoring. Results Clinical information had no significant effect on maximum PI-RADS v2 scoring for any of the six readers (P = .09-.99, 42 reader-variable pairs). Distributions of maximum PI-RADS v2 scores in the research context were similar to the distribution of the scores assigned clinically and had fair-to-excellent pairwise interrater agreement (ICC range: 0.53-0.76). Overall interrater agreement was good (ICC: 0.64; 95% confidence interval: 0.57, 0.71). Conclusion Clinical history does not appear to be a substantial bias in maximum PI-RADS v2 score assignment. This is potentially important for clinical nomograms that plan to incorporate PI-RADS v2 score and clinical data into their algorithms (ie, PI-RADS v2 scoring is not confounded by clinical data).

Though the capabilities of available imaging technologies to assess intestinal damage have substantially improved, emerging alternative non-invasive imaging methods may offer advancements in detecting and quantifying intestinal fibrosis in the inflammatory bowel diseases. Both the immediate clinical need to measure fibrosis for therapeutic decision-making and the near-future need for tools to assess pipeline anti-fibrotic medications highlight the demand for better non-invasive biomarkers of fibrosis in Crohn’s disease. Developing imaging platforms assessing tissue mechanical properties, perfusion characteristics, and structural protein content provide new perspectives and possibilities for approaching intestinal fibrosis quantitation. In this chapter, we will discuss existing, emerging, and experimental imaging methods using ultrasound elastography, novel MRI sequences, and photoacoustic imaging to measure fibrosis in Crohn’s disease.

Crohn disease is a chronic inflammatory condition that can lead to intestinal strictures. The presence of fibrosis within strictures alters optimal management but is not reliably detected by current imaging methods.To correlate the MRI features of surgically resected small-bowel strictures in pediatric Crohn disease with histological inflammation and fibrosis scoring.We included children with Crohn disease who had symptomatic small-bowel strictures requiring surgical resection and had preoperative MR enterography (MRE) within 3 months of surgery (n = 20). Two blinded radiologists reviewed MRE examinations to document stricture-related findings. A pediatric pathologist scored stricture histological specimens for fibrosis (0-4) and inflammation (0-4). MRE findings were correlated with histological data using Spearman correlation (ρ) and exact logistic regression analysis.There was significant positive correlation between histological bowel wall fibrosis and inflammation in resected strictures (ρ = 0.55; P = 0.01). Confluent transmural histological fibrosis was associated with pre-stricture upstream small-bowel dilatation3 cm at univariate (odds ratio [OR] = 51.7; 95% confidence interval [CI]: 7.6- 999.9; P = 0.0002) and multivariate (OR = 43.4; 95% CI: 6.1- 999.9; P = 0.0006, adjusted for age) analysis. The degree of bowel wall T2-weighted signal intensity failed to correlate with histological bowel wall fibrosis or inflammation (P-values0.05). There were significant negative correlations between histological fibrosis score and patient age at resection (ρ = -0.48, P = 0.03), and time from diagnosis to surgery (ρ = -0.73, P = 0.0002).Histological fibrosis and inflammation co-exist in symptomatic pediatric Crohn disease small-bowel strictures and are positively correlated. Pre-stenotic upstream small-bowel dilatation greater than 3 cm is significantly associated with confluent transmural fibrosis.

Introduction The use of multidetector computed tomography (CT) and magnetic resonance imaging (MRI) with imaging protocols optimized for imaging of the pancreas has improved the localization as well as the detection and the characterization of pancreatic lesions. Although the typical radiological appearances of common pancreatic lesions is well known, there are several potential pitfalls that can be encountered in pancreatic imaging, such as pancreatic anatomical variants mimicking pancreatic lesions, inflammatory conditions mimicking malignancy, atypical radiological appearance of pancreatic adenocarcinoma, and cystic pancreatic lesions and peripancreatic lesions mimicking intrapancreatic lesions. An understanding of these potential pitfalls in pancreatic imaging is essential to avoid misdiagnosis that can result in inappropriate patient management.

High-resolution imaging modalities, such as multi-detector computed tomography, MR imaging, and endoscopic ultrasound, are frequently used alone or in combination to characterize focal solid and cystic pancreatic neoplasms. Imaging in solid pancreatic neoplasms, typically adenocarcinoma and neuroendocrine tumors, is primarily used to detect and stage the extent of the tumor and to determine if complete surgical resection for cure is feasible. In cystic pancreatic masses, imaging aims to differentiate benign nonmucinous cystic lesions from potentially or frankly malignant mucin-producing cysts. Several noninvasive and invasive treatment options can be performed if surgical resection is not possible or contraindicated.

Small bowel obstruction (SBO) accounts for a considerable proportion of emergency room visits, inpatient admissions, and surgical interventions in the United States. Multi-detector computed tomography (MDCT) plays a key role in imaging patients presenting with acute symptoms suggestive of SBO, which helps in establishing the diagnosis, elucidating the cause of obstruction, and detecting complications, such as ischemia or frank bowel necrosis and perforation. Recently, management of patients with SBO has shifted toward a more conservative approach with supportive care and nasogastric tube decompression, as the obstruction in many cases can resolve spontaneously without the need for operative intervention. However, management decisions in SBO remain notoriously difficult, relying on a combination of clinical, laboratory, and imaging factors to help stratify patients into conservative or surgical treatment. Imaging is often an important factor assisting in the decision-making process since traditional clinical signs of vascular compromise, such as acidosis, fever, leukocytosis, and tachycardia are often unreliable in predicting the need for operative intervention. Thus, it is critically important for radiologists to identify imaging features that suggest or indicated high likelihood of bowel vascular compromise in order to help optimize management prior to the development of bowel ischemia and eventually necrosis. By excluding signs of potentially ischemic or necrotic bowel on MDCT, patients may be spared unnecessary surgery, thus decreasing postsurgical complications and averting potential increase for the risk of future SBO and repeated surgery. Conversely, if imaging features indicate potential vascular compromise of the bowel wall that may lead to bowel ischemia, urgent surgical intervention may prevent progression to bowel necrosis and subsequent perforation.

MR enterography is a powerful tool for the non-invasive evaluation of patients with Crohn's disease (CD) without ionizing radiation. The following paper describes the current consensus on optimal imaging technique, interpretation, and future advances from the Society of Abdominal Radiology CD-focused panel.

Imaging is a key component of diagnosis and staging of pancreatic cancer. CT, MRI, and endoscopic ultrasound are the most used and approved imaging modalities. The updated NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Pancreatic Adenocarcinoma feature a recently published Pancreatic Ductal Adenocarcinoma Radiology Reporting Template endorsed by the Society of Abdominal Radiology and the American Pancreatic Association. The goal of the template is to standardize the reporting of the imaging findings and to improve communication among the various team members treating patients with pancreatic cancer, to ensure appropriate patient management.

Background Endoscopic balloon dilation (EBD) is an effective method for treating stricture-related obstruction in Crohn's disease. We aimed to identify factors predictive of successful avoidance of surgery, including endoscopic features, in patients undergoing balloon dilation. Methods We performed a retrospective review of patients with symptomatic Crohn's disease-related intestinal strictures undergoing EBD. Clinical, medication use, laboratory, and dilation data, including the minimum and maximum balloon sizes used, and number of balloons used per endoscopic session were collected. Multivariate analysis by Cox proportional hazard regression was used to model future surgical bowel resection. Results In a total of 135 subjects undergoing 292 dilations, multivariate modeling demonstrated that failure to achieve a maximum dilation of 14 mm or more increased the risk of surgery (hazard ratio [HR] 2.88, 95% confidence limit [CL], 1.10-7.53). Although there was no difference in the risk of future surgery between maximum EBD sizes of 14 to 15 mm and 16 to 18 mm, those reaching 16 to 18 mm exhibited a longer interval between subsequent dilations (mean 240 ± 136.7 versus 456 ± 357.3 d, respectively, P = 0.023). Endoscope passage at index dilation was not predictive of future surgery (HR 0.63, 95% CL, 0.31-1.26). Adjusting for covariates of EBD size, stricture location and type, a C-reactive protein >1.5 mg/dL (HR 2.60, 95% CL, 1.12-5.94), and anti-tumor necrosis factor initiation after index EBD (HR 2.39, 95% CL, 1.09-5.25) increased the risk of future surgery. Conclusions Although dilation calibers larger than 14 to 15 mm were not more protective against future surgery, those reaching 16 to 18 mm underwent maintenance dilation less frequently. The risk of surgery associated with post-EBD anti-tumor necrosis factor initiation suggests that effective therapy is often used too late in the disease course.

Purpose To identify computed tomographic (CT) findings that are predictive of recurrence of colonic diverticulitis. Materials and Methods Institutional review board approval was obtained for this HIPAA-compliant, retrospective cohort study. Six abdominal fellowship-trained radiologists reviewed the CT studies of 440 consecutive subjects diagnosed with acute colonic diverticulitis between January 2004 and May 2008 to determine the involved segments, maximum wall thickness in the inflamed segment, severity of diverticulosis, presence of complications (abscess, fistula, stricture, or perforation), and severity of the inflammation. Electronic medical records were reviewed for a 5-year period after the patients' first CT study to determine clinical outcomes. Predictors of diverticulitis recurrence were assessed with univariate and multiple Cox proportional hazard regression models. Results Colonic diverticulitis most commonly involved the rectosigmoid (70%, 309 of 440) and descending (30%, 133 of 440) colon segments. Complicated diverticulitis was present in 22% (98 of 440) of patients. On the basis of the results of univariate analysis, significant predictors of diverticulitis recurrence were determined to be maximum colonic wall thickness in the inflamed segment (hazard ratio [HR], 1.07 per every millimeter of increase in wall thickness; P < .001), presence of a complication (HR, 1.75; P = .002), and subjective severity of inflammation (HR, 1.36 for every increase in severity category; P value for linear trend = .003). The difference in maximum wall thickness in the inflamed segment (HR, 1.05 per millimeter; P = .016) and subjective inflammation severity (HR, 1.29 per category; P = .018)remained statistically significant in a Cox multiple regression model. Conclusion Maximum colonic wall thickness and subjective severity of acute diverticulitis allow prediction of recurrent diverticulitis and may be useful for stratifying patients according to the need for elective partial colectomy. © RSNA, 2017 Online supplemental material is available for this article.

Ductal adenocarcinoma and its variants account for most pancreatic malignancies. High-quality multiphase imaging can help to preoperatively distinguish between patients eligible for resection with curative intent and those with unresectable disease. Systemic therapy is used in the neoadjuvant or adjuvant pancreatic cancer setting, as well as in the management of locally advanced unresectable and metastatic disease. Clinical trials are critical for making progress in treatment of pancreatic cancer. The NCCN Guidelines for Pancreatic Adenocarcinoma focus on diagnosis and treatment with systemic therapy, radiation therapy, and surgical resection.

PURPOSE: In the current study we examined the ability of diffusion MRI (dMRI) to predict pathologic response in pancreatic cancer patients receiving neoadjuvant chemoradiation. METHODS: We performed a prospective pilot study of dMRI in patients with resectable pancreatic cancer. Patients underwent dMRI prior to neoadjuvant chemoradiation. Surgical specimens were graded according to the percent tumor cell destruction. Apparent diffusion coefficient (ADC) maps were used to generate whole-tumor derived ADC histogram distributions and mean ADC values. The primary objective of the study was to correlate ADC parameters with pathologic and CT response. RESULTS: Ten of the 12 patients enrolled on the study completed chemoradiation and had surgery. Three were found to be unresectable at the time of surgery and no specimen was obtained. Out of the 7 patients who underwent pancreaticoduodenectomy, 3 had a grade III histopathologic response (> 90% tumor cell destruction), 2 had a grade IIB response (51% to 90% tumor cell destruction), 1 had a grade IIA response (11% to 50% tumor cell destruction), and 1 had a grade I response (> 90% viable tumor). Median survival for patients with a grade III response, grade I-II response, and unresectable disease were 25.6, 18.7, and 6.1 months, respectively. There was a significant correlation between pre-treatment mean tumor ADC values and the amount of tumor cell destruction after chemoradiation with a Pearson correlation coefficient of 0.94 (P = .001). Mean pre-treatment ADC was 161 × 10− 5 mm2/s (n = 3) in responding patients (> 90% tumor cell destruction) compared to 125 × 10− 5 mm2/s (n = 4) in non-responding patients (> 10% viable tumor). CT imaging showed no significant change in tumor size in responders or non-responders. CONCLUSIONS: dMRI may be useful to predict response to chemoradiation in pancreatic cancer. In our study, tumors with a low ADC mean value at baseline responded poorly to standard chemoradiation and would be candidates for intensified therapy.

To determine for expert and novice radiologists repeatability of major diagnostic features and scoring systems (ie, Liver Imaging Reporting and Data System [LI-RADS], Organ Procurement and Transplantation Network [OPTN], and American Association for the Study of Liver Diseases [AASLD]) for hepatocellular carcinoma (HCC) by using magnetic resonance (MR) imaging.Institutional review board approval was obtained and patient consent was waived for this HIPAA-compliant, retrospective study. The LI-RADS discussed in this article refers to version 2013.1. Ten blinded readers reviewed 100 liver MR imaging studies that demonstrated observations preliminarily assigned LI-RADS scores of LR1-LR5. Diameter and major HCC features (arterial hyperenhancement, washout appearance, pseudocapsule) were recorded for each observation. LI-RADS, OPTN, and AASLD scores were assigned. Interreader agreement was assessed by using intraclass correlation coefficients and κ statistics. Scoring rates were compared by using McNemar test.Overall interreader agreement was substantial for arterial hyperenhancement (0.67 [95% confidence interval {CI}: 0.65, 0.69]), moderate for washout appearance (0.48 [95%CI: 0.46, 0.50]), moderate for pseudocapsule (0.52 [95% CI: 050, 0.54]), fair for LI-RADS (0.35 [95% CI: 0.34, 0.37]), fair for AASLD (0.39 [95% CI: 0.37, 0.42]), and moderate for OPTN (0.53 [95% CI: 0.51, 0.56]). Agreement for measured diameter was almost perfect (range, 0.95-0.97). There was substantial agreement for most scores consistent with HCC. Experts agreed significantly more than did novices and were significantly more likely than were novices to assign a diagnosis of HCC (P.001).Two of three major features for HCC (washout appearance and pseudocapsule) have only moderate interreader agreement. Experts and novices who assigned scores consistent with HCC had substantial but not perfect agreement. Expert agreement is substantial for OPTN, but moderate for LI-RADS and AASLD. Novices were less consistent and less likely to diagnose HCC than were experts.

BACKGROUND Epidermal growth factor receptor overexpression is associated with poor outcomes in urothelial carcinoma (UC). Cetuximab (CTX) exhibited an antitumor effect in in vivo UC models. The efficacy of gemcitabine/cisplatin (GC) with or without CTX in patients with advanced UC was evaluated. METHODS Patients with advanced UC, measurable disease, and adequate organ function were randomized 1:2 to cisplatin (70 mg/m2) on day 1 plus gemcitabine (1000 mg/m2) on days 1, 8, and 15 (arm A) or GC plus CTX (500 mg/m2) on days 1 and 15 (arm B). The primary endpoint was the overall response rate. The secondary endpoints were the response duration, safety, progression-free survival, overall survival, determination of whether or not CTX sensitized nonresponders to GC, and exploratory biomarker analysis. The accrual targets were 27 and 54 patients for the 2 arms, respectively. The overall response rate was reported by arm with binomial confidence intervals (CIs). Kaplan-Meier methods were used for time-to-event endpoints. RESULTS Eighty-eight eligible patients were randomized; 87 were toxicity-evaluable, and 85 were response-evaluable. The overall response rates were 57.1% for arm A (95% CI = 37%-76%) and 61.4% for arm B (95% CI = 48%-74%). The median progression-free survival times were 8.5 months for arm A (95% CI = 5.7-10.4 months) and 7.6 months for arm B (95% CI = 6.1-8.7 months). The median overall survival times were 17.4 months for arm A (95% CI = 12.8 months to unreached) and 14.3 months for arm B (95% CI = 11.6-22.2 months). The most common grade 3/grade 4 adverse events in both arms were myelosuppression and nausea. Thromboembolism, acneiform rash, fatigue, pain, hypersensitivity reactions, elevated transaminases, hyponatremia, and hypomagnesemia were more common in arm B; 3 grade 5 adverse events occurred in arm B. The presence of primary disease significantly correlated with thromboembolism. An increased soluble E-cadherin level after cycle 2 correlated with a higher risk of death. CONCLUSIONS GC plus CTX was feasible but was associated with more adverse events and no improvements in outcomes. Cancer 2014;120:2684–2693. © 2014 American Cancer Society.

Splenic lesions are often incidentally detected on abdominal-computed tomography (CT), ultrasound, or magnetic resonance imaging (MRI), and these can pose a diagnostic challenge in patients with suspected or known malignancy. This review will discuss the multimodality imaging features of various benign and malignant splenic pathologies including trauma, infection, infarct, granulomatous disease, benign neoplasms such as hemangioma, hamartoma, and littoral cell angioma, cystic entities such as peliosis, splenic cysts, and pseudocysts, and malignant processes such as metastasis, lymphoma, angiosarcoma, and leiomyosarcoma. While several of these splenic pathologies have characteristic imaging features that are helpful in diagnosis, others have nonspecific findings. In such clinical dilemmas, image-guided intervention may be essential, and we therefore discuss the role of non-vascular, image-guided splenic interventions for diagnostic and therapeutic purposes. The radiologist can play a key part in the clinical diagnosis and management of splenic lesions, and therefore a thorough knowledge of the imaging features of splenic lesions and a thoughtful approach to their management is crucial.

Pancreatic ductal adenocarcinoma is an aggressive malignancy with a high mortality rate. Proper determination of the extent of disease on imaging studies at the time of staging is one of the most important steps in optimal patient management. Given the variability in expertise and definition of disease extent among different practitioners as well as frequent lack of complete reporting of pertinent imaging findings at radiologic examinations, adoption of a standardized template for radiology reporting, using universally accepted and agreed on terminology for solid pancreatic neoplasms, is needed. A consensus statement describing a standardized reporting template authored by a multi-institutional group of experts in pancreatic ductal adenocarcinoma that included radiologists, gastroenterologists, and hepatopancreatobiliary surgeons was developed under the joint sponsorship of the Society of Abdominal Radiologists and the American Pancreatic Association. Adoption of this standardized imaging reporting template should improve the decision-making process for the management of patients with pancreatic ductal adenocarcinoma by providing a complete, pertinent, and accurate reporting of disease staging to optimize treatment recommendations that can be offered to the patient. Standardization can also help to facilitate research and clinical trial design by using appropriate and consistent staging by means of resectability status, thus allowing for comparison of results among different institutions.

There has been an increase in utilization of bariatric surgery and, as with any surgical procedure, the associated risk of complications. Many of the post bariatric surgical complications can be acute, necessitating an emergency room visit and imaging evaluation. Radiologists, especially in the emergency setting, need to be familiar with normal post-operative appearances and potential surgical complications. This review focuses on various bariatric surgical procedures that are performed, and illustrates normal and abnormal radiographic appearances seen on post-operative fluoroscopic upper GI studies and abdominal pelvis CT examinations.

In addition to clinical history and evaluations, the results of laboratory tests and imaging studies help clinicians in determining treatment strategies. Imaging plays a central role in the management of oncology patients including the initial diagnosis, staging, and follow-up to assess treatment response. Historically, radiologists have relied on free-style dictations to convey the results of imaging findings in radiology reports to referring clinicians. These unstructured free-style dictations can potentially be a source of frustration as the pertinent information needed to guide treatment may be omitted or difficult to extract from the report, thereby limiting its completeness and usefulness. These limitations can be overcome by adopting a structured and reproducible form of reporting imaging studies to help clinicians in deciding the best treatment strategy for each patient. There is a growing need to establish standardized radiology reporting templates for specific disease processes. One such example involves patients with pancreatic ductal adenocarcinoma, as imaging findings determine the treatment arm to which the patient is assigned. In this presentation, we outline a list of essential features that need to be included in a structured report and highlight this with illustrative case examples.

Apreviously healthy 37-year-old woman complained of episodic right upper abdominal pain. An extensive clinical workup had been negative, including physical examination, upper endoscopy, complete blood count, comprehensive metabolic panel, and coagulation studies. Contrast-enhanced computed tomography (CT) of the abdomen and pelvis demonstrated a solitary mass adjacent to the gastric antrum (Fig. 1). The mass had a lobulated contour with interdigitation of its parenchyma with the surrounding mesenteric fat along the inferior border. The mass did not appear to obstruct the gastric outlet, and there were no adjacent inflammatory changes. An ultrasound-guided percutaneous core needle biopsy was subsequently performed (not shown). The patient initially tolerated the procedure well and was discharged home. However, during the week following the biopsy, she developed acute right upper quadrant abdominal pain and presented to the emergency department. In the emergency department, she was found to be febrile (101.61F), with elevated white blood cell count (16,000 mm