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This review summarizes the relevant literature for the selection of the initial imaging in 4 clinical scenarios in patients with suspected inflammatory disease or postoperative complication of the anorectum. These clinical scenarios include suspected perianal fistula or abscess; rectovesicular or rectovaginal fistula; proctitis or pouchitis; and suspected complication following proctectomy, coloproctectomy, or colectomy with a pouch or other anastomosis. The appropriateness of imaging modalities as they apply to each clinical scenario is rated as usually appropriate, may be appropriate, and usually not appropriate to assist the selection of the most appropriate imaging modality in the corresponding clinical scenarios of anorectal disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

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.

Hepatic incidental findings often are seen on cross-sectional imaging examinations of the chest, spine, pelvis, or other nondedicated hepatic imaging. Radiologists are tasked with appropriately triaging, which requires further evaluation, even in the setting of an otherwise limited evaluation. This article reviews common benign entities encountered on ultrasound, computed tomography, or magnetic resonance imaging, along with their characteristic imaging features. Imaging features that are suspicious for malignancy or suggest the need for further evaluation also are discussed. Two algorithms are proposed to guide radiologists in their recommendations based on patient risk factors, focal hepatic abnormality size, and available imaging features.

PURPOSE: To develop a deep convolutional neural network (CNN) model to categorize multiphase CT and MRI liver observations using the Liver Imaging Reporting and Data System (LI-RADS) (version 2014). METHODS: A pre-existing dataset comprising 314 hepatic observations (163 CT, 151 MRI) with corresponding diameters and LI-RADS categories (LR-1–5) assigned in consensus by two LI-RADS steering committee members was used to develop two CNNs: pre-trained network with an input of triple-phase images (training with transfer learning) and custom-made network with an input of quadruple-phase images (training from scratch). The dataset was randomly split into training, validation, and internal test sets (70:15:15 split). The overall accuracy and area under receiver operating characteristic curve (AUROC) were assessed for categorizing LR-1/2, LR-3, LR-4, and LR-5. External validation was performed for the model with the better performance on the internal test set using two external datasets (EXT-CT and EXT-MR: 68 and 44 observations, respectively). RESULTS: The transfer learning model outperformed the custom-made model: overall accuracy of 60.4% and AUROCs of 0.85, 0.90, 0.63, 0.82 for LR-1/2, LR-3, LR-4, LR-5, respectively. On EXT-CT, the model had an overall accuracy of 41.2% and AUROCs of 0.70, 0.66, 0.60, 0.76 for LR-1/2, LR-3, LR-4, LR-5, respectively. On EXT-MR, the model had an overall accuracy of 47.7% and AUROCs of 0.88, 0.74, 0.69, 0.79 for LR-1/2, LR-3, LR-4, LR-5, respectively. CONCLUSION: Our study shows the feasibility of CNN for assigning LI-RADS categories from a relatively small dataset but highlights the challenges of model development and validation.

The following is an illustrative review of common pitfalls in liver MRI that may challenge interpretation. This article reviews common technical and diagnostic challenges encountered when interpreting dynamic multiphasic T1 -weighted imaging, hepatobiliary phase imaging, and diffusion-weighted imaging of the liver. Additionally, each section includes suggestions for avoiding diagnostic and technical errors. Level of Evidence: 5 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:41-58.

Author(s): Kielar, Ania Z; Chernyak, Victoria; Bashir, Mustafa R; Do, Richard K; Fowler, Kathryn J; Mitchell, Donald G; Cerny, Milena; Elsayes, Khaled M; Santillan, Cynthia; Kamaya, Aya; Kono, Yuko; Sirlin, Claude B; Tang, An | Abstract: The computed tomography / magnetic resonance imaging (CT/MRI) Liver Imaging Reporting a Data System (LI-RADS) is a standardized system for diagnostic imaging terminology, technique, interpretation, and reporting in patients with or at risk for developing hepatocellular carcinoma (HCC). Using diagnostic algorithms and tables, the system assigns to liver observations category codes reflecting the relative probability of HCC or other malignancies. This review article provides an overview of the 2017 version of CT/MRI LI-RADS with a focus on MRI. The main LI-RADS categories and their application will be described. Changes and updates introduced in this version of LI-RADS will be highlighted, including modifications to the diagnostic algorithm and to the optional application of ancillary features. Comparisons to other major diagnostic systems for HCC will be made, emphasizing key similarities, differences, strengths, and limitations. In addition, this review presents the new Treatment Response algorithm, while introducing the concepts of MRI nonviability and viability. Finally, planned future directions for LI-RADS will be outlined.Level of evidence5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;47:1459-1474.

The Liver Imaging Reporting and Data System (LI-RADS) was designed to standardize the interpretation and reporting of observations seen on studies performed in patients at risk for development of hepatocellular carcinoma (HCC). The LI-RADS algorithm guides radiologists through the process of categorizing observations on a spectrum from definitely benign to definitely HCC. Major features are the imaging features used to categorize observations as LI-RADS 3 (intermediate probability of malignancy), LIRADS 4 (probably HCC), and LI-RADS 5 (definite HCC). Major features include arterial phase hyperenhancement, washout appearance, enhancing capsule appearance, size, and threshold growth. Observations that have few major criteria are assigned lower categories than those that have several, with the goal of preserving high specificity for the LR-5 category of Definite HCC. The goal of this paper is to discuss LI-RADS major features, including definitions, rationale for selection as major features, and imaging examples.

The Liver Imaging Reporting and Data System (LI-RADS®) is an imaging-based diagnostic system applicable in patients at high risk of hepatocellular carcinoma (HCC). In LI-RADS, each liver observation is assigned a category that reflects probability of benignity, HCC, or other malignancy. Familiarity with the LI-RADS diagnostic algorithm is necessary to appropriately implement LI-RADS in clinical practice. This review discusses steps necessary for application of the LI-RADS algorithm and provides examples illustrating each step.

SummaryBackground Magnetic resonance imaging (MRI) is the gold standard for assessment of perianal fistulising Crohn's disease (CD). The Van Assche index is the most commonly used MRI fistula index. Aims To assess the reliability of the Van Assche index, and to modify the instrument to improve reliability and create a novel index for fistulising CD. Methods A consensus process developed scoring conventions for existing Van Assche index component items and new items. Four experienced radiologists evaluated 50 MRI images in random order on three occasions. Reliability was assessed by estimates of intraclass correlation coefficients (ICCs). Common sources of disagreement were identified and recommendations made to minimise disagreement. A mixed effects model used a 100 mm visual anologue scale (VAS) for global severity as outcome and component items as predictors to create a modified Van Assche index. Results Intraclass correlation coefficients (95% confidence intervals) for intra-rater reliability of the original and modified Van Assche indices and the VAS were 0.86 (0.81-0.90), 0.90 (0.86-0.93) and 0.86 (0.82-0.89). Corresponding ICCs for inter-rater reliability were 0.66 (0.52-0.76), 0.67 (0.55-0.75) and 0.58 (0.47-0.66). Sources of disagreement included number, location, and extension of fistula tracts, and rectal wall involvement. A modified Van Assche index (range 0-24) was created that included seven component items. Conclusions Although “almost perfect” intra-rater reliability was observed for the assessment of MRI images for fistulising CD using the Van Assche index, inter-rater reliability was considerably lower. Our modification of this index should result in a more optimal instrument.

The Liver Imaging Reporting and Data System (LI-RADS) uses an algorithm to assign categories that reflect the probability of hepatocellular carcinoma (HCC), non-HCC malignancy, or benignity. Unlike other imaging algorithms, LI-RADS utilizes ancillary features (AFs) to refine the final category. AFs in LI-RADS v2017 are divided into those favoring malignancy in general, those favoring HCC specifically, and those favoring benignity. Additionally, LI-RADS v2017 provides new rules regarding application of AFs. The purpose of this review is to discuss ancillary features included in LI-RADS v2017, the rationale for their use, potential pitfalls encountered in their interpretation, and tips on their application.

Small-bowel obstruction (SBO) is a common and important disease, for which machine learning tools have yet to be developed. Image annotation is a critical first step for development of such tools. This study assesses whether image annotation by eye tracking is sufficiently accurate and precise to serve as a first step in the development of machine learning tools for detection of SBO on CT. Seven subjects diagnosed with SBO by CT were included in the study. For each subject, an obstructed segment of bowel was chosen. Three observers annotated the centerline of the segment by manual fiducial placement and by visual fiducial placement using a Tobii 4c eye tracker. Each annotation was repeated three times. The distance between centerlines was calculated after alignment using dynamic time warping (DTW) and statistically compared to clinical thresholds for diagnosis of SBO. Intra-observer DTW distance between manual and visual centerlines was calculated as a measure of accuracy. These distances were 1.1 ± 0.2, 1.3 ± 0.4, and 1.8 ± 0.2 cm for the three observers and were less than 1.5 cm for two of three observers (P

Background & Aims There is no validated magnetic resonance imaging (MRI) index for assessment of perianal fistulas in patients with Crohn’s disease (CD). We developed and internally validated a new instrument. Methods We used paired baseline and week-24 MRI scans from 160 participants in a randomized placebo-controlled trial of stem cell therapy for patients with perianal fistulizing CD. Four radiologists scored disease activity using index items identified during previous studies and exploratory items. Reliability was assessed using intraclass correlation coefficients. We developed an index using backward elimination linear regression analysis, in which potential independent variables were items having intraclass correlation coefficients of at least 0.4 and the dependent variable was perianal fistulizing disease activity, measured on a 100-mm visual analogue scale. The final model was internally validated using the .632 bootstrap method to correct model optimism and quantify calibration accuracy. We evaluated responsiveness of the index by assessing longitudinal validity and estimating standardized effect sizes. Results We developed the magnetic resonance novel index for fistula imaging in CD (MAGNIFI-CD) using 6 items. The optimism-corrected R2 of the model was 0.71, which was comparable to R2 for the original sample (0.74). The calibration slope for the model was 0.98. Compared with the original and modified versions of the Van Assche Index, the MAGNIFI-CD had improved operating characteristics. Estimates of intraclass correlation coefficients for MAGNIFI-CD, the modified Van Assche Index, and Van Assche Index were 0.85 (95% confidence interval [CI], 0.77–0.90), 0.81 (95% CI, 0.74–0.86), and 0.81 (95% CI, 0.71–0.86) for intra-rater reliability, and 0.74 (95% CI, 0.63–0.80), 0.67 (95% CI, 0.55–0.75) and 0.68 (95% CI, 0.56–0.77) for inter-rater reliability. Corresponding standardized effect size estimates were 1.02 (95% CI, 0.65–1.39), 0.84 (95% CI, 0.48–1.21), and 0.68 (95% CI, 0.33–1.03). Conclusions We developed an index called the MAGNIFI-CD, which is based on 6 items. It assesses MRI data and determines perianal fistulizing CD activity with improved operating characteristics compared to previous indices. This index may be used as an outcome measure in clinical trials comparing treatment effects in patients with perianal fistulizing CD. Although the performance of the MAGNIFI-CD indicates its stability and reasonable external validity, external validation is needed.

The following is an illustrative review of common pitfalls in liver MRI that may challenge interpretation. This article reviews common technical and diagnostic challenges encountered when interpreting dynamic multiphasic T

The computed tomography / magnetic resonance imaging (CT/MRI) Liver Imaging ReportingData System (LI-RADS) is a standardized system for diagnostic imaging terminology, technique, interpretation, and reporting in patients with or at risk for developing hepatocellular carcinoma (HCC). Using diagnostic algorithms and tables, the system assigns to liver observations category codes reflecting the relative probability of HCC or other malignancies. This review article provides an overview of the 2017 version of CT/MRI LI-RADS with a focus on MRI. The main LI-RADS categories and their application will be described. Changes and updates introduced in this version of LI-RADS will be highlighted, including modifications to the diagnostic algorithm and to the optional application of ancillary features. Comparisons to other major diagnostic systems for HCC will be made, emphasizing key similarities, differences, strengths, and limitations. In addition, this review presents the new Treatment Response algorithm, while introducing the concepts of MRI nonviability and viability. Finally, planned future directions for LI-RADS will be outlined.5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;47:1459-1474.

Purpose To determine in a large multicenter multireader setting the interreader reliability of Liver Imaging Reporting and Data System (LI-RADS) version 2014 categories, the major imaging features seen with computed tomography (CT) and magnetic resonance (MR) imaging, and the potential effect of reader demographics on agreement with a preselected nonconsecutive image set. Materials and Methods Institutional review board approval was obtained, and patient consent was waived for this retrospective study. Ten image sets, comprising 38-40 unique studies (equal number of CT and MR imaging studies, uniformly distributed LI-RADS categories), were randomly allocated to readers. Images were acquired in unenhanced and standard contrast material-enhanced phases, with observation diameter and growth data provided. Readers completed a demographic survey, assigned LI-RADS version 2014 categories, and assessed major features. Intraclass correlation coefficient (ICC) assessed with mixed-model regression analyses was the metric for interreader reliability of assigning categories and major features. Results A total of 113 readers evaluated 380 image sets. ICC of final LI-RADS category assignment was 0.67 (95% confidence interval [CI]: 0.61, 0.71) for CT and 0.73 (95% CI: 0.68, 0.77) for MR imaging. ICC was 0.87 (95% CI: 0.84, 0.90) for arterial phase hyperenhancement, 0.85 (95% CI: 0.81, 0.88) for washout appearance, and 0.84 (95% CI: 0.80, 0.87) for capsule appearance. ICC was not significantly affected by liver expertise, LI-RADS familiarity, or years of postresidency practice (ICC range, 0.69-0.70; ICC difference, 0.003-0.01 [95% CI: -0.003 to -0.01, 0.004-0.02]. ICC was borderline higher for private practice readers than for academic readers (ICC difference, 0.009; 95% CI: 0.000, 0.021). Conclusion ICC is good for final LI-RADS categorization and high for major feature characterization, with minimal reader demographic effect. Of note, our results using selected image sets from nonconsecutive examinations are not necessarily comparable with those of prior studies that used consecutive examination series. © RSNA, 2017.

Background: Magnetic resonance enterography is increasingly utilized for assessment of luminal Crohn's disease activity. The Magnetic Resonance Index of Activity and the London Index are the most commonly used outcome measures in clinical trials. We assessed the reliability of these indices and several additional items. Methods: A consensus process clarified scoring conventions and identified additional items based on face validity. Four experienced radiologists evaluated 50 images in triplicate, in random order, at least 1 month apart, using a central image management system. Intra- and interrater reliability were assessed by calculating and comparing intraclass correlation coefficients. Results: Intrarater intraclass correlation coefficients (95% confidence intervals) for the Magnetic Resonance Index of Activity, London, and London "extended" indices and a visual analogue scale were 0.89 (0.84 to 0.91), 0.87 (0.83 to 0.90), 0.89 (0.85 to 0.92), and 0.86 (0.81 to 0.90). Corresponding interrater intraclass correlation coefficients were 0.71 (0.61 to 0.77), 0.67 (0.55 to 0.75), 0.70 (0.61 to 0.76), and 0.71 (0.62 to 0.77). Reliability for each index was greatest in the terminal ileum and poorest in the rectum. All 3 indices were highly correlated with the visual analogue scale; 0.79 (0.71 to 0.85), 0.78 (0.71 to 0.84), and 0.79 (0.72 to 0.85) for the Magnetic Resonance Index of Activity, London, and the London "extended" indices, respectively. Conclusions: "Substantial" interrater reliability was observed for all 3 indices. Future studies should assess responsiveness to treatment in order to confirm their utility as evaluative indices in clinical trials and clinical practice.

Hepatocarcinogenesis is a multi-step process characterized by progressive cellular and molecular dedifferentiation of hepatocytes and culminating in the emergence of hepatocellular carcinoma (HCC). Knowledge of hepatocarcinogenesis is important because familiarity with the associated imaging features can lead to improved diagnosis of HCC at its early stages. The article reviews the alterations that accumulate leading to HCC result in abnormal imaging features, many of which are included in LI-RADS v2017 as major and ancillary features.

Author(s): Kielar, Ania Z; Chernyak, Victoria; Bashir, Mustafa R; Do, Richard K; Fowler, Kathryn J; Santillan, Cynthia; Sirlin, Claude B; Mitchell, Donald G; Cerny, Milena; Tang, An; Elsayes, Khaled M; Kamaya, Aya; Kono, Yuko; Arora, Sandeep S

The Liver Imaging Reporting and Data System (LI-RADS) is an American College of Radiology (ACR)-endorsed diagnostic system of standardized terminology, interpretation, and reporting for imaging examinations of the liver in patients at high risk for hepatocellular carcinoma (HCC). LI-RADS assigns a category to observations in the liver indicating the likelihood of benignity or HCC. LI-RADS categories include LR-1: Definitely Benign, LR-2: Probably Benign, LR-3: Intermediate Probability for HCC, LR-4: Probably HCC, LR-5: Definite HCC, LR-5V: Definite HCC with Tumor in Vein, LR-Treated: Treated HCC, LR-M Probable Malignancy, not specific for HCC. This article reviews the types of nodules seen in the cirrhotic liver, examines core LI-RADS concepts and definitions, and utilizes the LI-RADS v2014 algorithm to categorize representative observations depicted at magnetic resonance imaging in a case-based approach.

The Liver Imaging Reporting and Data System (LI-RADS) was created to provide a standardized way to both assess and communicate the likelihood of benignity or malignancy of observations seen in patients at risk for development of hepatocellular carcinoma (HCC). The LI-RADS categories allow radiologists to convey the full spectrum of concern for malignancy, from definitely benign to definitely HCC. Additional categories are available for non-categorizable observations, observations that are concerning for a non-HCC malignancy, and the presence of tumor in vein. The goal of this paper is to discuss the LI-RADS categories, including criteria for each category, and point out changes to the categories from prior versions of LI-RADS.

The Liver Imaging Reporting and Data System (LI-RADS) uses an algorithm to assign categories that reflect the probability of hepatocellular carcinoma (HCC), non-HCC malignancy, or benignity. Unlike other imaging algorithms, LI-RADS utilizes ancillary features (AFs) to refine the final category. AFs in LI-RADS v2017 are divided into those favoring malignancy in general, those favoring HCC specifically, and those favoring benignity. Additionally, LI-RADS v2017 provides new rules regarding application of AFs. The purpose of this review is to discuss ancillary features included in LI-RADS v2017, the rationale for their use, potential pitfalls encountered in their interpretation, and tips on their application.

Author(s): Kono, Yuko; Lyshchik, Andrej; Cosgrove, David; Dietrich, Christoph F; Jang, Hyun-Jung; Kim, Tae Kyoung; Piscaglia, Fabio; Willmann, Juergen K; Wilson, Stephanie R; Santillan, Cynthia; Kambadakone, Avinash; Mitchell, Donald; Vezeridis, Alexander; Sirlin, Claude B

Although the overall prevalence of peptic ulcer disease (PUD) and related hospitalizations are decreasing, the initial presentation of complicated PUD on CT remains common. It, therefore, remains critical for radiologists to recognize the findings of PUD at CT for initial diagnosis. While the CT findings of complicated PUD have been previously described in the literature, the CT findings of uncomplicated PUD have not been well documented. Furthermore, although CT is certainly not the diagnostic evaluation of choice for patients with suspected uncomplicated PUD, many patients with PUD will nonetheless present to the emergency department with unexplained abdominal pain and undergo MDCT evaluation as the initial diagnostic test. Therefore, recognizing the MDCT findings of uncomplicated PUD can help appropriately direct patient management, and help prevent the development of complications. To facilitate improved recognition of PUD on abdominal CT, we present an overview of the CT findings of both uncomplicated and complicated PUD, as well as several diagnostic pitfalls which can result in misdiagnosis from peptic ulcer mimics.

The Liver Imaging-Reporting and Data System (LI-RADS) is a comprehensive system for standardized interpretation and reporting of computed tomography and magnetic resonance examinations performed in patients at risk for hepatocellular carcinoma. LI-RADS includes a diagnostic algorithm, lexicon, and atlas as well as suggestions for reporting, management, and imaging techniques. This primer provides an introduction to LI-RADS for radiologists including an explanation of the diagnostic algorithm, descriptions of the categories, and definitions of the major imaging features used to categorize observations with case examples.

Due to advances in technology, magnetic resonance is an increasingly popular method for evaluating the small bowel and colon because of the lack of radiation, wealth of information provided by the images, and growing demand from gastroenterologists, surgeons, and oncologists. Careful attention to proper technique, however, is necessary to obtain high-quality images. Factors that need to be considered for successful magnetic resonance of the bowel include method for administration of oral or rectal contrast, patient positioning, need for antiperistaltic medication, and imaging sequences and planes.

The American College of Radiology supported Liver Imaging Reporting And Data System (LI-RADS) is a comprehensive system for standardized interpretation and reporting of imaging examinations performed in patients at risk for hepatocellular carcinoma (HCC). As reviewed in the first article of a two-part series, LI-RADS uses 5 major imaging features to categorize LR-3, LR-4, and LR-5 observations. The major features are arterial phase enhancement, washout appearance, capsule appearance, diameter, and threshold growth. In addition to the major imaging features, LI-RADS uses ancillary imaging features to adjust the LI-RADS category to increase or decrease the suspicion for HCC. In this second article of a two-part series, we would discuss and illustrate a selection of LI-RADS ancillary imaging features.

The purpose of this article is to review and illustrate the Liver Imaging Reporting and Data System (LI-RADS) major features for interpretation and reporting of liver imaging examinations performed in patients at risk for hepatocellular carcinoma (HCC).

Purpose To determine the proportion of untreated Liver Imaging Reporting and Data System (LI-RADS) version 2014 category 2, 3, and 4 observations that progress, remain stable, or decrease in category and to compare the cumulative incidence of progression in category. Materials and Methods In this retrospective, longitudinal, single-center, HIPAA-compliant, institutional review board-approved study, 157 patients (86 men and 71 women; mean age ± standard deviation, 59.0 years ± 9.7) underwent two or more multiphasic computed tomographic (CT) or magnetic resonance (MR) imaging examinations for hepatocellular carcinoma surveillance, with the first examination in 2011 or 2012. One radiologist reviewed baseline and follow-up CT and MR images (mean follow-up, 614 days). LI-RADS categories issued in the clinical reports by using version 1.0 or version 2013 were converted to version 2014 retrospectively; category modifications were verified with another radiologist. For index category LR-2, LR-3, and LR-4 observations, the proportions that progressed, remained stable, or decreased in category were calculated. Cumulative incidence curves for progression were compared according to baseline LI-RADS category (by using log-rank tests). Results All 63 index LR-2 observations remained stable or decreased in category. Among 166 index LR-3 observations, seven (4%) progressed to LR-5, and eight (5%) progressed to LR-4. Among 52 index LR-4 observations, 20 (38%) progressed to a malignant category. The cumulative incidence of progression to a malignant category was higher for index LR-4 observations than for index LR-3 or LR-2 observations (each P < .001) but was not different between LR-3 and LR-2 observations (P = .155). The cumulative incidence of progression to at least category LR-4 was trend-level higher for index LR-3 observations than for LR-2 observations (P = .0502). Conclusion Observations classified according to LI-RADS version 2014 categories are associated with different imaging outcomes. (©) RSNA, 2016 Online supplemental material is available for this article.

Splenic lymphangioma is a rare, benign lesion of the spleen that is characterized microscopically by a proliferation of thin-walled vascular channels filled by proteinacious material. Based on microscopic features, three types of lymphangiomas are described as simple capillary, cavernous, and cystic; however, the distinction between these types is not uniformly accepted. The cystic type is the most common type and has well described imaging characteristics. However, little is known about the less common cavernous and capillary forms of lymphangioma. Herein, we present a case of a patient with two synchronous colon cancers that presented with a concomitant splenic mass that was initially suspected to be metastatic disease. Despite the use of multiple imaging modalities including computed tomography (CT), magnetic resonance imaging (MRI), nuclear imaging, and contrast-enhanced ultrasound, the final diagnosis of cavernous lymphangioma was made following core needle biopsy of the lesion. A thorough review of literature and this case now demonstrate the difficulty in differentiating atypical forms of splenic lymphangiomas from other benign lesions such as hemangioma.

The uni- and multicentric forms of Castleman disease can occur within the retroperitoneum and should always be considered when a homogeneous vascular mass with contrast kinetics that follow the surrounding large arteries is identified along a lymph node chain.

Capsular retraction is an infrequent but characteristic feature of malignant liver lesions such as hepatic metastases and intrahepatic cholangiocarcinoma. Rarely, this finding may be observed in association with benign lesions, such as atypical haemangiomas. Capsular retraction has not previously been reported in association with hepatic inflammatory pseudotumour (IPT). Hepatic IPT is an uncommon benign hepatic lesion with a good clinical prognosis. In this report, we discuss the case of a 48-year-old woman with capsular retraction secondary to multifocal hepatic inflammatory IPTs.

Chronic liver disease is a major public health problem worldwide. Liver fibrosis, a common feature of almost all causes of chronic liver disease, involves the accumulation of collagen, proteoglycans, and other macromolecules within the extracellular matrix. Fibrosis tends to progress, leading to hepatic dysfunction, portal hypertension, and ultimately cirrhosis. Liver biopsy, the standard of reference for diagnosing liver fibrosis, is invasive, costly, and subject to complications and sampling variability. These limitations make it unsuitable for diagnosis and longitudinal monitoring in the general population. Thus, development of a noninvasive, accurate, and reproducible test for diagnosis and monitoring of liver fibrosis would be of great value. Conventional cross-sectional imaging techniques have limited capability to demonstrate liver fibrosis. In clinical practice, imaging studies are usually reserved for evaluation of the presence of portal hypertension or hepatocellular carcinoma in cases that have progressed to cirrhosis. In response to the rising prevalence of chronic liver diseases in Western nations, a number of imaging-based methods including ultrasonography-based transient elastography, computed tomography–based texture analysis, and diverse magnetic resonance (MR) imaging–based techniques have been proposed for noninvasive diagnosis and grading of hepatic fibrosis across its entire spectrum of severity. State-of-the-art MR imaging–based techniques in current practice and in development for noninvasive assessment of liver fibrosis include conventional contrast material–enhanced MR imaging, double contrast-enhanced MR imaging, MR elastography, diffusion-weighted imaging, and MR perfusion imaging. © RSNA, 2009

Lipomas are benign neoplasms composed of adipocytes encased in a fibrous capsule. Intravascular lipomas are rare and almost always incidental findings. In the published literature, the majority are described within the inferior vena cava (IVC) and less frequently reported in the superior vena cava, brachiocephalic vein, subclavian vein, internal jugular vein, external iliac vein and common femoral vein. We present the case of a 59-year-old male who presented with a symptomatic ureteral calculus and was found to have an intravascular lipoma of the right renal vein with extension into the IVC. To our knowledge, this is the first ever report of an intravascular lipoma in the renal vein. We discuss the imaging characteristics of intravascular lipomas and the differential diagnosis that should be considered.

This is the protocol for a review and there is no abstract. The objectives are as follows: The primary objective is to systematically review the current literature describing the development and operating characteristics of MRI scoring indices used for evaluation of disease activity in Crohn's disease.

The Liver Imaging Reporting and Data System (LI-RADS) is an American College of Radiology (ACR)-endorsed diagnostic system of standardized terminology, interpretation, and reporting for imaging examinations of the liver in patients at high risk for hepatocellular carcinoma (HCC). LI-RADS assigns a category to observations in the liver indicating the likelihood of benignity or HCC. LI-RADS categories include LR-1: Definitely Benign, LR-2: Probably Benign, LR-3: Intermediate Probability for HCC, LR-4: Probably HCC, LR-5: Definite HCC, LR-5V: Definite HCC with Tumor in Vein, LR-Treated: Treated HCC, LR-M Probable Malignancy, not specific for HCC. This article reviews the types of nodules seen in the cirrhotic liver, examines core LI-RADS concepts and definitions, and utilizes the LI-RADS v2014 algorithm to categorize representative observations depicted at magnetic resonance imaging in a case-based approach.

OBJECTIVE. The purpose of this article is to review the imaging features and Liver Imaging Reporting and Data System (LI-RADS) categorization of benign and likely benign entities, including typical cirrhotic nodules, distinctive nodular observations, and benign entities that may simulate hepatocellular carcinoma. CONCLUSION. LI-RADS is a system of standardized criteria for interpreting liver CT and MR images of patients at risk of hepatocellular carcinoma. Most of the observations in these patients are not malignant. With the development of fibrosis and cirrhosis, these benign entities may take on an altered appearance. © American Roentgen Ray Society.

Magnetic resonance enterography (MRE) is a relatively new imaging modality that has shown promise for diagnosing, staging, and monitoring Crohn's disease (CD) and its complications while avoiding exposure to ionizing radiation. In addition to clinical implications, MRE has the potential to be used as an objective measure of disease activity for clinical trials. We provide the rationale for MRE, indications for its use, and an overview of the typical procedure and common findings for institutions who want to begin or refine the use of MRE for CD.

Computed tomography (CT) and magnetic resonance (MR) enterography are now widely used to diagnose and monitor Crohn’s disease. We sought to assess the use of enterography for management of inflammatory bowel disease (IBD) in our medical center. We performed a retrospective review of all patients diagnosed with IBD who underwent MR or CT enterography from November 1, 2010 to October 25, 2012 at our institution. We assessed disease complications identified by enterography, agreement between disease activity determined by endoscopy and enterography, association between inflammatory markers and enterography-determined disease activity and recommended changes in medical and surgical management following enterography. A total of 311 enterography studies (291 MR and 20 CT enterographies) were performed on 270 patients, including 258 (83.0 %) on patients with presumed Crohn’s disease and 53 (17.0 %) with presumed ulcerative colitis. Active small bowel (SB) disease was noted in 73/311 (23.5 %) studies. Complications including strictures, perianal fistulas, abscesses and SB fistulas were noted in 108/311 (34.7 %) studies. Endoscopic and enterography defined active disease had an agreement of κ = 0.36 in the ileum (n = 179). A total of 142/311 (45.7 %) enterographies were associated with recommended medication changes within 90 days while surgery or endoscopic dilation of stricture was recommended following 41/311 (13.2 %) enterographies. Enterography resulted in a change in diagnosis from ulcerative colitis to Crohn’s in 5/311 (1.6 %) studies. Enterography reveals active disease and complications not evident on endoscopy and should be considered in the initial diagnosis, assessment of disease activity, and monitoring of therapy in patients with IBD.

Multidetector computed tomography (CT) is a powerful tool for the assessment of patients with small bowel obstruction (SBO). CT can provide important information about the cause and site of obstruction and the presence of a closed-loop obstruction or ischemia. Under investigation is the ability of CT to accurately identify patients without clear indications for urgent surgery who may benefit from earlier intervention. This article reviews the appropriate CT technique for assessment of SBO, common causes for obstruction, imaging findings in SBO, and the significance of those findings for determining whether a patient is likely to require surgical management for SBO.

A bifid ureter with a blind-ending branch is a rare congenital anomaly. Although typically found incidentally, this anomaly can be symptomatic and radiologists should be aware of this important variant. To our knowledge, there has been no previous report of this anomaly as seen on multidetector CT urography. We present a patient with haematuria and review the clinical significance, radiological findings and embryological aetiology of this anomaly.

To evaluate testicular microlithiasis (TM) prospectively with modern state-of-the-art equipment.Information concerning indication for examination, presence and degree of TM, presence of testicular tumor, and patient age was prospectively recorded for all patients referred for scrotal ultrasonography between 1996 and 1999. High-frequency linear transducers (7.5 MHz or higher) were used. TM was divided into classic (CTM) and limited (LTM) on the basis of the presence of five or more microliths on one or more images of the testes. Fisher exact tests were used for determining significant differences in proportions.Data in 1,079 patients were analyzed. The overall prevalence of TM was 18.1% (195 of 1,079). Forty (3.7%) patients had CTM, and 155 (14.4%) had LTM; 15 (1.4%) had tumors visible at US. Tumors were present in three (8%) of 40 patients with CTM (seminoma in two, embryonal cell in one), nine (5.8%) of 155 with LTM (seminoma in six, mixed germ cell in one, Leydig cell in two), and three (0.3%) of 884 with no TM (seminoma in two, other in one). There was no difference between CTM and LTM (P =.72) in the rate of coexisting tumor. There was a significant difference between no TM and CTM or LTM (P/=.001) in the rate of coexisting tumor. Eighty percent (12 of 15) of patients with tumor at presentation had CTM or LTM.Approximately one of 27 patients had CTM, and one of seven had LTM. Although a majority of patients with testicular tumors had coexistent TM, more than 90% with TM (both CTM and LTM) did not have tumor at presentation.

Conclusions: The majority of strictures in CD patients treated by surgery are consistent with a mixed type inflammation (acute inflammation plus fibrosis). The presence of stratified BS pattern shows a significantly higher degree of fibrosis while the evidence of high mural signal intensity on T2-weighted fatsaturated images on MRI reflects histological features of acute inflammation. Even if the ideal definition of the type of the strictures in CD still remains significantly far to be obtained, the combined use of BS and MRI can offer useful information in a sub-group of patients needing surgery for complicating CD.

Conclusions: The majority of strictures in CD patients treated by surgery are consistent with a mixed type inflammation (acute inflammation plus fibrosis). The presence of stratified BS pattern shows a significantly higher degree of fibrosis while the evidence of high mural signal intensity on T2-weighted fatsaturated images on MRI reflects histological features of acute inflammation. Even if the ideal definition of the type of the strictures in CD still remains significantly far to be obtained, the combined use of BS and MRI can offer useful information in a sub-group of patients needing surgery for complicating CD.