This ECCO topical review of the European Crohn's and Colitis Organisation [ECCO] focused on prediction, diagnosis, and management of fibrostenosing Crohn's disease [CD]. The objective was to achieve evidence-supported, expert consensus that provides guidance for clinical practice.

Haemangiomas are common focal liver lesions, generally detected in the work-up of asymptomatic patients. From the pathological point of view, they can be classified as small (capillary) or large, with cavernous vascular spaces that may show thrombosis, calcifications and hyalinisation. The polymorphic imaging appearance of haemangiomas depends on their histological features and flow pattern. The widespread use of cross-sectional imaging has allowed an increased detection rate and a better characterisation of this benign tumour. Recent developments of ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) providing high spatial and temporal resolution, together with the use of new contrast agents and/or pulse sequences has broadened the spectrum of imaging findings, contributing to diagnostic refinement in difficult cases. The scope of the present article is to provide an overview of the range of appearances of haemangiomas, explored with recent crosssectional imaging modalities, emphasising its atypical findings as explored by temporally resolved contrast-enhanced imaging.

The portal vein (PV) is the main vessel of the portal venous system (PVS), which drains the blood from the gastrointestinal tract, gallbladder, pancreas, and spleen to the liver. There are several variants affecting the PV, and quite a number of congenital and acquired pathologies.In this pictorial review, we assess the embryological development and normal anatomy of the PVS, displaying selected cases consisting of normal variants, congenital anomalies, and a large and heterogeneous group of acquired conditions that may affect the PV.

Gastrointestinal (GI) bleeding is a common clinical condition that is increasingly seen in an aging population and frequently requires hospitalization and intervention, with significant morbidity and mortality. Obscure GI bleeding (OGIB) is defined as loss of blood with no source identified after upper endoscopy and colonoscopy. Whether an obscure site of bleeding is clinically evident or silent, it constitutes a diagnostic and therapeutic challenge for the clinician. Gastroenterology and radiology provide the essential diagnostic tools used to evaluate suspected OGIB, each with its strengths and weaknesses. Small bowel series and conventional enteroclysis have a limited role in OGIB. Computed tomographic (CT) enterography and CT enteroclysis are noninvasive techniques with promising results in evaluation of small bowel disease and silent OGIB. CT angiography is a useful triaging tool for diagnosing or excluding active GI hemorrhage, localizing the site of bleeding, and guiding subsequent treatment. Tagged red blood cell scanning is the most sensitive technique for detection of active GI bleeding and allows imaging over a prolonged period, making it useful for detecting intermittent bleeding. Capsule endoscopy has emerged as an important tool for investigating OGIB, but it may soon have competition from double-balloon enteroscopy, a diagnostic technique that can also facilitate therapy.

).Abbreviations FNH = focal nodular hyperplasia, FSE = fast spin echo, HCC = hepatocellular carcinoma, SI = signal intensity. ABSTRACTThe vast majority of focal liver lesions are hyperintense on T2-weighted magnetic resonance (MR) images. Rarely, however, hepatic nodules may appear totally or partially hypointense on those images. Causes for this uncommon appearance include deposition of iron, calcium, or copper and are related to the presence of blood degradation products, macromolecules, coagulative necrosis, and other conditions. Although rare, low signal intensity relative to surrounding liver on T2-weighted images may be seen in a wide spectrum of lesions. Examples include cases of focal nodular hyperplasia, hepatocellular adenoma, hepatocellular carcinoma, metastases, leyomioma, siderotic or dysplastic nodules, nodules in Wilson disease, granuloma, and hydatid cyst. On fat-suppressed T2-weighted images, nodules with a lipomatous component, such as lipoma, angiomyolipoma, hepatocellular adenoma, and hepatocellular carcinoma may also appear partially or totally hypointense. The conjunction of other MR imaging findings and their integration in the clinical setting may allow a correct diagnosis in a considerable proportion of cases. The cause for T2-weighted hypointensity may not be, however, always recognized, and only pathologic correlation may provide the answer. The aims of this work are to discuss the causes and mechanisms of hypointensity of liver lesions on T2-weighted images and proposing an algorithm for classification that may be useful as a quick reminder for the interested reader. INTRODUCTIONMagnetic resonance (MR) imaging of liver lesions is of pivotal importance in clinical practice. In abdominal MR imaging, T1-and T2-weighted sequences remain a basic requirement for lesion characterization. MR signal intensity (SI) of focal liver lesions is affected by numerous pathologic factors. Histologic features strongly affect T1 and T2 relaxation times and MR imaging is unique in its ability to explore intracellular content and recognize the presence of substances that may govern signal behavior. Owing to their high cellular water content, the majority of focal liver lesions appear hyperintense on T2-weighted images. In contrast to this most frequently seen MR imaging pattern, liver nodules may show total or partial hypointensity on T2-weighted images. The hypointense appearance can be classified as absolute or relative, depending on the native SI of adjacent liver parenchyma and sequence parameters (Fig 1). Although relative hypointensity depends on the native SI of liver, which can be modified by several circumstances (eg, inflammation, diffuse iron deposition, etc), it may be more commonly encountered when