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Positron emission tomography (PET) magnetic resonance (MR) enterography is a novel hybrid imaging technique that is gaining popularity in the study of complex inflammatory disorders of the gastrointestinal system, such as inflammatory bowel disease (IBD). This imaging technique combines the metabolic information of PET imaging with the spatial resolution and soft tissue contrast of MR imaging. Several studies have suggested potential roles for PET/MR imaging in determining the activity status of IBD, evaluating treatment response, stratifying risk, and predicting long-term clinical outcomes. However, there are challenges in generalizing findings due to limited studies, technical aspects of hybrid MR/PET imaging, and clinical indications of this imaging modality. This review aims to further elucidate the possible role of PET/MR in IBD, highlight important technical aspects of imaging, and address potential pitfalls and prospects of this modality in IBDs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Purpose: Previous studies have indicated an increased risk of prostate carcinoma (PCa) associated with inflammatory bowel disease (IBD). Prostate MRI of IBD patients could be expected to show a mixture of inflammation as well as higher than normal rates of PCa, which could impact interpretation and MRI performance. The purpose of this study is to evaluate the characteristics of prostate MRI in patients with IBD., Methods: 3140 patients with prostate MRI were evaluated. Coexisting IBD, PI-RADS score, and pathological results of prostate lesions (clinically significant PCa [csPCa]: Gleason score [GS] 7+, Non-csPCa: benign or GS 6) were assessed. The distribution of PI-RADS scoring and pathological result was assessed by chi-square test., Results: 71 patients had IBD (IBD group), whereas the remaining 3069 patients did not (Non-IBD group). The proportion of abnormal MRI (PI-RADS 3, 4 or 5) was 51 % (36/71) in IBD group and 47 % (1436/3069) in Non-IBD groups (p = 0.513). Total of 1285 patients underwent biopsy or prostatectomy. The proportion of csPCa at pathology was 35 % (12/34) in IBD group and 56 % (699/1251) in non-IBD groups (p = 0.017). The positive predictive value of abnormal MRI for csPCa was significantly lower in IBD group (39 %, 19/31) compared to Non-IBD group (63 %, 657/1047) (p = 0.007)., Conclusion: The proportion of csPCa at pathology and positive predictive value of abnormal MR for csPCa were lower in patients with IBD group compared to Non-IBD group., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Approximately 25% of Inflammatory Bowel Disease (IBD) patients present before the age of 18 years; early-onset IBD is defined as disease presenting before 10 years of age. Although early-onset disease is rare, it presents a particular challenge both in terms of treatment and diagnosis. There is a strong genetic component to these diseases and it is now possible to identify specific genetic mutations associated with certain patterns of early-onset IBD. All of these children require specific clinical work-up that is often performed at specialist centres. Young children with IBD, present a particular challenge to the radiologist because conventional bowel imaging techniques such as MR Enterography require general anaesthetic and other techniques such as CT or fluoroscopy must be carefully considered given the increased susceptibility to radiation in this young patient population. In this paper, we present a review of the aetiology, clinical work-up, differential diagnosis, and latest theories on the genetics of early-onset and very-early onset (<6 years) IBD. We also present our experience in the imaging of these children with particular focus on the difficulties and nuances that this group present to the radiologist., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Paediatric magnetic resonance enterography (MRE) has been increasingly employed in the evaluation of inflammatory bowel disease (IBD) in the past decade. This is in parallel with a global rise in paediatric-onset IBD, greater recognition of the hazards of ionizing radiation, especially in children, and improved treatment options. MRE is now the reference standard for assessing the small bowel in suspected or proven paediatric IBD, and is central to the diagnosis of Crohn's disease (CD), helping distinguish it from ulcerative colitis. This review will discuss the standard and advanced techniques applied in paediatric MRE to define the presence, extent and severity of intestinal IBD, and increasingly colonic and perianal disease. Its role in demonstrating enteric and extra-enteric disease and characterizing this as active inflammation and/or damage will be explored, including the utility of cinematic, diffusion weighted and magnetization transfer imaging. While MRE is increasingly used to guide medical versus surgical management, considerable overlap exists between conventional MRE imaging features for inflammation and damage, as reflected pathologically, which is driving ongoing research. Paediatric MRE-based scoring systems for CD are currently under development that will further consolidate the role of MRE in paediatric IBD, reinforced by implementation of standardized analysis, interpretation and reporting. As an imaging biomarker, MRE performs well when referenced against endoscopy and clinical biomarkers for evidence of mucosal healing, the current treatment goal. MRE is anticipated to have even greater impact as an imaging biomarker through demonstration of transmural disease and healing, not amenable to endoscopic assessment., (Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.)

Quantitative imaging is a crucial component of the assessment of therapies that target the vasculature of angiogenic or inflamed tissue. Dynamic contrast-enhanced ultrasound (DCE-US) using microbubble contrast offers the advantages of being sensitive to perfusion, non-invasive, cost effective and well suited to repeated use at the bedside. Uniquely, it employs an agent that is truly intravascular. This papers reviews the principles and methodology of DCE-US, especially as applied to anti-angiogenic cancer therapies. Reproducibility is an important attribute of such a monitoring method: results are discussed. More recent technical advances in parametric and 3D DCE-US imaging are also summarised and illustrated., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Ultrasound is a widely available, cost-effective, real-time, non-invasive and safe imaging modality widely used in the clinic for anatomical and functional imaging. With the introduction of novel molecularly-targeted ultrasound contrast agents, another dimension of ultrasound has become a reality: diagnosing and monitoring pathological processes at the molecular level. Most commonly used ultrasound molecular imaging contrast agents are micron sized, gas-containing microbubbles functionalized to recognize and attach to molecules expressed on inflamed or angiogenic vascular endothelial cells. There are several potential clinical applications currently being explored including earlier detection, molecular profiling, and monitoring of cancer, as well as visualization of ischemic memory in transient myocardial ischemia, monitoring of disease activity in inflammatory bowel disease, and assessment of arteriosclerosis. Recently, a first clinical grade ultrasound contrast agent (BR55), targeted at a molecule expressed in neoangiogenesis (vascular endothelial growth factor receptor type 2; VEGFR2) has been introduced and safety and feasibility of VEGFR2-targeted ultrasound imaging is being explored in first inhuman clinical trials in various cancer types. This review describes the design of ultrasound molecular imaging contrast agents, imaging techniques, and potential future clinical applications of ultrasound molecular imaging., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To evaluate the accuracy of quantitative analysis of bowel wall enhancement in inflammatory bowel disease (IBD) with contrast enhanced ultrasound (CEUS) by comparing the results with vascular density in a biopsy sample from the same area of the intestinal tract, and to determine the usefulness of this analysis for the prediction of disease activity., Materials and Methods: This prospective study was approved by our institute's ethics committee and all patients gave written informed consent. We enrolled 33 consecutive adult patients undergoing colonoscopy and biopsy for IBD. All patients underwent CEUS and the results were quantitatively analyzed. Vessel count per high-power field on biopsy specimens was compared with colonoscopy, baseline ultrasonography, and CEUS findings, and with analysis of peak intensity, time to peak, regional blood volume, mean transit time, and regional blood flow. Results in patients with high and low vascular density were compared using Fisher's test, t-test, Pearson's correlation test, and receiver operating characteristic curve (ROC) analysis. Cutoff values were determined using ROC analysis, and sensitivity and specificity were calculated., Results: High vascular density (>265 vessels per field) on histological examination was significantly correlated with active disease on colonoscopy, baseline ultrasonography, and CEUS (p<.0001). Quantitative analysis showed a higher enhancement peak, a shorter time to peak enhancement, a higher regional blood flow and regional blood volume in patients with high vascular density than in those with low vascular density. Cutoff values to distinguish between active and inactive disease were identified for peak enhancement (>40.5%), and regional blood flow (>54.8 ml/min)., Conclusion: Quantitative analysis of CEUS data correlates with disease activity as determined by vascular density. Quantitative parameters of CEUS can be used to predict active disease with high sensitivity and specificity., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

CT colonography (CTC), or virtual colonoscopy, is a non-invasive imaging method that uses CT data sets combined with specialized imaging software to examine the colon. CTC is not used routinely in patients with inflammatory bowel disease (IBD). However, investigating contemporarily the colon, other abdominal organs and the peritoneum with CTC is at times useful in patients with IBD, especially when other diagnostic tools fail. Furthermore, since symptoms of colorectal cancer sometimes superimpose to those of inflammatory disease, it may happen to image patients with IBD incidentally. If clinical signs are suggestive for inflammatory disease, exam technique should be modified accordingly and distinguishing radiological findings searched for.

Intestinal US has to be performed very accurately, to obtain an exploration of both small bowel and cholical loops that will be the most complete that is possible; so, this technique requires adequately trained operators. Convex and linear probes with frequency between 3.5 and 7.5 MHz are used: the first ones for the panoramic evaluation and to study the middle-distal sigma and rectum; the second ones to perform a detailed examination of the bowel wall. US allows to evaluate not only the thickness and structure of the bowel wall, but also the content and peristalsis of the loops, their compressibility and movability, the perivisceral spaces and the abdominal organs. In Crohn's disease, US, completed everytime by the color-power-Doppler, shows wall thickening until 20 mm and above, with multi-stratified structure that could be regular, or more and more altered until the hypoechogenic view; the bowel vascularisation could be absent or less or more increased, due to the stadium of the disease itself. Furthermore, US allows to demonstrate the presence of stenosis and various other complications (abscesses inside or outside the walls, fistulas, involvement of other organs, free fluid collections); the use of II generation US contrast media could afford information about the activity of the disease. US has a very important role in the follow-up of patients with diagnosis of Crohn's disease, to monitor the response to the medical therapy and to discover complications; US must be performed as first in subjects with abdominal pain and diarrhea, to select the ones that need more invasive examinations.

Purpose: To evaluate routine use of CT Enterography (CTE) in patients presenting with non-traumatic acute abdominal pain with respect to patient tolerance, imaging of intestinal detail along with conventional abdominal evaluation., Materials and Methods: Modified CTE was performed in 165 consecutive patients with acute abdominal pain: ingestion, as tolerated, of 900-1200 ml of 2% barium suspension + 5 ml of Gastrografin over 45 min; 150 ml of iv contrast given in two boluses (50 and 100 ml) 3 min apart (split bolus injection protocol). Axial, coronal and sagittal reformats were reviewed by two radiologists and graded on a 5-point scale (5 best) in regard to GI tract luminal opacification and distension and abdominal organ and vascular enhancement., Results: In 81 patients the cause of abdominal pain was identified (intestinal in 54 and extraintestinal in 27). Oral contrast reached cecum in 76% of the patients and the small bowel was well distended and opacified (medians=4). Mucosa detail was good (median=3) and there was significant (p<0.0001) correlation between bowel opacification and distension for both jejunum and ileum. A combined nephrographic and excretory phase was achieved (medians 4 and 5, respectively), while the great vessels were well opacified, allowing for vascular evaluation (median=5). The rest of the abdominal structures were well visualized., Conclusion: Modified CTE is well tolerated by patients with acute non-traumatic abdominal pain, and can be used routinely as a non-invasive examination informative of bowel, vessel and organ pathology in Emergency Department patients.

Inflammatory changes of the intestine leading to acute abdomen could represent a frequent diagnostic challenge for radiologists actively involved in the emergency area. MDCT imaging findings needs to be evaluated considering the clinical history and symptoms and other abdominal findings that could be of help in differential diagnosis. Several protocols have been suggested and indicated in the imaging of patient with acute intestine. However, a CT protocol in which the precontrast scanning of the abdomen is followed by i.v. administration of contrast medium using the 45-55 s delay could be effective for an optimal visualization of the bowel wall. It is important to learn to recognize how the intestine reacts to the injury and how it "talks", in order to become aware of the different patterns of disease manifestation related to an acute intestinal condition, for an effective diagnosis of active and acute inflammatory bowel disease.

Colorectal perforation is an emergent medical condition in which the diagnosis and the etiology are often established on CT, the common imaging modality used for evaluating the acute abdomen. The cardinal, direct CT features suggesting perforation are extraluminal air and enteric contrast, added by secondary signs of bowel pathology, such as focal bowel wall thickening and bowel wall defect. This pictorial review will illustrate the CT findings of colorectal perforation caused by various clinical entities.

The colon is affected by a number of diseases, mainly inflammatory, ischemic, and neoplastic conditions. Depending upon clinical indications endoscopy, US, CT, or other radiological methods are used for evaluation. The fact that US is frequently used as the initial imaging method in patients with non-specific clinical symptoms allows for greater influence in further diagnostic evaluation and with treatment, provided the investigator is familiar with the features of different intestinal diseases. This article will describe the anatomical characteristics of the colon, the US technique for examination of the colon, and the typical US features of the more common diagnoses of the colon.

Inflammatory bowel disease, including Crohn's disease and UC, is a chronic disorder of the gastrointestinal tract. The inflammatory process in UC is confined to the mucosa and submucosa and it involves only the colon. In contrast, in Crohn's disease the inflammation process extends through the bowel wall layers and it can involve any part of gastrointestinal tract. Moreover, inflammatory bowel disease of the colon may be associated with complications, such as toxic megacolon, fulminant colitis, acute bleeding, fistulas and abscesses. Radiographic imaging studies are useful for the diagnosis of inflammatory bowel disease, and may be used to assess the extent and severity of disease, rule out complications, and monitor the response to therapy. The double-contrast barium study is a valuable technique for diagnosing inflammatory bowel disease colonic alterations, even in patients with early mucosal abnormalities. The earliest finding of UC is characterized by a fine granular appeareance of the colonic mucosa, usually involving the rectosigmoid junction. In chronic UC double-contrast enema may reveal marked colonic shortening with tubular narrowing of the bowel and loss of haustration. The earliest radiographics findings of Crohn's disease are represented by aphthous ulcers. As disease progresses, aphthous ulcers may enlarge and coalesce to form stellate or linear areas of ulceration. In advanced Crohn's disease, transmural ulceration may lead to the development of fissures, sinus tracts, fistulas, and abscesses. Cross sectional studies such as computed tomography, magnetic resonance imaging and sometimes ultrasound, are useful alternative tools not only in the assessment of bowel wall abnormalities, but also for the assessment of extraluminal alterations in patients with advanced disease.

Unlabelled: The diagnosis of inflammatory bowel disease (IBD) needs a complex diagnostic work-up. Beside verifying the disease itself, it is fundamental to assess disease extent and activity and to detect associated complications, to find the most effective treatment and for follow up. Scintigraphy with radiolabelled leukocytes is able to provide a complete survey of the whole intestinal tract, both the small and large bowel, and detects septic complications successfully with negligible risk. Radionuclide procedures are useful in establishing or ruling out IBD in patients with intestinal complaints, in assessing disease severity, and in the evaluation of extraintestinal septic complications. Widely available radionuclide procedures are discussed, i.e. scintigraphy by 111Indium oxime or 99mTechnetium HMPAO labelled white blood cells and immunoscintigraphy with 99mTc anti-granulocyte antibodies. Advantages and disadvantages of all three methods are stressed out., Patients and Methods: The immunoscintigraphies with 99mTc anti-granulocyte antibodies (ANTI-GRANULOCYTE(R) BW 250/183) of 27 patients with suspicion of IBD were retrospectively analysed. Planar anterior and posterior images were obtained 4 and 24 h postinjection, respectively. The bowel was divided into six segments and the activity was visually graded with reference to bone marrow in each segments. The scans were compared with the results of radiological and endoscopical investigations. The diagnosis of IBD was proved or ruled out by means of enteroclysis, large bowel enema or endoscopy., Results: In the 27 patients, 74 bowel segments with increased activity were detected. In the case of 30 segments in 16 patients, bowel inflammation was revealed by the other methods (true positives). In the case of 44 bowel segments, no underlying bowel inflammation could be verified, and these activities were regarded as aspecific activity. We could not differentiate between true positive and aspecific activity based on scan pattern or intensity., Discussion: These findings of aspecific bowel activity using imuunoscintigraphy are in contrast with the results of former studies, while the existence of non-specific activity decreases the reliability of the method. Based on the literature and our experiences, we conclude that 99mTc HMPAO labelling should be the method of choice for the investigation of IBD patients.

The usefulness of 99mTc-nanocolloid for the assessment of localization and disease activity of colitis in patients suffering from inflammatory bowel disease (IBD) was investigated in 10 patients. Results of 99mTc-nanocolloid scintigraphy were compared with Indium-111 autologous granulocyte scintigraphy and the activity index according to Van Hees. In none of the patients a true positive result of the 99mTc-nanocolloid scintigraphy was encountered, while 111In-granulocyte scintigraphy was positive in 7 of 10 patients with active disease. Radioactivity became visible in the small bowel starting 2 h after injection of 99mTc-nanocolloid most likely because of excretion by the liver of degradation products of the radiopharmaceutical. The authors conclude that despite a previous communication 99mTc-nanocolloid cannot replace 111In-granulocytes for the assessment of IBD patients with active colitis.