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Objective: The aim was to provide a more efcient and tolerable oral contrast agent for bowel distension with fewer side efects due to its pH-sensitive nature. Methods: Mixtures of uncoated powder and enteric-coated granule forms of locust bean and xanthan gum (LBXG, 1:1 ratio) were developed. Locust bean and xanthan gum and commercially available oral contrast agents were examined using 3-tesla MR and MDCT units to determine imaging characteristics. In addition, LBXG was tested in a rabbit by a 3-tesla MR system. Results: Enteric-coated LBXG had a minimum of 10 times water absorption and swelling in the intestinal environment (pH 4.5-7.4). The lactulose solution was hyperdense, and the other contrast agents (including LBXG) were isodense on CT images. Methylcellulose solutions showed clumping in all environments despite sufcient shaking, and this type of clumping was not observed in other solutions. All solutions were hypointense on T1-weighted images and hyperintense on T2-weighted MR images. Although the enteric-coated LBXG granules were homogeneously soluble in water and an alkaline environment, they did not dissolve and precipitated in the acidic bufer despite sufcient shaking. LBXG showed biphasic character on MR images of the rabbit. Conclusion: Enteric-coated LBXG granules may be an efective oral contrast agent for enterography examinations. Because of its target-specifc nature, it may provide fewer side efects and a higher diagnostic efciency/toleration capacity. It can be used for enterography exams and bowel cleansing before enterography, endoscopy, and/or surgery. [ABSTRACT FROM AUTHOR]

Crohn disease is an inflammatory condition of the gastrointestinal tract with episodes of exacerbation and remission occurring in children, adolescents, and adults. Crohn disease diagnosis and treatment depend upon a combination of clinical, laboratory, endoscopic, histological, and imaging findings. Appropriate use of imaging provides critical information in the settings of diagnosis, assessment of acute symptoms, disease surveillance, and therapy monitoring. Four variants are discussed. The first variant discusses the initial imaging for suspected Crohn disease before established diagnosis. The second variant pertains to appropriateness of imaging modalities during suspected acute exacerbation. The third variant is a substantial discussion of recommendations related to disease surveillance and monitoring of Crohn disease. Finally, panel recommendations and discussion of perianal fistulizing disease imaging completes the document. 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. [ABSTRACT FROM AUTHOR]

Purpose of Review: The purpose is to provide a review of cross-sectional imaging updates in the assessment of gastrointestinal diseases, relevant to clinical practice and research. Recent Findings: New magnetic resonance imaging contrast agents (Eovist) are taken up by hepatocytes and excreted via the biliary tree. As such, a lesion will retain contrast only if hepatocytes are present, which aids in refining the differential diagnosis. Magnetic resonance enterography is a method for non-invasively diagnosing and following various GI conditions, predominantly inflammatory bowel disease. Contrast-enhanced ultrasound uses gas-filled microbubbles providing superb temporal resolution most notably in the arterial phase, which aids in differentiating lesions. Elastography is a new technique which assesses stiffness of liver for evaluating fibrosis. Summary: These new techniques provide more accurate diagnoses and information, often limiting ionizing radiation exposure from other modalities. While ultrasound will still remain the initial imaging modality, familiarity with these other options is valuable for appropriate pathology workup. [ABSTRACT FROM AUTHOR]

Objectives: To assess the accuracy of Magnetic Resonance Enterography (MRE) in determining site, extent and complications of Crohn’s disease, in correlation with capsule endoscopic and colonoscopy findings. Patients and methods: We performed an observational prospective study for 30 patients with suspected Crohn’s disease or already diagnosed patients with Crohn’s disease (CD). Bowel inflammatory changes were analyzed for each involved bowel segment. Associated lymph nodes, abscesses, and fistulas were also evaluated. Results: MRE was diagnostic for small bowel inflammatory changes with sensitivity and specificity values of 76% and 90% respectively as compared to 80% and 88% for capsule endoscopy, with an overall accuracy of 83% as compared to capsule endoscopy. For large bowel inflammatory changes, MRE showed sensitivity and specificity values of 82% and 80% respectively as compared to 84% and 85% for colonoscopy, with an overall accuracy of 81% as compared to colonoscopy. All severely inflamed segments were correctly identified, and there were no false positive findings in this study. Conclusion: MRE is practicable, non-invasive and provides additional information regarding areas not accessible with endoscopy.

Purpose: The purpose was to find an oral contrast agent that can be utilized in MRI of the small bowel and fulfill the following criteria: natural, with no or minimal side effects, non-expensive, causes the maximum bowel distension and has the best imaging quality with no artifacts. Methods: Fourteen healthy volunteers were included. Each volunteer underwent 3 MRI examinations on different days using 3 different oral contrast materials; water, milk and pineapple juice. Coronal T2WI MRI was done at KAUH Diagnostic Radiology department. Standardized questionnaire was used to study post-MRI abdominal complaint. Statistical analysis was done using SPSS program version 17.0. Results: All tested contrast agents could significantly distend the small bowel loops with the p value

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract that can affect any part of the gastrointestinal tract from the mouth to the anus. It typically involves multiple discontinuous sites, with a tendency toward remission and relapse. Abdominal symptoms may be nonspecific and can result from active inflammation or from fibrotic scarring and stricture formation. Activity assessment of the disease is important to optimize the therapy. MR enterography has a high soft-tissue contrast so it plays an important role in management of the patient with Crohn disease. It can differentiate active inflammation from chronic fibrosis and strictures and advance the patient to a more aggressive pharmacologic therapy or to surgical intervention if a significant stricture is found. [ABSTRACT FROM AUTHOR]

Objectives To assess the accuracy of Magnetic Resonance Enterography (MRE) in determining site, extent and complications of Crohn’s disease, in correlation with capsule endoscopic and colonoscopy findings. Patients and methods We performed an observational prospective study for 30 patients with suspected Crohn’s disease or already diagnosed patients with Crohn’s disease (CD). Bowel inflammatory changes were analyzed for each involved bowel segment. Associated lymph nodes, abscesses, and fistulas were also evaluated. Results MRE was diagnostic for small bowel inflammatory changes with sensitivity and specificity values of 76% and 90% respectively as compared to 80% and 88% for capsule endoscopy, with an overall accuracy of 83% as compared to capsule endoscopy. For large bowel inflammatory changes, MRE showed sensitivity and specificity values of 82% and 80% respectively as compared to 84% and 85% for colonoscopy, with an overall accuracy of 81% as compared to colonoscopy. All severely inflamed segments were correctly identified, and there were no false positive findings in this study. Conclusion MRE is practicable, non-invasive and provides additional information regarding areas not accessible with endoscopy. [ABSTRACT FROM AUTHOR]

• Hybrid PET/MR imaging may be superior to conventional MR or PET/CT imaging in visualizing disease activity in inflammatory bowel diseases. • Standardization of technical aspects of imaging is of paramount importance in ensuring the reproducibility of imaging outputs. • PET/MR imaging could contribute to follow up of patients with IBD, with determining probability of response to treatment and providing prognostication about long term clinical outcome. 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. [ABSTRACT FROM AUTHOR]

Aim: To assess the impact of an extended oral preparation magnetic resonance (MR) enterography protocol on bowel distension, timing of imaging, and the quality of diagnostic images. Materials and Methods: An analysis of 52 patients who underwent divided oral preparation and 39 patients who underwent standard preparation for MR enterography examination was done. Distension was assessed by measuring the transverse diameters of the jejunum, ileum, and the ileocecal region. Diagnostic quality of the examination was assessed subjectively by two radiologists and graded as poor, diagnostic, and excellent (Grades 1-3). Correlation between bowel diameter and diagnostic quality was assessed using regression analysis. Results: The mean diameters of the jejunum, ileum, and colon in patients who underwent divided preparation were 1.90 ± 0.47, 2.14 ± 0.41, and 4.27 ± 0.96 cm, respectively, and the mean diameters in patients who underwent standard preparation were 1.46 ± 0.47, 2.02 ± 0.47, and 4.45 ± 0.90 cm, respectively. A total of 96.6% of patients on divided dose had diagnostic distension of the bowel (Grades 2 and 3). A total of 87.9% of the patients on standard dose had diagnostic distension of the bowel (Grades 2 and 3). A greater number of patients who underwent divided preparation had diagnostic quality examinations compared to those given standard preparation (96.6% vs. 87.9%). A greater number of patients who underwent divided preparation had Grade 3 quality examinations compared to those on standard preparation (75.5% vs. 68.5%). There was significant difference between diagnostic (Grades 2 and 3) and optimal grades (Grade 3) of the jejunal diameters in patients having divided or standard preparation (89.7% vs. 66.6%, P < 0.05; 40.8% vs. 25%, P < 0.05, respectively). Linear regression showed a positive correlation between increasing bowel diameter and diagnostic grade of the examination (ρ = 0.76). Conclusion: Using an extended oral preparation with divided dose resulted in the majority of patients being scanned in a single visit to the MRI suite. Dividing the oral contrast into aliquots can promote uniform distension of the entire small bowel and provide better bowel distension and improve the diagnostic quality.

Purpose To evaluate the fused, colorized diffusion weighted imaging (DWI) and anatomic T2 images compared to routine contrast-enhanced T1 images at pediatric magnetic resonance enterography (MRE). Methods Fused, colorized DWI/T2 images were created from patients with magnetic resonance enterography (MRE) and colonoscopy/biopsy. Radiologists noted inflammation in five bowel segments (terminal ileum–rectosigmoid colon) on postcontrast images and DWI/T2 images. Test characteristics and agreement were calculated. Results For 20 patients, sensitivity/specificity/positive predictive value (PPV)/negative predictive value (NPV) were 0.53/0.90/0.77/0.76 for DWI/T2 and 0.45/0.90/0.72/0.73 for postcontrast images. Intraobserver agreement was ҡ=0.45–0.73. Interobserver agreement was ҡ=0.53 for DWI/T2 and ҡ=0.63 for postcontrast images. Conclusion DWI/T2 images are similar in sensitivity/specificity to contrast-enhanced images and with moderate intra/interobserver reliability. [ABSTRACT FROM AUTHOR]

Objective The objective was to show efficiency of magnetic resonance enterography (MRE) with our previously assessed new oral contrast agent. Materials and methods Each bowel segments was evaluated for luminal distension, wall conspicuity, wall thickening, and hyperintensity on fat-saturated (FS) T2-weighted and contrast enhancement on postcontrast FS T1-weighted images. Also, consensus scoring results of MRE exams were compared with the gold standard tests in terms of active inflammatory bowel disease detection. Results Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of MRE for active inflammatory bowel disease detection were 62%, 98%, 80%, 96%, and 71.4%, respectively. Conclusion MRE obtained with the new mixture has a high reliability and shows good correlation with endoscopic examination ± biopsy. [ABSTRACT FROM AUTHOR]

Purpose The purpose was to find an oral contrast agent that can be utilized in MRI of the small bowel and fulfill the following criteria: natural, with no or minimal side effects, non-expensive, causes the maximum bowel distension and has the best imaging quality with no artifacts. Methods Fourteen healthy volunteers were included. Each volunteer underwent 3 MRI examinations on different days using 3 different oral contrast materials; water, milk and pineapple juice. Coronal T2WI MRI was done at KAUH Diagnostic Radiology department. Standardized questionnaire was used to study post-MRI abdominal complaint. Statistical analysis was done using SPSS program version 17.0. Results All tested contrast agents could significantly distend the small bowel loops with the p value <0.05. Pineapple juice could distend up to 5 segments in 7 volunteers. Good image quality was depicted in 50% of volunteers using juice, while water showed the worst results where 75% had bad image quality. The highest percentage of image artifacts was found with milk (64.3%). Conclusion Pineapple juice has the highest ability of bowel distention and good image quality with insignificant image artifacts and no reported side effects. [ABSTRACT FROM AUTHOR]

Objectives To assess if erythromycin increases gastric emptying and hence improves small intestinal distention during MR enterography. Methods Gastric, small intestinal, and large intestinal volumes were assessed with MR after neutral oral contrast (1350 ml in 45 min) and balanced randomization to erythromycin (200 mg i.v., age 31 ± 3y, 13 females), or placebo (37 ± 3y, 13 females) in 40 healthy asymptomatic volunteers. Fat-suppressed T2-weighted MR images of the abdomen were acquired on a 1.5 T magnet at standard delay times for enterography. Gastric, small, and large intestinal volumes were measured by specialized software. In addition, two radiologists manually measured diameters and percentage distention of jejunal and ileal loops. Treatment effects were evaluated by an ITT analysis based on ANCOVA models. Results All subjects tolerated erythromycin. MRI scans of the stomach and intestine were obtained at 62 ± 2 (mean ± SEM) and 74 ± 2 min respectively after starting oral contrast. Gastric volumes were lower ( P < 0.0001) after erythromycin (260 ± 49 ml) than placebo (688 ± 63 ml) but jejunal, ileal, and colonic volumes were not significantly different. However, maximum (76–100%) jejunal distention was more frequently observed ( P = 0.03) after erythromycin (8/20 subjects [40%]) than placebo (2/20 subjects [10%]). The diameter of a representative ileal loop was greater ( P = 0.001) after erythromycin (18.8 ± 4.3 mm) than placebo (17.3 ± 2.8 mm) infusion. Conclusions After ingestion of oral contrast, erythromycin accelerated gastric emptying but effects on small intestinal dimensions were variable. In balance, erythromycin did not substantially enhance small intestinal distention during enterography using current standard delay times. [ABSTRACT FROM AUTHOR]

Crohn's disease is a chronic inflammatory bowel disease (IBD) that can affect the entire GI tract, and adequate visualization of the small bowel is imperative for both diagnosis and management. Magnetic resonance and computed tomography enterography have gradually replaced barium-based studies. Magnetic resonance enterography has the distinct advantage of avoiding ionizing radiation to which many patients with IBD are overexposed. Endoscopy-based techniques, including capsule endoscopy and device-assisted enteroscopy, allow direct visualization of the small bowel mucosa. Deep enteroscopy has the additional benefit of allowing sampling of the mucosa for histological analysis. Small intestine contrast ultrasound is rapidly gaining credence as an excellent, radiation-free imaging technique, but is not available in all countries. Other imaging modalities, such as positron emission tomography and leucocyte scintigraphy, continue to be studied and may have a role in specific circumstances. This review summarizes the evidence for the various techniques for evaluating the small bowel in IBD. [ABSTRACT FROM AUTHOR]

Aim: To assess the impact of an extended oral preparation magnetic resonance (MR) enterography protocol on bowel distension, timing of imaging, and the quality of diagnostic images. Materials and Methods: An analysis of 52 patients who underwent divided oral preparation and 39 patients who underwent standard preparation for MR enterography examination was done. Distension was assessed by measuring the transverse diameters of the jejunum, ileum, and the ileocecal region. Diagnostic quality of the examination was assessed subjectively by two radiologists and graded as poor, diagnostic, and excellent (Grades 1-3). Correlation between bowel diameter and diagnostic quality was assessed using regression analysis. Results: The mean diameters of the jejunum, ileum, and colon in patients who underwent divided preparation were 1.90 ± 0.47, 2.14 ± 0.41, and 4.27 ± 0.96 cm, respectively, and the mean diameters in patients who underwent standard preparation were 1.46 ± 0.47, 2.02 ± 0.47, and 4.45 ± 0.90 cm, respectively. A total of 96.6% of patients on divided dose had diagnostic distension of the bowel (Grades 2 and 3). A total of 87.9% of the patients on standard dose had diagnostic distension of the bowel (Grades 2 and 3). A greater number of patients who underwent divided preparation had diagnostic quality examinations compared to those given standard preparation (96.6% vs. 87.9%). A greater number of patients who underwent divided preparation had Grade 3 quality examinations compared to those on standard preparation (75.5% vs. 68.5%). There was significant difference between diagnostic (Grades 2 and 3) and optimal grades (Grade 3) of the jejunal diameters in patients having divided or standard preparation (89.7% vs. 66.6%, P < 0.05; 40.8% vs. 25%, P < 0.05, respectively). Linear regression showed a positive correlation between increasing bowel diameter and diagnostic grade of the examination (ρ = 0.76). Conclusion: Using an extended oral preparation with divided dose resulted in the majority of patients being scanned in a single visit to the MRI suite. Dividing the oral contrast into aliquots can promote uniform distension of the entire small bowel and provide better bowel distension and improve the diagnostic quality. [ABSTRACT FROM AUTHOR]

MRI is increasingly advocated as a robust method for quantifying disease activity in Crohn's disease. In particular, T1-weighted gadolinium-enhanced imaging shows considerable promise as a marker of inflammatory activity. However, interpretation of the literature must be made with an understanding of (i) the technical limitations of T1-weighted acquisition protocols and enhancement measurements; (ii) differences in standards of reference for disease activity employed between published studies; and (iii) important underlying macro and micro vascular changes in Crohn's disease. This review will focus specifically on the value of T1-weighted gadolinium-enhanced imaging in the assessment of wall inflammation and fibrosis. [ABSTRACT FROM AUTHOR]

Recently, magnetic resonance imaging has emerged as a valuable tool in evaluation of small bowel Crohn's disease. MRI provides several advantages to other imaging modalities, including the lack of ionizing radiation, multiplanar capability, and functional information. Intravenous contrast administration is a routine portion of MR enterography protocol, and aids in detection of disease extent, extramural complications such as fistula and abscess, and assessment of activity. Additionally, promising techniques such as dynamic contrast-enhanced MRI may provide quantitative measures to assess bowel perfusion, which may enhance evaluation of disease activity. This article will provide an overview of the technical aspects of contrast-enhanced MR enterography, describe common pathologic findings involving the small bowel in Crohn's disease, summarize its role in determination of activity with an emphasis on endoscopic and histologic correlation, and compare its efficacy with other imaging modalities. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: Patients with known Crohn''s disease (CD) and an acute onset of severe abdominal pain attending an emergency room frequently undergo contrast-enhanced emergency computed tomography (CT) for complication assessment. To assess small bowel changes, an additional dedicated imaging procedure such as magnetic resonance enterography (MRE) is regularly performed. Therefore, these patients undergo two imaging procedures, although the clinical and diagnostic value of such an approach is not known. In a retrospective study, we compared the diagnostic value of a conventional abdominal CT with a dedicated small bowel MRE to assess bowel wall changes as well as typical complications in patients with advanced CD. Materials and Methods: We retrospectively evaluated 53 patients with CD having a conventional abdominal multidetector-CT (MD-CT) and MRE within 2 days. Image quality and bowel inflammation was analyzed for each bowel segment. Lymph nodes, abscesses, and fistulas were evaluated. Results: For small bowel and colon assessment, there was no significant difference for image quality between CT and MRE. Inflammation diagnosis was not significantly different between CT (69.4%) and MRE (71.4%). Colonic inflammation was diagnosed in 30.2% based on CT and 14.3% based on MRE. The difference for the detection of lymph nodes was significant (CT 49; MRE 27), whereas the differences between fistula (CT 25, MRE 27) or abscesses (CT and MRE 32) detection were not significant. Conclusions: In patients with known advanced CD with acute abdominal pain conventional abdominal MD-CT, which is frequently performed as an emergency imaging procedure, is sufficient for bowel wall assessment. Based on our data, additional dedicated small bowel imaging such as MRE seems not to be necessary. [Copyright &y& Elsevier]