Bowel Wall Changes Research Articles

Diffusion-weighted imaging in Crohn's disease.

Diffusion-weighted MRI (DWI) is routinely used in abdominal imaging. In addition to neoplastic diseases, inflammatory changes can be delineated and diagnosed based on diffusion restriction in DWI. DWI is also increasingly used in the context of MRI of the small and large intestine. This article focuses on the technical aspects of DWI and its role in the diagnosis of Crohn's disease (CD) as well as in the grading of disease severity and in treatment monitoring. Guidelines, basic research papers, and review articles were analyzed. Diffusion-weighted MRI is aspecialized MRI technique that visualizes the diffusion of water molecules in biological tissues. In the context of MRI of the small and large intestine, DWI facilitates the diagnosis of inflammatory bowel disease and assessment of treatment response. DWI enables detection of not only intra- and transmural changes, but also extramural pathologies and complications. However, DWI also has its limitations and challenges. This article provides acomprehensive overview of the use of DWI for diagnostic evaluation of bowel wall changes and extramural complications in the setting of CD. It also summarizes the relevant evidence available in the literature.

Magnetresonanz-Enterographie/Enteroklysma

Magnetic resonance enterography/enteroclysma (MRE) is an examination technique without ionizing radiation that allows assessment of bowel wall changes and extraluminal pathologies/complications such as in chronic inflammatory bowel diseases, among others. To discuss requirements for optimal MR imaging of the small bowel, technical basis of MRE and principles for the development and optimization of aMRE protocol, and clinical indications for this specific imaging technique. Guidelines, basic and review papers will be analyzed. MRE enables the diagnosis of inflammatory bowel diseases and neoplasms and their evaluation during therapy. In addition to intra- and transmural changes, extramural pathologies and complications can also be detected. Standard sequences include steady-state free precession sequences, T2-weighted single-shot fast spin echo sequences, and three-dimensional (3D) T1-weighted gradient echo (GRE) sequences with fat saturation after contrast administration. Prior to image acquisition, optimal patient preparation and distension of the bowel using intraluminal contrast agents is necessary. Careful patient preparation for MRE, understanding of optimal imaging technique, and appropriate clinical indications are essential to achieve high-quality images of the bowel for accurate assessment and diagnosis as well as therapy monitoring of small bowel disease.

Computed tomography and magnetic resonance imaging of colonic diseases

Early diagnosis of aluminal colonic disease is of essential clinical importance to start timely optimised therapy and detect complications early. This paper aims to provide an overview of the use of radiological methods in diagnosing neoplastic and inflammatory luminal diseases of the colon. Characteristic morphological features are discussed and compared. Based on an extensive literature review, the current state of knowledge regarding the imaging diagnosis of luminal pathologies of the colon and their importance in patient management is presented. Technological advances in imaging have made the diagnosis of neoplastic and inflammatory colonic diseases using abdominal computed tomography and magnetic resonance imaging the established standard. Imaging is performed as part of the initial diagnosis in clinically symptomatic patients, to exclude complications, as afollow-up assessment under therapy and as an optional screening method in asymptomatic individuals. Accurate knowledge of the radiological manifestations of the numerous luminal disease patterns, the typical distribution pattern and characteristic bowel wall changes are essential to improve diagnostic decision-making.

Comprehensive Evaluation and Unique Morphologic Features of Nonsteroidal Anti-Inflammatory Drug (NSAID) Enteropathy in the Terminal Ileum.

Differentiating NSAID enteropathy from Crohn disease can be challenging on terminal ileum biopsy. It is important to distinguish these two entities for management. In this study, clinical, radiographic, endoscopic, and histologic features of 30 patients diagnosed with NSAID enteropathy and 30 patients diagnosed with Crohn disease on terminal ileal biopsy were compared. None of the patients in the NSAID cohort demonstrated significant changes on imaging performed prior to biopsy. Depending on disease severity, patients with Crohn disease showed imaging findings ranging from minimal changes to significant bowel wall and/or luminal changes. Endoscopically, erythema, erosions, and/or ulcers in the terminal ileum were observed in a majority of NSAID cases. Patients with active Crohn disease were noted to have erythema, ulcers, strictures, and/or visible inflammation throughout the distal ileum and colon. Histologically, at least 80% of cases in each cohort showed ulceration/erosion and cryptitis/crypt abscesses. The Crohn disease cohort had significantly higher degree of lymphoplasmacytic inflammation in the lamina propria compared to the NSAID cohort. In contrast, a significantly higher percentage of the NSAID cohort had gland/crypt atrophy. A decrease in number of Paneth cells was found in the NSAID cohort. Decreased lamina propria lymphoplasmacytic inflammation was the most specific and the presence of gland atrophy the most sensitive feature favoring NSAID enteropathy. In summary, the combination of gland/crypt/Paneth cell atrophy with decreased lamina propria lymphoplasmacytic inflammation can aid in differentiating NSAID enteropathy from Crohn disease in terminal ileal biopsies; however, correlation with clinical, radiographic, and endoscopic findings is still required.

Correlation of CT findings with intra-operative outcome in closed-loop small bowel obstruction (CL-SBO)

PurposeTo correlate CT-findings in patients with closed-loop small bowel obstruction (CL-SBO) with perioperative findings, to identify patients who require immediate surgical intervention. Secondary purpose was to substantiate the role of radiologists in predicting perioperative outcome. MethodsData were retrospectively obtained from patients with surgically confirmed CL-SBO, between September 2013 and September 2019. Three radiologists reviewed CTs to assess defined CT features and predict patient outcome for bowel wall ischemia and necrosis using a likelihood score. Univariate statistical analyses were performed and diagnostic performance parameters and interobserver agreement were assessed for each feature. ResultsOf 148 included patients, 28 (19%) intraoperatively had viable bowel and 120 (81%) had bowel wall ischemia or necrosis. Most CT characteristics, as well as the likelihood of ischemia and necrosis, found fair or moderate multirater agreement. Increased attenuation of bowel wall and mesenteric vessels on non-contrast-enhanced CT had a specificity for bowel ischemia or necrosis of 100% (sensitivity respectively 48% (p < 0.001) and 21% (p = 0.09)). Mesenteric edema had high sensitivity for ischemia or necrosis (90%), but specificity of only 26% (p < 0.001). For mesenteric fluid, sensitivity was 60% and specificity 57% (p = 0.004). Decreased enhancement of bowel wall in both arterial and PV-phase showed significant correlation, respectively a sensitivity of 58% and 42%, and specificity of 88% and 79% (both p < 0.001). Likelihood of both ischemia and necrosis were significantly correlated with perioperative outcome (p < 0.001). ConclusionCT findings concerning mesenteric and bowel wall changes, as well as radiologists’ judgement of likelihood of ischemia and necrosis are significantly correlated with perioperative outcome of bowel wall ischemia and necrosis in patients with CL-SBO.

Use of Small Bowel Ultrasound to Predict Response to Infliximab Induction in Pediatric Crohn's Disease.

The goal of this study was to explore the utility of small bowel ultrasound (SBUS) as a noninvasive tool to assess induction response to infliximab (IFX) in pediatric Crohn's disease (CD). Inflammatory bowel disease management has shifted to a treat-to-target and tight control strategy utilizing noninvasive serum and fecal markers to monitor disease activity in response to therapy. Bowel wall changes as seen on cross-sectional imaging may be a more accurate marker of treatment success. Pediatric patients with CD with small bowel involvement initiating IFX were prospectively enrolled. Clinical activity, biomarkers, and SBUS findings were evaluated at baseline (T0) and postinduction at week 14 (T1). The primary outcome was to describe the changes in SBUS parameters pre and post IFX induction and how they associate with clinical and biomarker response. Descriptive statistics summarized the data and univariate analysis tested associations. All 13 CD patients achieved steroid-free clinical remission (P<0.001) and a decrease in C-reactive protein (P=0.01) postinduction. Bowel wall hyperemia (BWH) (P=0.01) and bowel segment length involved (P=0.07) decreased postinduction. Decrease in fecal calprotectin at T1 moderately correlated with a decrease in bowel segment length (r=0.57; P=0.04). No correlation was seen with a change in bowel wall thickness or BWH postinduction. Our pilot study suggests that SBUS is a feasible, noninvasive tool to measure early treatment response to IFX. BWH, not bowel wall thickness, is the first parameter to change. Larger longitudinal studies are warranted to validate the utility of SBUS as part of a disease monitoring strategy.

Mesenteric ischemia: can multidetector computed tomography angiography be a one-stop diagnostic solution?

Background Mesenteric ischemia is a medical condition in which inflammation and injury of the small intestine result from inadequate blood supply. Mesenteric ischemia is caused by a reduction in intestinal blood flow and is classified as acute (sudden onset of intestinal hypoperfusion) or chronic depending on the time course of symptoms. Multi Detector Computed Tomography MDCT has high sensitivity and specificity for diagnosing acute primary mesenteric ischemia. Aim and objectives Our objective was to evaluate the role of MDCT angiography in evaluation of patients with suspected mesenteric ischemia as regards vascular and intestinal abnormalities. Patients and methods This prospective study was performed on 60 patients clinically suspected of having mesenteric ischemia, referred to the radiology department of Cairo University hospitals from the emergency hospital and the out-patient clinics and in-patient departments of general surgery and of Endemic Infectious diseases and Hepatogastroenterology. Patients suspected clinically to have mesenteric ischemia were initially examined by Doppler and if showed mesenteric vascular suspicious findings by Doppler, they were referred to CT angiography examination. Results In our study we found that 40 patients (66.7%) out of 60 patients showed abnormal MDCT findings which explained the cause of mesenteric ischemia in these patients. The most prevalent CT findings in 40 patients with positive CT angiographic findings in acute mesenteric ischemia (AMI) were bowel wall thickening in 12 patients (30%), bowel distension in 8 patients (20%) and lack of mural enhancement in 10 patients (25%). Computed tomography angiography (CTA) detected accurately the cause of AMI where arterial thrombo-embolism was common cause of AMI (62.5%) and the SMA was the most frequent site in patients with AMI than mesenteric venous thrombosis with AMI (37.5%). 50% of patients with AMI showed pneumatosis intestinalis and surgical exploration revealed bowel infarction and resection anastomosis was done. Conclusion MDCT is fast, safe, accurate and non-invasive imaging modality of choice in patients with suspected mesenteric ischemia which is able to evaluate not only mesenteric vascular structures but also evaluate bowel wall changes and adjacent mesentery, thus detecting the primary cause of mesenteric ischemia that can lead to earlier diagnosis and intervention, also confirmation or exclusion of various other differential diagnoses of acute abdominal conditions.

The role of multi detector computed tomography in diagnosis of mesenteric vascular occlusion

ObjectiveTo assess the role of multislice computed tomography (MSCT) in the diagnosis of mesenteric vascular occlusion. Patients and methodsThis study was performed on 30 patients clinically suspected and radiologically confirmed to have mesenteric vascular occlusion, they were examined with 64 row MSCT and were evaluated for evidence of bowel wall changes and abnormal mesenteric vascular changes. ResultsWe found that the most prevalent MSCT findings were bowel wall thickening followed by diminished wall enhancement. MSCT gave an accurate diagnosis of the cause of mesenteric vascular occlusion as proved by the final diagnosis based on surgical exploration, laboratory investigations and clinical follow-up. ConclusionMSCT is accurate, fast and non invasive technique which should be used in clinically suspected patients with MVO in order to confirm the diagnosis, identify the aetiology and in addition assessing the bowel loop status for adequate management with good prognosis.

Acute and chronic mesenteric ischemia: Multidetector CT and CT angiographic findings

Aim of the workTo assess the role of multidetector CT (MDCT) and CT angiography (CTA) in the diagnosis of acute and chronic mesenteric ischemia. Patients and methodsThis prospective study was performed on 57 consecutive patients clinically suspected of having mesenteric ischemia, they were examined with 16-row multidetector CT, MDCT and CTA were evaluated for evidence of bowel wall changes and abnormal mesenteric vascular changes. ResultsTwenty one patients of studied 57 patients had an abnormal CTA finding diagnostic of mesenteric ischemia and they constituted the material of this study, the most prevalent MDCT findings were bowel wall thickening, bowel distension and non-enhanced bowel wall. MDCT and CTA gave an accurate diagnosis of the cause of mesenteric ischemia as proved by the final diagnosis based on surgical exploration, conventional angiography, laboratory investigations and clinical follow up with 100% sensitivity and specificity. ConclusionMDCT and CTA are fast, safe, accurate and non-invasive imaging modalities of choice in patients with suspected mesenteric ischemia which are able to evaluate not only mesenteric vascular structures but also evaluate bowel wall changes and adjacent mesentery, thus detecting the primary cause of mesenteric ischemia that can lead to earlier diagnosis and intervention.

CT findings of small bowel strangulation: the importance of contrast enhancement

The purpose of this study is to illustrate computed tomography (CT) findings suggestive of small bowel strangulation. We have performed the precontrast and postcontrast CT with single and multidetector CT scanners and evaluated the bowel wall changes and mesentery changes and correlated them with the operative findings. The direct CT findings suggestive of small bowel strangulation included high-density bowel wall on precontrast scans; lack of, or diminished contrast enhancement of the involved bowel wall; localized mesenteric fluid accumulation (mesenteric congestion); and localized pneumatosis. The indirect CT signs included C- or U-shaped loops with mesenteric vessels converging toward the obstruction site, ascites, target sign, two adjacent collapsed round loops, and whirl sign. We particularly emphasize the importance of contrast enhancement of bowel mucosa for early diagnosis to differentiate strangulation from a mechanical obstruction without bowel ischemia, and also the importance to differentiate proximal secondary gas-filled dilated small bowel loops from distal primary involved fluid-filled small bowel loops because these two types of small bowel loops are present in the single peritoneal cavity. As early recognition of small bowel strangulation may help improve the patient outcome because the involved bowel loops can be preserved without resection, it is essential to become familiar with the CT signs suggested small bowel obstruction strangulation.

Ultrasound Elasticity Imaging for Detecting Intestinal Fibrosis and Inflammation in Rats and Humans With Crohn's Disease

Intestinal fibrosis causes many complications of Crohn's disease (CD). Available biomarkers and imaging modalities lack sufficient accuracy to distinguish intestinal inflammation from fibrosis. Transcutaneous ultrasound elasticity imaging (UEI) is a promising, noninvasive approach for measuring tissue mechanical properties. We hypothesized that UEI could differentiate inflammatory from fibrotic bowel wall changes in both animal models of colitis and humans with CD. Female Lewis rats underwent weekly trinitrobenzene sulfonic acid enemas yielding models of acute inflammatory colitis (n = 5) and chronic intestinal fibrosis (n = 6). UEI scanning used a novel speckle-tracking algorithm to estimate tissue strain. Resected bowel segments were evaluated for evidence of inflammation and fibrosis. Seven consecutive patients with stenotic CD were studied with UEI and their resected stenotic and normal bowel segments were evaluated by ex vivo elastometry and histopathology. Transcutaneous UEI normalized strain was able to differentiate acutely inflamed (-2.07) versus chronic fibrotic (-1.10) colon in rat models of inflammatory bowel disease (IBD; P = .037). Transcutaneous UEI normalized strain also differentiated stenotic (-0.87) versus adjacent normal small bowel (-1.99) in human CD (P = .0008), and this measurement also correlated well with ex vivo elastometry (r = -0.81). UEI can differentiate inflammatory from fibrotic intestine in rat models of IBD and can differentiate between fibrotic and unaffected intestine in a pilot study in humans with CD. UEI represents a novel technology with potential to become a new objective measure of progression of intestinal fibrosis. Prospective clinical studies in CD are needed.

Comparison of high-resolution ultrasound and MR-enterography in patients with inflammatory bowel disease.

To compare the results of high-resolution ultrasound (HR-US) and magnetic resonance enterography (MRE) examinations in patients with inflammatory bowel disease (IBD). The reports of 250 consecutive cases with known IBD, who had an MRE and HR-US examination, were retrospectively analyzed. Using a patient-based approach we evaluated morphological disease features such as affected bowel wall, stenosis, abscess and fistula. The comparison between the two modalities was based on the hypothesis, that any pathological change described in any imaging modality was a true finding, as no further standard of reference was available for complete assessment. Two hundred and fifty examinations representing 207 different patients were evaluated. Both modalities assessed similar bowel wall changes in 65% of the examinations, with more US findings in 11% and more MRE findings in 15%. When the reports were analyzed with regard to "bowel wall inflammation", US reported more findings in 2%, while MRE reported more findings in 53%. Stenoses were assessed to be identical in 8%, while US found more in 3% and MRE in 29% (P < 0.01). For abscess detection, US showed more findings in 2% (n = 4) while MRE detected more in 6% (n = 16). US detected more fistulas in 1% (n = 2), while MRE detected more in 13% (n = 32) (P < 0.001). The most common reason for no detected pathology by US was a difficult to assess anatomical region (lesser pelvis, n = 72). US can miss clinically relevant pathological changes in patients with IBD mostly due to difficulty in assessing certain anatomical regions.

Color Doppler sonography of small bowel wall changes in 21 consecutive cases of acute mesenteric ischemia

To describe the small bowel wall changes observed with color Doppler sonography in acute mesenteric ischemia with comparison with its outcome.

Comparison of Conventional Abdominal CT with MR-Enterography in Patients with Active Crohn's Disease and Acute Abdominal Pain

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. 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. 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. 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.

The evaluation and management of obscure and occult gastrointestinal bleeding

Gastrointestinal (GI) bleeding is a common clinical presentation increasing in an aging population, frequently requiring hospitalization and emergent intervention, with significant morbidity, mortality, and costs. It may manifest overtly as hematemesis, melena, or hematochezia, or as an asymptomatic occult bleed. Management typically involves an esophagogastroduodenoscopy or a colonoscopy; these in combination sometimes do not identify a source of bleeding, with the source remaining obscure. Further work up to identify an obscure source frequently requires radiologically detecting the leakage of an intravascular tracer (using tagged red blood cells or angiography) with brisk bleeding or in other cases CT enterography (CTE) to detect bowel wall changes consistent with a bleeding source. Recent advances including capsule endoscopy, CTE, and double-balloon endoscopy have helped to identify bleeding sources beyond the reach of conventional endoscopy. Clinical decision-making about their use is complex and evolving. Knowing their relative merits and weaknesses including yield, contraindications, complications, and cost is essential in coming up with an appropriate management plan. This review covers the rationale for clinical management of obscure sources of GI bleeding, mentioning the approach to and the yield of conventional methods, with an emphasis on the recent advances mentioned above.

Anastomotic recurrence of Crohn’s disease after ileocolic resection: comparison of MR enteroclysis with endoscopy

The purpose of this study was to assess the accuracy of MR enteroclysis in patients with Crohn's disease recurrence after ileocolic resection and to establish an MR scoring sytem. MR enteroclysis and endoscopy were performed in 30 patients with suspected Crohn's disease recurrence after ileocolic resection. Findings were evaluated by three radiologists, using an MR score based on image quality, contrast enhancement, and mural and extramural bowel-wall changes: MR0 (no abnormal features), MR1 (minimal mucosal changes), MR2 (diffuse aphtoid ileitis, moderate recurrence), and MR3 (severe recurrence with trans- and extramural changes). The endoscopic Rutgeerts score defines changes at the ileum on a scale from I0 to I4. In 3/30 (10%) patients, evaluation was not possible. The mean overall image quality was rated as 1.7 (kappa 0.78). Comparing MR and Rutgeerts score, the mean observer agreement for the total score rating was 77.8% (kappa 0.67). When comparing only scores below or above MR2-the threshold indicative of the necessity of medical treatment-there was a total agreement of 95.1% (kappa 0.84). MR enteroclysis allows assessment of Crohn's disease recurrence after ileocolic resection. The MR score is reproducible and shows high agreement with the approved endoscopic Rutgeerts score.

MRT des Darms bei Kindern - beschleunigte Bildgebung in einem Atemzug

To compare highly accelerated parallel MRI of the bowel with conventional balanced FFE sequences in children with inflammatory bowel disease (IBD). 20 children with suspected or proven IBD underwent MRI using a 1.5 T scanner after oral administration of 700 -1000 ml of a Mannitol solution and an additional enema. The examination started with a 4-channel receiver coil and a conventional balanced FFE sequence in axial (2.5 s/slice) and coronal (4.7 s/slice) planes. Afterwards highly accelerated (R = 5) balanced FFE sequences in axial (0.5 s/slice) and coronal (0.9 s/slice) were performed using a 32-channel receiver coil and parallel imaging (SENSE). Both receiver coils achieved a resolution of 0.88 x 0.88 mm with a slice thickness of 5 mm (coronal) and 6 mm (axial) respectively. Using the conventional imaging technique, 4 - 8 breathholds were needed to cover the whole abdomen, while parallel imaging shortened the acquisition time down to a single breathhold. Two blinded radiologists did a consensus reading of the images regarding pathological findings, image quality, susceptibility to artifacts and bowel distension. The results for both coil systems were compared using the kappa-(kappa)-coefficient, differences in the susceptibility to artifacts were checked with the Wilcoxon signed rank test. Statistical significance was assumed for p = 0.05. 13 of the 20 children had inflammatory bowel wall changes at the time of the examination, which could be correctly diagnosed with both coil systems in 12 of 13 cases (92 %). The comparison of both coil systems showed a good agreement for pathological findings (kappa = 0.74 - 1.0) and the image quality. Using parallel imaging significantly more artifacts could be observed (kappa = 0.47) without impairing the diagnostic impact. The comparison of the bowel distension showed no significant differences. The highly accelerated parallel MRI using the SENSE technique and a 32-channel surface coil enables the examination of the entire bowel in a single breathhold without relevant restrictions in image quality and diagnostic impact.

Endoscopic and external bowel changes and histopathology in patients with Crohn's disease.

The relationships between intraoperative endoscopic findings, exterior bowel wall changes and transmural histopathology were investigated in 23 patients with Crohn's disease (24 resections). Villous atrophy and leucocyte infiltration of the epithelium, lamina propria and submucosa were common in intestine without endoscopic lesions. Minor endoscopic ulcers were associated with leucocyte infiltration, ulcers and pyloric metaplasia, and large endoscopic ulcers and stricture with severe transmural inflammation, fibrosis and fissures. In ileal Crohn's disease (19 resections), correlation was close between endoscopic stage and histopathology (rs = 0.77, P < 0.0001), but an exterior lesion index showed worse correlations with endoscopy and histology (rs = 0.57 and rs = 0.59 respectively). The difference was attributable to patients with previous resection and/or fistula showing exterior lesions without concomitant histological or endoscopic abnormalities. Intraoperative surgical decisions should be guided by endoscopic observations rather than by assessment of exterior bowel wall changes.

MUSCULARIS MUCOSAE, FIBROSIS AND NODULAR LYMPHOCYTE AGGREGATES IN CROHN'S DISEASE – NOVEL ULTRASONOGRAPHIC FINDINGS IN VITRO

Purpose: Transabdominal ultrasound (US) is applied in the examination of patients with Crohn's disease (CD). Advances in US technology enables detailed imaging of the gastrointestinal wall like evaluation of normal and abnormal wall layers and intramural structures. The aim of this study was to improve interpretation of US images of bowel wall changes in CD by comparing US images of bowel resection specimens with the corresponding histological sections. Materials and methods: Bowel resection specimens of 7 patients with CD were examined with a 10 MHZ linear array US transducer in a saline reservoir. Marking needles were placed in the specimen corresponding to the US plane. After formalin fixation, histological sections were taken according to these markings. 78 histological sections were examined with special emphasis on muscularis mucosae(MM) thickness, fibrosis and nodular lymphocyte aggregates. Results: A thickened MM was seen in 47/78 histological sections and MM could be identified on 31 US images. Significant fibrosis was seen as reduced echogenicity in the normally hyperechoic submucosa layer and as enhanced echogenicity in the normally hypoechoic muscularis propria layer. Nodular lymphocyte aggregates in close relation to the outer border of the proper muscle were seen in 43/78 histological sections. US images indicated hypoechoic areas corresponding to these aggregates on 37/43 images. Conclusions: High frequency ultrasound could visualise characteristic bowel wall changes in CD like thickened muscularis mucosa, fibrosis and nodular lymphocyte aggregates.

Diagnostik chronisch entzündlicher Darmerkrankungen bei Kindern und Jugendlichen: MRT mit True-FISP als neuer Goldstandard?

To evaluate the impact of magnetic resonance imaging (MRI) with use of True-FISP sequences in the evaluation of inflammatory bowel-wall changes in children and adolescents with Crohn's disease. Furthermore, the diagnostic procedure in children and adolescents with chronic inflammatory bowel disease (IBD) will be discussed in light of the relevant literature. Twenty-four children and adolescents aged between 7 and 21 years with suspected or known IBD underwent MRI on a 1.5 T-scanner (Philips ACS-NT, Best, Netherlands). One hour after 1 l of a 2.5 % mannitol solution was given orally, MR imaging was performed using coronal HASTE-M2D, coronal fat-suppressed T2-TSE, axial dynamic T1-weighted GE-sequences before and after i. v.-contrast material injection (0.1 mmol/kg Gd-DTPA) and using a 2D-balanced-FFE-sequence (True-FISP) before and after i. v.-contrast material injection in coronal and axial planes. The MR-images were correlated with endoscopy and the clinical findings. In 14 patients, a recently performed conventional radiographic enteroclysis was available. Each performed MRI sequence was evaluated by three experienced radiologists regarding the sensitivity and specificity of each sequence in the detection of inflammatory bowel wall changes. In addition, the image quality was assessed regarding the different tissue contrasts and the susceptibility to artifacts. The distension of the bowel wall and the patients' acceptance of the MRI examination were recorded. With a sensitivity in detecting inflammatory small bowel changes of 93.3 % (axial pre-contrast, coronal post-contrast) and 100 % (axial post-contrast, coronal pre-contrast), the True-FISP outnumbers the other performed sequences (T1 = 80 %, HASTE = 13.3 % and T2-TSE = 53.3 %). The difference between True-FISP and contrast-enhanced T1 was not statistically significant, whereas the difference between True-FISP and HASTE and T2-TSE, respectively, was statistically significant. The True-FISP sequences revealed a statistically significant superiority regarding the soft-tissue differentiation in comparison to all other performed MR-sequences. The distension of the bowel wall was good in all patients. The patients' acceptance of the MRI examination was excellent. The described small bowel MRI examination is appropriate for children and adolescents. With the use of True-FISP sequences, it is a convincing method with an outstanding sensitivity in the diagnosis of IBD. Not least because of the lack of radiation exposure, small bowel MRI ought to replace conventional enteroclysis as a gold standard for IBD diagnosis in children and adolescents.