Magnetic resonance imaging in inflammatory bowel disease

Grading of Crohn's disease activity using CT, MRI, US and scintigraphy: a meta-analysis

PURPOSE

To assess the grading of Crohn's disease activity using CT, MRI, US and scintigraphy.

MATERIALS AND METHODS

MEDLINE, EMBASE and Cochrane databases were searched (January 1983-March 2014) for studies evaluating CT, MRI, US and scintigraphy in grading Crohn's disease activity compared to endoscopy, biopsies or intraoperative findings. Two independent reviewers assessed the data. Three-by-three tables (none, mild, frank disease) were constructed for all studies, and estimates of accurate, over- and under-grading were calculated/summarized by fixed or random effects models.

RESULTS

Our search yielded 9356 articles, 19 of which were included. Per-patient data showed accurate grading values for CT, MRI, US and scintigraphy of 86% (95% CI: 75-93%), 84% (95% CI: 67-93%), 44% (95% CI: 28-61%) and 40% (95% CI: 16-70%), respectively. In the per-patient analysis, CT and MRI showed similar accurate grading estimates (P = 0.8). Per-segment data showed accurate grading values for CT and scintigraphy of 87% (95% CI: 77-93%) and 86% (95% CI: 80-91%), respectively. MRI and US showed grading accuracies of 67-82% and 56-75%, respectively.

CONCLUSIONS

CT and MRI showed comparable high accurate grading estimates in the per-patient analysis. Results for US and scintigraphy were inconsistent, and limited data were available.

KEY POINTS

• CT and MRI have comparable high accuracy in grading Crohn's disease. • Data on US and scintigraphy is inconsistent and limited. • MRI is preferable over CT as it lacks ionizing radiation exposure.

Contrast-enhanced MR enterography as a stand-alone tool to evaluate Crohn's disease in a paediatric population

AIM

To assess the performance of contrast-enhanced T1-weighted magnetic resonance imaging (MRI) alone in the evaluation of Crohn's disease in comparison to all magnetic resonance enterography (MRE) imaging sequences together in an attempt to suggest limitation of the number of overall unenhanced sequences need for the follow-up evaluation.

MATERIALS AND METHODS

Twenty-five paediatric patients (mean age 14.1 ± 3.7 years, male = 12, female = 13) underwent MRE at 1.5 T for evaluation of Crohn's disease. Two radiologists reviewed only contrast-enhanced T1-weighted images in consensus on the first session. Whole images including unenhanced (steady-state free precession, single-shot fast spin-echo (HASTE), fat-suppressed T2-weighted) and contrast-enhanced T1-weighted sequences were reviewed in consensus during the second session with a 1 month interval, which was used as a reference standard. The readers evaluated the presence or absence of disease in 10 bowel segments in each patient. For the abnormal bowel segments, the readers then evaluated for active versus inactive disease and for the presence or absence of abscess. Sensitivity, specificity, and overall accuracy were calculated for detecting active inflammation.

RESULTS

There were 53/250 bowel segments with active inflammation using the reference standard imaging method. The sensitivity, specificity, and accuracy for diagnosing active inflammation using contrast-enhanced images alone were 83.3%, 86.9%, and 84.9%. In five of the false-positive cases of detecting abscess from contrast-enhanced imaging alone, absence of abscesses was confirmed on the non-fat-suppressed HASTE images.

CONCLUSION

The number of MRE sequences in paediatric Crohn's patients can be decreased while maintaining diagnostic accuracy using contrast-enhanced T1 and non-fat-suppressed HASTE images.

A computer-assisted model for detection of MRI signs of Crohn's disease activity: future or fiction?

Magnetic resonance imaging is increasingly used for abdominal evaluation and is more and more considered as the optimal imaging technique for detection of mural inflammation in patients with Crohn's disease. Grading the disease activity is important in daily clinical practice to monitor the medical treatment and is assessed by evaluating different magnetic resonance imaging features. Unfortunately, only moderate interobserver agreement is reported for most of the subjective features and should be improved. A computer-assisted model for automatic detection of abnormalities, ability to grade disease severity, and thereby influence clinical disease management based on magnetic resonance imaging is missing. Recent techniques have focused on semi-automated methods for classification and segmentation of the bowel and also on objective measurement of bowel wall enhancement using absolute T1-values or dynamic contrast-enhanced imaging. This article reviews the available computerized techniques, as well as preferred developments.

Dynamic contrast-enhanced MRI in patients with luminal Crohn's disease

OBJECTIVES

To prospectively assess dynamic contrast-enhanced (DCE-)MRI as compared to conventional sequences in patients with luminal Crohn's disease.

METHODS

Patients with Crohn's disease undergoing MRI and ileocolonoscopy within 1 month had DCE-MRI (3T) during intravenous contrast injection of gadobutrol, single shot fast spin echo sequence and 3D T1-weighted spoiled gradient echo sequence, a dynamic coronal 3D T1-weighted fast spoiled gradient were performed before and after gadobutrol. Maximum enhancement (ME) and initial slope of increase (ISI) were calculated for four colon segments (ascending colon+coecum, transverse colon, descending colon+sigmoid, rectum) and (neo)terminal ileum. C-reactive protein (CRP), Crohn's disease activity index (CDAI), per patient and per segment Crohn's disease endoscopic index of severity (CDEIS) and disease duration were determined. Mean values of the (DCE-)MRI parameters in each segment from each patient were compared between four disease activity groups (normal mucosa, non-ulcerative lesions, mild ulcerative and severe ulcerative disease) with Mann-Whitney test with Bonferroni adjustment. Spearman correlation coefficients were calculated for continuous variables.

RESULTS

Thirty-three patients were included (mean age 37 years; 23 females, median CDEIS 4.4). ME and ISI correlated weakly with segmental CDEIS (r=0.485 and r=0.206) and ME per patient correlated moderately with CDEIS (r=0.551). ME was significantly higher in segments with mild (0.378) or severe (0.388) ulcerative disease compared to normal mucosa (0.304) (p<0.001). No ulcerations were identified at conventional sequences. ME correlated with disease duration in diseased segments (r=0.492), not with CDAI and CRP.

CONCLUSIONS

DCE-MRI can be used as a method for detecting Crohn's disease ulcerative lesions.

Low-Radiation-Dose Modified Small Bowel CT for Evaluation of Recurrent Crohn's Disease

Crohn's disease affects any part of the GI tract, commonly the terminal ileum. To decrease radiation exposure we developed a low-radiation-dose unenhanced CT (modified small Bowel CT, MBCT) to evaluate the small bowel using hyperdense oral contrast. Technique. MBCT was investigated in patients with pathologically proven Crohn's disease presenting with new symptoms from recurrent inflammation or stricture. After ethics board approval, 98 consecutive patients were retrospectively evaluated. Kappa values from two independent reviewers were calculated for presence of obstruction, active inflammation versus chronic stricture, and ancillary findings. Forty-two patients underwent surgery or colonoscopy within 3 months. Results. Kappa was 0.84 for presence of abnormality versus a normal exam and 0.89 for differentiating active inflammation from chronic stricture. Level of agreement for presence of skip areas, abscess formation, and fistula was 0.62, 0.75, and 0.78, respectively. In the subset with “gold standard” follow-up, there was 83% agreement. Conclusions. MBCT is a low-radiation technique with good to very good interobserver agreement for determining presence of obstruction and degree of disease activity in patients with Crohn's disease. Further investigation is required to refine parameters of disease activity compared to CT enterography and small bowel follow through.

Utility of high-resolution MR imaging in demonstrating transmural pathologic changes in Crohn disease

Magnetic resonance (MR) imaging has emerged as an imaging modality that can be used to help diagnose and evaluate Crohn disease of the small and large bowel. MR imaging has high diagnostic accuracy in the detection of Crohn disease, and high-resolution thin-section MR images can demonstrate transmural pathologic changes of Crohn disease from the level of the mucosa to that of the mesentery. High-resolution MR image data also may be used to construct high-quality multiplanar and endoluminal views that may provide additional diagnostic information. Knowledge of the MR imaging findings of Crohn disease and how they correlate with the pathologic features of the disease is important to facilitate accurate diagnosis and detect complications.

Magnetic resonance imaging of the small bowel with the true FISP sequence: intra- and interobserver agreement of enteroclysis and imaging without contrast material

PURPOSE

This study aimed to determine the reliability of magnetic resonance imaging (MRI) without luminal contrast medium versus MR enteroclysis for evaluating small bowel pathology, to compare MRI and MRE findings per observer, and to compare these findings with those of an expert reader in order to determine the influence of luminal contrast medium on morphological evaluations.

CONCLUSION

The use of luminal contrast medium bowel improves reliability for measuring bowel wall thickness and for the diagnosis and grading of obstruction when evaluating the small bowel.

Magnetic resonance imaging of the small bowel in children with idiopathic inflammatory bowel disease: evaluation of disease activity

BACKGROUND

Examinations using ionizing radiation are frequently used in the evaluation of disease activity in children affected by idiopathic inflammatory bowel disease (IBD).

OBJECTIVE

To develop an MR imaging protocol without the need for fluoroscopic insertion of an enteral tube and to assess the disease activity in children with IBD.

MATERIALS AND METHODS

Included in the study were 37 children (22 girls and 15 boys; age range 7-15 years, mean 11.67 years) with IBD who underwent MR imaging of the small bowel. Of these 37 children, 32 had Crohn disease and 5 had indeterminate colitis. A water solution containing herbal fibres was administered orally or through a nasogastric tube. Patients were imaged on a 1.5-T MR scanner with T1-weighted and Tau2-weighted sequences followed by a dynamic study using 3-D T1-W images after intravenous administration of gadolinium.

RESULTS

The percentage enhancement of the bowel wall was significantly increased in patients with abnormal C-reactive protein (CRP) values compared to patients with CRP values in the normal range (P<0.001). A relatively weak but significant correlation between percentage enhancement of the bowel wall and CRP values was noted during all phases of enhancement.

CONCLUSION

This MR imaging protocol is a safe and well-tolerated method for evaluating disease activity and extraintestinal manifestations of IBD in children.

Mural inflammation in Crohn disease: location-matched histologic validation of MR imaging features

PURPOSE

To validate proposed magnetic resonance (MR) imaging features of Crohn disease activity against a histopathologic reference.

MATERIALS AND METHODS

Ethical permission was given by the University College London hospital ethics committee, and informed written consent was obtained from all participants. Preoperative MR imaging was performed in 18 consecutive patients with Crohn disease undergoing elective small-bowel resection. The Harvey-Bradshaw index, the C-reactive protein level, and disease chronicity were recorded. The resected bowel was retrospectively identified at preoperative MR imaging, and wall thickness, mural and lymph node/cerebrospinal fluid (CSF) signal intensity ratios on T2-weighted fat-saturated images, gadolinium-based contrast material uptake, enhancement pattern, and mesenteric signal intensity on T2-weighted fat-saturated images were recorded. Precise histologic matching was achieved by imaging the ex vivo surgical specimens. Histopathologic grading of acute inflammation with the acute inflammatory score (AIS) (on the basis of mucosal ulceration, edema, and quantity and depth of neutrophilic infiltration) and the degree of fibrostenosis was performed at each site, and results were compared with MR imaging features. Data were analyzed by using linear regression with robust standard errors of the estimate.

RESULTS

AIS was positively correlated with mural thickness and mural/CSF signal intensity ratio on T2-weighted fat-saturated images (P < .001 and P = .003, respectively) but not with mural enhancement at 30 and 70 seconds (P = .50 and P = .73, respectively). AIS was higher with layered mural enhancement (P < .001), a pattern also commonly associated with coexisting fibrostenosis (75%). Mural/CSF signal intensity ratio on T2-weighted fat-saturated images was higher in histologically edematous bowel than in nonedematous bowel (P = .04). There was no correlation between any lymph node characteristic and AIS.

CONCLUSION

Increasing mural thickness, high mural signal intensity on T2-weighted fat-saturated images, and a layered pattern of enhancement reflect histologic features of acute small-bowel inflammation in Crohn disease.

Magnetic resonance imaging of the small bowel in children with idiopathic inflammatory bowel disease: evaluation of disease activity

BACKGROUND

Examinations using ionizing radiation are frequently used in the evaluation of disease activity in children affected by idiopathic inflammatory bowel disease (IBD).

OBJECTIVE

To develop an MR imaging protocol without the need for fluoroscopic insertion of an enteral tube and to assess the disease activity in children with IBD.

MATERIALS AND METHODS

Included in the study were 37 children (22 girls and 15 boys; age range 7-15 years, mean 11.67 years) with IBD who underwent MR imaging of the small bowel. Of these 37 children, 32 had Crohn disease and 5 had indeterminate colitis. A water solution containing herbal fibres was administered orally or through a nasogastric tube. Patients were imaged on a 1.5-T MR scanner with T1-weighted and Tau2-weighted sequences followed by a dynamic study using 3-D T1-W images after intravenous administration of gadolinium.

RESULTS

The percentage enhancement of the bowel wall was significantly increased in patients with abnormal C-reactive protein (CRP) values compared to patients with CRP values in the normal range (P<0.001). A relatively weak but significant correlation between percentage enhancement of the bowel wall and CRP values was noted during all phases of enhancement.

CONCLUSION

This MR imaging protocol is a safe and well-tolerated method for evaluating disease activity and extraintestinal manifestations of IBD in children.

Assessment of dynamic contrast enhancement of the small bowel in active Crohn's disease using 3D MR enterography

PURPOSE

To retrospectively compare the dynamic contrast enhancement of the small bowel segments with and without active Crohn's disease at 3D MR enterography (MRE).

MATERIALS AND METHODS

Thirteen patients (five men, eight women; mean age 41.2 years; range 29-56) were imaged on a 1.5-T MR scanner (Sonata, Siemens Medical) with standard MR sequences after having ingested 1000 ml of a 3% mannitol solution. Subsequently, high resolution 3D gradient-echo (volumetric interpolated breath-hold examination=VIBE) data sets were obtained pre-contrast and 20-40s, 60-80s, and 120-140 s after i.v. Gd-DOTA administration (0.2 mmol/kg). Signal enhancement was measured on single slices both in normal and histologically confirmed (12/13) inflamed small bowel wall segments as well as in the aorta, the psoas muscle, and the background to calculate signal-to-noise (SNR) and contrast-to-noise ratios (CNR).

RESULTS

Small bowel wall enhancement was significantly higher (p<0.05) in inflamed compared to normal segments at 20-40s (SNR inflamed: 58.7+/-33.8 vs normal: 36.0+/-19.8; p=0.048; CNR inflamed: 34.8+/-23.4 vs normal: 16.3+/-11.2; p=0.017) and at 60-80s (SNR: 60.3+/-25.1 vs 41.9+/-20.0; p=0.049; CNR: 34.9+/-15.1 vs 19.3+/-13.2; p=0.01) after i.v. contrast administration, respectively. Even at 120-140 s CNR was still increased in inflamed segments (33.7+/-16.0 vs 18.1+/-13.2; p=0.04), while differences in SNR did not attain statistical significance (63.0+/-26.2 vs 45.3+/-23.3; p=0.15).

CONCLUSION

In active Crohn's disease, histologically confirmed inflamed small bowel wall segments demonstrate a significantly increased early uptake of gadolinium on 3D VIBE sequences compared to normal small bowel segments.

Role of MRI in Crohn's disease

The traditional imaging of Crohn's disease has relied on barium and computed tomography (CT) examinations. In recent years magnetic resonance imaging (MRI) has emerged as an imaging method that can be used in the diagnosis and assessment of Crohn's disease. The advantages of MRI include lack of ionizing radiation and its superior tissue contrast resolution. The clinical progression of Crohn's disease can be variable, and MRI can be used to assess inflammatory status, disease progression, and complications of Crohn's disease. MRI of the small bowel is an evolving technique and it has the potential to become the preferred technique for imaging of small bowel Crohn's disease in the future.

Dynamic contrast enhanced magnetic resonance imaging of the terminal ileum: differentiation of activity of Crohn's disease

AIM

To prospectively investigate a new high resolution MRI technique for dynamic evaluation of the enhancement kinetics of bowel parietal layers and to correlate it with CDAI, CRP, endoscopic activity and histologic features.

METHODS

About 16 consecutive patients with proven diagnosis of CD underwent ileocolonoscopy with biopsy and serial bowel dynamic contrasted-MRI (D-CE-MRI) evaluated in blind fashion. Quantitative analysis of bowel wall enhancement kinetics was performed basing on signal to noise ratio (SNR) of inner parietal layers (Mucosa-Submucosa, M-SM) and outer parietal layers (Muscular-Serosa, Ms-S). Disease activity was defined by CDAI > 150, serum CRP > 5 mg/dL and histologic results.

RESULTS

About 9 patients showed a layered enhancement of bowel wall (8 active, 1 inactive), whereas inactive (7 cases) group presented a homogeneous pattern. In active patients we found a significant difference in parietal layered enhancement curves (M-SM vs. Ms-S, P < 0.03) not observed in inactive disease and controls (intra-group analysis). M-SM and Ms-S enhanced curves in clinically active patients were significantly different respect to those of patients with inactive CD (P < 0.001) (inter-group analysis). Parietal D-CE-MRI pattern well correlated with histologic features (r = 0.8; P < 0.001, Spearman test).

CONCLUSIONS

D-CE-MRI can be a useful tool for clinical follow-up and in the treatment strategies in CD patients.

Detection of inflammatory bowel disease: diagnostic performance of cross-sectional imaging modalities

Different cross-sectional imaging techniques can be used as a diagnostic tool for the evaluation of inflammatory bowel disease (IBD). In this report the diagnostic performances of ultrasonography, magnetic resonance imaging and computed tomography in the detection of IBD and the evaluation of known IBD are described, together with a short update on patient preparation and imaging technique of the respective modalities discussed.

Inflammatory bowel disease diagnosed with US, MR, scintigraphy, and CT: meta-analysis of prospective studies

PURPOSE

To compare, by performing a meta-analysis, the accuracies of ultrasonography (US), magnetic resonance (MR) imaging, scintigraphy, computed tomography (CT), and positron emission tomography (PET) in the diagnosis of inflammatory bowel disease (IBD).

MATERIALS AND METHODS

MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched for studies on the accuracy of US, MR imaging, scintigraphy, CT, and PET, as compared with a predefined reference standard, in the diagnosis of IBD. Sensitivity and specificity estimates were calculated on per-patient and per-bowel-segment bases by using a bivariate random-effects model.

RESULTS

Thirty-three studies, from a search that yielded 1406 articles, were included in the final analysis. Mean sensitivity estimates for the diagnosis of IBD on a per-patient basis were high and not significantly different among the imaging modalities (89.7%, 93.0%, 87.8%, and 84.3% for US, MR imaging, scintigraphy, and CT, respectively). Mean per-patient specificity estimates were 95.6% for US, 92.8% for MR imaging, 84.5% for scintigraphy, and 95.1% for CT; the only significant difference in values was that between scintigraphy and US (P = .009). Mean per-bowel-segment sensitivity estimates were lower: 73.5% for US, 70.4% for MR imaging, 77.3% for scintigraphy, and 67.4% for CT. Mean per-bowel-segment specificity estimates were 92.9% for US, 94.0% for MR imaging, 90.3% for scintigraphy, and 90.2% for CT. CT proved to be significantly less sensitive and specific compared with scintigraphy (P = .006) and MR imaging (P = .037)

CONCLUSION

No significant differences in diagnostic accuracy among the imaging techniques were observed. Because patients with IBD often need frequent reevaluation of disease status, use of a diagnostic modality that does not involve the use of ionizing radiation is preferable.

MRI scoring system including dynamic motility evaluation in assessing the activity of Crohn's disease of the terminal ileum

RATIONALE AND OBJECTIVES

We sought to investigate the value of a MRI scoring system including dynamic motility evaluation in the assessment of small bowel Crohn's disease activity.

MATERIALS AND METHODS

From March 2005 to December 2006, 52 patients with suspected Crohn's disease onset or relapse underwent MRI on a 1.5-T magnet. Bowel distention was achieved orally assuming a mean of 1.6 L of a polyethyleneglycol (PEG) preparation. Per-patient assessment of disease activity was based on a scoring system including evaluation of morphology and motility of the small bowel and perivisceral structures (true-FISP, cine-true-FISP, and HASTE T2W sequences) and dynamic assessment of parietal contrast enhancement (FLASH T1W sequence). Patients were included in three categories, using endoscopic biopsy as the standard reference: no activity/quiescent disease, mild activity, or moderate-to-severe activity. Patients without terminal ileum involvement were excluded from data analysis.

RESULTS

MRI allowed a detailed and panoramic evaluation of the small bowel in all subjects examined. MRI properly assessed 14 of 16 (87.5%) cases of no activity/quiescent disease, 12 of 14 (85.7%) cases of mild activity, and 15 of 15 (100%) cases of severe activity. Overall, activity score led to a per-patient misdiagnosis of disease activity in a nonsignificant proportion of subjects (4 of 45; 8.8%) (P > .05), determining two false-positive and two false-negative results of mild disease activity. Sensitivity, specificity, PPV, NPV, and overall accuracy in assessing disease activity were 93.1%, 87.5%, 93.1%, 87.5%, and 91.1%, respectively.

CONCLUSION

Accurate assessment of Crohn's disease activity is achieved by using an activity score providing an overall interpretation of MRI findings.

Long-standing colonic inflammation is associated with a low prevalence of diverticuli in inflammatory bowel disease patients

BACKGROUND

Diverticulosis is associated with high intracolonic pressure and a weakened bowel wall. Chronic colitis is characterized by liquid stools suggestive of low intracolonic pressure and a thickened bowel wall. Therefore, the aim of this study was to assess the prevalence of diverticulosis in colitis patients.

METHODS

Colonoscopy results of patients with inflammatory bowel disease (IBD)-associated colitis older than 50 years were retrospectively evaluated and compared with those of patients who underwent screening colonoscopy. Only patients with biopsy-proven disease, disease duration of more than 5 years, and disease beyond the distal 20 cm were included.

RESULTS

In all, 1037 patients were diagnosed by colonoscopy as suffering from IBD-associated colitis between 1987-2005. After exclusion of patients who did not meet the inclusion criteria the study population consisted of 314 IBD patients and 1023 age-matched control patients. A significantly higher percent of diverticuli was detected in the control group compared with the IBD group (15% versus 3.5%, P < 0.001). No significant difference in the prevalence of diverticuli was detected between the three subtypes of IBD patients (2% in ulcerative colitis versus 4.7% in Crohn's colitis versus 7.6% in indeterminant colitis). Neither disease duration nor the specific colonic segment involved had a significant influence on the prevalence of diverticulosis.

CONCLUSIONS

Long-standing colonic inflammation in IBD patients is associated with a lower prevalence of diverticuli.

Virtual colonoscopy-induced perforation in a patient with Crohn's disease

We report a case of sigmoid colon perforation in a patient with Crohn's disease undergoing computed-tomographic (CT) colonography. A 70-year-old patient with Crohn's disease with terminal ileitis and sigmoid stricture underwent CT colonography after incomplete conventional colonoscopy. During the procedure, the colon was inflated by air insufflation and the patient developed abdominal pain with radiological evidence of retroperitoneal and intraperitoneal free gas. Hartmann's operation was performed. This case highlights that CT colonography is not risk-free. The risk of perforation may be higher in patients with inflammatory bowel disease.

Feasibility of evaluating Crohn's disease activity at 3.0 Tesla

PURPOSE

To determine whether abdominal 3.0T MRI can be used for evaluation of Crohn's disease (CD) compared with ileocolonoscopy (CS), and to determine patient preference for MRI as opposed to CS.

MATERIALS AND METHODS

Twenty patients scheduled for CS underwent MRI. At CS, disease severity was graded and the Crohn's Disease Endoscopic Index of Severity (CDEIS) was determined. Radiological grading (by two observers) was compared with endoscopic grading and CDEIS. Patient experience and preference were determined.

RESULTS

In respectively 10 (observer 1) and 13 patients (observer 2) exact agreement between radiological and endoscopic grading was found. In respectively 10 and 7 patients radiological and endoscopic grading differed one level. No statistically significant correlation was found between radiological grading and CDEIS. Between bowel wall thickness and CDEIS weak to moderate correlations were found, and between bowel wall enhancement and CDEIS weak correlations were found. All patients preferred MRI over CS.

CONCLUSION

It is feasible to perform abdominal 3.0T MRI using orally administered contrast medium for evaluation of CD, and this method can be considered a patient-friendly alternative to CS.

Diagnostic yield, safety, and efficacy of push enteroscopy in pediatrics

BACKGROUND

Push enteroscopy has not been compared to standard endoscopy in children.

OBJECTIVE

The aim of this study was to determine the feasibility of push enteroscopy in children with suspected proximal small bowel disease, and to compare its diagnostic yield and safety with standard endoscopy.

DESIGN/SETTING

Database review.

PATIENTS

A database analysis was performed on all children who underwent push enteroscopy at The Johns Hopkins Children's Center from 2001 to 2005. Patient demographics, clinical history, and indication for push enteroscopy were all recorded. Clinical utility was qualified based on the influence of PE on therapy.

MAIN OUTCOME MEASUREMENTS

Diagnostic yield and safety of push enteroscopy in children.

RESULTS

Push enteroscopy was performed on 44 children (27 M; 17 F) with a median age (range) of 10 (2-18) years. The most common indications for push enteroscopy were suspected proximal small bowel disease based on radiological criteria (21), and bleeding (9). Push enteroscopy confirmed the diagnosis of proximal small bowel Crohn's disease (CD) in 23, polyps in 5, eosinophilic gastroenteritis in 4, celiac disease in 1, microvillous inclusion disease in 1, and lymphoproliferative disease in 1 patient. An isolated non-Crohn's related gastric (1) and jejunal ulcer (1) was also identified. Just 9 of these identifiable lesions were within reach by esophagogastroduodenoscopy (EGD). Seven patients had a normal push enteroscopy. The clinical management was modified in 34 patients. Push enteroscopy was not shown to significantly alter the time of procedure when compared to EGD.

CONCLUSIONS

Push enteroscopy is a safe diagnostic tool with proven clinical utility in children with suspected proximal small bowel disease. Larger studies are needed to establish the widespread application of push enteroscopy in pediatrics.

Magnetic resonance imaging of experimental mouse colitis and association with inflammatory activity

BACKGROUND

Ulcerative colitis and Crohn's disease are the major chronic inflammatory bowel diseases affecting the gastrointestinal tract in humans. Imaging techniques such as endoscopy and computed tomography are used to monitor disease activity. Magnetic resonance imaging (MRI) is emerging as a diagnostic modality, and studies have shown that MRI can be used in the diagnostic procedure of patients with inflammatory bowel disease. The aim of the present study was to investigate the role of MRI in quantitatively reflecting inflammation in an experimental mouse colitis model.

METHODS

Colonic inflammation was induced by exposing mice to dextran sulfate sodium. MRI was used to assess colon wall thickness, T2-weighted (T2w) signal, and contrast-enhanced T1-weighted (T1w) signal in inflamed and healthy animals in vivo. Haptoglobin and interleukin-1beta served as systemic and local inflammatory markers, and macroscopic ex vivo scoring of the colon was performed to assess colonic inflammation.

RESULTS

Dextran sulfate sodium-exposed animals displayed increased levels of inflammatory markers and higher inflammatory score compared with healthy animals. Colon wall thickness and contrast-enhanced T1w signal were significantly increased in dextran sulfate sodium-exposed compared with healthy animals. In addition, the T2w signal was positively correlated with haptoglobin levels and colon wall thickness in the inflamed animals.

CONCLUSIONS

Our results show that MRI can be used to depict healthy and inflamed mouse colon and that the T2w signal, contrast-enhanced T1w signal, and colon wall thickness may be used to characterize inflammation in experimental colitis. These potential biomarkers may be useful in the evaluation of putative drugs in longitudinal studies in both mice and humans.

Dynamic Contrast-Enhanced MRI of the Bowel Wall for Assessment of Disease Activity in Crohn's Disease

OBJECTIVE

The purpose of this study was to evaluate the role of contrast-enhanced dynamic MRI in predicting the disease activity of Crohn's disease.

MATERIALS AND METHODS

Forty-eight patients in two hospitals who had clinically suspected exacerbation of Crohn's disease were included in this study. In three levels of thickened small-bowel wall, axial dynamic T1-weighted sequences were performed every 4-6 sec for a total duration of 2-3 min after contrast administration; static T1-weighted turbo spin-echo sequences were acquired both before and after contrast administration. The slope of enhancement, enhancement ratio, time to enhancement, enhancement time, and thickness of the small-bowel wall were determined. These MRI results were compared with overall clinical grade, Crohn's disease activity index (CDAI), and Van Hees activity index. Clinical grade was based on clinical information, physical findings, laboratory studies, endoscopy, surgery, and other imaging studies. Spearman's correlation coefficient and p values were determined per hospital. Fisher's z-transformation was applied before pooling the correlation coefficients from both hospitals.

RESULTS

The enhancement ratio based on the static series showed significant correlation with the clinical grade (r = 0.29, p = 0.045), CDAI (r =0.31, p = 0.033), and Van Hees activity index (r = 0.36, p = 0.016). The enhancement ratio based on the dynamic series correlated significantly with the CDAI (r = 0.38, p = 0.016). Wall thickness correlated significantly with clinical grade (r = 0.47, p = 0.003) and Van Hees activity index (r = 0.41, p = 0.007).

CONCLUSION

These data suggest that the enhancement ratio of bowel wall after IV administration of gadodiamide and bowel wall thickness are weak to moderate indicators of the severity of Crohn's disease.

Ulcerative colitis: value of MR imaging

Recent technologic advances have greatly improved the quality of abdominal magnetic resonance imaging (MRI) by allowing the identification of abnormalities in inflammatory bowel disease. Thus far, the role of MRI has been extensively investigated in Crohn disease (CD) and, to a minor extent, in ulcerative colitis (UC), likely due to intrinsic differences between these two diseases. In UC the inflammatory lesions, unlike CD, are confined to the colon, have a predictable spreading, and affect only the inner wall layer; thus endoscopy alone can assess the extent and severity of disease in most cases. However, preliminary studies have demonstrated that MRI also can be a reliable diagnostic tool for UC because it is useful for integrating clinical and endoscopic data. MRI can be valuable in distinguishing CD from UC in uncertain cases by assessing the sparing of the distal ileum and the continuity of colonic involvement. Moreover, MRI can provide important information if endoscopy is incomplete, e.g., due to tight strictures, or contraindicated, e.g., in severely acute disease, due to a high risk of perforation. MRI can detect most of the typical findings of the diseases, such as wall thickening, mural stratification, loss of haustrations, and several complications including fibrotic or neoplastic strictures. In addition, MRI can be extremely valuable in assessing disease activity by monitoring the degree of wall gadolinium enhancement and T2 signal at the level of the affected bowel segments, thus influencing pharmacologic and surgical planning. In the next few years, MRI will likely become the imaging modality of choice in the clinical management of this disease.

Capsule endoscopy in 2005: facts and perspectives

Capsule endoscopy has recently been introduced to explore endoscopically the whole small intestine, fulfilling a gap between examinations of the upper and lower gastrointestinal tract. The technique consists of a miniaturized endoscope, embedded in a swallowable capsule that is propulsed by peristalsis and achieves the journey to the right colon in five to eight hours. Images captured by the capsule are recorded on a hard drive worn in a belt by the patient. The main indication for capsule examination is the examination of the small bowel to find a bleeding lesion in patients with obscure bleeding. Several studies have shown that the diagnostic yield of capsule endoscopy is superior to that of push enteroscopy in this indication. Other possible indications are patients with suspected intestinal location of Crohn's disease, familial adenomatous polyposis, complicated coeliac disease and lesions due NSAIDs. The review contains information on the technical aspects of capsule endoscopy and discusses the indications. Issues of safety and tolerance are also discussed.

Bowel wall enhancement in magnetic resonance colonography for assessing activity in Crohn's disease

BACKGROUND

This study focuses on the correlation of the signal intensity (SI) of the bowel wall in magnetic resonance (MR) colonography with the inflammation activity in Crohn's disease.

MATERIAL AND METHODS

We performed MR colonography in 42 patients and compared the change of the SI of the bowel wall (T1-weighted/paramagnetic contrast medium) with colonoscopic findings.

RESULTS

Change of the SI and colonoscopically assessed inflammatory activity are significantly correlated (r=.676, P<or=.01).

CONCLUSION

The degree of the contrast enhancement of the bowel wall may be a criterion for the degree of inflammation in Crohn's disease.

Magnetic resonance imaging compared with ileocolonoscopy in evaluating disease severity in Crohn's disease

BACKGROUND & AIMS

Abdominal magnetic resonance imaging (MRI) has shown promising results in the detection of Crohn's disease (CD)-related lesions. The purpose of this study was to assess the value of MRI in measuring disease activity in CD patients in comparison with ileocolonoscopy.

METHODS

Thirty-one patients undergoing ileocolonoscopy because of suspicion of relapsing CD underwent MRI with water as intraluminal contrast medium. At endoscopy, disease severity was graded (4-point scale), and Crohn's Disease Endoscopic Index of Severity (CDEIS) was determined. Two radiologists independently interpreted the MRI scans. Radiologic grading (4-point scale) was compared with endoscopic grading of disease severity and CDEIS (overall, for all segments). Wall thickness and enhancement were compared with CDEIS. Patient experience and preference were determined.

RESULTS

In, respectively, 14 and 14 patients (radiologist 1) and 16 and 11 patients (radiologist 2) an exact match or 1 level of difference in grading was scored with the endoscopist. Correlation between severity rated at MRI and CDEIS was moderate to strong with r = 0.61 (P < .001) for observer 1 and r = 0.63 (P < .001) for observer 2. Per segment, best correlation was seen in the terminal ileum (r = 0.63; P < .001, for both observers). Wall thickness correlated moderately to strongly with CDEIS (r = 0.57, P < .001 and r = 0.50, P < .001 for observers 1 and 2), whereas enhancement correlated weakly to moderately (r = 0.45, P < .001 and r = 0.42, P < .001). Patients experienced more pain during endoscopy, and all patients except 2 preferred MRI to endoscopy.

CONCLUSION

MRI can correctly identify disease severity in patients with CD and is a patient-friendly alternative to ileocolonoscopy.

MRI in Crohn's disease

Technological developments have extended the role of MRI in the evaluation of the gastrointestinal tract. The potential of MRI to evaluate disease activity in Crohn's disease has been investigated extensively, as MRI has intrinsic advantages over other techniques, including noninvasiveness and the absence of ionizing radiation. For perianal fistulizing disease MRI has become a mainstay in evaluation of disease, as localization and extent of disease can be very well appreciated using both T2-weighted and T1-weighted sequences, fat suppression, and intravenous contrast medium. Imaging of the small bowel and colon in Crohn's disease is more complicated due to bowel peristalsis and respiratory movement. However, using fast breathhold sequences and intravenous spasmolytic medication, images of good diagnostic quality can be acquired. To obtain sufficiently distended bowel, which in our estimation is a prerequisite for evaluation of the bowel, MR enteroclysis can be performed. However, applicability of different oral contrast media has been studied, as a noninvasive method for bowel distension would be preferable. Abdominal MRI is a valuable imaging technique for evaluation of luminal, transmural, and extraintestinal manifestations of Crohn's disease as degree of disease activity, presence of luminal pathology (e.g., stenoses), and extraintestinal manifestations of disease (e.g., abscesses, fistulas) can be accurately assessed.

Magnetic resonance imaging of the small bowel in Crohn's disease

OBJECTIVE

There may be advantages in using magnetic resonance imaging (MRI) in small-bowel disease. The aims of this study were to optimize the MRI examination technique and to evaluate the capabilities of MRI compared with those of conventional enteroclysis (CE).

MATERIALS AND METHODS

MRI and CE were performed in 36 patients suspected of Crohn's disease. Based on 26 pilot studies optimal oral administration of plum juice and bulk fibre laxative was found. T2-weighted and gadolinium enhanced T1-weighted images were obtained using a breath-holding technique and butylscopolamine. Virtual endoscopy was performed. Conventional enteroclysis entailed duodenal intubation and administration of barium and air. Two radiologists evaluated the examinations independently. Finally, each patient scored the degree of discomfort, and preference for either MRI or CE was found.

RESULTS

The MRI technique ensured sufficient distension of the small bowel and small-bowel changes were found in 12 patients. In 3 patients this was not seen on conventional enteroclysis, which did not reveal any pathology that was not already seen on MRI. Pathological abdominal changes were found in 70% more patients during MRI than during conventional enteroclysis (p < 0.001). Endoscopic examination corresponded with the MRI findings. The examination quality decreased with increasing age (p = 0.002) and the interobserver agreement of the pathological changes was high (p < 0.001). Virtual endoscopy resulted in excellent demonstration of the mucosal surface. The examination discomfort scores obtained during the MRI were lower than those during conventional enteroclysis (p < 0.001).

CONCLUSIONS

MRI using the current technique is preferable to conventional enteroclysis because of superior demonstration of the entire small-bowel pathology, low level of patient discomfort and absence of radiation exposure.

A combination of small bowel imaging methods: conventional enteroclysis with complementary magnetic resonance enteroclysis

AIM

The aim of this prospective study was to evaluate the overall findings of conventional enteroclysis (CE) with complementary magnetic resonance enteroclysis (MRE) in small bowel disease.

METHODS

The study included 32 patients referred from various clinical departments, with known or suspected small bowel disease and abnormalities on CE. Immediately after CE, true fast imaging with steady-state precession (true FISP), and unenhanced and gadolinium-enhanced T1-weighted fast low-angle shot (FLASH) sequences with fat saturation were obtained. Mucosal, mural and luminal changes of the small bowel were evaluated by each technique. In addition, bowel wall thickening, bowel wall enhancement and perienteric changes were assessed by MRE. The radiological findings obtained were evaluated together as a combination, and the role of MRE in the determination of the activity and complications of the small bowel disease was assessed. Radiological findings were correlated with clinical evaluation and follow-up in all cases, including endoscopy in 14 cases and surgery in 5 cases.

RESULTS

MRE provided important supplementary mural and extramural information, including degree of pathological wall thickness, mural enhancement pattern associated with disease activity, perivisceral collection, abscess formation, mesenteric fibrofatty proliferation, lymphadenopathy and increase in perienteric vascularity. Short strictures were not revealed on MRE; however, for patients with a history of abdominal malignancy, MRE helped characterize the level of any obstruction and the extent of the disease.

CONCLUSION

We recommend MRE for patients who have findings of advanced inflammatory bowel disease or neoplasm on CE examination. The combination of these two techniques can provide important information on the degree and extent of the disorder.

Magnetic resonance imaging of the gastrointestinal tract

Comprehensive bowel examination results from the combined use of T2-weighted single-shot and breath hold T1-weighted gradient echo, minus/plus fat suppression, and gadolinium-enhanced 3D gradient echo (3D VIBE, T1 FAME, 3D THRIVE). Gadolinium-enhanced imaging should be performed dynamically, but the venous 60- to 90-second delayed phase images with fat suppression are generally the most valuable. Removal of fat signal for detection of enhancing normal and abnormal structures is critical. Newly available True-FISP (FIESTA, BFFE) sequences obtained in the 2D form can be very helpful in delineation of bowel wall pathology and overall bowel anatomy, particularly when combined with a water-based intraluminal distending agent. Advantages include rapid acquisition, high signal-to-noise, and motion insensitivity. Generalized protocol for comprehensive evaluation of the entire abdomen and pelvis can be used for the following bowel indications: type and severity of inflammatory bowel disease (IBD); identifying enteric abscesses and fistulae; preoperative staging of malignant neoplasms, including rectal carcinoma; differentiating postoperative and radiation therapy changes from recurrent carcinoma; follow-up evaluation of metastases response to localized ablative or systemic chemotherapy. For improved visualization of bowel wall in dedicated examinations, bowel distension should be achieved using either orally or rectally delivered contrast agents to produce either bright or dark lumen. We have found 2D True-FISP without fat suppression superior to 3D True-FISP and to single-shot echo-train sequences to provide a T2-weighted image of bowel morphology. Strengths include: performed without fat suppression results in the very dark bowel wall being sandwiched between intermediate high signal fat adjacent to bowel serosa, and very high lumen signal from water-distending agent; 2D True-FISP provides motion insensitivity that is lost if 3D is used; True-FISP produces better edge sharpness than single-shot echo-train, higher contrast, and resists flow void artifacts commonly seen with single-shot echo-train imaging combined with a water distending agent. Drawbacks of this technique include: artifacts related to extreme sensitivity to field inhomogeneity, including air-soft tissue interfaces at the patient skin surface, and from retained bowel gas; retained bowel gas is dark against dark bowel wall, impairing bowel wall assessment; and True-FISP does not provide sensitivity for edema, which is superior on single-shot echo-train imaging. Small/large bowel indications for MRI include: inflammatory bowel disease, infectious disease including abscess evaluation or for appendicitis, inflammatory conditions including ischemia, and partial obstruction, malnutrition, and neoplasm search.

IRM et exploration du tube digestif — Aspects techniques et perspectives d’évolution

Barium enema remains the reference method for the detection of morphological intraluminal alterations of the bowel. Optimal filling of intestinal loops allows high diagnostic sensitivity and specificity. US, CT and MRI are useful diagnostic procedures in the evaluation of mural and extramural alterations. In recent years, MR-enteroclysis and MR colonography have been developed, both enable the evaluation of luminal, extraluminal and mural alterations of the bowel. While these modalities provide good imaging evaluation of the bowel, visualization of the different layers, as seen on US, is still not available. Use of high resolution endoluminal coil on MR could improve mural evaluation of bowel to differentiate inflammatory diseases and provide accurate TNM classification of tumoral lesion with minimally invasive procedure.

Pediatric jejunoileitis: a severe Crohn's disease phenotype that requires intensive nutritional management

BACKGROUND

Jejunoileitis (JI) is an unusual manifestation of Crohn's disease (CD) that has been associated with high morbidity and the frequent need for surgical intervention. Although the disease has been well-described in adults, the true prevalence and clinical phenotype in children is unknown.

AIM

To compare the clinical course and nutritional impact of CD in children with and without proximal small bowel involvement.

METHODS

Patients with either Crohn's jejunitis or JI with or without colonic involvement were identified through a clinical database (1996--2002). All radiologic studies were reviewed by an experienced radiologist blinded to the clinical diagnosis. Thirty-six patients with CD without histologic or radiologic signs of proximal small bowel involvement were used for comparison. All medical, surgical, and hematologic parameters were compared in both disease groups.

RESULTS

Among the 134 patients with CD, 23 (17%) had radiologic signs of JI, including intestinal fold thickening (57%), luminal narrowing (31%), and skip lesions (13%). Enteric fistula (6%) and strictures (6%) were less common. Patients with JI were likely to be stunted at the time of diagnosis, require surgical intervention (P < 0.03) and nutritional therapy in the form of nasogastric tube feeds (P < 0.03). Nutritional therapy was also associated with an improvement in height in patients with proximal small bowel disease (OR:5.87).

DISCUSSION

JI is a relatively common disease phenotype in children with CD that requires aggressive nutritional and surgical intervention. Future studies are required to determine if the early detection and use of immune modulators may lessen the morbidity associated with proximal small bowel disease.

Clinical relevance of transabdominal ultrasonography and magnetic resonance imaging in patients with inflammatory bowel disease of the terminal ileum and large bowel

BACKGROUND

Ileocolonoscopy represents the diagnostic standard in the work-up of patients with inflammatory bowel diseases (IBD). Patients are often reluctant to be colonoscoped because of the invasiveness and pain sensation during colonoscopy.

AIMS

To compare the usefulness oftransabdominal ultrasound (US) and magnetic resonance imaging (MRI) in assessing disease extension and activity in patients with IBD restricted to the terminal ileum and large bowel.

PATIENTS AND METHODS

61 patients with IBD [37 Crohn's disease (CD) and 24 ulcerative colitis (UC)] were prospectively studied. All patients underwent clinical and laboratory assessment, ileocolonoscopy, transabdominal sonography, and MRI within 5 days. Involved bowel segments were defined as those with bowel wall thickness >3 mm and increased Doppler signal on US or contrast enhancement of the bowel wall on MRI. To compare disease activity endoscopic, MRI and US findings were graded with newly developed scores.

RESULTS

The segment-by-segment analysis revealed an overall accuracy of 89% for US and 73% for MRI in identifying active IBD. The accuracy was better in patients with UC than in patients with CD for both US and MRI. The endoscopic activity index (EAI) correlated stronger with the US activity index (r = 0.884) than with the MRI activity index (r = 0.344). The correlation of US and MRI activity indices with EAI was better in patients with UC compared with patients with CD. All three imaging methods showed a significant correlation with clinical disease activity in patients with UC but not in patients with CD.

CONCLUSION

This study provides strong evidence that US should be considered as a first-choice method for follow-up of patients with IBD of the terminal ileum and large bowel.

Exploration de l’intestin grêle par les techniques d’imagerie en coupes

Recent advances of cross sectional imaging allow optimal evaluation of the small bowel. This chapter will detail technical considerations and emphasize the role of imaging in the evaluation of the most common diseases of the small bowel.

Gadolinium-enhanced magnetic resonance imaging: a useful radiological tool in diagnosing pediatric IBD

BACKGROUND

Recent advances in gadolinium-enhanced magnetic resonance imaging (G-MRI) have been developed to enhance the resolution of the intestinal mucosa and facilitate the differentiation of ulcerative colitis (UC) from Crohn's disease (CD). The objective of this study is to apply this technology in Pediatrics.

METHODS

A G-MRI was performed on 58 consecutive children with suspected IBD between 1999 and 2002 using intravenous gadolinium, fat suppression, and respiration-suspended sequences to enhance the resolution of the intestinal wall. The sensitivity and specificity in diagnosing either UC or CD was determined by comparing the G-MRI to the established histologic diagnosis.

RESULTS

G-MRI confirmed the diagnosis of either CD (21) or UC (7) with a sensitivity and specificity of 96% and 92%, respectively. Among the 21 patients with CD, 14 showed proximal small bowel involvement by G-MRI. In total, 17 patients were diagnosed with indeterminate colitis (IC) based on histologic criteria alone, and among these patients, G-MRI had a significantly lower non-classification rate (P < 0.02). In comparison, endoscopy was less sensitive (57%), but more specific (100%) than either histology or G-MRI in diagnosing IBD. G-MRI also showed a strong concordance with computed tomography in diagnosing CD (P = 0.001).

CONCLUSION

G-MRI is a both a sensitive and specific radiologic tool in diagnosing pediatric IBD. In patients with CD, G-MRI may be useful in identifying proximal small bowel involvement. Longitudinal follow-up studies are needed in those patients diagnosed with IC to determine the predictive value of G-MRI testing.

MR enteroclysis

MR enteroclysis provides adequate image quality and sufficient distention of the entire small bowel. The functional information provided by MR enteroclysis equals that provided by conventional enteroclysis, which implies the ability reliably to depict even low-grade SBO. The inherent advantages of enteroclysis over conventional enteroclysis are the potential to detect extraluminal pathologic conditions and the ability to provide detailed information about the wall of the small bowel and the entire abdomen. Unlike conventional enteroclysis, MR enteroclysis does not have problems with overlapping bowel loops. MR enteroclysis has the potential to be an excellent diagnostic method for examinations of small bowel disease because of the functional information, the soft tissue contrast, and multiplanar imaging capabilities.

Small bowel magnetic resonance imaging for inflammatory bowel disease

The presented concept of hydro-magnetic resonance imaging (MRI) using a 2.5% mannitol solution as an orally applicable intraluminal contrast agent is a meaningful, reproducible, and reliable imaging method for the depiction of the small bowel. Especially in patients with Crohn's disease, hydro-MRI is the imaging method of first choice because hydro-MRI offers the advantage of a superior depiction of the inflamed bowel wall and the extramural complications of this disease without radiation exposure. In addition, hydro-MRI allows for a reliable assessment of the inflammatory activity, especially for the differentiation between an active and an inactive (scarred) stenosis. In particular, the mural enhancement, the length as well as the wall thickness of inflamed bowel segments, are considered to be significant MR parameters for the determination of the activity of Crohn's disease. Hydro-MRI of the colon is suitable for the depiction of pathologic changes in ulcerative colitis, but in contrast to Crohn's disease, the assessment of disease activity by hydro-MRI is unreliable in ulcerative colitis, probably because of the low spatial resolution (mucositis in ulcerative colitis vs. transmural inflammation in Crohn's disease). Hydro-MRI does not allow a reliable classification of inflammatory bowel diseases, but in ambiguous cases, hydro-MRI may provide helpful information for the differentiation of Crohn's disease and ulcerative colitis. There are no data of larger patient groups published regarding MR findings in inflammatory bowel diseases besides Crohn's disease and ulcerative colitis, but hydro-MRI is a promising imaging tool for these entities, which should be assessed in additional studies.

Noninvasive assessment of Crohn's disease activity: a comparison of 18F-fluorodeoxyglucose positron emission tomography, hydromagnetic resonance imaging, and granulocyte scintigraphy with labeled antibodies

OBJECTIVES

Detection of disease activity in Crohn's disease (CD) is of crucial importance for diagnosis and management of the disease. Noninvasive methods for monitoring are desirable and comprise hydromagnetic resonance imaging (hydro-MRI) and leukocyte scintigraphy. In addition, a recent case report indicated the potential of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to assess CD activity. However, comparative prospective studies are lacking.

METHODS

Between February, 1999 and August, 2000, 59 patients with CD were enrolled in a prospective study to assess disease activity by FDG-PET, hydro-MRI, and immunoscintigraphy with anti-nonspecific cross-reacting antigen 95 antigranulocyte antibodies. In 28 of these patients, colonoscopy could be performed. Twelve patients with irritable bowel syndrome and 20 tumor patients without gut inflammation served as controls. Results were compared by statistical analysis.

RESULTS

FDG-PET detected 127 pathological findings (average maximum standardized uptake value = 4.4 +/- 1.1) in the terminal/neoterminal ileum (37), small bowel (24), and colon (66) of 54 patients with CD, whereas no pathological findings were seen in five patients with CD, the control patients with irritable bowel syndrome, and the tumor patients without gut inflammation. In contrast, examination with hydro-MRI or granulocyte antibodies detected less pathological findings in CD patients. Forty-five of the detected foci were accessible to endoscopic verification. The correlation of the foci with endoscopic findings showed a high specificity (>89%) of all three methods to detect inflamed areas in the terminal ileum and colon of patients with CD, although analyses by hydro-MRI and granulocyte antibody scan had strikingly lower sensitivities (40.9% and 66.7%) than FDG-PET analysis (85.4%).

CONCLUSIONS

FDG-PET appears to be a reliable noninvasive tool for simultaneous detection of inflamed areas in the small and large bowel of patients with CD. FDG-PET can be used to detect disease activity in the terminal ileum and colon of CD patients with high sensitivity and specificity.

Inflammatory bowel disease in the pediatric and adolescent patient

Advances in genetic testing have confirmed the presence of susceptibility loci on chromosomes 12 and 16 for UC and CD. These loci show a strong association with particular disease phenotypes that may explain the clinical heterogeneity of IBD. Whether multiple genotypes will be found to explain these phenotypes remains to be determined. Pharmacogenetic differences in 6-mercaptopurine metabolism can be used clinically to predict patient susceptibility to drug-induced toxicity. Novel treatment strategies are being developed at The Johns Hopkins Medical Center Hospital based on these inherent genetic differences. The aim is to improve treatment efficacy and clinical response times and prevent untoward drug-induced toxicity.

Magnetic resonance imaging of inflammatory bowel disease: evaluation in a rabbit model

PURPOSE

To correlate intestinal contrast enhancement and wall thickening with the degree of inflammation in an experimental model of inflammatory bowel disease.

MATERIALS AND METHODS

Inflammatory bowel disease was elicited in 39 New Zealand White rabbits by rectal instillation of 2,4,6-trinitrobenzene sulphonic acid (TNBA). Magnetic resonance imaging (MRI) was used to determine bowel wall thickness and intestinal contrast enhancement after the administration of 0.1 mmol/kg of gadodiamide intravenously. MR measurements were compared with the complete histopathologic analysis.

RESULTS

MR measurements of bowel wall thickness correlated well with histopathologic measurements in vitro (r = 0.85, P < 0.0001) and with histopathologic evidence of chronic inflammatory bowel disease (P < 0.02). Chronic inflammation was characterized by increased intestinal contrast enhancement (137 +/- 25%) when compared to normal bowel (86 +/- 7%, P = 0.04).

CONCLUSION

Contrast-enhanced MRI accurately reflects inflammatory bowel disease in the rabbit model.

MR imaging evaluation of the activity of Crohn's disease

OBJECTIVE

The purpose of this study was to evaluate the sensitivity and specificity of MR imaging in assessing the activity of Crohn's disease.

SUBJECTS AND METHODS

Thirty symptomatic patients with Crohn's disease but uncertain disease activity were prospectively examined using MR imaging. Twenty-nine patients were scored using the Crohn's disease activity index. Six hundred milliliters of water orally and 1 mg of glucagon intramuscularly were given before imaging. Breath-hold images were obtained using T2-weighted turbo spin-echo, T1-weighted fast low-angle shot, and fat-suppressed gadolinium-enhanced T1-weighted fast low-angle shot sequences. Images were assessed by two radiologists who were unaware of the patient's symptoms, clinical scoring, and other imaging tests, and who reached a consensus about the imaging findings (bowel wall thickening, bowel wall enhancement, and perienteric changes) and determined the absence or presence of active disease in each patient. MR imaging findings were correlated with endoscopy and surgery.

RESULTS

Twenty-three patients had active disease and seven patients had inactive disease. One hundred twenty-four of a total of 168 bowel segments were examined with both MR imaging and endoscopy or surgery. On a per patient basis, MR imaging had an overall sensitivity of 91% and a specificity of 71% for active disease. The Crohn's disease activity index had a sensitivity of 92% and a specificity of 28%. On a per segment basis, MR imaging had a sensitivity of 59% and a specificity of 93%. Bowel wall thickening of greater than 4 mm, bowel wall enhancement (ratio of signal intensity of abnormal to normal bowel > 1.3:1), and increased mesenteric vascularity were useful in identifying active disease. A layered enhancement pattern after the IV administration of gadolinium was highly specific for active inflammation.

CONCLUSION

MR imaging is useful in assessing the activity of Crohn's disease and may be helpful when clinical scoring is equivocal.

The prognostic value, in active ulcerative colitis, of an increased intensity of colonic perivisceral fat signal on magnetic resonance imaging with ferumoxil

OBJECTIVE

In active ulcerative colitis (UC), magnetic resonance imaging (MRI) with ferumoxil, a superparamagnetic oral contrast agent, accurately evaluates, in our experience, the increased wall thickness and frequently shows a stronger perivisceral fat signal intensity (PFSI). The aim of our study was to evaluate the clinical significance of these MRI findings in active UC.

METHODS

Twenty-four consecutive patients affected by moderate pancolitis were enrolled. At entry, each patient underwent MRI with ferumoxil to evaluate wall thickness and PFSI. Two groups of patients were individuated: group A (increased PFSI) and group B (normal PFSI). After obtaining remission, the number of relapses and, at each flare-up, the clinical activity index (CAI) were evaluated in all patients in a 2-yr follow-up period. The mean CAI was calculated at the end of the follow-up in each patient. Where there was colectomy, a complete histological examination of the colon was performed.

RESULTS

PFSI was increased in 16 patients (group A) and was normal in the remainder (group B). There was a significant difference of wall thickness, number of relapses/yr, and mean CAI between the two groups of patients. No difference was observed with regard the duration of disease. Six patients of group A and no patient of group B underwent colectomy. The histological evaluation showed an increased thickness of the entire colonic wall with significant changes of the perivisceral fat structures.

CONCLUSIONS

An increased

Hydro-MRI in Crohn's disease: appraisal of disease activity

RATIONALE AND OBJECTIVES

To appraise the value of hydro-MRI in the assessment of activity in Crohn's disease.

METHODS

After bowel opacification with 1000 mL of an orally administered 2.5% mannitol solution was achieved, axial and coronal breath-hold sequences (T2-weighted half-Fourier acquisition single-shot turbo spin-echo sequences with or without fat saturation, dynamic T1-weighted fast low-angle shot sequences, and contrast-enhanced T1-weighted fast low-angle shot with fat saturation sequences) were acquired in 82 patients with proved Crohn's disease at 1.0 T. Enhancement of the bowel wall was correlated with other MRI findings, with the Crohn's disease activity index (CDAI), and with levels of C-reactive protein (CRP).

RESULTS

In Crohn's disease, contrast enhancement of the affected bowel wall was markedly increased in comparison with the normal bowel wall (+80% +/- 22% versus +43% +/- 12%; P = 3 x 10(-15)). Positive correlations could be established between the increase in bowel wall enhancement and many other MRI findings. Between the increase in bowel wall enhancement and the CDAI, only a poor correlation was found (r = 0.25, P = 0.02). There was no statistical correlation between the increase in bowel wall enhancement and CRP.

CONCLUSIONS

Hydro-MRI seems to be superior to the CDAI and CRP for the registration of Crohn's disease activity. In particular, differentiation between an active and an inactive (scarred) stenosis, which is crucial for the choice of therapeutic procedures, seems to be more reliable by the interpretation of several morphological and functional parameters on hydro-MRI than by the use of CDAI and CRP.

Assessment of disease activity and extent by magnetic resonance imaging in ulcerative colitis

BACKGROUND

We determined whether magnetic resonance imaging (MRI) could determine the activity and site of involvement in ulcerative colitis.

METHODS

Colonoscopy, double-contrast barium enema and gadodiamide-enhanced MRI were performed prospectively in six patients with ulcerative colitis, including three females aged 10-22 years, both in the active and the remission stages.

RESULTS

Characteristic findings of MRI in the active stage of ulcerative colitis were loss of haustral markings and thickening and contrast enhancement of the colonic wall. In five of six patients, the site of disease distribution determined by MRI was in accordance with that determined by colonoscopy.

CONCLUSIONS

Gadodiamide-enhanced MRI is a safe and useful method of determining disease activity and extent in patients with ulcerative colitis.

Small-bowel disease: comparison of MR enteroclysis images with conventional enteroclysis and surgical findings

PURPOSE

To investigate if magnetic resonance (MR) enteroclysis can be performed routinely and to compare MR enteroclysis findings with those of conventional enteroclysis or surgery.

MATERIALS AND METHODS

MR enteroclysis was prospectively performed in 30 patients with symptoms of inflammatory bowel disease or small-bowel obstruction (SBO). A methylcellulose-water solution was used to distend the small bowel. To monitor dynamic changes in the small bowel, a single-shot fast spin-echo T2-weighted sequence was applied. For morphologic assessment, breath-hold T2-weighted fast spin-echo and coronal T1-weighted gradient-recalled-echo MR images were obtained without and with gadolinium enhancement. Image quality and degree of small-bowel distention were graded. MR imaging findings and degree of SBO were compared with findings at conventional enteroclysis (n = 25) or surgery (n = 5).

RESULTS

MR enteroclysis was well tolerated and provided adequate image quality and sufficient small-bowel distention. SBO grade based on MR enteroclysis images (n = 10) was identical to that based on conventional enteroclysis images (n = 6) or surgical findings (n = 4). There was exact agreement between MR enteroclysis and retrospective findings in all five patients who underwent surgery, and MR findings were identical to those at enteroclysis in 18 patients, superior in six patients, and inferior in one patient.

CONCLUSION

MR enteroclysis can be performed routinely with adequate image quality and sufficient small-bowel distention. The functional information provided by MR enteroclysis is identical to that provided at conventional enteroclysis.