Is magnetic resonance imaging a reliable diagnostic tool in the evaluation of active Crohn's disease in the small bowel?

Magnetic resonance imaging in the management of Crohn's disease: a systematic review and meta-analysis

Objectives

Crohn’s disease (CD) is a condition that can occur in any part of the gastrointestinal tract, although usually forms in the colon and terminal ileum. Magnetic resonance imaging (MRI) has become a beneficial modality in the evaluation of small bowel activity. This study reports on a systematic review and meta-analysis of magnetic resonance enterography for the prediction of CD activity and evaluation of outcomes and possible complications.

Methods

Following the PRISMA guidelines, a total of 25 low-risk studies on established CD were selected, based on a QUADAS-II score of ≥ 9.

Results

A sensitivity of 90% was revealed in a pooled analysis of the 19 studies, with heterogeneity of χ² = 81.83 and I² of 80.3%. Also, a specificity of 89% was calculated, with heterogeneity of χ² = 65.12 and I² of 70.0%.

Conclusion

It was concluded that MRI provides an effective alternative to CT enterography in the detection of small bowel activity in CD patients under supervision of radiologist for assessment of disease activity and its complications. Its advantages include the avoidance of radiation exposure and good diagnostic accuracy.

Magnetic Resonance Enterography Cannot Replace Upper Endoscopy in Pediatric Crohn Disease: An Imagekids Sub-study

OBJECTIVES

Although magnetic resonance enterography (MRE) can accurately reflect ileal inflammation in pediatric Crohn disease (CD), there are no pediatric data on the accuracy of MRE to detect upper gastrointestinal tract (UGI) lesions. We aimed to compare MRE and esophagogastroduodenoscopy (EGD) in detecting the spectrum and severity of UGI disease in children.

METHODS

This is an ancillary study of the prospective multi-center ImageKids study focusing on pediatric MRE. EGD was performed within 2 weeks of MRE (at disease onset or thereafter) and explicitly scored by SES-CD modified for the UGI and physician global assessment. Local and central radiologists scored the UGI region of the MRE blinded to the EGD. Accuracy of MRE compared with EGD was examined using correlational coefficients (r) and area under receiver operating characteristic curves (AUC).

RESULTS

One hundred and eighty-eight patients were reviewed (mean age 14 ± 1 years, 103 [55%] boys); 66 of 188 (35%) children had macroscopic ulcerations on EGD (esophagus, 13 [7%]; stomach, 34 [18%]; duodenum, 45 [24%]). Most children had aphthous ulcers, but 10 (5%) had larger ulcers (stomach, 2 [1%]; duodenum, 8 [4%]). There was no agreement between local and central radiologists on the presence or absence of UGI inflammation on MRE (Kappa = -0.02, P = 0.71). EGD findings were not accurately detected by MRE, read locally or centrally (r = -0.03 to 0.11, P = 0.18-0.88; AUC = 0.47-0.55, P = 0.53-1.00).No fistulae or narrowings were identified on either EGD or MRE.

CONCLUSIONS

MRE cannot reliably assess the UGI in pediatric CD and cannot replace EGD for this purpose.

The role of imaging in the preoperative assessment of children with inflammatory colitis

BACKGROUND

Accurate diagnosis of Crohn's disease or ulcerative colitis is essential for surgical planning. This study compared the accuracy, safety, and utility of small bowel follow-through (SBFT) and magnetic resonance enterography (MRE) for detecting small bowel (SB) involvement preoperatively.

METHODS

A retrospective review of children who underwent colectomy for inflammatory bowel disease (2000-2014) was performed. Preoperative SBFT and MRE were independently reviewed by two radiologists blinded to clinical data. Gold standard for diagnosis was surgical pathology.

RESULTS

68 patients (36 female) were included. 45 patients had SBFT prior to colectomy, 17 patients had MRE, and 6 both. Interrater reliability for radiologic interpretation was 90% (SBFT) and 91% (MRE). Mean study durations were 190min (SBFT) and 59min (MRE). Median effective dose for SBFT was 1.5mSv, while MRE involved no ionizing radiation. Specificities for diagnosing SB involvement were 87.5% (SBFT) and 94% (MRE). 54 patients underwent subtotal colectomy and ileostomy, 12 restorative proctocolectomy, and 2 colectomy with ileorectal anastomosis. Preoperative imaging correlated with surgical pathology in 83% (SBFT) and 90% (MRE).

CONCLUSION

MRE is at least as effective as SBFT for assessing SB disease in children with colitis prior to colectomy. MRE requires less time and does not expose children to ionizing radiation. Retrospective Case Series, Level 4 Evidence.

Fecal Calprotectin for predicting Relapse and Activity in Patients with Crohn's Disease: A Meta-analysis

AIMS

We aimed to perform a meta-analysis of the predictive capacity of fecal calprotectin (FC) in activity and relapse of Crohn's disease (CD).

MATERIALS AND METHODS

MEDLINE, EMBASE, and the Cochrane Library databases were searched systematically. Pooled sensitivity, specificity, and other diagnostic indices were evaluated.

RESULTS

A total of 1,252 CD patients from 18 different studies were analyzed. The pooled sensitivity and specificity of FC at a cutoff value of 50 μg/g to predict activity of CD were 0.91 [95% confidence interval (CI): 0.87-0.95] and 0.47 (95% CI: 0.35-0.59) respectively. The pooled sensitivity and specificity of FC at a cutoff value of larger than 150 μg/g to monitor relapse of CD was 0.75 (95% CI: 0.67-0.82) and 0.71 (95% CI: 0.66-0.76) respectively. The area under the summary receiver operating characteristic (SROC) curve of FC for detecting CD activity was 0.78 (50 μg/g), 0.88 (100 μg/g), 0.85 (>150 μg/g), and the diagnostic odds ratio (DOR) was 10.21 (50 μg/g), 10.20 (100 μg/g), 11.68 (>150 μg/g) respectively.

CONCLUSION

As a simple and noninvasive marker, FC is useful to predict the activity and relapse in CD patients, and the capacity of FC to predict CD activity was superior to its application in monitoring relapse of CD.

HOW TO CITE THIS ARTICLE

Zhuge Y, Huang Q-P, Li Q, Wang J-S. Fecal Calprotectin for predicting Relapse and Activity in Patients with Crohn's Disease: A Meta-analysis. Euroasian J Hepato-Gastroenterol 2016;6(2):116-124.

Magnetic Resonance Imaging of the Small Bowel in Crohn's Disease: A Systematic Review and Meta-Analysis

Introduction. Crohn's disease is most commonly found in the terminal ileum and colonic region. Magnetic resonance has become a useful modality for assessing small bowel activity. In this study, we performed a systematic review and meta-analysis on the use of MR in detecting small bowel activity as well as extramural complications in Crohn's patients. Methods. Two independent reviewers sorted through articles until October 2, 2014. We included both studies providing raw data for pooling and studies without raw data. Sensitivity, specificity, likelihood ratios, and 95% confidence intervals were calculated for each study. Results. There were 27 included studies, of which 19 were included in the pooled analysis. Pooled analysis of the 19 studies (1020 patients) with raw data revealed a sensitivity of 0.88 (95% CI 0.86 to 0.91) and specificity was 0.88 (95% CI 0.84 to 0.91). In regard to detecting stenosis, pooled sensitivity was 0.65 (95% CI 0.53 to 0.76) and specificity was 0.93 (95% CI 0.89 to 0.96). Conclusion. MR imaging provides a reliable alternative in detecting small bowel activity in patients with Crohn's disease. Its advantages include high diagnostic accuracy and no radiation exposure while its disadvantages include high cost and limited availability.

Systematic review with meta-analysis: magnetic resonance enterography signs for the detection of inflammation and intestinal damage in Crohn's disease

BACKGROUND

In the treatment of Crohn's disease (CD), mucosal healing has become a major goal, with the hope of avoiding intestinal damage from chronic inflammation. Magnetic resonance enterography (MRE) has emerged as a non-invasive means of monitoring inflammation and damage.

AIMS

As part of the development of MRE-based multi-item measures of inflammation and damage for paediatric studies, we carried out a systematic review and meta-analysis to identify MRE variables used to describe these two distinct concepts.

METHODS

2501 studies of MRI and CD were identified. Studies written in any language reporting individual MRE signs for patients diagnosed with CD were included. Two-hundred-and-forty-four studies were fully reviewed and 62 were included (inflammation, n = 51; damage, n = 24). Sensitivity, specificity and associated confidence intervals were calculated, and hierarchical summary ROC curves were constructed for each MRE sign.

RESULTS

A total of 22 MRE signs were used to reflect inflammation, and 9 to reflect damage. Diagnostic accuracy of MRE signs of inflammation and damage was heterogeneous; however, wall enhancement, mucosal lesions and wall T2 hyperintensity were the most consistently useful for inflammation (most sensitivities >80% and specificities >90%), and detection of abscess and fistula were most consistently useful for damage (most sensitivities >90%, specificities >95%).

CONCLUSIONS

Identifying the best MRE variables to reflect inflammation and damage will maximise the utility of this rapidly emerging technique and is the first stage of constructing MRE-based indices for evaluating inflammation and intestinal damage.

Inflammatory bowel disease-the role of cross-sectional imaging techniques in the investigation of the small bowel

Abstract

Background: The diagnosis of inflammatory bowel disease (IBD) in children and adolescents is based on the integration of clinical, biological, endoscopic, histological and radiological data. Methods: The most important part of the diagnosis is the histology, which is acquired by endoscopy. Imaging of the small bowel has changed in recent years, but the imaging goals are primarily to determine the extent of small bowel involvement, assess complications and define candidates for surgery. Imaging techniques are divided into conventional and cross-sectional ones. Results: The spectrum of imaging findings of cross-sectional techniques is discussed, emphasising the advantages and limitations of each technique, acknowledging the specificities of the paediatric population. Cross-sectional techniques have advanced the ability to diagnose and monitor inflammatory disease of the small bowel. Conclusion: MR enterography is the technique of choice in children with known IBD, for the investigation of the small bowel and the whole GI tract. US should be the first choice examination in children with suspected IBD, while CT should be reserved for cases in which MRI is contraindicated or in acute emergency situations when US is inadequate.

Teaching Points

• Cross-sectional imaging of the small bowel is essential in paediatric IBD.

• Endoscopy is unable to assess extramural disease and examine the entire small bowel.

• US should be the first choice examination in children with suspected IBD.

• MR enterography is the technique of choice in children with known IBD.

• There are still controversies regarding the prediction of disease activity or fibrosis.

Systematic review with meta-analysis: magnetic resonance enterography vs. computed tomography enterography for evaluating disease activity in small bowel Crohn's disease

BACKGROUND

Magnetic resonance enterography (MRE) has been proposed as a non-ionising alternative method to computed tomography enterography (CTE). Some studies have directly compared CTE and MRE in patients with small bowel Crohn's disease (CD) with variable results.

AIM

To compare the overall diagnostic accuracy in assessing the activity of small bowel and complications.

METHODS

MEDLINE, EMBASE and Cochrane databases were searched for studies on the accuracy of MRE and CTE, as compared with a pre-defined reference standard. Pooled sensitivity, specificity, the weighted area under the curve (AUC), incremental yield (IY) and other diagnostic indices were evaluated.

RESULTS

A total of 290 CD patients from six different studies were analysed. The pooled sensitivity and specificity for MRE in detecting active small bowel CD was 87.9% [95% confidence interval (CI), 81.8-92.5] and 81.2% (95% CI: 71.9-88.4) respectively. The AUC under the summary receiver-operating characteristic (sROC) of MRE was 0.905 (SEM 0.03, standard error of the mean). Likewise, the pooled sensitivity and specificity of CTE in detecting active small bowel CD was 85.8% (95% CI: 79.2-90.9) and 83.6% (95% CI: 75.3-90.1) with the AUC of 0.898. The AUC of MRE in detecting fistula, stenosis and abscess was 0.936, 0.931 and 0.996, respectively, compared to 0.963, 0.616 and 0.899 of CTE. No statistically significant IY for MRE vs. CTE was found (fixed model, P > 0.05).

CONCLUSIONS

Magnetic resonance enterography has a diagnostic effectiveness comparable to computed tomography enterography, thus may serve as a radiation-free alternative for evaluation of patients with Crohn's disease.

Training readers to improve their accuracy in grading Crohn's disease activity on MRI

OBJECTIVES

To prospectively evaluate if training with direct feedback improves grading accuracy of inexperienced readers for Crohn's disease activity on magnetic resonance imaging (MRI).

METHODS

Thirty-one inexperienced readers assessed 25 cases as a baseline set. Subsequently, all readers received training and assessed 100 cases with direct feedback per case, randomly assigned to four sets of 25 cases. The cases in set 4 were identical to the baseline set. Grading accuracy, understaging, overstaging, mean reading times and confidence scores (scale 0-10) were compared between baseline and set 4, and between the four consecutive sets with feedback. Proportions of grading accuracy, understaging and overstaging per set were compared using logistic regression analyses. Mean reading times and confidence scores were compared by t-tests.

RESULTS

Grading accuracy increased from 66 % (95 % CI, 56-74 %) at baseline to 75 % (95 % CI, 66-81 %) in set 4 (P = 0.003). Understaging decreased from 15 % (95 % CI, 9-23 %) to 7 % (95 % CI, 3-14 %) (P < 0.001). Overstaging did not change significantly (20 % vs 19 %). Mean reading time decreased from 6 min 37 s to 4 min 35 s (P < 0.001). Mean confidence increased from 6.90 to 7.65 (P < 0.001). During training, overall grading accuracy, understaging, mean reading times and confidence scores improved gradually.

CONCLUSIONS

Inexperienced readers need training with at least 100 cases to achieve the literature reported grading accuracy of 75 %.

KEY POINTS

• Most radiologists have limited experience of grading Crohn's disease activity on MRI. • Inexperienced readers need training in the MRI assessment of Crohn's disease. • Grading accuracy, understaging, reading time and confidence scores improved during training. • Radiologists and residents show similar accuracy in grading Crohn's disease. • After 100 cases, grading accuracy can be reached as reported in the literature.