Magnetic resonance enterocolonography in detecting erosion and redness in intestinal mucosa of patients with Crohn's disease

Assessment of activity and severity of inflammatory bowel disease in cross-sectional imaging techniques: a systematic review

BACKGROUND AND AIMS

Cross-sectional imaging techniques, including intestinal ultrasonography (IUS), computed tomography enterography (CTE), magnetic resonance enterography (MRE), are increasingly used for the evaluation of inflammatory bowel diseases (IBD). We aimed to systematically review literature evidence on the assessment of disease activity, and/or severity through cross-sectional imaging in IBD patients, and to offer guidance on their most effective utilization.

METHODS

We performed a systematic review of PubMed, EMBASE, and Scopus to identify citations pertaining to the assessment of disease activity and/or severity at cross-sectional imaging techniques compared to a reference standard (ie, other radiological techniques, endoscopy, histopathology, and surgery) in IBD patients published until December 2023.

RESULTS

Overall, 179 papers published between 1990 and 2023 were included, with a total of 10 988 IBD patients (9304 Crohn's disease [84.7%], 1206 ulcerative colitis [11.0%], 38 IBD-U [0.3%], 440 unspecified [4.0%]). Of the 179 studies, 39 investigated IUS, 22/179 CTE, and 101/179 MRE. In the remaining papers, 2 techniques were addressed together. In 81.6% of the papers, endoscopy (with or without histopathology) was used as a reference standard. All studies included evaluated disease activity, while just over half (100/179, 55.8%) also evaluated disease severity of the addressed cross-sectional methodology. Pooled sensitivity, specificity, and overall accuracy of IUS, MRE, and CTE compared to the reference standard were 60%-99%, 60%-100%, and 70%-99%, respectively.

CONCLUSIONS

All cross-sectional imaging techniques demonstrated moderate-to-good accuracy in assessing disease activity and severity of IBD. This finding highlights the potential, especially for MRE and IUS to be widely utilized in managing IBD in both clinical practice and clinical trials.

Comparison of the magnetic resonance scoring systems for Crohn's disease activity: MaRIA, simplified MaRIA, and Nancy scores

PURPOSE

The most widely used score for assessing the activity of Crohn's disease (CD) is the Magnetic Resonance Index of Activity (MaRIA) score, but it is time-consuming. The aim of this study was to compare the diagnostic accuracy of MaRIA score to the other two easily calculated scores.

METHODS

Between January 2011 and May 2021, 67 patients with CD who underwent MRE and ileocolonoscopy within 2 weeks were enrolled. The MRE-based scores including the MaRIA score, simplified MaRIA (sMaRIA) score, and Nancy score for each colonic segment and terminal ileum were calculated and correlated with the ileocolonoscopic findings. The simplified endoscopic score for Crohn's disease (SES-CD) was considered the gold standard.

RESULTS

A total of 343 intestinal segments were included in the analysis, of which 109 (31.8%) showed active inflammation on ileocolonoscopy. The areas under the receiver operating characteristic curve (AUC) of the MaRIA, sMaRIA, and Nancy scores for detecting active disease were 0.752, 0.764, and 0.765, respectively. In the sub-analysis for different indications, the MaRIA and sMaRIA scores showed a higher AUC (0.721 and 0.741) than the Nancy score (0.652) for disease monitoring.

CONCLUSION

The sMARIA and Nancy scores showed comparable diagnostic accuracy to the MaRIA score, and thus could be used as alternatives to the MaRIA score. Furthermore, considering the range of application, especially for disease monitoring, the sMaRIA score may be more suitable for use in clinical practice.

Replacing Endoscopy with Magnetic Resonance Enterography for Mucosal Activity Assessment in Terminal Ileal Crohn's Disease: Are We There Yet?

Crohn's disease (CD) is a chronic immune mediated disorder that most commonly affects the small bowel and/or the large bowel. Treatment targets in CD include mucosal healing assessed via ileocolonoscopy and transmural healing assessed through cross-sectional imaging modalities such as magnetic resonance enterography (MRE). More recently, histological healing in CD has emerged as a treatment target, though it is made cumbersome given its reliance on frequent endoscopic examinations. With expert guidelines now recommending regular objective assessments as part of a treat-to-target approach, accurate non-invasive assessment will become increasingly critical. MRE has an established role in the assessment of small bowel CD, with growing data supportive of its ability in detecting disease activity at mucosal and histological levels. This could therefore potentially reduce the need for serial endoscopic assessment. Thus, this review will assess the capacity of individual MRE parameters and MRE indices for detecting mucosal and histological small bowel CD activity. Furthermore, challenging scenarios, such as CD activity detection in post-operative clinical scenarios and abnormal findings in the context of a normal ileocolonoscopy, will be explored.

Challenges and Strategies to Optimising the Quality of Small Bowel Magnetic Resonance Imaging in Crohn's Disease

Magnetic resonance enterography (MRE) is one of the most highly utilised tools in the assessment of patients with small bowel Crohn's disease (CD). As a non-invasive modality, it has both patient and procedure-related advantages over ileocolonoscopy which is the current gold standard for Crohn's disease activity assessment. MRE relies upon high-quality images to ensure accurate disease activity assessment; however, few studies have explored the impact of image quality on the accuracy of small bowel CD activity assessment. Bowel distension and motion artifacts are two key imaging parameters that impact the quality of images obtained through MRE. Multiple strategies have been employed to both minimise the effects of motion artifacts and improve bowel distension. This review discusses the definitions of bowel distension and motion artifacts within the literature with a particular focus on current strategies to improve bowel distension and limit motion artifacts in MRE.

Prospective comparison of diffusion-weighted magnetic resonance enterography and contrast enhanced computed tomography enterography for the detection of ileocolonic Crohn's disease

BACKGROUND AND AIMS

Crohn's disease (CD) is a chronic and relapsing course with various status of different segments, and there were no investigations comparing the lesion detection between magnetic resonance (MR) and computed tomography (CT) in term of the severity of CD. We aim to assess the performances of diffusion-weighted MR enterography (DW-MRE) and contrast enhanced CT enterography (CTE) for detecting different grade lesions in ileocolonic CD.

METHODS

Forty-one consecutive patients finally diagnosed with ileocolonic CD were included. All the patients prospectively underwent DW-MRE, contrast enhanced CTE, and ileocolonoscopy within 2 weeks. DW-MRE and CTE images were interpreted for the presence or absence of active CD segments by two experienced radiologists independently. Ileocolonic segments (terminal ileum, right colon, transverse colon, left colon, and rectum) were graded as inactive (0-2), mild (3-6), or moderate-severe (≥ 7) by the simplified endoscopic score for CD (SES-CD). Diagnostic efficiencies of DW-MRE and CTE for mild and/or moderate-severe CD segments were calculated and compared, using ileocolonoscopy as reference standard.

RESULTS

According to SES-CD, 190 ileocolonic segments from 41 CD patients were scored as 91 inactive, 68 mild, and 31 moderate-severe CD lesions. The sensitivity of DW-MRE for detecting active from inactive segments was higher than that of CTE, and the specificities of them had no significant differences. As for the subgroup analysis, DW-MRE was more sensitive for mild CD lesions than CTE (76.5% vs 60.3%; P = 0.019), while the sensitivities for moderate-severe CD were similar between these two modalities (96.8% for DW-MRE and 93.5% for CTE; P = 1.00).

CONCLUSIONS

Both DW-MRE and CTE had comparably excellent performances for moderate-severe CD detection; DW-MRE demonstrated better sensitivity in mild lesions compared with CTE and could be more suitable for the diagnosis of mild CD.

Lemann Index for Assessment of Crohn's Disease: Correlation with the Quality of Life, Endoscopic Disease Activity, Magnetic Resonance Index of Activity and C- Reactive Protein

AIM

Crohn's disease (CD) is characterized by continuing inflammation and progressive gut damage. Despite many scoring indices of CD, there is a lack of more global assessment tools for the evaluation of the total disease impact on the gut.

METHODS

Fift y-three adult patients with proven CD underwent magnetic resonance enterocolonography (MR-EC), colonoscopy, and clinical activity assessment, including CRP. Quality of life was assessed using IBDQ. MR-EC was used to evaluate the Magnetic Resonance Index of Activity (MaRIA- global (G)) and the Lemann Index (LI). The CD Endoscopic Index of Severity (CDEIS) was used to score the endoscopic activity of the disease.

RESULTS

A signifi cant correlation between the LI and IBDQ was found (r=-0.812, P<0.01). LI and MaRIA-G correlated moderately, while the LI did not correlate significantly with CRP and CDEIS. For the detection of endoscopically active CD, MaRIA-G was more sensitive and specific (83.3%; 73.3%) compared to the LI (66.7%; 60.0%). There was a moderate correlation between CRP and MaRIA-G, as well as CRP and CDEIS (r=0.496; r=0.527,<0.01).

CONCLUSION

A signifi cant negative correlation between the LI and quality of life, measured by IBDQ, was found in our study, suggesting that the LI could resemble more global features of the disease, besides inflammatory activity of the gut.

Quantitative diffusion-weighted magnetic resonance enterography in ileal Crohn's disease: A systematic analysis of intra and interobserver reproducibility

BACKGROUND

Magnetic resonance enterography (MRE) is increasingly attractive as a noninvasive and radiation-free tool for assessing Crohn's disease (CD). Diffusion-weighted imaging (DWI) is recommended as an optional MRE sequence for CD by the European Society of Gastrointestinal and Abdominal Radiology, and has shown a superb potential as a quantitative modality for bowel inflammation evaluation. However, the measurement reproducibility of quantitative DWI analysis in MRE has not been ascertained so far. To facilitate the application of quantitative diffusion-weighted MRE in the clinical routine, systematic investigations of the intra and interobserver reproducibility of DWI quantitative parameters should be performed.

AIM

To evaluate the intra and interobserver reproducibility of quantitative analysis for diffusion-weighted MRE (DW-MRE) in ileal CD.

METHODS

Forty-four subjects (21 with CD and 23 control subjects) who underwent ileocolonoscopy and DW-MRE (b = 800 s/mm2) within one week were included. Two radiologists independently measured apparent diffusion coefficients (ADC) of the terminal ileum and signal intensity ratio (SR) of the terminal ileum to ipsilateral psoas muscle on DWI images (b = 800 s/mm2). Between- and within-reader agreements were assessed using intraclass correlation coefficients (ICC), coefficients of variation (CoV), and 95% limits of agreement of Bland-Altman plots (BA-LA LoA). Diagnostic performances of ADC and SR for identifying inflamed terminal ileum from the normal were evaluated by receiver operating characteristic (ROC) curve analysis.

RESULTS

There were no significant differences in ADC or SR values between the two sessions or between the two radiologists either in the CD or control group (paired t-test, P > 0.05). The intra and interobserver reproducibility of ADC (ICC: 0.952-0.984; CoV: 3.73-6.28%; BA-LA LoA: ±11.27% to ±15.88%) and SR (ICC: 0.969-0.989; CoV: 3.51%-4.64%; BA-LA LoA: ±10.62% to ±15.45%) was excellent for CD. Agreement of ADC measurements was slightly less in control subjects (ICC: 0.641-0.736; CoV: 10.47%-11.43%; BA-LA LoA: ± 26.59% to ± 30.83%). SR of normal terminal ileum demonstrated high intra and interobserver reproducibility (ICC: 0.944-0.974; CoV: 3.73%-6.28%; BA-LA LoA: ± 18.58% to ± 24.43%). ADC and SR of two readers had outstanding diagnostic efficiencies (area under the ROC curve: 0.923-0.988).

CONCLUSION

Quantitative parameters derived from DW-MRE have good to excellent intra and interobserver agreements with high diagnostic accuracy, and can serve as robust and efficient quantitative biomarkers for CD evaluation.

Combination of colonoscopy and magnetic resonance enterography is more useful for clinical decision making than colonoscopy alone in patients with complicated Crohn's disease

BACKGROUND/AIMS

The small bowel is affected in more than half of patients with Crohn's disease (CD) at the time of diagnosis, and small bowel involvement has a negative impact on the long-term outcome. Many patients reportedly have active lesions in the small intestine even in patients in clinical remission. This study was performed to compare findings of magnetic resonance enterography (MRE) and ileocolonoscopy.

METHODS

A single-center retrospective study was conducted in 50 patients (60 imaging series) with CD, for whom MRE was additionally performed during the bowel preparation for subsequent ileocolonoscopy. Endoscopic remission was defined as a Simple Endoscopic Score for CD (SES-CD) of <5. MRE remission was defined as a Magnetic Resonance Index of Activity (MaRIA) score of <50. The time to treatment escalation was assessed by the log-rank test.

RESULTS

Importantly, 7 of 29 patients (24.1%) with endoscopic remission had a MaRIA score of ≥50. Both SES-CD and MaRIA correlated with the need for treatment escalation (P = 0.025, P = 0.009, respectively). MRE predicted the need for treatment escalation even in patients with endoscopic remission. Although no correlation was present between SES-CD and MaRIA score in patients with structuring/penetrating disease, or insufficient ileal insertion (<10cm), a high MaRIA score still correlated with the need for treatment escalation in stricturing or penetrating disease (P = 0.0306).

CONCLUSIONS

The MaRIA score predicts the need for treatment escalation even in patients with endoscopic remission, indicating that addition of MRE to conventional ileocolonoscopy alone can be a useful, noninvasive tool for monitoring CD especially in stricturing or penetrating disease.

Comparison of Conventional Ultrasound and Contrast Enhanced Magnetic Resonance (MR) Enterography in Evaluation Patients with Crohn's Disease

INTRODUCTION

The small intestine is a challenging organ for clinical and radiological evaluation, and by introducing imaging radiological techniques, not significantly disturbing the comfort and safety of patients, it attempts to obtain adequate diagnosis and valuable information.

AIM

The research was conducted with the aim of checking the comparability and potential of diagnostic modality of ultrasound and dynamic contrast enhanced MR Enterography (DCE-MR) in patients with Crohn's disease.

METHODS

55 patients were examined prospectively, and ultrasound examination of the abdomen was performed for all patients before the MR enterography. They were subsequently endoscopically examined or treated surgically, which was taken as a reference. Four parameters characterizing the disease itself were analyzed: bowel wall thickening, presence of abscess, fistula and lymphadenopathy.

RESULTS

Comparing the accuracy of the results of ultrasound findings and findings of MR enterography, it was found that there is a significant difference in the results obtained. The study found that the sensitivity for MR enterography for bowel wall thickening was 97.8%, and the specificity was 70%, while the sensitivity for ultrasound for the bowel wall thickening was 51% and the specificity was 100%. In the diagnosis of abscess, there was no significant difference between the results obtained by ultrasound and magnetic resonance imaging (MRI) findings, while in fistula and lymphadenopathy there was a significant difference.

CONCLUSION

Conventional ultrasound is a good orientation method in the initial evaluation of patients with Crohn's disease, while contrast enhanced MR enterography provides an excellent assessment for disease activity as well as the complications that accompany it.

A review of magnetic resonance enterography-based indices for quantification of Crohn's disease inflammation

Magnetic resonance enterography (MRE) is a leading radiological modality in Crohn's disease (CD) and is used together with laboratory findings and endoscopic examinations for the evaluation of patients during initial diagnosis and follow up. Over the years, there has been great progress in the understanding of CD and there is a continuous strive to achieve better monitoring of patients and to develop new modalities which will predict disease course and thus help in clinical decisions making. An objective evaluation of CD using a quantification score is not a new concept and there are different clinical, endoscopies, radiological and combined indices which are used in clinical practice. Such scores are a necessity in clinical trials on CD for evaluation of disease response, however, there is no consensus of the preferred MRE score and they are not routinely used. This review presents MRE-based indices in use in the last decade: the Magnetic Resonance Index of Activity (MaRIA), the Clermont score, the Crohn's Disease Magnetic Resonance Imaging (MRI) Index (CDMI), the Magnetic Resonance Enterography Global Score (MEGS) and the Lemann index. We compare the different indices and evaluate the clinical research that utilized them. The aim of this review is to provide a reference guide for researchers and clinicians who incorporate MRE indices in their work. When devising future indices, accumulated data of the existing indices must be taken into account, as each of the current indices has its own strengths and weakness.

Evaluation by MR Enterocolonography of Lansoprazole-induced Collagenous Colitis Accompanied with Protein-losing Enteropathy

We herein describe a 69-year-old man suffering from chronic diarrhea caused by lansoprazole (LPZ)-induced collagenous colitis (CC) accompanied with protein-losing enteropathy (PLE), diagnosed by increased fecal alpha-1 antitrypsin clearance and the findings of leakage from the descending colon to the sigmoid colon on scintigraphy. MR enterocolonography (MREC) was also performed for differentiating digestive diseases, and inflamed findings were observed around the same portion as those on scintigraphy, suggesting that this region was responsible for protein loss in this case. The MREC findings improved after the cessation of LPZ, and hypoalbuminemia also improved simultaneously. This case suggests that MREC may be a new and useful diagnostic tool for CC with PLE.

Increasing efficiency of MRE for diagnosis of Crohn's disease activity through proper sequence selection: a practical approach for clinical trials

PURPOSE

To derive the best magnetic resonance enterography (MRE) approach for detecting activity and severe lesions in Crohn's disease (CD) to use for selecting patients and measuring response to treatment in clinical trials.

METHODS

We compared the accuracies of MRE (T2-weighted sequences, DWI (b = 800 s/mm²) sequences, combined T2-weighted and DWI sequences, combined T2-weighted or DWI sequences, and MaRIA score based on T2-weighted and contrast-enhanced T1-weighted sequences) versus ileocolonoscopy (SES-CD) performed within 1 month. Bowel segments were classified as inactive (SES-CD < 2), active (SES-CD ≥ 2), or active with severe lesions (ulcers seen at endoscopy). McNemar's test was used to compare the accuracies of the different approaches against endoscopy.

RESULTS

224 segments in 43 patients were analyzed. For detecting active disease, the combination of findings from T2 and DWI sequences results in the highest specific and accurate sequence combination. Combined T2-weighted and DWI sequences had similar sensitivity to those of MaRIA (P = 0.25) but lower specificity (P = 0.007) and accuracy (P = 0.0013) than MaRIA score. For detecting severe lesions, T2-weighted sequences alone had greater accuracy [similar to MaRIA score (P > 0.999)] than other noncontrast approaches.

CONCLUSIONS

T2-weighted sequences should be used as a first screening step, and followed by contrast-enhanced T1-weighted sequences only when abnormal findings are identified; adding DWI does not improve the accuracy of MRE.

Magnetic resonance index of activity (MaRIA) and Clermont score are highly and equally effective MRI indices in detecting mucosal healing in Crohn's disease

BACKGROUND

Magnetic resonance index of activity (MaRIA) and Clermont score are currently the two main MRI indices that have been validated compared to endoscopy in Crohn's disease (CD).

AIMS

To compare the accuracy of MaRIA and Clermont score in assessing CD mucosal healing.

METHODS

Fourty-four CD patients underwent prospectively and consecutively MRI and colonoscopy.

RESULTS

Considering 207 segments, MaRIA>7 and Clermont score>8.4 demonstrated substantial accuracy to detect endoscopic ulcerations (73.9% and 74.0%, respectively) and presented with high specificity (82.1% and 81.3%) and high negative predictive value (NPV) (82.1% and 82.4%) for MaRIA and Clermont score, respectively. The sensitivity for detecting deep ulcerations was 90.9% for both MaRIA>11 and Clermont score>12.5, with a specificity of 82.0% and 80.0%, respectively. Among 44 patients, deep MRI remission predicted mucosal healing with specificity=85.3% and NPV=85.3% according to Barcelona criteria (no segmental MaRIA>7), and specificity=88.2% and NPV=85.7% according to Clermont criteria (no segmental Clermont score>8.4). In addition, MRI remission predicted mucosal healing with specificity=76.5% and NPV=86.7% according to Barcelona criteria (no segmental MaRIA>11), and specificity=79.4% and NPV=84.4% according to Clermont criteria (no segmental Clermont score>12.5).

CONCLUSION

MaRIA and Clermont score are equally effective in detecting CD endoscopic ulcerations supporting their use as therapeutic endpoints.

Diffusion-weighted imaging in quiescent Crohn's disease: correlation with inflammatory biomarkers and video capsule endoscopy

AIM

To investigate the role of restricted diffusion in quiescent Crohn's disease (CD) patients and its association with inflammatory biomarkers and endoscopic disease.

MATERIAL AND METHODS

Fifty-two quiescent CD patients prospectively underwent magnetic resonance enterography (MRE) and video capsule endoscopy (VCE) and were tested for the inflammatory biomarkers, faecal calprotectin (FCP) and C-reactive protein (CRP). Restricted diffusion in the distal ileum was qualitatively (absence/presence) and quantitatively (apparent diffusion coefficient [ADC]) assessed by two readers. The VCE-based Lewis score was calculated for the distal ileum. Restricted diffusion sensitivity and specificity for VCE ulcerations were assessed for patients with elevated (>100 μg/g) or normal (<100 μg/g) FCP. Receiver operating characteristic (ROC) curve was used to assess the ability of ADC to identify patients with concurrent VCE ulceration and elevated FCP.

RESULTS

The sensitivity and specificity of restricted diffusion for patients with VCE ulceration were higher in patients with elevated FCP (reader 1: 71.4%, 80%, reader 2: 76.2%, 100%, respectively) compared to patients with normal FCP (reader 1: 46.2%, 61.5%; reader 2: 15.4%, 76.9%, respectively). The ADC had a high diagnostic accuracy for identifying patients that had concurrent VCE ulceration and elevated FCP (reader 1: AUC=0.819, reader 2: AUC=0.832).

CONCLUSION

In quiescent CD patients, the presence of restricted diffusion is suggestive of an active inflammation, associated with elevated FCP. Thus, DWI may serve as a clinical tool in the follow-up of these patients, implying subclinical inflammatory flares.

Quantification of inflammatory activity in patients with Crohn's disease using diffusion weighted imaging (DWI) in MR enteroclysis and MR enterography

Background Individual studies have demonstrated the potential of diffusion-weighted magnetic resonance imaging (DWI-MRI) for identifying inflamed bowel segments. However, these studies were conducted with rather small patient cohorts and in most cases by means of MR enterography only. Purpose To demonstrate the feasibility of detecting inflamed bowel segments in a large collective of patients with Crohn's disease using DWI in MR enteroclysis and MR enterography and to compare the results of both techniques, also considering clinical parameters by means of the Harvey-Bradshaw Index (HBI). Material and Methods Ninety-six patients underwent MRI enteroclysis and 35 patients MR enterography, both with additional DWI. The HBI as well as apparent diffusion coefficients (ADC) in areas of inflamed and normal bowel wall were determined. Thus resulting in 208 bowel segments that were visualized and subsequently statistically analyzed. Results There were no significant differences in ADC values in MR enteroclysis and MR enterography ( P = 0.383 in inflammation, P = 0.223 in normal wall). Areas of inflammation showed statistically highly significant lower ADC values than areas of normal bowel wall ( P < 0.001). An ADC threshold of 1.56 × 10^-3mm²/s can distinguish between normal and inflamed bowel segments with a sensitivity of 97.4% and a specificity of 99.2%. A highly significant correlation could be shown between ADC and HBI values ( P = 0.001). Conclusion DWI-MRI facilitates recognition of inflamed bowel segments in patients with Crohn's disease and the ADC values show an excellent correlation to the HBI. There were no significant differences in ADC values in MR enteroclysis and MR enterography. An ADC threshold of 1.56 × 10^-3mm²/s differentiates between normal and inflamed bowel wall.

Diffusion-weighted MRI in Crohn's disease: Current status and recommendations

Over the past years, technological improvements and refinements in magnetic resonance imaging (MRI) hardware have made high-quality diffusion-weighted imaging (DWI) routinely possible for the bowel. DWI is promising for the detection and characterization of lesions in Crohn's disease (CD) and has been advocated as an alternative to intravenous gadolinium-based contrast agents. Furthermore, quantification using the apparent diffusion coefficient may have value as a biomarker of CD activity and has shown promise. In this article we critically review the literature pertaining to the value of DWI in CD for detection, characterization, and quantification of disease activity and complications. Although the body of supportive evidence is growing, it is clear that well-designed, multicenter studies are required before the role of DWI in clinical practice can be fully established. J. Magn. Reson. Imaging 2016;44:1381-1396.

DWI at MR Enterography for Evaluating Bowel Inflammation in Crohn Disease

OBJECTIVE

The purpose of this article is to provide a comprehensive review regarding DWI enterography used for evaluating Crohn disease and to summarize the relevant evidence.

CONCLUSION

Active bowel inflammation in Crohn disease causes restricted diffusion on MR enterography with DWI. Enterographic DWI to evaluate Crohn disease is increasingly drawing attention for both academic research and clinical practice and has shown potential as a quantitative tool for assessing bowel inflammation. DWI enterography also has multiple unresolved issues and limitations.

Diffusion-weighted Magnetic Resonance Enterography for Evaluating Bowel Inflammation in Crohn's Disease: A Systematic Review and Meta-analysis

BACKGROUND

To systematically determine the performance of diffusion-weighted imaging magnetic resonance enterography (DWI-MRE) for evaluating bowel inflammation in Crohn's disease and sources of heterogeneity between reported results.

METHODS

We identified research studies that investigated DWI-MRE to diagnose bowel inflammation (present versus absent) or to assess bowel inflammatory severity in Crohn's disease by performing a systematic search of PubMed MEDLINE and EMBASE (until March 31, 2015). Study quality was assessed using QUADAS-2. For studies reporting dichotomous diagnosis of bowel inflammation, study heterogeneity and threshold effect were analyzed, summary sensitivity and specificity were estimated, and meta-regression analysis was performed to further explore study heterogeneity. For studies reporting assessment of inflammatory severity, a qualitative summary was performed.

RESULTS

Of 159 articles screened, we found 12 studies (1515 bowel segments) reporting a diagnosis of bowel inflammation and 6 studies (1066 bowel segments) reporting assessment of inflammatory severity. The summary sensitivity and specificity were 92.9% (95% CI, 85.8%-96.6%; I = 87.9%) and 91% (95% CI, 79.7%-96.3%; I = 95.1%), respectively. Sensitivity and false-positive rate were inversely correlated (r = -0.650; P = 0.022). Lack of blinding to contrast-enhanced MRE when interpreting DWI-MRE (P = 0.01) and use of contrast-enhanced MRE as a reference standard (P < 0.01) in some studies were significant factors for study heterogeneity and likely caused overestimation of DWI-MRE accuracy. There was rather clear correlation between diffusion-related parameters and bowel inflammation severity, although the strengths were heterogeneous (correlation coefficient, 0.39-0.98).

CONCLUSIONS

DWI-MRE accuracy was very heterogeneous between studies and was likely overestimated in some studies. Despite rather clear correlation between diffusion-related parameters and bowel inflammatory severity, its strength was variable.

Diffusion-weighted magnetic resonance enterocolonography in predicting remission after anti-TNF induction therapy in Crohn's disease

BACKGROUND

Diffusion-weighted magnetic resonance entero-colonography (DW-MREC) with no rectal distension and with no bowel cleansing is accurate to assess inflammatory activity in ileocolonic Crohn's disease (CD).

AIM

To study DW-MREC parameters as predictors of remission (CDAI < 150 and CRP < 5mg/L) after anti-TNF induction therapy.

METHODS

Forty consecutive CD patients were prospectively and consecutively included. All the patients underwent DW-MREC with apparent diffusion coefficient (ADC) and MaRIA calculation before starting anti-TNF. Mean ADC was defined as the mean of the segmental ADC.

RESULTS

Twenty patients (50.0%) experienced remission at W12. Low mean ADC (2.05 ± 0.22 vs 1.89 ± 0.25, p = 0.03) and high total MaRIA (39.2 ± 16.6 vs 51.7 ± 18.2, p = 0.03) were predictive of remission at W12. Using a ROC curve, we determined a mean ADC of 1.96 as predictive cut-off of remission at W12 (AUC = 0.703 [0.535-0.872]) with sensitivity, specificity, positive predictive value and negative predictive value of 70.0%, 65.0%, 66.7% and 68.4%, respectively. In multivariate analysis, mean ADC < 1.96 (OR = 4.87, 95% CI [1.04-22.64]) and total MaRIA > 42.5 (OR = 5.11, 95% CI [1.03-25.37]), reflecting high inflammatory activity, were predictive of remission at week 12.

CONCLUSIONS

DW-MREC using quantitative parameters i.e. ADC, is useful in detecting and assessing inflammatory activity but also to predict efficacy of anti-TNF induction therapy in CD.

Assessment of colon and bladder crosstalk in an experimental colitis model using contrast-enhanced magnetic resonance imaging

BACKGROUND

Inflammatory bowel disease (IBD) consists of two chronic remitting-relapsing inflammatory disorders in the colon referred to as ulcerative colitis and Crohn's disease (CD). Inflammatory bowel disease affects about 1.4 million Americans. 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis is a widely used model of experimental intestinal inflammation with characteristic transmural and segmental lesions that are similar to CD.

METHODS

Here, we report on the use of contrast-enhanced magnetic resonance imaging (CE-MRI) to monitor in vivo bladder permeability changes resulting from bladder crosstalk following colon TNBS exposure, and TNBS-induced colitis. Changes in MRI signal intensities and histology were evaluated for both colon and bladder regions.

KEY RESULTS

Uptake of contrast agent in the colon demonstrated a significant increase in signal intensity (SI) for TNBS-exposed rats (p < 0.01) compared to controls. In addition, a significant increase in bladder SI for colon TNBS-exposed rats (p < 0.001) was observed compared to saline controls. Histological damage within the colon was observed, however, bladder histology indicated a normal urothelium in rats with TNBS-induced colitis, despite increased permeability seen by CE-MRI.

CONCLUSIONS & INFERENCES

Contrast-enhanced MRI was able to quantitatively measure inflammation associated with TNBS-induced colitis, and assess bladder crosstalk measured as an increase in urothelial permeability. Although CE-MRI is routinely used to assess inflammation with IBD, currently there is no diagnostic test to assess bladder crosstalk with this disease, and our developed method may be useful in providing crosstalk information between organ and tissue systems in IBD patients, in addition to colitis.

Diffusion-weighted magnetic resonance imaging is effective to detect ileocolonic ulcerations in Crohn's disease

BACKGROUND

Magnetic resonance entero-colonography enables accurate assessment of ileocolonic Crohn's disease, but the need for bowel cleansing and rectal enema limits considerably its use in daily practice.

AIM

We evaluated the accuracy of diffusion-weighted magnetic resonance entero-colonography with neither bowel cleansing nor rectal enema to assess endoscopic activity.

METHODS

Forty-four Crohn's disease patients underwent prospectively and consecutively diffusion-weighted magnetic resonance entero-colonography [with apparent diffusion coefficient (ADC) and Clermont score calculation] and ileocolonoscopy [with Crohn's Disease Endoscopic Index of Severity (CDEIS) and Simplified Endoscopic score for Crohn's Disease (SES-CD) calculation].

RESULTS

Mean ADC was inversely correlated with total CDEIS (ρ = -0.40; P = 0.0067) and total SES-CD (ρ = -0.33; P = 0.032). Considering the 194 segments, ADC was inversely correlated with segmental CDEIS (-0.48; P < 0.001) and segmental SES-CD (-0.44; P < 0.001). ADC values were lower in segments with deep ulcers (1.30 ± 0.23) or superficial ulcerations (1.75 ± 0.64) than in non-ulcerated segments (2.15 ± 0.5) (P = 0.001). Using a receiver operating curve, we determined that segmental ADC <1.42 detected endoscopic deep ulcerations with sensitivity = 0.91 and specificity = 0.83 (Area under the curve = 0.84; P < 0.001). Segmental ADC <1.88 detected endoscopic superficial ulcerations with sensitivity = 0.64 and specificity = 0.75. The segmental ADC values decreased when the ulcerations size increased (P = 0.0001). Clermont score correlated with ileal CDEIS (0.63; P < 0.05) and ileal SES-CD (0.58; P < 0.05). Clermont score was higher in ulcerated segments (23.3 ± 8.4) than in non-ulcerated segments (12.4 ± 10.0) (P = 0.006) and increased with ulcers size (P = 0.012). Clermont score >18.9 detected ulcerations with sensitivity = 0.79 and specificity = 0.73.

CONCLUSION

Diffusion-weighted magnetic resonance entero-colonography using apparent diffusion coefficient and Clermont score was effective to indirectly detect endoscopic ulcerations in ileocolonic Crohn's disease.