Bowel Wall Visualization Using MR Enterography in Relationship to Bowel Lumen Contents and Patient Demographics

Feasibility of Intestinal MR Elastography in Inflammatory Bowel Disease

BACKGROUND

While MR enterography allows detection of inflammatory bowel disease (IBD), the findings continue to be of limited use in guiding treatment-medication vs. surgery.

PURPOSE

To test the feasibility of MR elastography of the gut in healthy volunteers and IBD patients.

STUDY TYPE

Prospective pilot.

POPULATION

Forty subjects (healthy volunteers: n = 20, 37 ± 14 years, 10 women; IBD patients: n = 20 (ulcerative colitis n = 9, Crohn's disease n = 11), 41 ± 15 years, 11 women).

FIELD STRENGTH/SEQUENCE

Multifrequency MR elastography using a single-shot spin-echo echo planar imaging sequence at 1.5 T with drive frequencies of 40, 50, 60, and 70 Hz.

ASSESSMENT

Maps of shear-wave speed (SWS, in m/s) and loss angle (φ, in rad), representing stiffness and solid-fluid behavior, respectively, were generated using tomoelastography data processing. Histopathological analysis of surgical specimens was used as reference standard in patients.

STATISTICAL TESTS

Unpaired t-test, one-way analysis of variance followed by Tukey post hoc analysis, Pearson's correlation coefficient and area under the receiver operating characteristic curve (AUC) with 95%-confidence interval (CI). Significance level of 5%.

RESULTS

MR elastography was feasible in all 40 subjects (100% technical success rate). SWS and φ were significantly increased in IBD by 21% and 20% (IBD: 1.45 ± 0.14 m/s and 0.78 ± 0.12 rad; healthy volunteers: 1.20 ± 0.14 m/s and 0.65 ± 0.06 rad), whereas no significant differences were found between ulcerative colitis and Crohn's disease (P = 0.74 and 0.90, respectively). In a preliminary assessment, a high diagnostic accuracy in detecting IBD was suggested by an AUC of 0.90 (CI: 0.81-0.96) for SWS and 0.84 (CI: 0.71-0.95) for φ.

DATA CONCLUSION

In this pilot study, our results demonstrated the feasibility of MR elastography of the gut and showed an excellent diagnostic performance in predicting IBD.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 1.