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Magnetic resonance colonography accurately assessed ulcerative colitis activity, severity
Magnetic resonance colonography may be an alternative to colonoscopy for the assessment of disease activity and severity in patients with ulcerative colitis, according to recent results.
Researchers performed colonoscopy and magnetic resonance colonography (MRC) on 50 patients with ulcerative colitis (UC). Each segment of the colon was assessed according to wall thickness, wall signal intensity before and after contrast, relative contrast enhancement (RCE), mural edema, engorged perienteric vasculature (the comb sign) and the presence of enlarged lymph nodes.
Of 250 colonic segments evaluated via MRC, 32.4% were considered inactive, 37.2% had mild-to-moderate activity (inflammation without ulcers) and 30.4% had severe activity (ulceration). Significant differences were observed across the three activity levels for all assessed parameters, excluding the comb sign when compared between mild-to-moderate and severe segments (P=.072 for difference).
Disease activity was associated with edema (P=.031), enlarged lymph nodes (P=.011) and the comb sign (P<.001). Severe activity was associated with RCE (P=.002), enlarged lymph nodes (P<.001) and the comb sign (P=.002). Investigators established a simplified MRC index (MRC-S) ranging from 0 to 4, with the presence of edema, enlarged lymph nodes, the comb sign and an RCE more than 100% each equivalent to one point.
According to ROC analysis, an MRC-S score of 1 or more accurately diagnosed endoscopic inflammation, with a sensitivity of 87% and specificity of 88% (AUC=0.95, P<.001). An MRC-S of 2 or more accurately detected severe lesions, with a sensitivity of 83% and specificity of 82% (AUC=0.91, P<.001). Investigators observed a strong correlation between MRC-S and endoscopy results as measured by the modified Baron score (r=0.81) and radiologists’ assessments of disease severity in patients (r=0.77) (P<.001 for both comparisons).
“We demonstrate that MRC can accurately assess disease activity and severity in UC using simple objective [magnetic resonance imaging] parameters,” the researchers wrote. “Accordingly, MRC can be used in the clinical setting as a complementary [or even alternative] imaging modality to endoscopy for the evaluation of patients with UC, particularly in patients with severe disease in whom colonoscopy may be contraindicated or in those with incomplete colonoscopy to reassess disease extension.”