Prevalence of Sclerosing Cholangitis Detected by Magnetic Resonance Cholangiography in Patients With Long-term Inflammatory Bowel Disease

BACKGROUND & AIMS: The prevalence of primary sclerosing cholangitis (PSC) among patients with inflammatory bowel disease (IBD) is unclear. Patients with IBD might be screened for PSC using magnetic resonance cholangiography (MRC). We aimed to estimate the frequency and distribution of MRC-detected lesions that indicate PSC in patients with IBD 20 years after their initial diagnosis and to identify clinical characteristics associated with these findings. METHODS: We performed a follow-up analysis of a population-based cohort of 756 patients in South-Eastern Norway diagnosed with IBD from January 1, 1990 through December 31, 1993. Of these subjects, 470 attended a follow-up evaluation 20 years later in which they were offered routine clinical blood testing and ileocolonoscopy; 322 were screened by MRC (222 with ulcerative colitis and 100 with Crohn's disease). Two radiologists independently evaluated results from the MRC examinations. RESULTS: In the MRC examination, 24 patients (7.5%) were found to have PSC-like lesions; only 7 of these patients (2.2%) were known to have PSC. One patient was initially missed and 1 had small-duct PSC, so the final prevalence of PSC was 8.1%. Extensive colitis, a high prevalence of colectomy, and chronic and continuous symptoms of IBD occurred in significantly more patients with suspected PSC than without PSC (P =.029, P =.002, and P =.012, respectively). Among patients with subclinical features of PSC, the MRC progression score for PSC increased when they were re-examined after a median 3.2 years (P =.046). CONCLUSIONS: Using MRC analysis of patients with long-term IBD, we found the prevalence of PSC to be around 3-fold higher than that detected based on symptoms. Sixty-five percent of patients had subclinical PSC associated with progressive IBD, with no biochemical abnormalities and mild disease, based on radiology findings. PSC appears to progress in patients with subclinical disease, but long-term outcomes are not known.