Magnetic resonance cholangiopancreatography in the diagnosis of primary sclerosing cholangitis

Background and study aims: Magnetic resonance cholangiopancreatography (MRCP) is a less-invasive alternative to endoscopic retrograde cholangiopancreatography (ERCP) for the diagnosis of primary sclerosing cholangitis (PSC). This study evaluated the diagnostic accuracy of MRCP in PSC compared with ERCP, and assessed the diagnostic accuracy of different T2w sequences. Patients and methods: 95 patients (69 PSC, 26 controls) were evaluated using both ERCP and MRCP. Exclusion criteria included secondary sclerosing cholangitis and contra indications to MRCP. The diagnosis of PSC was confirmed in 69 patients based on ERCP as the reference gold standard. MRCP was performed using a 1.5 Tesla MR unit, using breath hold, coronal and transverse half-Fourier acquisition single-shot turbo spin-echo (HASTE), coronal-oblique, fat-suppressed half-Fourier rapid acquisition with relaxation enhancement (RARE), and coronal-oblique, fat-suppressed, multisection, thin-section HASTE (TS-HASTE) sequences. The MRCP morphological criteria of PSC were evaluated and compared with ERCP. Results: The sensitivity, specificity, and diagnostic accuracy were 86%, 77%, and 83%, respectively, using the MRCP-RARE sequence, and increased further to 93%, 77%, and 88%, respectively, by the inclusion of follow-up MRCP in 52 patients, performed at 6 - 12-month intervals. HASTE and TS-HASTE sequences showed significantly lower diagnostic accuracy but provided additional morphologic information. Conclusions: MRCP can diagnose PSC but has difficulties in early PSC and in cirrhosis, and in the differentiation of cholangiocarcinoma, Caroli's disease, and secondary sclerosing cholangitis. A positive MRCP would negate some diagnostic ERCP studies but a negative MRCP would not obviate the need for ERCP.