Evaluation of MRI as a diagnostic method in biliary tract conditions

Abstract: The diagnostic value of modern fast pulse sequences and breath-hold technique was evaluated in a prospective study of patients with suspected biliary diseases. The cost-effectiveness of MRI compared to ultrasound was calculated. Characteristics of acute cholecystitis and cholangitis were evaluated, the appearance of bile in MRCP with reference to its chemical and physical properties was studied, as well as MRI appearance after cholecystectomy with and without postoperative abdominal complications. The sensitivity and specificity to diagnose acute cholecystitis was 88% and 89% for MRI and 65% and 89% for US. The sensitivity of US, MRI and ERCP for correct diagnosis in jaundiced or not jaundiced patients was 53, 93 and 89% and 50, 100, and 70%, respectively. MRI is superior to US giving correct diagnosis in patients with right upper quadrant abdominal pain or to diagnose biliary tract conditions. Screening with US and supplemental MRI in non-diagnostic cases was estimated to cost 80% of the total amount compared to examining with MRI only. Relaxation rates 1/T1 and 1/T2 of gallbladder bile in vitro showed large inter-individual variation but a consistent linear relationship was found. The relaxation rates increased with increasing amounts of substances in the bile. No single chemical parameter showed dominating influence on relaxation rates. Occasionally bile shows very high relaxation rates leading to unsuccessful MRCP. Early MR findings following cholecystectomy consist normally of only subtle changes, mainly in the gallbladder fossa. A postoperative surgical complication is unlikely if MRI fails to show a fluid collection. Acute cholangitis has multiple findings on MRI, biliary ductal dilatation was the most consistent finding and inflammatory changes were observed in 50% of patients. MRI has the potential to confirm the diagnosis acute cholangitis and exclude alternative diagnosis especially in older patients where the clinical symptoms may be vague. MRI is a reliable method providing high quality images performed with a minimum of inconvenience for the patient. In the future the non-invasive MRI will play a greater role as the primary imaging technique to provide maximum clinical utility when the MRI system will be even more easy to manage, faster, more cost-efficient and, compared with CT, MRI has a significant advantage since no ionizing radiation is involved.