Obstructive diseases of the biliary tree: an imaging analysis of 76 cases

Objective: To test the value of magnetic resonance cholangiopancreatography (MRCP) with half-Fourier acquisition single-shot (HASTE) sequence in the diagnosis of the biliary obstructive diseases in comparison with other imaging examinations.

Methods: Altogether 76 patients with pancreaticobiliary duct diseases underwent MRCP on Siemens 1.5T Vision Plus scanner, and a heavily T2-weighted HASTE was obtained during a breath-hold. The findings of MRCP images were analyzed and compared with those of ultrasound, CT, (endoscopic retrograde cholangiopancreatography ERCP) or PTC.

Results: The sensitivity, specificity and accuracy of MRCP were 91.0%, 96.50%, and 94.00% respectively in detecting both benign and malignant obstructions. The diagnostic accuracy of MRCP was close to ERCP, and obviously superior to CT and ultrasound (P<0.05). Benign obstructions were characterized by dilatation of proximal end of the common bile duct (CBD) and gradual stenosis in the distal CBD with tapered margin without interruptions, known as "duct-penetrating sign". It was most commonly seen that malignant obstructive ends presented "truncated form" and "rat-tail" form.

Conclusions: T2-weighted HASTE is the T2 optional noninvasive technique with excellent accuracy in diagnosing biliary obstruction and defining their causes. The degree of biliary dilation, the pattern of obstructive ends and the "double duct sign"and "duct-penetrating sign" may serve as important indicators for differentiating benign and malignant obstructions.