Value of MR cholangiopancreatography (MRCP) in the diagnosis of pancreaticobiliary diseases

The diagnostic value and visualization rate of MRCP were assessed in comparison with endoscopic retrograde cholangiopancreatography (ERCP) in cases in which both had been performed. The subjects were 338 patients with pancreatic or biliary diseases (169 males and 169 females; 19-94 years old; 12 with bile duct carcinoma, 17 with gallbladder carcinoma, 5 with carcinoma of the papilla of Vater, 28 with pancreatic carcinoma, 33 with common bile duct (CBD) stones, 100 with gallbladder stones, 29 with chronic pancreatitis, 44 with pancreatic cysts, 46 healthy subjects, and 33 patients with other pancreatobiliary diseases). MRCP was performed by two methods. The first was the multi-slice method of the half-Fourier acquisition single-shot turbo spin echo (HASTE) with a slice width of 5 mm, and 13 slices were imaged in the coronal plane. The second was the single-shot rapid acquisition with relaxation enhancement (RARE) method, and the slice width was 20 mm. Images of 5 slices were aquired (2 coronal section, two in the oblique position, one in a direction in which the gallbladder and the bile duct could be imaged, and one in a direction in which the lesions were located in the center). The visualization rates of the right and left hepatic bile duct, CBD, and gallbladder in the healthy subjects were 97.6%, 97.6%, and 100.0%, respectively. The visualization rates of the main pancreatic duct (MPD) in the head, the body, and the tail of the pancreas, and of the duct of Santorini were 95.7%, 100.0%, 71.7%, and 37.0%, respectively. The sensitivity, specificity, and accuracy of MRCP based on the ERC images were 87.5%, 100%, and 99.7%, respectively, for stricture of the intrahepatic ducts, 100%, 100%, and 100%, respectively, for defects of the intrahepatic ducts 95.9%, 98.4%, and 97.3%, respectively, for stricture of the CBD, and 95.5%, 98.5%, and 98.0%, respectively, for stricture of the MPD. The accuracy of CBD and MPD in diagnosing strictures and defects of the intrahepatic ducts was excellent, but it was difficult to detect lesions of the MPD in the tail and stones 3 mm or less in diameter in the CBD. Diagnostic ability for pancreatic and biliary disease exceeded 80%, and was 100% for bile duct carcinoma, 88.2% for gallbladder carcinoma, 80.0% for carcinoma of the papilla of Vater, 81.0% for gallbladder stones, 90.9% for CBD stones, 93.4% for pancreatic carcinoma, 86.7% for chronic pancreatitis, and 97.7% for pancreatic cysts. Although its resolution is not equivalent to that of ERCP, MRCP is useful as a screening method for pancreaticobiliay diseases. (K.H.)