MR cholangiopancreatography of pancreaticobiliary diseases: comparison of single-shot RARE and multislice HASTE sequences

Aims: We prospectively compared two breath-hold magnetic resonance cholangiopancreatography (MRCP) sequences: single-shot rapid acquisition with relaxation enhancement (RARE) and multislice half-Fourier acquisition single-shot turbo spin echo (HASTE) in imaging the pancreaticobiliary system.

Patients and methods: The diagnostic accuracy of single-shot RARE and multislice HASTE was studied in 34 subjects who had undergone conventional cholangiopancreatography. Overall image quality, duct conspicuity, image artifact, signal intensity and contrast-to-noise ratios were assessed independently by two radiologists who were unaware of the underlying diagnosis.

Results: Both sequences had comparable diagnostic accuracy regarding a normal biliary system, choledocholithiasis, extra-hepatic and intra-hepatic strictures. Single-shot RARE was superior to multislice HASTE in diagnosing a normal pancreatic system, pancreatic and intrahepatic duct strictures, while providing significantly better image quality (mean +/- SE 3.7 +/- 0.07 vs 3.3 +/- 0.08: P = 0.02) and significantly less image artifact (mean +/- SE 3.6 +/- 0.07 vs 3.2 +/- 0.08: P = 0.01). Single-shot RARE provided significantly better duct conspicuity regarding the pancreatic duct within the body (2.7 +/- 0.2 vs 2.1 +/- 0.2: P = 0.003) and tail (2.4 +/- 0.2 vs 1.6 +/- 0.2;P = 0.0001), as well as the intrahepatic ducts (3.0 +/- 0.1 vs 2.6 +/- 0.1: P = 0.004) but there was no significant difference regarding the remainder of the biliary tree.

Conclusion: Single-shot RARE provides superior image quality, duct conspicuity with the added advantage of less image artifact and shorter acquisition time. However, volume averaging can cause common bile duct stones to be missed. Therefore, multislice HASTE sequences should still be acquired if choledocholithiasis is suspected. Larger studies are required to assess the diagnostic efficacy of single-shot RARE sequences in pancreatic duct and intra-hepatic duct disease.Morrin, M. M. (2000). Clinical Radiology55, 866-873.