title: In vitro and clinical studies of image acquisition in breath-hold MR cholangiopancreatography: single-shot projection technique versus multislice technique.
abstract: OBJECTIVE
  This study was undertaken to compare the in vitro and clinical value of two-dimensional multislice breath-hold MR cholangiopancreatography (MRCP) with a single-shot projection technique using a half-Fourier acquisition single-shot turbo spin-echo sequence.
  
  
  METHODS
  We examined 108 patients with pancreaticobiliary diseases, using breath-hold MRCP and a half-Fourier acquisition single-shot turbo spin-echo sequence on a 1.5-T MR unit with a body phased-array coil. Two data acquisition techniques were employed: multislice acquisition postprocessed by maximum intensity projection (MIP) (multislice technique) and single-shot projection with a thick slice (projection technique). In the multislice technique, nine contiguous slices were obtained with a thickness of 5 mm (acquisition time. 18 sec). In the projection technique, a single slice was obtained with a thickness of 30, 50, or 70 mm (acquisition time. 2 sec). Contrast-to-noise ratio (CNR) between the common bile duct and the liver as well as detectability of normal structures and diseases were compared for these two acquisition techniques. In the multislice technique, source images were also evaluated. ERCP or percutaneous transhepatic cholangiography images were used as the gold standard.
  
  
  RESULTS
  Most of the pancreatic duct and common bile duct was revealed on 54% and 100% of the projection images, respectively, and on 35% and 98% of the MIP images, respectively, CNR was significantly higher with the multislice technique than with the projection technique (p < .01). With the projection technique, CNR decreased as slice thickness increased. Dilatation and occlusion of the pancreaticobiliary tree were equally well revealed by the two imaging techniques. However, abnormalities in the periampullary region and anomalies in the pancreaticobiliary tree were more clearly seen on projection images than on MIP images (p < .05). Stones in the common bile duct, gallbladder, or intrahepatic bile duct were best seen on source images acquired by the multislice technique (83% sensitivity).
  
  
  CONCLUSIONS
  Because of the absence of misregistration and the speed of image acquisition, breath-hold single-shot MRCP using the projection technique with a slice thickness of 30 or 50 mm consistently revealed the pancreaticobiliary tree and periampullary region with an acceptable CNR. Stones in the bile duct were best seen on the source images acquired by the MIP technique.
authors.affiliation: Department of Radiology, Kumamoto University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Y
authors.initials: Y
authors.lastname: Abe
authors.forename: Y
authors.initials: Y
authors.lastname: Tang
authors.forename: J
authors.initials: J
authors.lastname: Urata
authors.forename: S
authors.initials: S
authors.lastname: Sumi
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D001660:Biliary Tract Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D002758:Cholangiography; D002760:Cholangiopancreatography, Endoscopic Retrograde; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010182:Pancreatic Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity