title: The T2-shortening effect of gadolinium and the optimal conditions for maximizing the CNR for evaluating the biliary system: a phantom study.
abstract: OBJECTIVE
  Clear depiction of the common bile duct is important when evaluating neonatal cholestasis in order to differentiate biliary atresia from other diseases. During MR cholangiopancreatography, the T2-shortening effect of gadolinium can increase the contrast-to-noise ratio (CNR) of the bile duct and enhance its depiction. The purpose of this study was to confirm, by performing a phantom study, the T2-shortening effect of gadolinium, to evaluate the effect of different gadolinium chelates with different gadolinium concentrations and different magnetic field strengths for investigating the optimal combination of these conditions, and for identifying the maximum CNR for the evaluation of the biliary system.
  
  
  METHODS
  MR imaging using a T2-weighted single-shot fast spin echo sequence and T2 relaxometry was performed with a sponge phantom in a syringe tube. Two kinds of contrast agents (Gd-DTPA and Gd-EOB-DTPA) with different gadolinium concentrations were evaluated with 1.5T and 3T scanners. The signal intensities, the CNRs and the T2 relaxation time were analyzed.
  
  
  RESULTS
  The signal intensities significantly decreased as the gadolinium concentrations increased (p < 0.001) with both contrast agents. These signal intensities were higher on a 3T (p < 0.001) scanner. The CNRs were higher on a 1.5T (p < 0.001) scanner and they showed no significant change with different gadolinium concentrations. The T2 relaxation time also showed a negative correlation with the gadolinium concentrations (p < 0.001) and the CNRs showed decrease more with Gd-EOB-DTPA (versus Gd-DTPA; p < 0.001) on a 3T scanner (versus 1.5T; p < 0.001).
  
  
  CONCLUSIONS
  A T2-shortening effect of gadolinium exhibits a negative correlation with the gadolinium concentration for both the signal intensities and the T2 relaxation time. A higher CNR can be obtained with Gd-DTPA on a 1.5T MRI scanner.
authors: Department of Radiology and the Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University, College of Medicine, Seoul 120-752, Korea.
authors: Mi-Jung
authors: MJ
authors: Lee
authors: Myung-Joon
authors: MJ
authors: Kim
authors: Choon-Sik
authors: CS
authors: Yoon
authors: Si Young
authors: SY
authors: Song
authors: Kyungsoo
authors: K
authors: Park
authors: Woo Sun
authors: WS
authors: Kim
references: J Magn Reson Imaging. 1999 Feb;9(2):172-6
references: 10077010
references: Radiology. 1995 Jun;195(3):785-92
references: 7754011
references: Radiology. 1990 Feb;174(2):379-81
references: 2296649
references: Eur J Pediatr. 2007 Mar;166(3):211-4
references: 16960695
references: Radiology. 2000 Jul;216(1):232-6
references: 10887253
references: Magn Reson Med Sci. 2009;8(4):143-8
references: 20035122
references: AJR Am J Roentgenol. 2002 Mar;178(3):755-61
references: 11856714
references: Radiology. 1999 Jul;212(1):249-56
references: 10405749
references: Radiology. 1985 Mar;154(3):723-6
references: 3969477
references: Eur Radiol. 1997;7(1):126-32
references: 9000414
references: AJR Am J Roentgenol. 2002 Jul;179(1):87-92
references: 12076911
references: Korean J Radiol. 2009 May-Jun;10(3):294-302
references: 19412518
references: Invest Radiol. 2005 Nov;40(11):715-24
references: 16230904
references: Eur Radiol. 2005 Aug;15(8):1607-14
references: 15627176
references: AJR Am J Roentgenol. 1984 Mar;142(3):619-24
references: 6607655