title: Direct MR arthrography of the shoulder at 3 Tesla: optimization of gadolinium concentration.
abstract: OBJECTIVE
  To determine the optimal concentration of gadopentetate dimeglumine for direct shoulder MR arthrography at 3T in vivo.
  
  
  METHODS
  Sixty-eight consecutive shoulder MR arthrograms were obtained with 1 mmolGd/L (n = 12), 2 mmolGd/L (n = 12), 4 mmolGd/L (n = 12), 6 mmolGd/L (n = 12), 9 mmolGd/L (n = 10) and 12 mmolGd/L (n = 10). All postinjection fat-suppressed T1-weighted and T2-weighted images were analyzed retrospectively. For qualitative evaluation, image contrast was graded on a subjective three-level scale (excellent, moderate, and poor). For quantitative analysis, the contrast-to-noise ratio (CNR) of intra-articular fluid to muscle was measured.
  
  
  RESULTS
  All postinjection T1-weighted images and T2-weighted images with 1 mmolGd/L, 2 mmolGd/L, 4 mmolGd/L, and 6 mmolGd/L were qualitatively evaluated as excellent or moderate. Two of the ten 9-mmolGd/L images and seven of the ten 12-mmolGd/L images were rated as poor with regard to the T2 image contrast. On the T1-weighted images, no significant difference existed between the CNRs of the six concentrations, but a peak CNR was seen at the concentration of 6 mmolGd/L. On the T2-weighted images, CNRs at concentrations of 1 mmolGd/L, 2 mmolGd/L, 4 mmolGd/L, 6 mmolGd/L, and 9 mmolGd/L showed no statistical difference, but were all significantly higher than that with 12 mmolGd/L.
  
  
  CONCLUSIONS
  The acceptable concentration of gadopentetate dimeglumine for shoulder MR arthrography at 3T was found to be in the range of 1 mmolGd/L to 6 mmolGd/L. 6 mmolGd/L may be the optimal concentration.
authors: Department of Radiology, Peking University Third Hospital, Haidian District, Beijing, China.
authors: Yao
authors: Y
authors: Shang
authors: Zhuo-zhao
authors: ZZ
authors: Zheng
authors: Xuan
authors: X
authors: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001175:Arthrography / Q000379:methods*; D003287:Contrast Media; D004305:Dose-Response Relationship, Drug; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007592:Joint Diseases / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D012189:Retrospective Studies; D012785:Shoulder Joint / Q000473:pathology*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA