title: Hypointense hepatocellular nodules on hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI: can increasing the flip angle improve conspicuity of lesions?
abstract: OBJECTIVE
  To compare the conspicuity of hypointense hepatocellular nodules in patients with chronic liver disease on hepatobiliary phase (HP) of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) acquired with low to high flip angles (FAs).
  
  
  METHODS
  A total of 95 patients with chronic liver disease who underwent Gd-EOB-DTPA-enhanced MRI were included. HP images were obtained at 20 minutes, with 15°, 20°, and 30° FAs. For the detected hepatocellular nodule, liver-to-lesion contrast-to-phantom ratios (CPR) and lesion conspicuity (LCS) were assessed.
  
  
  RESULTS
  In all examinations, 96 hepatocellular nodules showing hypointensity on HP were identified. These lesions included 39 hypovascular nodules and 57 hypervascular nodules. Mean CPR and LCS showed the highest value on the 30° FA, followed by 20° and 15° FAs. CPR and LCS of 15° FA were significantly lower than those of 20° and 30° FAs (P < 0.001 to P = 0.007). CPR of 30° FA for hypervascular nodules was significantly greater than that of 20° FA (P < 0.001).
  
  
  CONCLUSIONS
  In the evaluation of hypointense hepatocellular nodules on HP of Gd-EOB-DTPA-enhanced MRI, higher FA such as 30° should be used rather than low FA such as 15°.
authors.affiliation: Department of Radiology, Kawasaki Medical School, Kurashiki, Japan. ttamada@med.kawasaki-m.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Tamada
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Ito
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yasokawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Higaki
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kanki
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Sato
authors.forename: Daigo
authors.initials: D
authors.lastname: Tanimoto
authors.forename: Hiroki
authors.initials: H
authors.lastname: Higashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D006528:Carcinoma, Hepatocellular / Q000453:epidemiology* / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007564:Japan / Q000453:epidemiology; D008113:Liver Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA