title: Distinguishing hepatic hemangiomas from metastatic tumors using T1 mapping on gadoxetic-acid-enhanced MRI.
abstract: OBJECTIVE
  The objective was to evaluate the usefulness of T1 mapping in distinguishing hepatic hemangiomas from metastatic tumors on gadoxetic-acid-enhanced magnetic resonance imaging.
  
  
  METHODS
  We examined 20 hemangiomas in 14 patients and 21 metastatic tumors in 11 patients. We performed T1 mapping using the double-flip angle method before and after the injection of gadoxetic acid. Quantitative evaluation was carried out using the pre- and post-contrast enhancement ratios (CERs), and qualitative evaluation was conducted to evaluate the added value of T1 mapping using receiver operating characteristics analysis.
  
  
  RESULTS
  The mean CERs of metastatic tumors at 70 s, 240 s and 20 min after the injection of gadoxetic acid were 1.54 (95% confidence interval: 1.37-1.71), 1.47 (1.34-1.6) and 1.30 (1.19-1.41); those of hemangiomas were 3.36 (2.41-4.31), 3.06 (2.44-3.68) and 2.20 (2.02-2.38), respectively. The mean CERs of hemangiomas were significantly higher than those of metastatic tumors (P<.05). When the mean CER cutoff value 20 min after the injection was set at 1.6, the diagnostic sensitivity of hepatic hemangiomas was 100%. There was no added value observed statistically in the qualitative evaluation of T1 mapping (P>.05).
  
  
  CONCLUSIONS
  It is valuable to evaluate quantitatively T1 mapping 20 min after hepatobiliary phase acquisition in the case of difficulty in distinguishing hepatic hemangiomas from metastatic tumors qualitatively.
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo 160-0023, Japan. bunoboo06@yahoo.co.jp
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Yoshimura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Saito
authors.forename: Toru
authors.initials: T
authors.lastname: Saguchi
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Funatsu
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Araki
authors.forename: Soichi
authors.initials: S
authors.lastname: Akata
authors.forename: Koichi
authors.initials: K
authors.lastname: Tokuuye
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008113:Liver Neoplasms / Q000473:pathology* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA