title: Gadoxetic acid disodium-enhanced hepatocyte phase MRI: can increasing the flip angle improve focal liver lesion detection?
abstract: OBJECTIVE
  To determine whether hepatocyte phase gadoxetic acid disodium (EOB)-enhanced MRI using a high flip angle (FA) improves focal liver lesion (FLL) detection compared with using a standard low FA.
  
  
  METHODS
  Sixty-two consecutive patients with 159 FLLs underwent EOB-enhanced MRI during the hepatocyte phase at 5, 10, 15, and 20 min, with both low (10°) and high (30°) FAs. Two blinded radiologists independently and randomly reviewed the two image sets using a four-point rating scale. Sensitivities and specificities were calculated and lesion-to-liver contrast ratio (LLC) on all hepatocyte phase images was measured.
  
  
  RESULTS
  The sensitivities with high FA for small (≤10 mm) malignant FLLs were significantly higher than those with low FA, at all time points, for both readers (P ≤ 0.05). Meanwhile, the specificities of the two protocols for the detection of all FLLs at all time points during the hepatocyte phase were high and same (98.2%) for both readers, without any significant differences (P = 1.00). LLCs with high FA were significantly higher than those with low FA at all time points (P ≤ 0.001).
  
  
  CONCLUSIONS
  Hepatocyte phase EOB-enhanced MRI with increasing FA can significantly increase LLC and improve the detection of FLLs, particularly small malignant lesions.
authors.affiliation: Department of Radiology, University of Brescia, Spedali Civili di Brescia, Brescia, Italy. karate.b@gmail.com
authors.forename: Hiroki
authors.initials: H
authors.lastname: Haradome
authors.forename: Luigi
authors.initials: L
authors.lastname: Grazioli
authors.forename: Khalid
authors.initials: K
authors.lastname: Al manea
authors.forename: Mika
authors.initials: M
authors.lastname: Tsunoo
authors.forename: Utaroh
authors.initials: U
authors.lastname: Motosugi
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Kwee
authors.forename: Taro
authors.initials: T
authors.lastname: Takaraha
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000494:pharmacology; D005260:Female; D019786:Gadolinium DTPA / Q000494:pharmacology*; D022781:Hepatocytes / Q000166:cytology / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000175:diagnosis / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011871:Radiology / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA