title: Reliable measurement procedure of virtual touch tissue quantification with acoustic radiation force impulse imaging.
abstract: OBJECTIVE
  The purpose of this study was to find a reliable procedure for performing virtual touch tissue quantification of the liver.
  
  
  METHODS
  Twenty healthy volunteers were enrolled after informed consent was obtained. The liver and spleen of each volunteer were examined on the same day by two different sonologists. The shear wave velocity values at deep and superficial locations of the right and left lobes of the liver and the spleen were obtained before and after food consumption and with and without deep inspiration. The measurements were performed 5 times in each location, and the mean shear wave velocities were recorded.
  
  
  RESULTS
  No statistically significant difference was found between the mean shear wave velocities obtained by the two operators. A difference was found between the velocities obtained in the deep portion of the right lobe (5.5 cm from the probe; mean ± SD, 1.17 ± 0.25 m/s on the intercostal scan and 1.35 ± 0.45 m/s on the subcostal scan) and the superficial portion (3.5 cm; 1.56 ± 0.43 and 1.74 ± 0.74 m/s; P < .001; P < .002, respectively), and the values obtained in the deep portion of the right lobe on the intercostal scan were lower than those obtained on the subcostal scan (P < .05). There were no differences in the mean shear wave velocities of the liver before and after food consumption or with and without deep inspiration. The velocities of the spleen did not differ before and after food consumption (2.33 ± 0.47 versus 2.39 ± 0.58 m/s).
  
  
  CONCLUSIONS
  In healthy people, mean shear wave velocities were dependent on the measurement site in the liver, and food consumption or deep inspiration did not affect velocity measurements of the liver or spleen.
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, Gunma University Hospital, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan. m09702037@gunma-u.ac.jp
authors.forename: Chie
authors.initials: C
authors.lastname: Kaminuma
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Tsushima
authors.forename: Noriko
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Takemi
authors.initials: T
authors.lastname: Kurabayashi
authors.forename: Ayako
authors.initials: A
authors.lastname: Taketomi-Takahashi
authors.forename: Keigo
authors.initials: K
authors.lastname: Endo
mesh_terms: D000162:Acoustics; D000328:Adult; D000465:Algorithms; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging* / Q000502:physiology* / Q000528:radiation effects; D008297:Male; D010173:Palpation / Q000379:methods*; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D033081:Shear Strength / Q000502:physiology / Q000528:radiation effects