title: Should the dose of contrast medium be determined solely on the basis of body weight regardless of the patient's sex?
abstract: OBJECTIVE
  The aim of this study was to evaluate prospectively the difference in contrast enhancement of liver parenchyma between male and female subjects when the total amount of contrast material is determined by the total body weight (TBW).
  
  
  METHODS
  Computed tomography of the abdomen was performed with a total amount of iodine of 597 ± 3.9 mg I/kg (mean ± SD) over a mean ± SD total injection time of 30 ± 0.26 s. Postcontrast attenuation during the portal venous phase was measured in the liver parenchyma, portal vein, and aorta. These values were summed for each and compared to those obtained before contrast injection. A total of 565 consecutive patients without a history of underlying liver/heart disease, including 297 male and 268 female subjects (age 16-92 years, mean 67 years) were scanned and analyzed using a two-tailed t-test.
  
  
  RESULTS
  The difference between precontrast and the portal venous phase in the male subjects was 315.4 ± 40.5 HU (mean ± SD), and that in female subjects was 358.6 ± 44.8 HU. This difference was statistically significant (P < 0.0001).
  
  
  CONCLUSIONS
  The contrast enhancement in females was 13.7% higher than that in males when the amount of iodine administered was based on the TBW. The difference can presumably be attributed to the difference in fat and muscle components. This result suggests that the amount of contrast material used in females should be reduced according to this difference.
authors: Department of Diagnostic Radiology, Saitama Medical University Hospital, 38 Morohongo, Moroyamamachi, Iruma-gun, Saitama 350-0495, Japan. jtanaka@saitama-med.ac.jp
authors: Junji
authors: J
authors: Tanaka
authors: Eito
authors: E
authors: Kozawa
authors: Kaiji
authors: K
authors: Inoue
authors: Yasumasa
authors: Y
authors: Okamoto
authors: Masahito
authors: M
authors: Toya
authors: Youichi
authors: Y
authors: Sato
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta; D001835:Body Weight; D003287:Contrast Media / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D054796:Drug Dosage Calculations; D005260:Female; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives; D008099:Liver / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012737:Sex Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D014283:Triiodobenzoic Acids / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C057937:iomeprol; D007472:Iohexol; D007479:Iopamidol; C054871:ioversol