Body size indexes for optimizing iodine dose for aortic and hepatic enhancement at multidetector CT: comparison of total body weight, lean body weight, and blood volume.
OBJECTIVE
To evaluate and compare total body weight (TBW), lean body weight (LBW), and estimated blood volume (BV) for the adjustment of the iodine dose required for contrast material-enhanced multidetector computed tomography (CT) of the aorta and liver.


METHODS
Institutional review committee approval and written informed consent were obtained. One hundred twenty patients (54 men, 66 women; mean age, 64.1 years; range, 19-88 years) who underwent multidetector CT of the upper abdomen were randomized into three groups of 40 patients each: (a) TBW group (0.6 g of iodine per kilogram of TBW), (b) LBW group (0.821 g of iodine per kilogram of LBW), and (c) BV group (men, 8.6 g of iodine per liter of BV; women, 9.9 g of iodine per liter of BV). Change in CT number between unenhanced and contrast-enhanced images per gram of iodine and maximum hepatic enhancement (MHE) adjusted for iodine dose were examined for correlation with TBW, LBW, and BV by using linear regression analysis.


RESULTS
In the portal venous phase, correlation coefficients for the correlation of change in CT number per gram of iodine with TBW for the aorta and liver were -0.71 and -0.79, respectively, in the TBW group; -0.80 and -0.86, respectively, in the LBW group; and -0.68 and -0.66, respectively, in the BV group. In the liver, they were marginally higher in the LBW group than in the BV group (P = .03). Adjusted MHE remained constant at 77.9 HU +/- 10.2 (standard deviation) in the LBW group with respect to TBW, but it increased in the TBW (r = 0.80, P < .001) and BV (r = 0.70, P < .001) groups as TBW increased.


CONCLUSIONS
When LBW, rather than TBW or BV, is used, the iodine dose required to achieve consistent hepatic enhancement may be estimated more precisely and with reduced patient-to-patient variability.
Kondo
Hiroshi
H
Department of Radiology, Gifu University Hospital, 1-1 Yanagido, 501-1194 Gifu, Japan.
Kanematsu
Masayuki
M
Goshima
Satoshi
S
Tomita
Yuhei
Y
Kim
Myeong-Jin
MJ
Moriyama
Noriyuki
N
Onozuka
Minoru
M
Shiratori
Yoshimune
Y
Bae
Kyongtae T
KT
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001018:Aortic Diseases / Q000000981:diagnostic imaging*; D001810:Blood Volume; D001835:Body Weight; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage*; D016014:Linear Models; D008107:Liver Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D007472:Iohexol