Evaluation of noncirrhotic hepatic parenchyma with and without significant portal vein stenosis using diffusion-weighted echo-planar MR on the basis of multiple-perfusion-components theory.
To determine whether diffusion-weighted echo-planar MR images are sensitive to liver perfusion difference. Noncirrhotic livers of 71 patients (43 males, 28 females; age range, 22-87 years; mean, 61 years) without (n=51) and with (n=20) significant (>70%) portal vein stenosis (accompanying proximal hepatic arterial stenosis and/or biliary tract obstruction in 10) by tumors were examined with diffusion-weighted echo-planar sequences (modified for b factors of 1, 28, 66, 288 and 600 s/mm²). On the basis of multiple-perfusion-components theory, i.e., assuming logarithm of signal intensity for liver perfusion is linearly attenuated versus logarithm of a smaller b factor, we defined the slope of the line as the perfusion-related D' value. The D' values of these livers were calculated from images with b factors of 1, 28, and 66 s/mm². The livers' apparent diffusion coefficient values for diffusion (ADC(d) values) were calculated from images with b factors of 288 and 600 s/mm². The livers with significant portal vein stenosis had statistically lower mean D' values than the livers without portal vein stenosis (P<.001 on the Mann-Whitney U test). However, there was no significant difference in ADC(d) values between these liver types (P>.05). The D' value calculated from diffusion-weighted echo-planar sequences with plural smaller b factors may be sensitive to liver perfusion difference.
Moteki
Takao
T
Department of Radiology, Fujioka General Hospital, Gunma 375-8503, Japan. pwd8ja227h@md.point.ne.jp
Horikoshi
Hiroyuki
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000098:blood supply* / Q000473:pathology; D008103:Liver Cirrhosis / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020246:Venous Thrombosis / Q000473:pathology*