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| Influence of blood perfusion on apparent diffusion coefficient measurement in the liver |
| SHI Yu, GUO Qi-yong, WANG Xiao-ming |
| Department of Radiology, Shengjing Hospital, China Medical University, Shenyang 110004, China |
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Abstract Objective: To assess whether hepatic diffusion measurements are influenced by hepatic perfusion changes due to different b values in both posterior and anterior segments of right lobe. Materials and Methods: DWI was performed on a 1.5T MRI unit among 26 healthy volunteers after an 8h fast and 1h after a standard meal(which is regarded as an effective method to increase hepatic perfusion including portal venous flow and hepatic sinusoidal perfusion), we used a breath-hold technique for 20.5s at b-values of 750, 500 and 250 and 0s/mm2. The hepatic apparent diffusion coefficient(ADC) values were measured and compared due to different prandial states in both posterior and anterior segments of right lobe. Results: Compared the two sets of ADCs before and after meal, the ADC measurements using b=750s/mm2 in both posterior and anterior right lobe were unaffected by the perfusion changes(t=1.419, P=0.178; t=1.943, P=0.072) whereas the ADC values from b=250s/mm2 increased significantly after meal in both posterior and anterior segments of right lobe(t=3.839, P=0.002; t=5.178, P<0.001). As for b=500s/mm2, only the ADCs in the posterior right lobe was unchanged significantly after meal(t=1.519, P=0.151) when compared to the significantly changed ADCs in the anterior right lobe(t=2.449, P=0.028). Conclusion: With regard to the measurements of ADC, the effect of perfusion can be minimized at the higher b values(b≥500s/mm2) and in the posterior right lobe at the fasted state, which may offer the most consistent ADC values and optimized measuring conditions for further studies of hepatic DWI.
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Received: 20 June 2007
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2007, Vol. 18 
