Intrasession and Intersession Repeatability of Diffusion Tensor Imaging in Healthy Human Liver

Objective The aim of this study was to evaluate the effect of signal to noise ratio (SNR) and number of gradient directions (NGD) on intra- and intersession repeatability of liver diffusion tensor imaging (DTI) metrics. Methods At each of 3 liver DTI scan sessions, liver diffusion was assessed in 5 healthy volunteers using a 6-direction DTI scan performed 9 separate times (ie, number of signal averages [NSA]). In addition, 4 combinations of NSA and NGD were acquired (NSA/NGD = 1/30, 3/10, 3/12, and 5/6) to determine the combined effect to DTI metrics, which was based on intersubject variability and intrasession (V intra) and intersession (V inter) repeatability. Results Intersubject variability was less than 20%, whereas V intra and V inter repeatability were less than 5% and less than 10%, respectfully. V inter was not affected by the NGD used. Decreases in V inter(FA), V inter(λ1), V inter(RD), and V inter(MD) were observed with increasing NSA, and hence SNR. Conclusion Increased SNR may improve intrasession and intersession repeatability of liver DTI metrics. Scan repeatability was not influenced by NGD.

Intrasession and Intersession Repeatability of Diffusion Tensor Imaging in Healthy Human Liver Journal Articles