Effect of different number of diffusion gradients on dispersion degree of FA values and its SNR
To study the effect of different number of diffusiongradient directions (NDGD) of diffusion tensor imaging (DTI) ondispersion degree of fractional anisotropy (FA) values and itssignal noise ratio (SNR) for adult brain tissues. Eight healthvolunteers were imaged by a 1.5T magnetic resonance scannerwith different NDGD (6, 9, 12, 15, 20, 25, and 30 noncollinear)respectively, and seven FA maps associated with the differentNDGD were obtained. Four region of interest (ROI) (genu andsplenial of corpus callosum, genu and posterior limb of internalcapsule) were chose in white matter of FA maps, and FA valuesand its SNR of the ROIs were computed and compared. Analysisof variance and independent-samples t-test were performed with a p value less than 0.05 regarded as statistical significance.Variance of FA values within the ROIs with stronger signals(genu and splenial of corpus callosum) fluctuated randomly andhad no linear relationship with NDGD, and SNR increasedslightly with NDGD increasing. But variance of FA values withinthe ROIs with weaker signals (genu and posterior limb ofinternal capsule) diminished significantly with NDGD increasingfrom 6 to 20, and slowly in the range from 20 to 30. SNR of Favalues within the ROIs with weaker signals was improvedsignificantly with NDGD increasing from 6 to 20 (P<0.05), andhad no significant change while NDGD increasing from 20 to 30(P>0.05). To detect FA values and its fluctuation and SNR of theROIs with stronger signals, NDGD=6 is enough. For detectingthose of the ROIs with weaker signals, however, considering thatreducing of scanning time to lower possibility of movement-derivedartifact and increasing of NDGD to improve precision ofFA values, NDGD=20 is an optimal choice.
Na Zhang Zhensheng Deng Xiaojuan Yin Xin Liu Hairong Zheng
Institute of Biomedical Engineering,School of Info-physics and Geomatics Engineering,Central South U Institute of Biomedical Engineering,School of Info-physics and Geomatics Engineering,Central South U Paul C.Lauterbur Research Centre for Biomedical Imaging, Institute of Biomedical and Health Engineer
国际会议
成都
英文
1-4
2010-06-18（万方平台首次上网日期，不代表论文的发表时间）