Clinical applications of diffusion tensor imaging

Abstract

Directionally-ordered cellular structures that impede water motion, such as cell membranes and myelin, result in water mobility that is also directionally-dependent. Diffusion tensor imaging characterizes this directional nature of water motion and thereby provides structural information that cannot be obtained by standard anatomic imaging. Quantitative apparent diffusion coefficients and fractional anisotropy have emerged from being primarily research tools to methods enabling valuable clinical applications. This review describes the clinical utility of diffusion tensor imaging, including the basic principles of the technique, acquisition, data analysis, and the major clinical applications.

Subclinical Cardiac Dysfunction and Brain Health in Midlife: CARDIA (Coronary Artery Risk Development in Young Adults) Brain Magnetic Resonance Imaging Substudy

“…It allows estimation of diffusion of water along brain fibers and ranges from 0 and 1, where 0 is isotropy (random motion of water) and 1 anisotropy (diffusion of water along 1 axis; ie, white matter tract) 22. Total brain volume was estimated as the sum of gray matter and white matter volumes from the sagittal 3‐dimensional T1 sequence.…”

Statistical group comparison of diffusion tensors via multivariate hypothesis testing

“…The formal statement of the hypothesis test is H 0 : FA 1 − FA 2 = 0 versus H 1 : FA 1 − FA 2 ≠ 0. The test statistic depends on the average difference in FA between the two groups normalized by the pooled standard deviation of the Normal PDF; i.e., [1] where , are the average within-group FA at a particular voxel and , are the sums of squares of FA. The test statistic U n 1 ,n 2 will have a t distribution with n 1 + n 2 − 2 degrees of freedom.…”

“…Diffusion tensor imaging (DTI) has identified white matter alterations in a wide number of neurological and psychiatric conditions including Alzheimer's disease, Parkinson's disease, schizophrenia, neurological complications of HIV infection, autism, multiple sclerosis, and numerous other conditions (1,2). DTI studies in clinical populations have thus far focused predominately on diffusion anisotropy; yet DTI provides information on both the degree and direction of the diffusion anisotropy in white matter (WM).…”

Brain MRI: Tumor evaluation

“…Brain abscesses often have restricted diffusion with DWI hyperintensity and apparent diffusion coefficient (ADC) hypointensity; however, these features are not entirely specific, since some cystic or peripherally-enhancing tumors (e.g., necrotic metastases) reveal similar findings. Greater tumor cellularity in high-grade gliomas (HGGs) results in greater diffusion restriction and thus decreased ADC values, whereas low-grade gliomas (LGGs) have increased ADC values (8). During therapy, increasing ADC values suggest therapy-induced necrosis, while decreasing ADC values suggest tumor progression (8).…”

“…Greater tumor cellularity in high-grade gliomas (HGGs) results in greater diffusion restriction and thus decreased ADC values, whereas low-grade gliomas (LGGs) have increased ADC values (8). During therapy, increasing ADC values suggest therapy-induced necrosis, while decreasing ADC values suggest tumor progression (8). Diffusion techniques can also help differentiate vasogenic edema from gliotic change.…”