Diffusion Tensor Imaging Biomarkers for Traumatic Axonal Injury: Analysis of Three Analytic Methods

Abstract

Traumatic axonal injury (TAI) is a common mechanism of traumatic brain injury not readily identified using conventional neuroimaging modalities. Novel imaging modalities such as diffusion tensor imaging (DTI) can detect microstructural compromise in white matter (WM) in various clinical populations including TAI. DTI-derived data can be analyzed using global methods (i.e., WM histogram or voxel based approaches) or a regional approach (i.e., tractography). While each of these methods produce qualitatively comparable results, it is not clear which is most useful in clinical research and ultimately in clinical practice. This study compared three methods of analyzing DTI-derived data with regard to detection of WM injury and their association with clinical outcomes. Thirty patients with TAI and 19 demographically similar normal controls were scanned using a 3T magnet. Patients were scanned approximately eight months post-injury, and underwent an outcomes assessment at that time. Histogram analysis of FA and MD showed global WM integrity differences between patients and controls. Voxel-based and tractography analyses showed significant decreases in FA within centroaxial structures involved in TAI. All three techniques were associated with functional and cognitive outcomes. DTI measures of microstructural integrity appear robust, as the three analysis techniques studied showed adequate utility for detecting WM injury.

Structural brain markers are differentially associated with neurocognitive profiles in socially marginalized people with multimorbid illness.

“…Despite technological limitations, DTI measures have demonstrated to be highly robust in identifying white matter abnormalities that are associated with significant neurocognitive consequences (Marquez de la Plata et al, 2011). Moreover, our multimethod approach yielded converging results, which increased our confidence that our pattern of findings reflected meaningful differences across the neurocognitive clusters.…”

Longitudinal changes of structural connectivity in traumatic axonal injury

“…From the 28 pairs of scans examined in the study, 8 acute scans were analyzed in our previous DTI study, 7 24 pairs of acute and chronic scans were used in the examination of the association between regional brain volumes and tractography measurements, 29 and 28 chronic scans were used to investigate the sensitivity of 3 DTI methods for detecting TAI. 30 Average age was 26.3 years (SD 10.6, range 16 -58, 71% men). Time from injury to acute scan ranged from 0 to 9 days (mean 2.5, SD 2.6, median 1.0 days) and time to chronic scan ranged from 6 to 11 months (mean 7.7, SD 1.8, median 7.5 months).…”

Impaired integrity of the brain parenchyma in non-geriatric patients with major depressive disorder revealed by diffusion tensor imaging

“…Additional indices that can be evaluated include skewness (the magnitude of symmetry of the histograms) and kurtosis (peakness of histograms) (Mori et al, 2008). Histogram analysis of DTI has been successfully used in brain tumor classification (Wang et al, 2012), investigation of clinical correlates in leukoariosis (Della Nave et al, 2007) and multiple sclerosis (Cercignani et al, 2001), differentiation between ischemic and non-ischemic patients with moyamoya disease (Mori et al, 2008), evaluation of traumatic brain inury (Marquez de la Plata et al, 2011), and so on. In this study, histogram analysis enabled a discrimination between the patients and normal subjects by its peak position, which is suggestive of its applicability in the evaluation of integrity of brain parenchyma in MDD.…”

“…The latter two techniques are better suited if the area of involvement is not known, or when an a priori spatial selection and hypothesis are not made. In addition, the latter two techniques do not involve placement of ROI  which requires an operator with expertise in neuroanatomy and involves some inherent subjectivity (Marquez de la Plata et al, 2011). Previous DTI studies on MDD have been performed using ROI-based analysis, voxel-based analysis, and/ or tract (tractography)-based analysis (e.g.…”