diffusion tensor imaging (dti)

Preoperative planning for glioma tumor resection and radiotherapy treatment requires proper delineation of the tumor and surrounding brain tumor regions. The present study aimed to investigate the importance of various diffusion parameters, especially the mean kurtosis (MK), in discriminating between recurrent tumors, edema, and normal areas.

A total of 19 patients with high-grade glioma underwent postoperative diffusion imaging. The authors extracted diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) models to evaluate the data in manually delineated regions of interest (ROI) and used their derived parameters to characterize edema, tumor, and normal brain areas. The Wilcoxon test was used to determine the significance of the parameters in the three groups: recurrent, edema, and normal. Moreover, the Mann-Whitney test was employed to determine the significance between the two groups of recurrent and normal, as well as between recurrent and edema.

Considering the p-value less than 0.05, the apparent diffusion coefficient (ADC), mean diffusion (MD), and MK parameters were significantly different between some of the three groups. The ADC and MD indicated significant differences between the two recurrent and normal groups, with P-values of 0.041 (P<0.05). In addition, there was a significant difference in MK between the two recurrent and normal groups with P-values of 0.02 (P<0.05).

Diffusion parameters are promising in differentiating between recurrent and normal areas in high-grade gliomas after surgery and after treatment

Methamphetamine (METH) is an illicit psychostimulant that is widely abused in the world. METH abuse may lead to white matter injury and to a range of behavioral disorder and psychosis. The present study sought to assess subtle white matter microstructural change as well as psychosis in long-term METH dependence.

We recruited 42 METH users’ subject meeting DSM-5 criteria and 21 healthy controls. Psychotic signs were measured using the Positive and Negative Syndrome Scale (PANSS). We applied tract-based spatial statistics (TBSS) to investigate group differences in mean diffusivity, fractional anisotropy, axial and radial diffusivity, and their association with psychotic symptoms.

This DTI study of whole brain white matter integrity based on TBSS and its relation with psychotic symptoms revealed two main findings in the METH group. (a) METH addicts had significantly lower FA and higher AD, RD, and MD in a wide range of white matter. (b) Subjects in theMETH group had significantly higher PANSS total score, when compared to the control group.

METH addicts show subtle patterns of impaired white matter integrity of distinct Cerebral nerve pathways relative to controls. The results are further suggestive of neuronal tract based pathology playing a key role in psychotic symptoms in METH dependence