Longitudinal Changes in Diffusion Tensor Imaging Following Mild Traumatic Brain Injury and Correlation With Outcome.

The chronic consequences of traumatic brain injury (TBI) may contribute to the increased risk for early cognitive decline and dementia, primarily due to diffusion axonal injury. Previous studies in mild TBI (mTBI) have been controversial in describing the white matter tract integrity changes occurring at acute and subacute post-injury. In this prospective longitudinal study, we aim to investigate the longitudinal changes of white matter (WM) using diffusion tensor imaging (DTI) and their correlations with neuropsychological tests. Thirty-three patients with subacute mTBI and 31 matched healthy controls were studied with an extensive imaging and clinical battery. Neuroimaging was obtained within 7 days post-injury for acute scans and repeated at 1 and 3 months post-injury. Using a region-of-interest-based approach, tract-based spatial statistics was used to conduct voxel-wise analysis on diffusion changes in mTBI and was compared to those of healthy matched controls, scanned during the same time period and rescanned with an interval similar to that of patients. We found decreased fractional anisotropy (FA) values in the left anterior limb of internal capsule (ALIC) and right inferior fronto-occipital fasciculus (IFOF) during the 7 days post-injury, which showed longitudinal evidence of recovery following 1 month post-injury. Increased FA values in these two tracts at 1 month post-injury were positively associated with better performance on cognitive information processing speed at initial assessment. By contrast, there were also some tracts (right anterior corona radiata, forceps major, and body of corpus callosum) exhibiting the continuing loss of integrity sustaining even beyond 3 months, which can predict the persisting post-concussion syndromes. Continuing loss of structural integrity in some tracts may contribute to the persistent post-concussion syndromes in mTBI patients, suggesting certain tracts providing an objective biomarker for tracking the pathological recovery process following mTBI.

The effects of tumor size and postoperative radiotherapy for patients with adult low-grade (WHO grade II) infiltrative supratentorial astrocytoma/oligodendroglioma: A population-based and propensity score matched study.

BACKGROUND: The update of 2018 NCCN guidelines (central nervous system cancers) recommended the risk classification of postoperative patients diagnosed as adult low-grade (WHO grade II) infiltrative supratentorial astrocytoma/oligodendroglioma (ALISA/O) should take tumor size into consideration. Moreover, the guidelines removed postoperative radiotherapy (PORT) for low risk patients. Our study aimed to explore the specific tumor size to divide postoperative patients into relatively low- or high risk subgroups and the effect of PORT for ALISA/O patients. METHODS: We conducted a retrospective study choosing 1277 postoperative ALISA/O patients from the Surveillance, Epidemiology, and End Results database. The X-tile analysis provided the optimal cutoff point based on tumor size. The differences between surgery alone and surgery +RT groups were balanced by propensity score-matched analysis. The multivariable analysis and the nomogram evaluated multiple prognostic factors based on cancer-specific survival (CSS) and overall survival (OS). RESULTS: X-tile plots defined 59 mm (P < 0.001) as the optimal cutoff tumor size value in terms of CSS, which was verified in multivariate analysis (P < 0.001). The Kaplan-Meier analysis showed that the surgery alone had higher CSS and OS than surgery +RT, while the low risk group had no statistical significance after propensity score match. Multivariable analysis showed that surgery +RT was independently associated with diminished OS and CSS for high risk group, which had no statistical significance for low-risk group. CONCLUSIONS: Our study suggested that tumor size of 59 mm was an optimal cutoff point to divide postoperative patients into relatively low- or high risk subgroups. PORT may not benefit patients, while the effects of PORT for low risk patients need further research.