- Automatic Spinal Cord Gray Matter Quantification: A Novel Approach
The authors assessed the reproducibility and accuracy of cervical spinal cord gray matter and white matter cross-sectional area measurements using magnetization inversion recovery acquisition images and a fully automatic postprocessing segmentation algorithm. The cervical spinal cord of 24 healthy subjects was scanned in a test-retest fashion on a 3T MR imaging system. Twelve axial averaged magnetization inversion recovery acquisition slices were acquired over a 48-mm cord segment. GM and WM were both manually segmented by 2 experienced readers and compared with an automatic variational segmentation algorithm with a shape prior modified for 3D data with a slice similarity prior. Reproducibility was high for both methods, while being better for the automatic approach. The accuracy of the automatic method compared with the manual reference standard was excellent. They conclude that the fully automated postprocessing segmentation algorithm demonstrated an accurate and reproducible spinal cord GM and WM segmentation.
- Altered Relationship between Working Memory and Brain Microstructure after Mild Traumatic Brain Injury
The authors investigated how working memory deficits relate to detectable WM microstructural injuries to discover robust biomarkers that allow early identification of patients with mild traumatic brain injury at the highest risk of working memory impairment. Multi-shell diffusion MR imaging was performed on a 3T scanner with 5 b-values. Diffusion metrics of fractional anisotropy, diffusivity and kurtosis (mean, radial, axial), and WM tract integrity were calculated. Auditory-verbal working memory was assessed using the Wechsler Adult Intelligence Scale. ROI analysis found a significant positive correlation between axial kurtosis and Digit Span Backward in mild traumatic brain injury mainly present in the right superior longitudinal fasciculus, which was not observed in healthy controls.