P3‐260: Simultaneous Quantification of White Matter Abnormalities and Vasogenic Edema in Early Alzheimer's Disease
Year: 2016
Type: article
Study design: Observational Study
Abstract: Cerebral vasogenic edema has been reported closely associated with the antiamyloid immunotherapy and could affect the integrity of both gray and white matter (WM) in AD patients. The presence of vasogenic edema would lead to non-specific detection of WM abnormalities using conventional diffusion tensor imaging (DTI). This study aims to examine whether diffusion basis spectral imaging (DBSI) could simultaneously quantify both WM integrity and WM edema . 226 participants were included in this study. The participants who had negative CSF measures (Aβ1-42 > 500 pg/ml, total tau <339 pg/ml, and ptau181 < 67 pg/ml) were classified as healthy controls (HC) (n=144). 82 participants received a clinical dementia rating (CDR) score of 0.5 (very mild dementia) and associated diagnosis of AD (early AD dementia). DTI and DBSI were performed on all participants. Fractional anisotropy (FA), axial, radial and mean diffusivities were derived from DTI and DBSI. DBSI-derived vasogenic edema fraction was also quantified on WM tracts generated from FSL (http://www.fmrib.ox.ac.uk/fsl). Age, gender, education, APOE e4 genotype and family history were controlling during statistical analysis. In the early AD dementia group, we found a significantly increased DBSI-derived edema fraction, suggesting the presence of vasogenic edema in several WM regions (tapetum was chosen as a representative example, Fig. 1A). Significantly reduced DBSI-derived axial diffusivity suggested the presence of axonal injury at this early AD dementia stage (Fig. 1B). In comparison, the significantly increased DTI-derived axial diffusivity suggested the failure of DTI to detect axonal injury, probably due to the confounding effect of vasogenic edema (Fig. 1B, red arrow). DTI-/DBSI-derived radial diffusivity and FA increased (Fig. 1C) and decreased (Fig. 1D), respectively, in the early AD dementia group, suggesting demyelination and white matter abnormality. However, DBSI-derived radial diffusivity and FA were not affected by vasogenic edema contamination and therefore reflected the white matter integrity with higher specificity and accuracy. Our data suggest that DBSI can separately quantify WM structural abnormalities and vasogenic edema in early symptomatic AD. In comparison, conventional DTI cannot separate the effect off WM abnormality from edema, limiting its usage in accurately characterizing the complicated pathological substrates in AD. Quantitative assessment of DTI-and DBSI-derived indices in Tapetum in HC and early AD dementia participants. Thick lines indicate means, boxes 25 to 75 percentiles, and thin lines indicate 5 and 95 percentiles. P < 0.05, P < 0.005.
Source: Alzheimer s & Dementia
Institution: Washington University in St. Louis
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4247542798