THE EFFECT OF FIELD STRENGTH TOWARD LONGITUDINAL TOTAL INTRACRANIAL VOLUME ESTIMATION AND HIPPOCAMPAL ATROPHY ON ADNI DATA

Background:When performing volume-based analysis on structural MRI data, it is necessary to normalize the structure volume with respect to the total intracranial volume (TIV) to account for the gross head size difference. Accurate TIV estimation is therefore crucial. Previously clinical MRI practice with scanners of 1.5 Tesla (T) field strength has been shifting to 3T. It is important to evaluate the effect of the resulted image difference towards the TIVestimation, as well as the consequent longitudinal data analysis of diseasespecific structural biomarker such as hippocampal atrophy. Methods: In this paper, we studied the intracranial volume estimation of images acquired for the same patients with both 1.5T and 3T scanner. Longitudinal data (up to 36 months) from 187 subjects were obtained from Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort. The longitudinal robustness of TIV estimation on both field strength were evaluated using three state-of-the-art