Automated Determination of Brain Parenchymal Fraction in Multiple Sclerosis (P03.055)

Abstract

Objective: To evaluate the use of synthetic tissue mapping to determine brain parenchymal fraction (BPF) in multiple sclerosis (MS). Background Brain atrophy is a feared consequence of multiple sclerosis (MS) and is widely measured as a reduction in the brain parenchymal fraction (BPF). Several methods exist for determining BPF in vivo using magnetic resonance imaging (MRI). In conventional MRI, tissue segmentation is based on image analysis and not on the physical properties of the tissue per se. In this study the approach of synthetic tissue mapping was applied, where the BPF was automatically calculated based on absolute quantification of the relaxation rates R1 and R2 and the proton density. Design/Methods: In this cross sectional study 99 cases with MS and 35 controls were scanned with the quantification method QRAPMASTER. SyMRI Brain Studio was used for synthetic tissue mapping and the calculation of BPF. Results: MS cases had significantly lower BPF (mean 0.852, SE=0.0041) compared with controls (0.890, SE=0.0040). There was also a significant correlation between BPF and expanded disability status scale scores (EDSS, r=-0.58; p Conclusions: Synthetic tissue mapping is a promising method for determining brain atrophy in MS, measured as a reduction in BPF. Results are highly congruent with those described using other methods. This method is advantageous since it determines BPF based on absolute tissue properties, thus removing arbitrary MRI scanner parameter scaling. It is also fully automatic enabling subjective components or differences in investigator experience to be excluded. This makes it highly interesting for routine determination of brain atrophy in basic clinical settings and in clinical trials. Supported by: An unconditional research grant from Biogen Idec, Sweden AB and by The Swedish Association for persons with Neurological Disabilities. Disclosure: Dr. Vagberg has received personal compensation for activities with Novartis, Biogen Idec, and Baxter. Dr. Vagberg has received research support from Biogen Idec. Dr. Lindqvist has nothing to disclose. Dr. Warntjes has received personal compensation for activities with SyntheticMR AB as an employee. Dr. Sundstrom has received personal compensation for activities with Biogen Idec and Novartis. Dr. Birgander has nothing to disclose. Dr. Svenningsson has received personal compensation for activities with Biogen Idec, Baxter, and Merck Serono. Dr. Svenningson has received research support from Biogen Idec.