Imaging 1Thursday, October 14, 2010, 15:30 - 17:00
Relation between quantitative venous vasculature assessment on susceptibility-weighted imaging and haemodynamic MRI metrics in multiple sclerosis patients G. Poloni, M. Dwyer, F. Parker, C. Magnano, C. Schirda, N. Bergsland, R. Zivadinov (Buffalo, US)
Background: The venous vasculature of the brain parenchyma is significantly less visible on susceptibility-weighted imaging (SWI) in patients with multiple sclerosis (MS) compared to healthy controls (HC), as previously described.
Objective: To investigate the relation between the altered venous vasculature visibility in the brain parenchyma and Cine Cerebrospinal Fluid (CSF) Imaging and Perfusion Weighted Imaging (PWI) MRI metrics in patients with relapsing-remitting (RR) and secondary-progressive (SP) MS disease course, and HC.
Methods: Fifty nine (59) MS patients [41 RR and 18 SP] and thirty three (33) age- and sex-matched HC were scanned on a 3T GE scanner using CSF imaging, PWI and SWI. Mean age at scan was 44.3 yrs, mean disease duration 13.2 yrs and median EDSS 2.5. CSF flow rates (positive, negative and net), Mean Transit Time (MTT), Cerebral Blood Flow (CBF) maps and Cerebral Blood Volume (CBV) maps were calculated. 3D multi-scale line filter was used to extract the venous vasculature from SWI images. Absolute venous volume (AVV) was estimated in milliliters (ml); relative venous intracranial fraction (VIF) was calculated to correct for head size and amount of brain atrophy. Vein volumes were classified by vein radius: <0.3mm, 0.3-0.6mm, 0.6-0.9mm and >0.9 mm. Voxel brain average distance-from-vein (DFV) maps were calculated.
Results: MS patients showed reduced AVV, volume of veins with diameter <0.3mm and VIF (p< .05) and increased DFV (all p< .001) with respect to HC. In MS patients lower AVV, volume of veins with diameter <0.3mm and VIF, and higher DVF were strongly related to lower net negative flow (Spearman r = .48 to .61, p< .001) and higher net positive flow (r = .53 to .64, p< .001). A similar relation was found with an increased MTT (gray matter: r = .36 to .43, p< .01; white matter: r = .40 to .46, p< .001) and a decreased CBF (gray matter: r = .38 to .45, p< .01; white matter: r = .37 to .49, p< .001). The relationships were consistently stronger in RR than SP MS patients. No significances where found for HC.
Conclusions: This study showed that lower brain parenchyma venous vasculature visibility on SWI is related to altered hemodynamic CSF flow and hypoperfusion in patients with MS. The events contributing to these findings are probably occurring early in the disease process. Further studies are needed to elucidate relationship between reduction of venous vasculature and the hemodynamic MRI parameters in MS patients.
Felicia Parker, Claudiu V. Schirda, Michael G. Dwyer, Guy U. Poloni, Niels Bergsland and Christopher Magnano have nothing to disclose.
Dr. Zivadinov received personal compensation from Teva Neuroscience, Biogen Idec, EMD Serono and Questcor Pharmaceuticals for speaking and consultant fees. Dr. Zivadinov received financial support for research activities from Biogen Idec, Teva Neuroscience, Genzyme, Bracco, Questcor Pharmaceuticals, EMD Serono and Bracco.