Contributions
Abstract: P1053
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Background: Graph theoretical analysis of resting state fMRI (rs-fMRI) can be used to describe the macroscale organization of the brain. These measures relate to cognitive performance in multiple sclerosis (MS), but previous work has primarily focused on cross-sectional studies at field strengths of 3 Tesla or less. 7 Tesla (7 T) rs-fMRI benefits from a higher signal-to-noise ratio, which can be translated into higher spatial and temporal resolution.
Objective: To investigate longitudinal changes in rs-fMRI graph theory measures at 7 T and their relationship with neuropsychological (NP) testing in MS.
Methods: 16 subjects with relapsing-remitting MS (12 female; mean age 43.1) underwent rs-MRI scanning (TR=1710 ms, TE=24 ms, 1.35 mm3 isotropic voxels, 246 TRs) at 7 T and NP testing on two visits at an average interval of 16 months. Using a functionally defined atlas, the cortex was segmented into 114 parcels for graph theory analysis. Degree centrality (DC), local efficiency (LE), and betweenness centrality (BC) were measured at baseline (BL) and follow-up (FU), for each subregion and additionally averaged for each functional network. Attention, memory, and language functions were assessed at BL and FU with the Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test (PASAT), Controlled Oral Word Association Test (COWAT), and Brief Visuospatial Memory Test (BVMT). Test performance was correlated both individually and as a four-test grouped average with longitudinal changes in graph theory metrics.
Results: The dorsal attention network (DAN) demonstrated a decrease in DC (12.5 at BL, 10.6 at FU, p< .0001) over time. Changes in NP scores, averaged as a group, correlated with changes in LE in the RH postcentral sulcus (r=.66, p=.005) and BC in the bilateral postcentral sulci (r=-.51, p=.038; r=-.60, p=.012), nodes of the DAN. SDMT changes correlated with LE changes in the LH lateral occipital node of the DAN (r=.556, p=.025), PASAT and BVMT with LE in the postcentral sulci of the DAN (r=.575, p=.019; r=.665, p=.004), and BVMT with DC in the RH inferior parietal sulcus of the DAN (r=.530, p=.033).
Conclusions: There is a meaningful association between longitudinal changes in 7 T rs-fMRI derived graph theoretical measures in the DAN and worsening cognitive performance in MS. This finding suggests that disconnection and decreased integration throughout the DAN, even over a short period of time, can result in worsening cognitive performance.
Disclosure:
Andrew W. Russo: nothing to disclose
Sean M. Tobyne: nothing to disclose
Kevin R. Patel: nothing to disclose
Natalya K. Machado: nothing to disclose
Eric C. Klawiter: has received research grants from Atlas5D, Biogen, EMD Serono and Roche; and consulting fees from Acorda, Atlas5D, Biogen, EMD Serono, Genentech and Shire.
Abstract: P1053
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Background: Graph theoretical analysis of resting state fMRI (rs-fMRI) can be used to describe the macroscale organization of the brain. These measures relate to cognitive performance in multiple sclerosis (MS), but previous work has primarily focused on cross-sectional studies at field strengths of 3 Tesla or less. 7 Tesla (7 T) rs-fMRI benefits from a higher signal-to-noise ratio, which can be translated into higher spatial and temporal resolution.
Objective: To investigate longitudinal changes in rs-fMRI graph theory measures at 7 T and their relationship with neuropsychological (NP) testing in MS.
Methods: 16 subjects with relapsing-remitting MS (12 female; mean age 43.1) underwent rs-MRI scanning (TR=1710 ms, TE=24 ms, 1.35 mm3 isotropic voxels, 246 TRs) at 7 T and NP testing on two visits at an average interval of 16 months. Using a functionally defined atlas, the cortex was segmented into 114 parcels for graph theory analysis. Degree centrality (DC), local efficiency (LE), and betweenness centrality (BC) were measured at baseline (BL) and follow-up (FU), for each subregion and additionally averaged for each functional network. Attention, memory, and language functions were assessed at BL and FU with the Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test (PASAT), Controlled Oral Word Association Test (COWAT), and Brief Visuospatial Memory Test (BVMT). Test performance was correlated both individually and as a four-test grouped average with longitudinal changes in graph theory metrics.
Results: The dorsal attention network (DAN) demonstrated a decrease in DC (12.5 at BL, 10.6 at FU, p< .0001) over time. Changes in NP scores, averaged as a group, correlated with changes in LE in the RH postcentral sulcus (r=.66, p=.005) and BC in the bilateral postcentral sulci (r=-.51, p=.038; r=-.60, p=.012), nodes of the DAN. SDMT changes correlated with LE changes in the LH lateral occipital node of the DAN (r=.556, p=.025), PASAT and BVMT with LE in the postcentral sulci of the DAN (r=.575, p=.019; r=.665, p=.004), and BVMT with DC in the RH inferior parietal sulcus of the DAN (r=.530, p=.033).
Conclusions: There is a meaningful association between longitudinal changes in 7 T rs-fMRI derived graph theoretical measures in the DAN and worsening cognitive performance in MS. This finding suggests that disconnection and decreased integration throughout the DAN, even over a short period of time, can result in worsening cognitive performance.
Disclosure:
Andrew W. Russo: nothing to disclose
Sean M. Tobyne: nothing to disclose
Kevin R. Patel: nothing to disclose
Natalya K. Machado: nothing to disclose
Eric C. Klawiter: has received research grants from Atlas5D, Biogen, EMD Serono and Roche; and consulting fees from Acorda, Atlas5D, Biogen, EMD Serono, Genentech and Shire.