title: Spontaneous BOLD signal fluctuations in young healthy subjects and elderly patients with chronic kidney disease.
abstract: Spontaneous fluctuations in blood oxygenation level-dependent (BOLD) images are the basis of resting-state fMRI and frequently used for functional connectivity studies. However, there may be intrinsic information in the amplitudes of these fluctuations. We investigated the possibility of using the amplitude of spontaneous BOLD signal fluctuations as a biomarker for cerebral vasomotor reactivity. We compared the coefficient of variation (CV) of the time series (defined as the temporal standard deviation of the time series divided by the mean signal intensity) in two populations: 1) Ten young healthy adults and 2) Ten hypertensive elderly subjects with chronic kidney disease (CKD). We found a statistically significant increase (P<0.01) in the CV values for the CKD patients compared with the young healthy adults in both gray matter (GM) and white matter (WM). The difference was independent of the exact segmentation method, became more significant after correcting for physiological signals using RETROICOR, and mainly arose from very low frequency components of the BOLD signal fluctuation (f<0.025 Hz). Furthermore, there was a strong relationship between WM and GM signal fluctuation CV's (R(2)= 0.87) in individuals, with a ratio of about 1:3. These results suggest that amplitude of the spontaneous BOLD signal fluctuations may be used to assess the cerebrovascular reactivity mechanisms and provide valuable information about variations with age and different disease states.
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, United States of America.
authors.forename: Hesamoddin
authors.initials: H
authors.lastname: Jahanian
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, United States of America; Department of Electrical Engineering, Stanford University, Stanford, California, Untied States of America.
authors.forename: Wendy W
authors.initials: WW
authors.lastname: Ni
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, United States of America.
authors.forename: Thomas
authors.initials: T
authors.lastname: Christen
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, United States of America.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Moseley
authors.affiliation: Geriatric Research and Education Clinical Center, Palo Alto Veterans Affairs Health Care System and Division of Nephrology, Stanford University, Stanford, California, United States of America.
authors.forename: Manjula
authors.initials: M
authors.lastname: Kurella Tamura
authors.affiliation: Department of Radiology, Stanford University, Stanford, California, United States of America.
authors.forename: Greg
authors.initials: G
authors.lastname: Zaharchuk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D001794:Blood Pressure; D001921:Brain / Q000098:blood supply / Q000502:physiology; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000378:metabolism; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010092:Oximetry / Q000379:methods; D010100:Oxygen / Q000378:metabolism*; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis* / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010100:Oxygen