Effect sizes of BOLD CVR, resting-state signal fluctuations and time delay measures for the assessment of hemodynamic impairment in carotid occlusion patients

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2018-10, Vol.179, p.530-539
• Main Authors: De Vis, Jill B., Bhogal, Alex A., Hendrikse, Jeroen, Petersen, Esben T., Siero, Jeroen C.W.
• Format: Article
• Language: English
• Subjects: Aged; Blood oxygen level dependent; Blood Volume; BOLD; Brain; Brain - blood supply; Brain - diagnostic imaging; Brain Mapping - methods; Brain research; Carbon; Carotid artery; Carotid Artery Diseases - diagnostic imaging; Cerebral blood flow; Cerebrovascular Circulation - physiology; Cerebrovascular disease; Cerebrovascular reactivity; Cerebrovascular system; Female; fMRI; Hemodynamics - physiology; Humans; Hypercapnia; Hyperoxia; Image Interpretation, Computer-Assisted - methods; Ischemia; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Middle Aged; MRI; NMR; Nuclear magnetic resonance; Patients; Resting-state fMRI; Spatial distribution; Studies
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2018.06.017

The BOLD signal amplitude as a response to a hypercapnia stimulus is commonly used to assess cerebrovascular reserve. Despite recent advances, the implementation remains cumbersome and alternative ways to assess hemodynamic impairment are desirable. Resting-state BOLD signal fluctuations (rsBOLD) have been proposed however data on its sensitivity and dependence on baseline venous cerebral blood volume (vCBV) is limited. The primary aim of this study was to compare the effect sizes of resting-state and hypercapnia induced BOLD signal changes in the detection of hemodynamic impairment. The second aim of the study was to assess the dependence of BOLD signal variability on vCBV. Fifteen patients with internal carotid artery occlusive disease and 15 matched healthy controls were included in this study. The BOLD signal was derived from a dual-echo gradient-echo echo-planar sequence during hypercapnia (HC) and hyperoxia (HO) gas modulations. BOLD (fractional) amplitude of low frequency fluctuations ((f)ALFF) was compared to HC-BOLD, BOLD response delays derived from time delay analysis and ΔBOLD in response to progressively increasing HC. Effect sizes (i.e. the standard mean difference between patients and controls) were calculated. HO-BOLD was used to estimate vCBV, and its contribution to the variability in rsBOLD signal was evaluated. The effect sizes of ALFF and fALFF (0.61 and 0.72) were lower than the effect sizes related to hypercapnia-based hemodynamic assessment analysis; 1.62, 1.56 and 0.90 for HC-BOLD, BOLD response delays and ΔBOLD in response to progressively increasing HC. A moderate relation was found between (f)ALFF and HC-BOLD in controls (R2 of 0.61 and 0.42), but this relation decreased in patients (R2 of 0.33 and 0.15). (f)ALFF did not differ between patients and controls whereas HC-BOLD did (p