Transient relationships among BOLD, CBV, and CBF changes in rat brain as detected by functional MRI. Magn Reson Med 2002 Dec;48(6):987-93
Date
12/05/2002Pubmed ID
12465108DOI
10.1002/mrm.10317Scopus ID
2-s2.0-0036893672 (requires institutional sign-in at Scopus site) 58 CitationsAbstract
The transient relationship between arterial cerebral blood flow (CBF(A)) and total cerebral blood volume (CBV(T)) was determined in the rat brain. Five rats anesthetized with urethane (1.2 g/kg) were examined under graded hypercapnia conditions (7.5% and 10% CO(2) ventilation). The blood oxygenation level-dependent (BOLD) contrast was determined by a gradient-echo echo-planar imaging (GE-EPI) pulse sequence, and CBV(T) changes were determined after injection of a monocrystalline iron oxide nanocolloid (MION) contrast agent using an iron dose of 12 mg/kg. The relationship between CBV(T) and CBF(A) under transient conditions is similar to the power law under steady-state conditions. In addition, the transient relationship between CBV(T) and CBF(A) is region-specific. Voxels with > or =15% BOLD signal changes from hypercapnia (7.5% CO(2) ventilation) have a larger power index (alpha = 3.26), a larger maximum possible BOLD response (M = 0.85), and shorter T(*)(2) (32 ms) caused by deoxyhemoglobin, compared to voxels with <15% BOLD signal changes (alpha = 1.82, M = 0.16, and T(*)(2) = 169 ms). It is suggested that the biophysical model of the BOLD signal can be extended under the transient state, with a caution that alpha and M values are region-specific. To avoid overestimation of the cerebral metabolic rate of oxygen changes seen using fMRI, caution should be taken to not include voxels with large veins and a large BOLD signal.
Author List
Wu G, Luo F, Li Z, Zhao X, Li SJMESH terms used to index this publication - Major topics in bold
AnimalsBlood Volume
Brain
Brain Mapping
Cerebrovascular Circulation
Contrast Media
Echo-Planar Imaging
Image Enhancement
Image Interpretation, Computer-Assisted
Male
Models, Animal
Oxygen
Oxygen Consumption
Probability
Rats
Rats, Sprague-Dawley
Sensitivity and Specificity
