In Vivo measurement of cerebral oxygen consumption and blood flow using ¹⁷O magnetic resonance imaging

Abstract

We used 17O NMR imaging techniques to measure the H2(17)O concentration in a 0.8-ml voxel in the cat brain following injection of an arterial bolus of enriched H2(17)O and during inhalation of enriched 17O2. We also measured the H2(17)O concentration in arterial blood during 17O2 inhalation. The data from the first measurement were used to calculate the blood flow in the voxel. The data from all three measurements were combined to calculate the oxygen consumption in the voxel. The values of cerebral blood flow and oxygen consumption calculated with 17O NMR techniques agree reasonably well with values calculated for a similar region of the cat brain using autoradiographic techniques.

Cerebral perfusion assessment by bolus tracking using hyperpolarized 13C

“…Furthermore, parametric compensation requires the accurate determination of MTTЈ (Eq. [11]), which is also limited by the available SNR. Under certain conditions, analysis without compensation may be an acceptable alternative since with this method high precision estimates are obtained.…”

In vivo17O NMR approaches for brain study at high field

“…In vivo 17 O approaches can be potentially applied to measuring and imaging two important physiological parameters, namely CMRO 2 and CBF. 6,8,14,16,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] The 17 O NMR approaches for in vivo determinations of CMRO 2 and CBF involve the measurement of (i) the amount of 17 O-labeled water metabolically generated from the inhaled 17 O 2 gas through the oxidative pathway, and (ii) the washout rate of the 17 O-labeled water tracer introduced by a bolus injection, respectively. In terms of methodology, there is a close similarity between the in vivo 17 O approaches and PET approaches, especially for CBF measurements.…”

17O relaxation time and NMR sensitivity of cerebral water and their field dependence

“…If the H 2 17 O tracer is given as a bolus injection, CBF can be extracted from the temporal behavior of the H 2 17 O signal detected from the brain (14) according to…”

“…This small change must be differentiated from basal fluctuations in the signal intensity of the large water proton resonance that occur due to instrumental instabilities or physiologic processes such as respiration, heart beat, and vasomotion. (14), following inhalation of molecular oxygen enriched with the 17 O 2 isotope, and to obtain a low-resolution CMR O2 image (0.8 ml voxel size). Nonlocalized 17 O-MRS with a surface coil was applied to measure basal CMR O2 in the occipital cortex of the human brain (18).…”