A metabolic threshold of irreversible ischemia demonstrated by PET in a middle cerebral artery occlusion-reperfusion primate model*

Abstract

The results indicate that CMRO2 is the best predictor of reversible or irreversible brain damage and the critical metabolic threshold level appears to be a reduction of oxygen metabolism to between 61% and 69% of the corresponding contralateral region.

Rapid Quantitative Measurement of CMRO2 and CBF by Dual Administration of 15O-Labeled Oxygen and Water During a Single PET Scan—a Validation Study and Error Analysis in Anesthetized Monkeys

“…Watabe et al (2002) showed that CBF images can be quantitated at much shorter interval than the previous protocol, typically at 90 secs, from sequential PET scanning Altman et al (1991) obtained OEF values of 0.5370.13 from arteriosinus blood sampling. Using steady-state PET, others have measured OEFs ranging from 0.42 to 0.58 in normal tissues of anesthetized monkeys (Altman et al, 1991;Pappata et al, 1993;Touzani et al, 1995;Young et al, 1996;Schumann et al, 1996;Frykholm et al, 2000). Moreover, the values of gCBF in the present PET study were 3079 mL 100/g min from three-step ARG, 3079 mL 100/g min from Previously reported values varied from 27 to 37 mL 100/g min for CBF and 2.4 to 3.4 mL 100/g min for CMRO 2 (Altman et al, 1991;Pappata et al, 1993;Touzani et al, 1995;Young et al, 1996;Schumann et al, 1996;Frykholm et al, 2000).…”

“…Using steady-state PET, others have measured OEFs ranging from 0.42 to 0.58 in normal tissues of anesthetized monkeys (Altman et al, 1991;Pappata et al, 1993;Touzani et al, 1995;Young et al, 1996;Schumann et al, 1996;Frykholm et al, 2000). Moreover, the values of gCBF in the present PET study were 3079 mL 100/g min from three-step ARG, 3079 mL 100/g min from Previously reported values varied from 27 to 37 mL 100/g min for CBF and 2.4 to 3.4 mL 100/g min for CMRO 2 (Altman et al, 1991;Pappata et al, 1993;Touzani et al, 1995;Young et al, 1996;Schumann et al, 1996;Frykholm et al, 2000). Variations are because of the differences in monkey species, physiologic conditions, anesthetic agent used, PET scanner, and methodology; the current results clearly show that the DARG method can be used to determine these physiologic parameters with a high degree of accuracy.…”

Interstitial pO2 in Ischemic Penumbra and Core are Differentially Affected following Transient Focal Cerebral Ischemia in Rats

“…Using autoradiographic methods, Ginsberg and co-workers have shown that increased glucose metabolic rate was a signature of the early penumbra, and that differential levels of blood flow in the penumbra and core were highly predictive of histological injury within the same focus Zhao et al, 1997). A recent study in a primate model showed that the CMRO 2 level obtained using PET scanning could predict penumbral regions (Frykholm et al, 2000). One important reason for this reduced CMRO 2 in penumbra is hypothesized to be decreased interstitial (or tissue) oxygen levels that are directly available for cells in the penumbra to utilize for metabolism.…”

Multimodal optical imaging of mouse Ischemic cortex

“…Metabolic measures are thought to be a strong indicator of tissue outcome [18] with oxygen and glucose metabolism being closely linked [19]. LSF imaging has previously been applied to cerebral ischemia [2] and it's advantages over laser Doppler flowmetry have been established.…”