A noninvasive technique for measuring local cerebral blood flow (LCBF) by xenonenhanced x-ray transmission computed tomography (CT) has been developed and reported quite extensively in recent years. In this method, nonradioactive xenon gas is inhaled and the temporal changes in radiographic enhancement produced by the inhalation are measured by sequential computed tomography. Time-dependent xenon concentration within various tissue segments in the brain are used to derive both local partition coefficient (Lambda) and LCBF. An assessment of this method reveals that although it has some distinct limitations, it provides functional mapping of blood flow with excellent anatomic specificity. While significant progress has been made in recent years in the understanding of the basic advantages and limitations of this methodology, various aspects of the derivational methodologies used are yet to be optimized and a comprehensive validation of this technique is yet to be completed. The main thrust of this continuation proposal is the comprehensive validation of the technique in critical low-flow states. While the proposed study will be carried out with non-human primates (Papio cynocephalus [anubis]), questions which concern possible future clinical use of such techniques will be addressed in detail. In this study protocols will be tested and optimized for clinical applications and results will be compared to those obtained by other well-established diffusible indicator methods, in particular, in critical low-flow states.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL027208-06
Application #
3338999
Study Section
Diagnostic Radiology Study Section (RNM)
Project Start
1984-09-01
Project End
1987-12-31
Budget Start
1986-09-01
Budget End
1987-12-31
Support Year
6
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Type
Schools of Medicine
DUNS #
053785812
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Nemoto, E M; Klementavicius, R; Melick, J A et al. (1996) Norepinephrine activation of basal cerebral metabolic rate for oxygen (CMRO2) during hypothermia in rats. Anesth Analg 83:1262-7
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Whitehurst, S L; Nemoto, E M; Yao, L et al. (1994) MAC of xenon and halothane in rhesus monkeys. J Neurosurg Anesthesiol 6:275-9
Chavko, M; Nemoto, E M; Melick, J A (1993) Regional lipid composition in the rat brain. Mol Chem Neuropathol 18:123-31
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Darby, J M; Nemoto, E M; Yonas, H et al. (1993) Local cerebral blood flow measured by xenon-enhanced CT during cryogenic brain edema and intracranial hypertension in monkeys. J Cereb Blood Flow Metab 13:763-72
Yao, L P; Bandres, J; Nemoto, E M et al. (1992) Effect of 33% xenon inhalation on whole-brain blood flow and metabolism in awake and fentanyl-anesthetized monkeys. Stroke 23:69-74
Nemoto, E M; Yao, L; Yonas, H et al. (1992) Active and basal whole brain blood flow, oxygen and glucose metabolism in monkeys. Adv Exp Med Biol 317:695-9
Marks, E C; Yonas, H; Sanders, M H et al. (1992) Physiologic implications of adding small amounts of carbon dioxide to the gas mixture during inhalation of xenon. Neuroradiology 34:297-300

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