Determination of flow and rate constants in a kinetic model of (/sup 99m/Tc)-hexamethyl-propylene amine oxime in the human brain

Journal Article · Thu Dec 01 04:00:00 EST 1988 · J. Cereb. Blood Flow Metab.; (United States)

DOI:https://doi.org/10.1038/jcbfm.1988.34· OSTI ID:6610899

Matsuda, H; Oba, H; Seki, H; Higashi, S; Sumiya, H; Tsuji, S; Terada, H; Imai, K; Shiba, K; Mori, H

The values for flow and rate constants for a kinetic model of (99mTc)-hexamethylpropyleneamine oxime (HM-PAO) distribution in the human brain were determined. The single-pass extraction ratio of HM-PAO was also determined in the rat brain by the indicator diffusion method; a value of 0.90 +/- 0.02 (mean +/- SEM, n = 5) was obtained. Time course data of brain activity and arterial blood activity of the tracer were fitted to a four compartment model: Values of blood flow and the first-order rate constants for backdiffusion of the diffusible tracer from brain to blood (k2), conversion of the lipophilic tracer to the hydrophilic one in brain (k3), and conversion of the diffusible tracer to the nondiffusible one in blood (k5) were determined. Conversion of hydrophilic tracer back to a lipophilic form in both blood and brain was assumed to be negligible during the course of the experiment. The values obtained for blood flow, k2, and k3 were, respectively, 0.40 +/- 0.03 ml/g/min, 0.38 +/- 0.04 min-1, and 0.92 +/- 0.05 min-1 in the gray matter (n = 4), and 0.23 +/- 0.01 ml/g/min, 0.17 +/- 0.01 min-1, and 1.01 +/- 0.05 min-1 in the white matter (n = 2) in patients with cerebrovascular disorder. The k5 value was 1.14 +/- 0.06 min-1 (n = 4). These experimentally determined values agree well with the theoretical ones previously reported by Lassen et al. The results suggest the relative constancy of the k3 and k5 values and the more prominent initial backdiffusion of the lipophilic HM-PAO from brain to blood in high flow regions compared to low flow regions.

• Research Organization: Kanazawa Univ. (Japan)
• OSTI ID: 6610899
• Journal Information: J. Cereb. Blood Flow Metab.; (United States), Journal Name: J. Cereb. Blood Flow Metab.; (United States) Vol. 8:6; ISSN JCBMD
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD FLOW
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DRUGS
HOURS LIVING RADIOISOTOPES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOMERIC NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MAN
MATHEMATICAL MODELS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOMETALLIC COMPOUNDS
ORGANS
OXIMES
PRIMATES
RADIOISOTOPES
RADIOPHARMACEUTICALS
RATS
RODENTS
TECHNETIUM 99
TECHNETIUM ISOTOPES
UPTAKE
VERTEBRATES
YEARS LIVING RADIOISOTOPES