Rubidium-82 kinetics after coronary occlusion: temporal relation of net myocardial accumulation and viability in open-chested dogs

Journal Article · Mon Sep 01 04:00:00 EDT 1986 · J. Nucl. Med.; (United States)

OSTI ID:5003730

Goldstein, R A

Serial assessment of perfusion and viability during myocardial infarction has not been feasible, in part, because of the long half-lives of available tracers. Rubidium-82 (82Rb) is a generator-produced, positron-emitting potassium analog with a short half-life (75 sec) that permits repeated studies. To determine the temporal relation of net myocardial /sup 82/Rb accumulation to loss of viability during prolonged ischemia, a 2-3 mCi bolus of /sup 82/Rb was given to 46 open-chested dogs while regional myocardial time-activity curves were obtained with beta probes at baseline, and serially after coronary occlusion lasting 1-6 hr. Hearts were then stained with triphenyl tetrazolium chloride (TTC) to assess the viability of the epicardium under the probe to a depth corresponding to the range of positrons. Irreversible injury occurred in two out of 16 experiments at 1 hr and ten out of 15 experiments at 3 hr and also at 6 hr (p less than 0.05 vs. 1 hr). In viable myocardial samples, rubidium extraction increased with low flow as compared with nonischemic controls for all time periods but was unchanged (failed to increase) in nonviable tissue. Net /sup 82/Rb accumulation decreased during 1 to 6 hr of occlusion in irreversibly injured samples (0.28 +/- 0.19 to 0.16 +/- 0.07, p less than 0.05) but remained unchanged in myocardial tissue subsequently shown to be viable. For myocardial samples that were nonviable at 3 and 6 hr, changes in net accumulation of tracer became abnormal only after 6 hr of occlusion. The mechanisms primarily responsible for the decrease in net accumulation of /sup 82/Rb at 6 hr appeared to be leakage of tracer after first pass. Therefore, failure to increase extraction at low flows may be an early indicator of cell death, whereas membrane leakage occurs several hours after loss of viability.

• Research Organization: Univ. of Texas Health Science Center, Houston
• OSTI ID: 5003730
• Journal Information: J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 9; ISSN JNMEA
• Country of Publication: United States
• Language: English

Related Subjects

550601 -- Medicine-- Unsealed Radionuclides in Diagnostics
560172* -- Radiation Effects-- Nuclide Kinetics & Toxicology-- Animals-- (-1987)
62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METAL ISOTOPES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CARDIOVASCULAR DISEASES
CARDIOVASCULAR SYSTEM
DIAGNOSTIC USES
DISEASES
DOGS
ELECTRON CAPTURE RADIOISOTOPES
HALF-LIFE
HEART
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISCHEMIA
ISOTOPES
MAMMALS
MINUTES LIVING RADIOISOTOPES
MUSCLES
MYOCARDIAL INFARCTION
MYOCARDIUM
NUCLEI
ODD-ODD NUCLEI
ORGANS
PERFUSED ORGANS
RADIOISOTOPES
RADIONUCLIDE KINETICS
RETENTION
RUBIDIUM 82
RUBIDIUM ISOTOPES
USES
VASCULAR DISEASES
VERTEBRATES