Myocardial thallium-201 kinetics: Dominant effect of flow over hypoxia and alterations in contractile state

Conference · Wed May 01 04:00:00 EDT 1985 · J. Nucl. Med.; (United States)

OSTI ID:6794312

Leppo, J A; Moring, A F

The clinical use of Tl-201 imaging with exercise, coronary reperfusion and dipyridamole depends on regional differences in coronary perfusion, but the myocardial metabolic and contractile states differ during these conditions. To evaluate these factors, independent of perfusion level, the authors studied 5 groups (n=7 each) of isolated working rabbit hearts having either; 1) normal flow and oxygen, 2) hypoxia and normal flow, 3) ischemia and normal oxygen, 4) normal conditions with isoproterenol infusion (enhanced contractility), and 5) normal conditions with reduced perfusate calcium (impaired contractility). Multiple timed collections of coronary sinus and arterial effluent were used to model myocardial Tl-201 activity during 30 min of constant uptake, followed by 30 min of cold washout. The mean (+- SD) Tl-201 uptake and washout rates (%/min) varied between 4.76 +- 0.87 and 7.18 +- 1.45 for all groups and there were no significant differences except ischemic hearts which demonstrated a rate constant decrease of 91% compared to normal (p < 0.01). Although isoproterenol significantly increased and low calcium and hyposia significantly reduced peak systolic pressure and +dP/dt (p<0.01), there was only a 20-25% difference (p=NS) in rate constants between these groups of hearts. The authors conclude that myocardial Tl-201 kinetics appear to be dominated by coronary flow and may not reflect marked alterations in the metabolic and contractile state. Therefore, normal Tl-201 uptake in impaired or hypercontractile cells, receiving normal flow, may not represent normal cellular function.

• Research Organization: Univ. Massachusetts Medical Center, Worcester, MA
• OSTI ID: 6794312
• Report Number(s): CONF-850611-
• Conference Information: Journal Name: J. Nucl. Med.; (United States) Journal Volume: 26:5
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
ANOXIA
BETA DECAY RADIOISOTOPES
BLOOD FLOW
BODY
CARDIOVASCULAR DISEASES
CARDIOVASCULAR SYSTEM
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DISEASES
DRUGS
DYNAMIC FUNCTION STUDIES
ELECTRON CAPTURE RADIOISOTOPES
EVALUATION
FUNCTIONS
HEART
HEAVY NUCLEI
ISCHEMIA
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
METABOLISM
MUSCLES
MYOCARDIUM
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RABBITS
RADIOISOTOPE SCANNING
RADIOISOTOPES
RADIONUCLIDE KINETICS
RADIOPHARMACEUTICALS
RETENTION FUNCTIONS
SCINTISCANNING
SECONDS LIVING RADIOISOTOPES
SINUSES
THALLIUM 201
THALLIUM ISOTOPES
UPTAKE
VASCULAR DISEASES
VERTEBRATES