Quantitative relationship between global left ventricular thallium uptake and blood flow: effects of propranolol, ouabain, dipyridamole, and coronary artery occlusion

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

OSTI ID:5270887

Melin, J A; Becker, L C

The quantitative relationship between fractional myocardial thallium uptake and radioactive microsphere-determined flow was studied in 33 open chest dogs under baseline conditions during increased coronary flow (dipyridamole), decreased coronary flow (propranolol and coronary artery stenosis), inhibition of Na-K ATPase (ouabain), and regional infarction. Myocardial contents of thallium and microspheres were compared in left ventricular (LV) biopsies taken 5, 10, 15, 30, and 60 min after thallium injection, expressed as fractions of injected dose. Maximal LV thallium uptake occurred 10 min after injection and the 10-min values were therefore used for subsequent comparisons. Combining all dogs, fractional LV thallium content (% injected dose) correlated well with fractional LV blood flow (% cardiac output) (r = 0.95). However, for fractional LV flows in the low, normal, or moderately elevated range (LV flow/cardiac output less than 9%), thallium content consistently exceeded flow by about 15%. This relationship was not altered by ouabain or regional ischemia or infarction. For greatly elevated fractional LV flows (greater than 9%), thallium content was not significantly different from flow. To explain these differences, myocardial and systemic extraction fractions for thallium were determined in eight dogs with a dual tracer method. At baseline, myocardial extraction fraction was significantly greater than systemic (88 +/- 0.4% compared with 75 +/- 1%, p less than 0.001). During dipyridamole, myocardial extraction fraction decreased and myocardial and systemic values were no longer significantly different (82 +/- 1% compared with 79 +/- 1%). These results show that the fraction of injected thallium dose taken up by the LV myocardium exceeds the delivered fraction of cardiac output and is not altered by ouabain-induced inhibition or regional myocardial infarction.

• Research Organization: Johns Hopkins Medical Institutions, Baltimore, MD
• OSTI ID: 5270887
• Journal Information: J. Nucl. Med.; (United States), Journal Name: J. Nucl. Med.; (United States) Vol. 5; ISSN JNMEA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ACID ANHYDRASES
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BLOOD FLOW
BODY
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
CORRELATIONS
DAYS LIVING RADIOISOTOPES
DOGS
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
GLYCOSIDES
HEART
HEAVY NUCLEI
HYDROLASES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MICROSPHERES
MUSCLES
MYOCARDIUM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
OUABAIN
PHOSPHOHYDROLASES
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
STROPHANTHINS
THALLIUM 201
THALLIUM ISOTOPES
UPTAKE
VERTEBRATES