Technetium-99m hexakis 2-methoxy-2-isobutyl isonitrile and thallium-201 extraction, washout, and retention at varying coronary flow rates in rabbit heart

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Circulation; (USA)

DOI:https://doi.org/10.1161/01.CIR.82.3.998· OSTI ID:6510766

Marshall, R C; Leidholdt, Jr, E M; Zhang, D Y; Barnett, C A ^[1]

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1. Veterans Affairs Medical Center, Martinez, CA (USA)

Technetium-99m hexakis 2-methoxy-2-isobutyl isonitrile (Tc-MIBI) and thallium-201 extraction, washout, and retention were investigated and compared in 20 isolated, isovolumic, retrograde blood-perfused rabbit hearts at flow rates ranging from 0.5 to 3.5 ml/g wet wt min-1 in the absence of tracer recirculation. Mean Tc-MIBI peak instantaneous extraction was lower (0.55 +/- 0.10, p less than 0.001) and more affected by flow rate (p less than 0.05) than 201Tl peak instantaneous extraction (0.83 +/- 0.06). In contrast, the rate of 201Tl washout was significantly faster (p less than 0.05) and initially more dependent on perfusion rate (p less than 0.05) than Tc-MIBI washout. Reflecting its higher peak instantaneous extraction, 201Tl retention was 55-79% higher immediately after isotope injection (p less than 0.001) than Tc-MIBI retention, and relative changes in maximal 201Tl net uptake correlated better (p less than 0.05) with relative flow changes than maximal Tc-MIBI net uptake. However, due to its faster washout rate, the superiority of thallium over Tc-MIBI as a perfusion indicator was lost within 10 minutes of tracer injection under the present single-pass experimental conditions. These data were interpreted to indicate that (1) Tc-MIBI is not as well extracted and has a slower washout rate than 201Tl; (2) varying the coronary flow rate has significant but divergent effects on the extraction, washout, and retention of Tc-MIBI and 201Tl; and (3) the present results support continued evaluation of Tc-MIBI as a possible perfusion indicator.

• OSTI ID: 6510766
• Journal Information: Circulation; (USA), Journal Name: Circulation; (USA) Vol. 82:3; ISSN 0009-7322; ISSN CIRCA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD FLOW
BODY
CARDIOVASCULAR SYSTEM
COMPARATIVE EVALUATIONS
DAYS LIVING RADIOISOTOPES
DRUGS
DYNAMIC FUNCTION STUDIES
ELECTRON CAPTURE RADIOISOTOPES
HEART
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANS
PERFUSED ORGANS
RABBITS
RADIOISOTOPES
RADIOPHARMACEUTICALS
RETENTION
SECONDS LIVING RADIOISOTOPES
TECHNETIUM 99
TECHNETIUM ISOTOPES
THALLIUM 201
THALLIUM ISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES