Progress in myocardial perfusion imaging has been slowed by the lack or
radiopharmaceuticals with suitable physical and
biologic characteristics.
Hexadecenoic acid, terminally labeled with 123I, partially overcomes these limitations by providing a compound that concentrates in the myocardium in proportion to relative regional blood flow and carries a gamma-emitter with desirable detection and imaging qualities. After
intravenous injection in experimental animals, the clearance half-times of
hexadecenoic acid for blood and myocardium are 1.7 and 20 min, respectively. These values compare favorably with 18-carbon
fatty-acid analogs labeled with 11C. In acute and chronic
infarction, similar distribution patterns are found for
hexadecenoic acid and 43K, which indicates that
hexadecenoic acid is a suitable substitute for the
potassium analogs now in use for myocardial imaging. Because of the high count rates obtainable with 123I-hexadecenoic
acid, good-guality images can be acquired in as little
as 2-3 min per view. Iodine-123-hexadecenoic
acid is potentially a useful
radiopharmaceutical for clinical application.