radionucleotide angiography
Last reviewed 01/2018
In radionucleotide angiographic studies, the gamma signal is provided by technetium-99m-labelled erythrocytes.
Labelled erythrocytes are injected intravenously and allowed to mix well with the blood. The heart is then imaged with a gamma-camera. Several hundred cardiac cycles are averaged to provide a clear image of the heart throughout the cycle.
This graphical information allows the calculation of the left ventricular ejection fraction.
The degree of contractility may be assessed qualitatively:
- post-myocardial infarction there is a permanent focal area of hypokinesia
- cardiomyopathy results in a global loss of contraction
- myocardial ischaemia results in temporary focal hypokinesia during exercise stress