photopenic defect
Pronunciation: FOH-toe-PEE-nik
Area of reduced or absent radiotracer uptake on nuclear imaging, indicating perfusion abnormality or scar.
Full Definition
A photopenic defect refers to an area of reduced or absent radiotracer uptake on nuclear cardiac imaging studies, appearing as a 'cold spot' or area of decreased signal intensity compared to surrounding normal myocardium. These defects can be seen on SPECT perfusion imaging, representing either reversible ischemia (if present only on stress images) or myocardial scar (if present on both stress and rest images). The term 'photopenic' literally means 'lacking in light/photons' and describes the visual appearance of these areas on nuclear images. The size, location, and reversibility of photopenic defects help determine the extent of coronary artery disease and guide treatment decisions.
Usage
Usage note: Specific to nuclear imaging; distinguish from artifacts and attenuation effects.
In Context
- "A large photopenic defect in the anterior wall was noted on stress images, normalizing at rest." — Nuclear cardiology report
- "The fixed photopenic defect in the inferior territory indicates prior myocardial infarction." — SPECT perfusion report