What it means
On a heart perfusion scan, a tracer injected into a vein spreads through the heart muscle in proportion to blood flow. Pictures are taken at rest and after exercise or a medicine that mimics it (stress). A perfusion defect is an area with less tracer, so less blood. If it appears only under stress, it is called reversible. If it appears in both sets, it is called fixed. Lung perfusion scans use the same term.
When it matters
A reversible defect suggests a narrowed artery that cannot supply enough blood when the heart works harder (ischemia). A fixed defect often points to scar from an earlier heart attack. It can also be an artifact, caused by breast tissue or the diaphragm blocking the view. The report usually gives the size, the severity and the artery likely involved. Your doctor may suggest further tests, such as a coronary CT angiogram or a catheter angiogram.
Questions to ask your doctor
- Is the defect reversible or fixed, and what does that mean for me?
- Could the defect be an artifact rather than a real problem?
- How large is the affected area, and which artery supplies it?
Read more: Myocardial Perfusion Scan: What Reversible and Fixed Defects Mean
