Interpretation and Reporting
Myocardial perfusion imaging should be interpreted systematically. Review technical quality before deciding whether a perfusion defect represents ischemia or infarction.
Interpretation Sequence¶
1. Review Study Quality¶
Before interpreting perfusion, assess:
- Stress adequacy and symptoms
- ECG and hemodynamic response
- Injected activity and timing
- Patient motion
- Count density
- Extracardiac activity
- Attenuation-correction alignment
- Gating and rhythm
- Raw projection images
- Positioning differences between rest and stress
Do not rely only on processed perfusion slices.
2. Review Perfusion¶
Evaluate short-axis, vertical long-axis, and horizontal long-axis images using identical scaling.
Describe each defect by:
- Location: coronary territory or myocardial segments
- Extent: small, medium, or large
- Severity: mild, moderate, or severe
- Type: reversible, fixed, or partially reversible
| Pattern | Interpretation |
|---|---|
| Reversible defect | Ischemia |
| Fixed defect with abnormal motion | Infarction/scar |
| Fixed defect with normal motion | Attenuation artifact more likely |
| Partial reversibility | Scar with peri-infarct ischemia |
| Normal relative perfusion with high-risk findings | Consider balanced ischemia |
3. Review Gated Images¶
Report:
- LV ejection fraction
- LV end-diastolic and end-systolic volumes
- Regional wall motion
- Regional thickening
- Post-stress LV dilation
- RV size and tracer uptake when abnormal
Normal motion and thickening within a fixed defect favor attenuation artifact rather than infarction.
4. Identify High-Risk Findings¶
- Large or multivessel ischemic burden
- Transient ischemic dilation
- Reduced post-stress LVEF
- Stress-induced fall in LVEF
- Increased lung uptake
- RV uptake
- Left-main or balanced-ischemia pattern
- Ischemic ECG changes or hypotension
A normal relative perfusion study does not completely exclude balanced multivessel ischemia.
Semiquantitative Scoring¶
The 17-segment model uses:
| Score | Uptake |
|---|---|
| 0 | Normal |
| 1 | Mildly reduced |
| 2 | Moderately reduced |
| 3 | Severely reduced |
| 4 | Absent |
SDS estimates the amount of reversibility. Automated scores should be visually confirmed.
Common Artifacts¶
- Breast attenuation: anterior or anterolateral defect
- Diaphragmatic attenuation: inferior defect
- Motion: misregistration or artifactual defects
- Subdiaphragmatic activity: inferior-wall interference
- Apical thinning: small fixed apical reduction
- LBBB or pacing: septal defect, especially with exercise
- CT misregistration: false attenuation-corrected defect
Interpret non-attenuation-corrected, attenuation-corrected, gated, and raw images together.
Reporting¶
Include:
- Indication and relevant history
- Stress method and adequacy
- Symptoms, ECG, and hemodynamic response
- Radiotracer and protocol
- Image quality and limitations
- Perfusion findings
- LV function and volumes
- High-risk findings
- Comparison with prior imaging
- Concise impression
Suggested Reporting¶
Normal myocardial perfusion without evidence of ischemia or infarction. Normal LV systolic function with a post-stress LVEF of ___%.
A small, mild reversible defect involving the ___ segments is consistent with ischemia.
A large, severe fixed defect involving the ___ segments with associated akinesis is consistent with prior infarction.
An inferior fixed defect demonstrates preserved wall motion and thickening and is favored to represent diaphragmatic attenuation artifact.
Perfusion is normal; however, transient ischemic dilation and a stress-induced reduction in LVEF raise concern for balanced multivessel ischemia.
Key Points¶
- Review raw data and technical quality first.
- Describe location, extent, severity, and reversibility.
- Use gated motion to distinguish scar from attenuation.
- Report high-risk nonperfusion findings.
- Automated analysis supports—but does not replace—visual interpretation.