RadteraMyocardial Perfusion SPECT (Rest/Stress Tc-99m Sestamibi)
NM+ ContrastCardiac
Indications
- Suspected or known coronary artery disease (chest pain, abnormal stress test)
- Risk stratification before noncardiac surgery
- Assessment of myocardial ischemia and viability
- Evaluation after revascularization (PCI/CABG)
Patient prep
- Fast 4-6 hours
- Hold caffeine/methylxanthines 12-24 h (for vasodilator stress: regadenoson/adenosine/dipyridamole)
- Hold beta-blockers per protocol if exercise stress (may blunt heart rate)
- Hold nitrates as directed
- No fasting from water; diabetics adjust medications/glucose
Contrast
AgentTc-99m sestamibi (or Tc-99m tetrofosmin)
RouteIV
DoseOne-day rest/stress: ~8-10 mCi rest then 24-30 mCi stress (3x). Two-day: ~25-30 mCi each day
TimingImaging 15-60 min post-injection (longer after pharmacologic/exercise to clear liver/gut)
Technique
- LEHR collimator, 140 keV, gated SPECT (8-16 frames/cycle)
- Supine +/- prone or upright imaging to reduce attenuation; SPECT/CT for attenuation correction
- Stress: exercise treadmill OR pharmacologic (regadenoson 0.4 mg IV, adenosine, dipyridamole, dobutamine)
- Gated acquisition yields LV ejection fraction, wall motion, volumes
Series / Sequences
| # | Series / Sequence | Plane | Notes |
|---|---|---|---|
| 1 | Rest gated SPECT | Short axis / vertical & horizontal long axis | Baseline perfusion |
| 2 | Stress gated SPECT | Short axis / long axis | Compare to rest; reversible defect = ischemia |
| 3 | Attenuation correction / prone (optional) | Tomographic | Differentiate attenuation artifact from true defect |
Key points
- Reversible defect (abnormal stress, normal rest) = ischemia; fixed defect = infarct/scar
- Hold caffeine and methylxanthines before vasodilator stress (antagonize adenosine receptors)
- Aminophylline available to reverse vasodilator side effects
- Diaphragmatic (inferior wall) and breast attenuation are common artifacts — use AC, prone, or gating to distinguish
- Transient ischemic dilation (TID) suggests severe/multivessel disease
References
• ASNC Imaging Guidelines for SPECT Nuclear Cardiology Procedures: Stress, Protocols, and Tracers (J Nucl Cardiol 2016)
• SNMMI/ASNC Myocardial Perfusion Imaging guidance
• Radiopaedia: Myocardial perfusion scintigraphy link
• SNMMI/ASNC Myocardial Perfusion Imaging guidance
• Radiopaedia: Myocardial perfusion scintigraphy link
Source: Researched — verify against your institution
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Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.