Perfusion scintigraphy of the myocardium under stress

A practical guide for referring physicians

Principle and method

Myocardial perfusion scintigraphy (myocardial perfusion SPECT, MPS) is a key nuclear medicine method for the non-invasive diagnosis of ischaemic heart disease (IHD), assessment of myocardial viability and risk stratification of patients.

The examination combines stress ergometry (physical stress on a bicycle ergometer or treadmill or pharmacological stress) with the administration of a perfusion radiopharmaceutical, which is taken up inside vital cardiomyocytes in proportion to coronary perfusion.

During exercise, coronary demands increase – the area supplied by a stenotic artery shows relative hypoperfusion, which appears as a defect on SPECT. By comparing images after exercise and at rest, reversible ischaemia can be distinguished from irreversible infarct damage.

myo3
myo5

Main clinical indications

1. Diagnosis of ischaemic heart disease

  • Detection of ischaemic foci in patients with chest pain and suspected IHD.
  • Assessment of the haemodynamic significance of coronary stenosis.

2. Prognostic stratification

  • Determination of the risk of future cardiac events (heart attack, sudden death).
  • The extent and severity of perfusion defects directly correlate with the patient's prognosis.

3. Indications for revascularisation

  • Distinguishing between viable and non-viable myocardium.
  • Deciding on the need for PCI or CABG.

4. Monitoring treatment efficacy

  • After coronary interventions or bypass surgery.
  • After pharmacological therapy for IHD.

5. Other indications

  • Assessment of the causes of shortness of breath and unclear chest pain.
  • Differential diagnosis between ischaemic and non-ischaemic cardiomyopathy.

Interpretation and clinical significance

Signs of stress ischaemia

  • Reversible defect – perfusion disorder during exercise, normalising at rest → evidence of ischaemia.
  • The location of the defect corresponds to the supply area of the affected coronary artery.

Signs of scarring

  • Fixed defect – persistent hypoperfusion even at rest → irreversible myocardial necrosis.

Other indicators

  • Quantification of defect extent (% of left ventricle).
  • Evaluation of ejection fraction and wall kinetics (gated SPECT).

Practical information for the referring physician

  • Patient preparation:
    • fasting for 4–6 hours,
    • discontinuation of beta-blockers or antianginal medication according to the cardiologist's instructions,
    • avoid caffeine 24 hours before the examination.
  • Examination procedure:
  1. the patient undergoes ergometry with graded exercise,
  2. upon reaching the target heart rate (85% of the maximum for the patient's age), a radiopharmaceutical is administered,
  3. distribution is followed by SPECT imaging,
  4. in the next step, a resting examination is performed for comparison.
  • Examination duration: 3–4 hours.
  • Radiation exposure: approx. 7–10 mSv.
  • Contraindications: acute MI, unstable angina, severe arrhythmias, decompensated heart failure, severe aortic stenosis.

Summary for practice

Stress myocardial perfusion scintigraphy is:

  • the gold standard for non-invasive diagnosis of ischaemic heart disease,
  • a method with high sensitivity and specificity for detecting myocardial ischaemia,
  • a tool for decision-making on revascularisation and prognostic stratification,
  • a safe, accessible and clinically highly beneficial method.

Correct indication and interpretation significantly improve the diagnosis and treatment management of patients with IHD and remain an indispensable tool in modern cardiology.