Myocardial Perfusion SPECT How to do it E. Moralidis Aristotelian University AHEPA Hospital Thessaloniki
Myocardial perfusion SPECT procedure Stress Imaging Data analysis and reporting
Myocardial perfusion SPECT: basic principles
Stressing techniques in myocardial perfusion SPECT Dynamic exercise Treadmill Upright bicycle Vasodilator drugs Adenosine Dipyridamole Regadenoson Inotropic drugs Dobutamine
Patient preparation Type of stress test Exercise Vasodilator Dobutamine Nitrates + + + β-blockers + ± + Methylxanthines (72 hrs) - + - Caffeine (12-24 hrs) - + - Persantine (48 hrs) + + - Light meal, preferably fasting for 2-3 hours before testing Food and insulin optimization in diabetics
Exercise stressing in myocardial perfusion SPECT ASNC Imaging Guidelines 2008 & 2009 on stress protocols and tracers All exercise tests should be symptom limited Achievement of target heart rate is not an indication for termination of the test 5 METS are required for an adequate work load
Coronary vasodilators
Vasodilator stressing ( 99m Tc-agents) ASNC Imaging Guidelines 2009: stress protocols and tracers dipyridamole Accomplished in COPD patients pretreated with bronchodilators Short adenosine infusion protocols adenosine regadenoson
Adenosine with mild exercise
Dobutamine protocol Stop β-blockers for 48 hrs Monitor HR, BP, 12-lead ECG IV esmolol / atenolol available
Selection of stress protocol Dynamic exercise provides optimal stress for those that can afford it. Pharmacological stress more appropriate if: Unable to achieve adequate work-load Contraindication to exercise LBBB More convenient Women (?)
Diagnostic performance of stressors 5,954 patients in 57 studies
SPECT 201 Tl in women AHA Scientific Sessions. Circulation 1995:92:1 Specificity (%)
Properties of perfusion agents Factors favouring Thallium-201 Superior biokinetics Low extracardiac activity Factors favouring 99m Tc-MIBI, 99m Tc-tetrofosmin Superior image quality Stress & imaging at a distance No resting injection May be better for viability evaluation Lower radiation burden to staff and family members ECG gated imaging with confidence Advantageous in obese, female, acute chest pain Lower radiation burden to the patient
Tracers in clinical practice Kapur A, et al. (ROBUST) Eur J Nucl Med 2002:29:1608-1616
201 Tl 99m Tc An obese woman 201 Tl 99m Tc 201 Tl 99m Tc
Tracers in clinical practice Kapur A, et al. (ROBUST) Eur J Nucl Med 2002:29:1608-1616 (%)
Tracers in clinical practice (mci) Thallium 99m Tc-agents Stress Reinjection Stress Rest Europe 2.5 1 12 36 USA 3.5 1.5 10 30 msv/mci 8.1 0.29
Myocardial perfusion SPECT: data acquisition
Myocardial perfusion SPECT: data acquisition
Issues in myocardial SPECT imaging Image acquisition Quality control Reconstruction methods Gated SPECT Patient positioning Orbit Acquisition type γ-camera system Acquired, original, processed data Filtered back projection Iterative reconstruction Filtering Motion correction ECG triggering Image processing, analysis, display Attenuation & scatter compensation Data analysis Visual, quantitative Integration of perfusion & function Viability assessment
Image processing
Myocardial perfusion SPECT: planes
Image display
Image interpretation Stress Rest normal perfusion no ischemia reversible defect induced ischemia fixed defect myocardial fibrosis
Myocardial perfusion SPECT quantitative analysis AHA, Circulation 2002;105:539-542 0 = normal 1 = slight reduction 2 = moderate reduction 3 = severe reduction 4 = no uptake SSS, SRS, SDS Small area of ischemia vs Moderate or Large area
Normalization error
Color scale
Standardized reporting of myocardial SPECT Patient details Indication Stress technique Tracer & imaging protocol Image quality Findings Conclusions Name, age, gender, date of study Relevant data from medical history Exercise and workload / Pharmacological Response to stress: heart rate, blood pressure, symptoms, ECG changes Including injected activities Including significant artifacts Presence, localization, extent and depth of stress and rest defects Pathology outside the left ventricle: right ventricle, lungs, etc Normal, inducible ischemia, myocardial infarction Extent and location Inconclusive study Correlation with clinical information or other data
Myocardial SPECT in 4 academic centers in Greece Preliminary results ( 3,000 pts) Stressor Institution A B C D Exercise 0 71% 24% 0 Pharmacological 100% 29% 76% 100% Perfusion agent Thallium-201 87% 80% 1% 94% 99m Tc-tetrofosmin 13% 20% 99% 6%
Myocardial SPECT in 4 academic centers in Greece 3.5% mean 7.2min 10% mean 5.7min
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