1. Yard.Doç. Dr. Nalan Alan Selçuk
Nuclear Cardiology
Yard.Doç. Dr. Nalan Alan Selçuk

2. Nuclear Cardiology
In recent years, radionuclide imaging technologies have evolved rapidly (with the development of new instrumentation
and new agents), and both the number and the complexity of choices for the clinician have increased

3. Nuclear Cardiology Myocardial perfusion imaging
Evaluated myocardial functions
Acut myocardial infarction scintigraphy
Myocardial viability study (PET)

4. Nuclear Cardiology
Myocardial perfusion imaging (MPI) is the foremost nuclear cardiology procedure
For perfusion imaging with SPECT, thallium-201 (201Tl) and two technetium-99m (99mTc) labelled radiopharmaceuticals (sestamibi and tetrofosmin) are available commercially

6. Nuclear Cardiology Tl 201 Half-life: 73 hours (ca. 3 days) Radiation:
68-80 keV photons ("mercury xrays")
keV gamma rays
Cyclotron produced

7. Nuclear Cardiology Thallium (Tl) 201 Acts as potassium analog
Dose mCi at peak exercise
4% of injected dose --> myocardium
Imaging: "exercise" (5-10 min), "redistribution" (3-4 hrs)
Views: anterior, LAO 45', left lateral

8. Nuclear Cardiology interpretation: normal
reversible abnl ==> exercise-induced ischemia
nonreversible abnl ==> prior MI
reverse redistribution ==> normal areas wash out faster
lung activity ==> LV failure during exercise

9. Nuclear Cardiology Tc-99m Half-life: 6.03 hr
Decay: isomeric transition
Radiation: gamma, 140 keV (98%)

10. Nuclear Cardiology Tc 99–m sestamibi
Myocardial uptake proportional to perfusion
No redistribution
Dose 25mCi
Imaging: optimal at 1hr but may be satisfactory out to three hours

12. İmaj kaydı

13. İnterpretasyon

14. İnterpretasyon

15. Treadmil exercise test or bicycle stress
Nuclear Cardiology
Stress applications
Treadmil exercise test or bicycle stress
-Bruce or modifiye Bruce protochol
-Target max rate:220-age
-β-Blockers : before h,
-Calcium antagonists: before 48 hr

16. Pharmacological stress test
-Adenosine is a direct coronary arteriolar dilator and in a normal coronary artery results in a three- to fourfold increase in myocardial blood flow.
-Dipyridamole is an indirect coronary arteriolar dilator that increases the tissue levels of adenosine by preventing the intracellular reuptake and deamination of adenosine.
Adenosine and dipyridamole result in a modest increase in heart rate and a modest decrease in both systolic and diastolic blood pressures.

17. Nuclear Cardiology Dipyridamole dose.
Dipyridamole should be given as a continuous infusion intravenously at 140 μg/kg/min over 4 min.
The tracer is injected 3–5 min after the completion of dipyridamole infusion.

18. Nuclear Cardiology
Dobutamine results in a dose-related increase in myocardial oxygen demand due to increase in heart rate and blood pressure and usually also in myocardial contractility

19. Nuclear Cardiology

20. Nuclear Cardiology Exercise stress Bicycle stress Treadmill stress
Pharmacological stress
Vasodilator agents
Adenosine
Dipyridamole
“Hybrid tests”: both can be combined with low-level exercise
Sympathomimetic agent
Dobutamine + atropine if necessary

21. Myocardial Perfusion Imaging
Diagnosis of coronary artery disease
Evaluation of prognosis
Coronary artery disease
After myocardial infarction
In patients with unsuitable angina
Before other surgery
Assessment myocardial viability

22. Tl-201 Myocardial Perfusion İmaging

23. İnterpretasyon

24. Myocardial Perfusion Imaging
İschemia=reduction in perfusion with stress compared to normal perfusion at rest
Myocardial infarction: reduction in both stress and rest images
Partial increased uptake (partial reversiblity, partial redistribution) scar + ischemia

25. Myocardial Perfusion Imaging
Advantages and disadvantages of using Tc-99m sestamibi/tetrofosmin rather than Tl-201
Advantage
Higher count rates
Higher energy photons (gated SPECT)
First-pass assesment of perfusion and function
Disadvantage
No redistribution
Lung uptake not diagnostic
Less extraction at hyperemic flows
Less sensitive than Tl-201 for viability assessment

26. Myocardial Perfusion Imaging
AÇ 40 yaş, bayan.
Anteroseptal iskemi şüphesi
Miyokard perfüzyon testi sırasındaki eforlu EKG normal.

28. Myocardial Perfusion Imaging
MP. 56 yaşında bayan hasta.
İnferior MI öyküsü olan hastada iskemi şüphesi
Miyokard perfüzyon testi sırasındaki eforlu EKG’de inferior derivasyonlarda belirgin Q dalgası.

30. Myocardial Perfusion Imaging
MPS has a higher sensitive than stress EKG, MPS shows degree and localization of ischemia
In clinical application of MPS Bayes teorisi.

31. Indication-CAD Moderate CAD: Asymptomatic, positive ECG
Chest pain without angina or suspected stress ECG
Atypical angina and negative stress ECG or uncomment ECG (LBBB, left ventricular hypertrophy)

32. Miyokard Perfüzyon Sintigrafisi
Ş A. 58 yaşında bayan
EKG’de anterior derivasyonlarda T(-), angiyografide LAD’de %67 darlık

34. Miyokard Perfüzyon Sintigrafisi
KY, 66 yaşında erkek
İnferior MI öyküsü olan hastada EKG’de V3-V6’da T(-)’liği mevcut

36. Miyokard Perfüzyon Sintigrafisi
TÖ, 65 yaşında erkek
EKG’de V1-V5’de ST elevasyonu ve T(-)’liği mevcut

38. Gated Myocardial Perfusion Imaging
Two advantages may be accrue when perfusion SPECT studies are acquired in an ECG-triggered, “gated” mode:
1. Evaluation of LV ejection fraction (EF) and volumes, and evaluation of LV regional wall motion
2. Improvement of the diagnostic accuracy of perfusion imaging in the event of attenuation problems
(apparently irreversible perfusion defects due to attenuation artefacts may be wrongly interpreted as scar tissue, though function is maintained).

39. Gated Myocardial Perfusion Imaging
Wall motion is classified as:
– Normal
– Hypokinetic
– Akinetic
– Dyskinetic (paradoxical)

40. Positron Emission Tomography
Clinical cardiac PET imaging is performed for the assessment of myocardial perfusion and/or viability.
The PET tracers used in clinical cardiac studies;
-13N-ammonia (half life 10 min)
-15O-water (half life 2 min)
-82Rb (half life 1.23 min)
-18F-FDG (half life 110 min)

41. Myocardial Functinal Imaging
First-pass radionuclide angiography (RNA)
RNV evaluate more accuracy than MUGA technique in right ventricule functions

42. Myocardial Functinal Imaging
Multigated equilibrium (MUGA)
The advantages of a MUGA Scan over an Echocardiography are:
Ejection fraction calculation by MUGA is volume dependent, which is more accurate than Echo imaging where the dependence is on the area of cardiac chambers
It is operator independent and therefore reproducible. This is essential in prognostication or the follow-up of certain cardiac conditions like CCF, etc.
A MUGA Scan can be easily performed in patients with a poor Echo window as encountered in patients with COPD, obesity or a thick chest wall.