1. NUCLEAR CARDIAC IMAGING
K.Michalová
Klinika nukleární medicíny a endokrinologie UK 2. LF a FN Motol

2. Nuclear medicine methods in Cardiology
are available for the evaluation of
1. Myocardial Perfusion
2. Ventricular Function
3. Cardiac Metabolism and Myocardial Viability
4. Myocardial Innervation
5. Infarct Imaging
Kupka K .a kol: Nukleární medicína, 2007

3. MYOCARDIAL PERFUSION SCINTIGRAPHY
This test is designed to evaluate regional myocardial perfusion under rest and stress condition
in order to define regional myocardial perfusion reserve.

4. MYOCARDIAL PERFUSION SCINTIGRAPHY
It involves the injecton of a radiolabelled substance which is extracted by the myocardium and accumulates in proportion to myocardial blood flow.
Such radipharmaceuticals are injected under stress as well as resting conditions, and images are obtained to define the regional distribution of radioactivity within the myocardium.

5. the detection and localization of myocardial ischaemia or scar.
MYOCARDIAL PERFUSION SCINTIGRAPHY
The main indication is
the detection and localization
of myocardial ischaemia or scar.

6. MYOCARDIAL PERFUSION SCINTIGRAPHY
Myocardial ischaemia is defined as a perfusion defect present during stress but not resting conditions.
Scar tissue is associated with a relative perfusion defect at rest as well as under stress.

7. MYOCARDIAL PERFUSION SCINTIGRAPHY
RADIOPHARMACEUTICALS
201Thallium
99mTc-Labeled Myocardial Perfusion Agents
99mTc-SESTAMIBI (MIBI, methoxy-isobutyl-isonitril, Cardiolite, CardioSPECT…)
99mTc-Tetrofosmin (Myoview)
99mTc-Teboroxim

8. MYOCARDIAL PERFUSION SCINTIGRAPHY
201Thallium
- is an analog of potassium
- it is actively transported
into cardiac muscle
via the sodium-potassium ATPase pump

9. MYOCARDIAL PERFUSION SCINTIGRAPHY
201Thallium
- is a cyclotron-produced radiopharmaceutical
- emits x-rays of energy 69- to 83 keV
- physical half-life is 74 h

10. MYOCARDIAL PERFUSION SCINTIGRAPHY
99mTc-SESTAMIBI x 201THALLIUM
ADVANTAGES :
- increased myocardial count density
- lower radiation doses
- no wash out of myocardium

11. MYOCARDIAL PERFUSION SCINTIGRAPHY
Tc-99m-Labeled Myocardial Perfusion Agents
99mTc-SESTAMIBI
= is a lipophilic cationic Tc-99m complex
- it enteres pasivelly into the cells
- and binds at the intracells membranes,
especially of mitochondrials
- it does not wash out of the myocardium in 3-4 hours

12. MYOCARDIAL PERFUSION SCINTIGRAPHY
99mTc-SESTAMIBI
99mTc - gamma rays of energy 140 keV
- half life T1/2 = 6 hours

14. Two-Day Patient Protocol
Exercise
Rest
Dose
700 MBq
700 MBq
Supine or prone
Supine or prone
Position
Delay Time (Intervals)
Injection - Imaging min min

15. Exercise Stress * is performed by cardiologist
* graded stress is usually performed
with bicycle ergometr
* it is necessary to reach the gender and
age predicted 85% maximal heart rate
* suboptimal stress level reduce sensitivity
of this procedure for detection of CAD
* the radiopharmaceutical is injected 1-2 minut
before end of exercise

17. Pharmacologic Stress Patients who are unable to exercise
for non cardiac reasons - e.g.arthritis, amputation,
neurologic diseases
or cardiac reasons - with LBBB
may be stress farmacologically

18. Pharmacologic Stress * vasodilators : adenosine dipyridamole
* inotropic : dobutamine

19. Pharmacologic Stress using dipyridamole
* mechanism of action different from exercise
* directly tests flow reserve
* dipyridamol causes vasodilatation
* normal vessel vasodilate, increasing flow five times
* stenotic vessels are already maximally vasodilatated,
cannot increase flow
* results in heterogenity on scan
* does not depend on induction of ischemia
* Heart rate increases 13 beats per minute (20%)
* Blood pressure decreases 6 mm Hg (2 ti 8%)
* Contraindication: Asthma bronchiale

20. Pharmacologic Stress produced by dobutamine
* similar to exercise
* indirectly tests flow reserve
* increases myocardial oxygen consumption
1) chronotropic effects
2) ionotropic effects

21. Acquisition SPECT study
Dual head gamma camera moves around the patient
viewing the object in 180 degrees in 64 steps for 25 seconds
45 deg.
RAO
135 deg.
LPO

23. GATED SPECT study ECG is acquired at the time of the SPECT acquisition
for simultaneous assessment of perfusion and
function of the left ventricle in one examination
evaluation of regional wall motion
ejection fraction
systolic thickening of the walls

24. GATED SPECT study We obtain myocardial perfusion images within
one representative cardiac cycle :
from end-diastole through end-systole to end-diastole
of next cardiac cycle
Kamínek M. et al. : Atlas of Nuclear Cardiology,

25. Initial Display
of selected study-
Reconstruction
With ellipse we select
region of the heart
in anterior view
in left lateral view.
The selected data sets
are processed.
We must alignment
axes of heart
for creation of the
vertical
long and short axis
tomograms
Summed image-
added multiple projec-
tion images

26. 99m Tc- MIBI slices in the short axis slices in the long axis vertical
slices in the long axis horisontal
99m Tc-
MIBI

28. MYOCARDIAL ISCHEMIA Can be identified by comparing
the results of exercise-injected studies and rest images .
As narrowing of coronary vessel approaches 70%
lesion is hemodynamically significant during exercise.

29. 99m-Tc-
MIBI

30. Polar maps
Short axis slices
are sequentially
diplayed from
base to apex.
Conical myocardium
is transformed into
a disk.

33. MYOCARDIAL PERFUSION IMAGING
INTERPRETATION CRITERIA
1. NORMAL FINDINGS
2. REVERSIBILE DEFECT - lesion is seen at stress
and improves on the rest - is usually due to ischemia
3. NONREVERSIBILE DEFECT - lesion at rest is
usually associated with myocardial scar or with
severe ischemia.

34. NORMAL FINDING
57 yo MALE

35. REVERSIBILE DEFECT

36. NONREVERSIBILE DEFECT

37. MYOCARDIAL PERFUSION IMAGING
Clinical Indications
Diagnosis of coronary artery disease
- presence
- location (coronary territory)
-extent (number of vascular territories
involved)
Determine prognosis
Society of Nuclear Medicine Procedure Guideline for Myocardial Perfusion Imaging

38. MYOCARDIAL PERFUSION IMAGING
Clinical Indications
Determination of the significance
of anatomic lesions detected by angiography

39. Monitoring treatment effect after coronary revascularization
MYOCARDIAL PERFUSION IMAGING
Clinical Indications
Monitoring treatment effect
after coronary revascularization

40. Determine prognosis risk stratification
MYOCARDIAL PERFUSION IMAGING
Determine prognosis
risk stratification
*Patients with normal perfusion imaging after adequate stress have a very low cardiac event rate independently
of the presence or absence of angiographic CAD (yearly
rate of myocardial infarction or death of less than 1%).
*A benign prognosis is asociated with a small fixed defect
and a normal global left ventricle function.

41. 57 yo MALE

42. Determine prognosis risk stratification
MYOCARDIAL PERFUSION IMAGING
Determine prognosis
risk stratification
* The risk of cardiac event can be suspected in all patients
with the reversible perfusion defect.
* A higher risk can be expected in patients
with a large perfusion defect,
when more territories are affected,
if the anterior wall is affected
or if signs of postress dysfunction appear (transient
ischemic dilation, deterioration of postress EF, increased
uptake 201Tl in the lungs).

44. MYOCARDIAL VIABILITY patients with chronic ischaemic left
detection of myocardial viability has clinical importance for
patients with chronic ischaemic left
ventricular dysfunction
and low left ventricle ejection fraction
it is necessary to know, if defect of myocardial perfusion is
- ischemia vs. scar
- predict improvement in function
following revascularization

45. REQUIREMENTS FOR CELLULAR VIABILITY
adequate myocardial blood flow
sarcolemmal metabolic integrity
preserved metabolic activity

46. MYOCARDIAL VIABILITY The gold standard method
evaluation of myocardial glucose utilisation with fluorine-18 fluorodeoxyglucose (FDG)
and positron emission tomography (PET)

47. MYOCARDIAL VIABILITY Principle
Under fasting conditions the normal myocardium primarily utilises free fatty acids.
In ischaemic myocardium glucose becomes an important energy substrate, FDG uptake will be enhanced.

48. VIABLE MYOCARDIUM NONREVERSIBILE PERFUSION DEFECT ( 99m-Tc MIBI) vs.
is characteristic in
NONREVERSIBILE PERFUSION DEFECT
( 99m-Tc MIBI)
vs.
PRESERVED MYOCARDIAL METABOLISM
(18-FDG)
= mismatch

49. - we can expect improvement in function
99mTc MIBI
18FDG
non viable
match
viable
mismatch
- we can expect improvement in function
following revascularization

50. 99m-Tc-
MIBI

51. SCAR NONREVERSIBILE PERFUSION DEFECT vs.
is characteristic in
NONREVERSIBILE PERFUSION DEFECT
( 99m-Tc MIBI)
vs.
NO PRESERVED MYOCARDIAL METABOLISM
(18-FDG )
= match

52. 99mTc MIBI 18FDG nonviable match viable mismatch
- we can´t expect improvement in function
following revascularization