Cardiac Positron Emission
Department of Nuclear Medicine
Asan Medical Center
University of Ulsan College of Medicine
Dae Hyuk Moon, MD
Advanced Cardiology… Anatomy to Physiology
PET-CT Fusion… Better Coronary Artery Disease Assessment
CAI – Vessel Tracking Perfusion
• Perfusion imaging
• Cardiac metabolism
• Pre & Post synaptic autonomous nervous system
• Other cardiac receptors
• Atherosclerotic plaque characterization
• Cardiac transgenic expression
• Cell therapy
Advantage: Cardiac PET over SPECT
• Higher spatial resolution
• Higher temporal resolution
• Quantitation of myocardial flow
• Assessment of myocardial metabolism
Clinical Issues in Cardiac PET
• More expensive than other methods
• Blunted ratio of cost-effectiveness
PET must demonstrate a complementary
and optimally unique clinical role in
comparison to less costly and more readily
available conventional imaging methods
Cardiac Radionuclide Imaging, 2003
• Acute Syndrome
• Chronic Syndrome: Vasodilator stress myocardial perfusion PET
Dx and risk stratification of pts with an intermediate or high LH of CAD
Equivocal myocardial perfusion SPECT (I)
To identify the extent, severity, & location of ischemia as the initial
diagnostic test in patients who are unable to exercise, or able to
exercise but have LBBB or electronically-paced rhythm (IIa)
• Heart Failure: Perfusion plus PET FDG imaging
Predicting improvement in LV function after revasc (I)
Predicting improvement in HF symptoms after revasc (IIa)
Predicting improvement in natural history after revasc (I)
ACC/AHA Guideline for PET
• Chronic Stable Angina, 2002
• Chronic Heart Failure, 2001
Coronary revascularization: Pts with CAD, angina, and HF (I, A)
Noninvasive imaging: known CAD, no angina, candidate for
revasc to detect ischemia & viability (IIa, C)
Noninvasive imaging: define the likelihood of CAD in pts with
LV dysfunction (IIb, C)
• Coronary Artery Bypass Graft Surgery, 2002
CABG: 2 VD (LAD), LV dysfunction or ischemia (I)
PCI or CABG: 1 or 2 VD, large viable, or high risk on imaging (I)
PCI or CABG: 1 or 2 VD, mod viable & ischemic on imaging (IIa)
• Percutaneous Coronary Intervention, 2001
PCI: large viable myocardium or myocardial ischemia (I)
[18F]FDG PET covered by Medicare in US, 2003
• Diagnosis, staging and restaging of lymphoma and lung,
head and neck, esophageal, melanoma and colorectal
• Staging & restaging of breast, and thyroid cancer
• Presurgical evaluation of refractory epilepsy
• Assessing myocardial viability
A positive myocardial perfusion imaging study when clinical evidence is
mixed. The decision to perform revascularization is based on the
probability that improved systolic function that can occur with viable
myocardium. FDG PET likely detects tissue that will not respond well to
revascularization when SPECT is positive and FDG is negative.
FDG PET To Assess Viability
• Regional Function
• Global LV Function
• Symptom and Performance
• Impact on Patient Management
Prediction of Improvement after Revascularization
• Myocardial perfusion:
N-13 ammonia, Rb-82 chloride, O-15 water
• Myocardial metabolism:
F-18 FDG, C-11 palmitate, C-11 acetate
Positron Emitters used
for Cardiac PET imaging
Myocardial Perfusion, FDG Uptake, and
Contraction in Relation to Tissue Classification
Contraction Perfusion FDG Uptake
Normal myocardium N N N
Repetitive stunning ↓ N N or ↑
Hibernation ↓ ↓/↓↓ N or ↑
Transmural scar ↓ ↓↓ ↓↓
Nontransmural scar ↓ ↓ ↓
N, normal; ↓, decreased; ↓↓, severely decreased; ↑, increased.
Bax et al. Semin Nucl Med 2000;30:281-98.
Viability: SN and SP for the Different Imaging Techniques
(based on weighted mean values from available studies)
No. of Sens Spec
Pts (%) 95% CI 99% CI (%) 95% CI 99% CI
Tc-99m MIBI 207 83 78-87 77-89 69 63-74 61-76
LDDE 448 84 82-86 81-87 81 79-84 79-84
Tl-201 reinjection 209 86 83-89 82-90 47 43-51 42-52
F-18 FDG PET 332 88 84-91 83-92 73 69-77 69-77
Tl-201 rest-redistribution 145 90 87-93 86-94 54 49-60 48-61
Bax et al. J Am Coll Cardiol 1997;30:451-60.
Declining specificity in viability studies
• Segments with nontransmural infarction or remodelling:
Not necessarily improve in function after revascularizationNot necessarily improve in function after revascularization
• The time of follow-up may be too early.
• Irreversible structural changes in long standing hibernation
• The adequacy of revascularization
• Patient selection bias: "true-negative" segments will not be
included in the analysis.
• Other benefit: LV remodeling, ventricular arrhythmia, MI
• Inclusion of severe LV dysfunction?
• Varying metabolic conditions
• Different imaging protocol
• Not uniform viability criteria
Limitations of the available viability data
Allman et al. J Am Coll Cardiol 2002;39:1151-8.
Myocardial Viability Testing & Impact of Revascularization
Prognosis in Pt with CAD and LV dysfunction: A meta-analysis
Survival of pts with viable myocardium: Revasc. > Medical tx?
Viability assessment improve selection of pts for revasc?
Improved outcomes after revasc are related to improved LV function?
Limitations of the available prognosis data
• No randomized controlled trials
• Retrospective studies: selection biases
• Small sample size, short f/u period, low event rate
• No standardized criteria for viability
• Limitation of binary grouping: viable vs non
• No standardized medical therapy
• Heterog. pts: CAD, Sx, HF, prior revasc, women
• Different type and completeness of revasc
• Lack of postrevasc study for completeness of revasc
Successful Viability Outcomes Study Design
• Randomized-controlled trial ideally (or large prospective cohort study).
• Large sample size.
• Follow-up for at least 5 years.
• Adequate power to detect clinically significant differences in mortality.
• Stricter inclusion criteria: EF ≤ 40% and epicardial vessels or major
branches with stenosis ≥ 70% on recent CAG (within 6 m).
• Use of accurate viability criteria: analysis of ≥ 17 segments, use of
Cox modeling or ROC curves to establish cutoff for significant viability.
• Use of both medical and revascularization groups (PCI and CABG),
with analysis using Kaplan-Meier and Cox-adjusted survival curves.
• Analysis of baseline characteristics btw subjects undergoing viability
and those not to establish magnitude of referral bias or adjust study
design to eliminate large differences.
• Identification of the prevalence of viability in a large cohort of patients
irrespective of treatment received.
• Recruitment of more women and minorities. Department of
• Prospective randomized trialrandomized trial with long-term clinical, perfusion and function
follow-up: Difficult because clinicians already accept "viability study”
• Require confirmation in larger serieslarger series: small number of patients with hard
• Extent of mismatchof mismatch with PET to suggest good outcome from
• Time course of recoverycourse of recovery after revascularization relative to preop index of
perfusion and contractile reserve
• Outcome of patients with extensive regions of viable myocardiumcome of patients with extensive regions of viable myocardium by PET
that lack contractile reserve
• LV volume measurementvolume measurement adds additional discriminatory value?
• Relationship between tissue viability and changes in LV geometrytissue viability and changes in LV geometry
• Limited data in women and patients with diabetes
Targets for Atherosclerosis Imaging
Necrotic core, Fibrous cap, Calcium, Inflammatory activity
Histopathology of Plaque Progression
PET: Smooth muscle cells, Macrophage, Lipid Core
With FDG PET
Rudd et al, Circulation
Imaging Large Vessel Arteritis with [18F]-FDG PET
M/81 recurrent fever
Circulation 2003;107:923, & Heart 2003;89:e9.
F/27 Takayasu’s arteritis
with LM stenosis
Inubushi et al. Circulation 2003;107:326-32.
PET Reporter Gene Expression Imaging in Rat Myocardium
Ad-CMV-HSV1-sr39tk IM injection and [18F]-FHBG PET imaging
Bioluminescence and PET: Cardiac Cell Transplantation
Rats receiving cardiomyoblast expressing HSV1-sr39tk
A: Optical imaging, BC: MicroPET with [18F]-FHBG and [13N]-NH3
Wu et al. Circulation 2003;108:1302-5.
Herreros J, et al. Eur Heart J 2003;24:2012-20.
13N Ammonia 18F FDG 13N Ammonia 18F FDG
Cultured Skeletal Muscle-derived Stem Cells in Infarction