Post on 22-Sep-2020
Timothy M. Bateman M.D. Co-Director, Cardiovascular Radiologic Imaging
Mid America Heart Institute Professor of Medicine
University of Missouri-Kansas City Kansas City, Missouri
Comparative Advantages of PET Over SPECT: Is PET Really Better?
Conflict of Interest Disclosure
Dr. Bateman declares that the following relationships constitute a potential conflict of interest with respect
to this presentation:
Research Grants: Astellas, GE, Lantheus, Philips, SpectrumDynamics Advisory Boards: Astellas, GE, Lantheus, SpectrumDynamics Royalties: ExSPECT IITM, ImagenPro/MD/QTM
Stock Ownership: Cardiovascular Imaging Technologies
Comparative Advantages of PET for Myocardial Perfusion Imaging
• Improved image quality vs traditional SPECT
• Higher diagnostic accuracy
• More data to strengthen interpretive confidence
• Lower dosimetry vs rest/stress SPECT
• Better through-put efficiency (Rb-82)
• Spatially-centric vs spatially-relative
• Improved prognostication
Situations When PET May Not Be Better Than SPECT for MPI
• Able to perform diagnostic-level exercise test
• Inability to lie still
• Slow circulation (CHF; PHTN) – Rb-82
• Morbid obesity – Rb-82
• Generator near EOL – Rb-82
• When adenosine only available vasodilator – Rb-82
Pharmacologic Stress Myocardial Perfusion Imaging
SPECT Rb-82 PET
Mid-LAD Ischemia RCA Ischemia
SPECT
PET
0
20
40
60
80
100
Men Women0
20
40
60
80
100
BMI<30 BMI>30
0
20
40
60
80
100
MVD
18% SPECT vs 4% PET studies were
in uncertain categories
SPECT
PET
Bateman, JNC 13: 24 – 33, 2006
0102030405060708090
Good Fair Sub-Optimal
Yoshinaga, JACC 48: 1029 – 39, 2006
Image Quality in 96 Pts Imaged With PET After a
Non-Definitive SPECT
ACCURACY BY GENDER ACCURACY BY BMI
MVD SENSITIVITY
48% 71%
*p=0.03
69% 84%
*p=0.05
67% 88%
*p=0.01
70% 87%
67% 85%
*p=0.05 *p=0.02
MIBI SPECT
Rb82 PET
Diagnostic Accuracy, PET
Beanlands and Youssef JNC 2010;17:683
Less than 5% of this data is from PET/CT
Jaarsma et al J Am Coll Cardiol 2012; 59: 1719-1728
SPECT, CMR, and PET for Detecting CAD
Rb-82 PET Vs SPECT for Diagnosis of Obstructive CAD: A Meta-Analysis
McArdle et al, J Am Coll Cardiol 2012; 60: 1828-1837
PET
SPECT
Rb-82 PET Vs SPECT for Diagnosis of Obstructive CAD: A Meta-Analysis Including Direct PET/SPECT
Comparison Studies
McArdle et al, J Am Coll Cardiol 2012; 60: 1828-1837
Rb-82 PET Vs SPECT for Diagnosis of Obstructive CAD: A Meta-Analysis Including Only AC-SPECT
p < 0.001
McArdle et al, J Am Coll Cardiol 2012; 60: 1828-1837
Information Content of a Contemporary PET MPI Study
1. High quality perfusion images: high count-density, minimal scatter, attenuation-corrected
2. High quality function images: each frame has high counts, each frame attenuation and scatter-corrected
3. Function images at rest and at peak stress (focus on changes in EF, ESV, average volume, & regional wall motion/thickening)
4. Rest and peak stress MBF
5. Presence and extent/severity of CAC
9 mA, 100 kVp, 5mm 5 secs breath-holding No ECG-gating
~ 0.18 mSv
• 492 pts
• 6 independent readers
• CACS categorized as 0, 1-9, 10-
99, 100-399, 400-999, >
1000
• 93% within 1 category
• Weighted kappa 0.89
Einstein et al, J Am Coll Cardiol 2010; 56: 1914 - 21
Rest EF 54% Peak Stress EF 60%
Rest ESV 29 Peak Stress ESV 25
Coronary Artery Calcium Score 0
67 y/o woman with atypical angina, multiple risk factors, in hospital with acute pancreatitis
Interpreted as low-risk scan, mild LAD distribution ischemia
One week later: Large anterior MI. Cath showed high-grade stenoses in the proximal
and mid portions of the LAD coronary artery
59 y/o male – normal PET MPI
1 month later = lateral MI Cath = LCx thrombus, 75% stenoses in LAD and RCA
Dosimetry Estimates for Radionuclide Myocardial Perfusion Imaging
Tracer Stress Dose
Rest Dose
mSv
Tc-99m MIBI 30 mCi 10 mCi 12 mSv Tc-99m MIBI SO 30 mCi 9 mSv
Tc-99m MIBI SO-SD 2 – 4 mCi 0.7 – 2 mSv Rb-82 40 mCi 40 mCi 3.6 mSv
NH3-Ammonia 20 mCi 20 mCi 3 mSv
Rb-82 ECG-Gated Rest/Stress Acquisition Protocol for Dedicated or Hybrid PET/CT
1 3.5 3.5
Tx Scan
Rb-82 40 mCi
Emission Scan, 3D
with gating
1
Tx Scan
Rb-82 40 mCi
1
Emission Scan, 3D
with gating
Dipyridamole, Dobutamine
Stress
25 minutes
Dorbala et al, JACC Imaging 2009;2:846-854
PET MPI Risk Stratification % Abnl Myocardium
As Function of LVEF Reserve
Lertsburapa et al, JNC 15: 745-753, 2008
MBFR Is an Independent Predictor of Major Adverse Cardiac Events (677 pts with median f/u 387days)
Ziadi et al, JACC 2011; 58: 740 - 748
Improved Risk Assessment With PET CFR
Murthy et al, Circulation October 17, 2011
Kaplan–Meier Survival Curves
Tonino PA et al. N Engl J Med 2009;360:213-224
Johnson et al, J Am Coll Cardiol Img 2012;5:193–202)
PET Coronary Flow Reserve Vs Tracer Uptake
Johnson et al, J Am Coll Cardiol Img 2012;5:193–202)
Theoretic and Practical Benefit of PCI: CFR Vs FFR
Radionuclide Myocardial Perfusion Imaging in 2013: Moving Away From One Test For All Purposes
MPI
Stress-Only SPECT
Rest/Stress SPECT
Rest/Stress PET