Comparative Advantages of PET Over SPECT: Is PET Really Better? 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 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 II TM, ImagenPro/MD/Q TM 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 100 80 60 40 ACCURACY BY GENDER *p=0.05 84% 69% *p=0.01 88% 67% 100 80 60 40 ACCURACY BY BMI *p=0.05 87% 70% *p=0.02 85% 67% 20 20 0 Men Women 0 BMI<30 BMI>30 SPECT PET 100 80 60 40 20 MVD SENSITIVITY *p=0.03 71% 48% 0 MVD 90 80 70 60 50 40 30 20 10 0 Image Quality in 96 Pts Imaged With PET After a Non-Definitive SPECT Good Fair Sub-Optimal 18% SPECT vs 4% PET studies were in uncertain categories Yoshinaga, JACC 48: 1029 39, 2006 Bateman, JNC 13: 24 33, 2006
MIBI SPECT Rb 82 PET Diagnostic Accuracy, PET Less than 5% of this data is from PET/CT Beanlands and Youssef JNC 2010;17:683
SPECT, CMR, and PET for Detecting CAD Jaarsma et al J Am Coll Cardiol 2012; 59: 1719-1728 Rb-82 PET Vs SPECT for Diagnosis of Obstructive CAD: A Meta-Analysis PET SPECT 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 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 NH 3 -Ammonia 20 mci 20 mci 3 msv Rb-82 ECG-Gated Rest/Stress Acquisition Protocol for Dedicated or Hybrid PET/CT Rb-82 40 mci Dipyridamole, Dobutamine Stress Rb-82 40 mci 25 minutes 1 3.5 1 3.5 Tx Scan Emission Scan, 3D with gating Tx Scan Emission Scan, 3D with gating
PET MPI Risk Stratification % Abnl Myocardium As Function of LVEF Reserve Lertsburapa et al, JNC 15: 745-753, 2008 Dorbala et al, JACC Imaging 2009;2:846-854 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
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 Johnson et al, J Am Coll Cardiol Img 2012;5:193 202)
Radionuclide Myocardial Perfusion Imaging in 2013: Moving Away From One Test For All Purposes MPI Stress-Only SPECT Rest/Stress SPECT Rest/Stress PET