PET vs SPECT An MPI Case Review Cardiac

PET vs. SPECT: An MPI Case Review “Cardiac PET MPI is a well-established and highly accurate technique for detecting hemodynamically significant CAD. The ability to reduce attenuation artifact is useful in all patients, but particularly the obese. ” 7 7. ASNC Model Coverage Policy: Cardiac positron emission tomographic imaging. J Nucl Cardiol 2013; 20: 916 -47

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Purpose § Present published data comparing the image quality and diagnostic accuracy of PET myocardial perfusion imaging (MPI) to SPECT MPI in similarly matched patient types § Report on Rb-82 PET MPI event-free survival and prognosis § Demonstrate, through patient case studies, the effect of better image quality in the treatment of patients § Gender bias § Body mass index (BMI) § Multi-vessel disease (MVD)

Image Quality: PET MPI vs. SPECT MPI Figure 1. Image quality scores for PET and SPECT perfusion and ECG-gated scans 1. Bateman, et. al. J Nucl Cardiol 2006 Jan-Feb; 13(1): 24 -33

Why is the Image Quality with PET Better than SPECT? Improved image quality for PET vs. SPECT due to: 1 -4, 6 § § Higher count rates (240% increase over SPECT) Improved spatial resolution: 3 mm PET vs. 6 mm SPECT Routine and robust attenuation correction on all scans Better detection of MVD 1. Bateman, et. al. J Nucl Cardiol 2006 Jan-Feb; 13(1): 24 -33 2. Merhige, et al. J Nucl Med 2007; 48: 1069– 1076 3. Yoshinaga, et al. J Amer Coll Cardiol 2006; 48(5): 1029 -1039 4. Chow, et al. J Nucl Med 2005; 46: 1095– 101 6. Dorbala et al. J Nucl Med 2007; 48(3): 349 -358

Diagnostic Accuracy: PET vs. SPECT BY BMI BY GENDER *P = 0. 55 *P = 0. 009 84% 69% *P = 0. 05 88% *P = 0. 02 85% 87% 70% 67% MVD SENSITIVITY *P = 0. 03 MEN WOMEN 71% BMI<30 BMI>30 48% SPECT PET MVD 1. Bateman, et. al. J Nucl Cardiol 2006 Jan-Feb; 13(1): 24 -33

PET MPI: Improved Interpretive Certainty vs. SPECT MPI Figure 2. Comparison of degrees of interpretive certainty of SPECT and PET studies 1. Bateman, et. al. J Nucl Cardiol 2006 Jan-Feb; 13(1): 24 -33

Rb-82 PET vs. Gated AC Tc-99 m SPECT SROC* SPECT: Pooled Sensitivity = 85% Pooled Specificity = 85% AUC: AUC 0. 909 Q ( ): 0. 841 *SROC: summary receiver operating characteristic curve Rb-82 PET SROC* PET: Pooled Sensitivity = 90% Pooled Specificity = 88% * AUC: AUC 0. 95 Q ( ): 0. 8907 *P < 0. 01 for Rb-82 PET vs. gated AC SPECT 5. Mc. Ardle et al. J Am Coll Cardiol 2012; 60(18): 1828 -37

Left ventricular ejection fraction (LVEF) reserve (%) Left Ventricular EF Reserve and Magnitude of Jeopardized Myocardium P< 0. 0001 P = 0. 003 Coronary angiogram results 6. Dorbala et al. J Nucl Med 2007; 48(3): 349 -358

Rb-82 PET MPI: Event-Free Survival Adjusted Event Free Survival Summed Stress Score, Total Cardiac Events 1. 00 0. 95 Normal 0. 90 Mild 0. 85 0. 80 Log-rank p=0. 001 Moderate - Severe 0. 75 0. 70 0 0. 5 1 1. 5 2 2. 5 3 3. 5 4 Follow up (years) 3. Yoshinaga K, et al. J Am Coll Cardiol 2006; 48: 1029 -39

Rb-82 PET MPI: Prognosis Prognostic Value of Stress Myocardial Perfusion Positron Emission Tomography: Results from a Multicenter Observational Registry Cardiac death (N = 6, 037) All-cause death (N = 7, 061) 7. Dorbala et al. J Am Coll Cardiol 2013 Jan; 61(2): 176 -8

CASE STUDIES

Case #1 Patient Profile § Demographics: 77 -year-old female § Body Habitus: Wt: 160 lbs; Ht: 61 inches; BMI: 31 § Risk Factor: hypertension § Reason for Test: atypical chest pain § ECG: normal sinus rhythm and nonspecific T-wave abnormalities § Meds: atenolol, famotidine, aspirin, anticoagulant Following are images of a patient who underwent a SPECT MPI and a PET MPI study 2 weeks apart at Harvard/Brigham & Women’s Hospital in Boston, MA. The case and study all images courtesy of Marcelo Di. Carli, MD (Harvard/Brigham & Women’s Hospital).

Case #1: SPECT Images

Case #1: Rb-82 PET Images

Case #1: SPECT and PET Images Tc-99 m Rb-82

Case #1: Summary Protocol Mode of Stress Clinical Response BP Response ECG Response Radiopharmaceutical Rest / Stress Dose Gated SPECT PET Adenosine (4 min) Dipyridamole (4 min) Non-ischemic Normal Negative Tc-99 m sestamibi Rubidium-82 11 m. Ci / 33 m. Ci 60 m. Ci / 60 m. Ci Yes Cardiac catheterization was not performed because the PET MPI study was normal.

Case #2 Patient Profile § Demographics: 59 -year-old female § Body Habitus: Wt: 140 lbs, H: 65 inches, BMI: 23. 5 § Reason for Test: evaluation of atypical chest pain and dyspnea § Meds: metoprolol, amlodipine, captopril, furosemide, aspirin, simvastatin, bupropion Following are images of a patient who underwent a SPECT MPI and a PET MPI study 12 days apart at Harvard/Brigham & Women’s Hospital in Boston, MA. The case and all study images courtesy of Marcelo Di. Carli, MD and Sharmila Dorbala, MBBS (Harvard/Brigham & Women’s Hospital).

Case #2: SPECT Images

Case #2: Rb-82 PET Images

Case #2: SPECT and PET Images Tc-99 m Rb-82

Case #2: Summary Protocol Mode of Stress Clinical Response BP Response ECG Response Radiopharmaceutical Rest / Stress Dose Gated SPECT PET Adenosine (4 min) Dipyridamole (4 min) Non-ischemic Normal Negative* Tc-99 m sestamibi Rubidium-82 12 m. Ci / 30 m. Ci 36 m. Ci / 36 m. Ci Yes *Patient had normal sinus rhythm and non-specific ST-T wave abnormalities on the resting ECG prior to the MPI studies.

Case #2: Report Comparison § SPECT MPI Report There was a small defect of moderate intensity in the mid to apical anterior wall that remained fixed on the rest images and most likely is due to breast attenuation artifact; however, a non-transmural myocardial scar cannot be excluded. § PET MPI Report There were no regional perfusion defects seen on the stress or rest images. The patient’s PET/CT test results are normal and suggest no evidence of flow-limiting CAD. The results suggest that the previously described fixed anterior wall defect (her prior SPECT study) is likely to represent an attenuation artifact. Cardiac catheterization was not performed because the PET MPI study was normal.

Case #3 Patient Profile § Demographics: 82 -year-old male § Body Habitus: Wt: 210 lbs; Ht: 70 inches; BMI: 30. 1 § Risk Factor: hypertension § Reason for Test: preoperative cardiac evaluation prior to hip replacement surgery § Meds: aspirin, bisoprolol Following are images of a patient who underwent a SPECT MPI and a PET MPI study 2 weeks apart at University Hospitals Case Medical Center in Cleveland, OH. The case and all images are courtesy of Jim O’Donnell, MD (University Hospitals Case Medical Center, Cleveland, OH).

Case #3: SPECT Images

Case #3: Rb-82 PET Images Case courtesy of Jim O’Donnell, MD, University Hospitals Health System, Cleveland, OH

Case #3: SPECT and PET Images Tc-99 m Rb-82

Case #3: Summary Protocol SPECT PET Mode of Stress Dipyridamole Clinical Response Non-ischemic Normal Negative Tc-99 m sestamibi Rubidium-82 10 m. Ci / 33 m. Ci 47 m. Ci / 47 m. Ci Yes 2. 5 hours 40 minutes BP Response ECG Response Radiopharmaceutical Rest / Stress Dose Gated Length of Time

Case #3: Report Comparison § SPECT MPI Report Fixed defect is noted at the apex, which does not move or thicken appropriately and likely represents a scar. There is no SPECT evidence of ischemia. LV ejection fraction of 40% (normal 45%). § PET MPI Report The PET images demonstrate the above-described apical scar pattern but also demonstrate a mild to moderate anterior ischemic pattern involving the distal half of the anterior segment. This is suggestive of mild peri-infarct ischemia. The LV ejection fraction in the PET study is 53% at rest rising to 57% with pharmacologic stress (normal left ventricular function). Statistically, the likelihood of a perioperative event is still fairly low.

Case #3: Final Note Even though this patient received pre-operative clearance for hip surgery, the detection of ischemia on the PET study provided prognostically useful information to assist in the management of this patient’s progressive CAD.

Case #4 Patient Profile § Demographics: 69 -year-old female § Risk Factor: hyperlipidemia, hypertension, Type II DM § Reason for Test: admitted to hospital after a CVA; found to be in atrial fibrillation with small increase in troponin-I; abnormal ECG § Meds: coumadin, lovenox, toprol XL, lipitor, altace (over the last 24 hrs. prior to imaging per rest/stress dipyridamole cardiogen-82 PET report) Following are images of a patient who underwent a rest/dipyridamole stress Rb -82 myocardial perfusion PET study. The case and all images are courtesy of Tim Bateman, MD (Cardiovascular Consultants, Kansas City, MO).

Case #4: Rb-82 PET Images Transient Ischemic Dilation (TID) Ratio: 1. 63 (normal = 1. 0) STRESS REST A larger cavity size on stress images can indicate a near -balanced flow reduction.

Case #4: Rb-82 PET Functional Images PEAK STRESS LVEF 50% REST LVEF 61% A lower EF during exercise vs. rest is considered an abnormal compensatory response at a time of increased demand.

Case #4: Report The combined test findings indicate the following: § Virtually diagnostic for the presence of CAD § Apical ischemia probably in the distribution of the left anterior descending coronary artery § Severe transient ventricular dilation, suggesting possible nearbalanced flow reduction in multiple coronary territories § Normal left ventricular function at rest (LVEF 61%) § Significant drop in LVEF in response to pharmacologic stress § Prognostically concerning scan, with numerous markers of high-risk for major adverse coronary events

Case #4: Catherization Correlation The combined test findings indicate the following: § Coronary angiography showed a 75% left main stenosis, a 90% stenosis of the mid LAD and a 70% right coronary artery stenosis § CABG surgery was performed after recovery from the CVA

Slide References 1. Bateman TM, Heller GV, Mc. Ghie AI, et al. Diagnostic accuracy of rest/stress ECG-gated Rb-82 myocardial perfusion PET: comparison with ECG-gated Tc-99 m sestamibi SPECT. J Nucl Cardiol 2006 Jan-Feb; 13(1): 24 -33 2. Merhige ME, Breeny WJ, Shelton V, et al. Impact of myocardial perfusion imaging with PET and 82 Rb on downstream invasive procedure utilization, costs, and outcomes in coronary disease management. J Nucl Med 2007; 48: 1069– 1076 3. Yoshinaga K, Chow B, Williams K, et al. What is the prognostic value of myocardial perfusion imaging using rubidium-82 positron emission tomography? J Amer Coll Cardiol 2006; 48(5): 1029 -1039 4. Chow BJW, Wong JW, Yoshinaga K, et al. Prognostic significance of dipyridamole-induced ST depression in patients with normal 82 Rb PET myocardial perfusion imaging. J Nucl Med 2005; 46: 1095– 101

Slide References 5. Mc. Ardle BA, Dowsley TF, de. Kemp RA, et al. Does rubidium-82 have superior accuracy to SPECT perfusion imaging for the diagnosis of obstructive coronary disease? J Am Coll Cardiol 2012; 60(18): 1828 -37 6. Dorbala S, Vangala D, Sampson U, et al. Value of vasodilator left ventricular ejection fraction reserve in evaluating the magnitude of myocardium at risk and the extent of angiographic coronary artery disease: A 82 Rb PET/CT study. J Nucl Med 2007; 48(3): 349 -358 7. Dorbala S, Di. Carli M, Beanlands R, et al. Prognostic value of stress myocardial perfusion positron emission tomography: Results from a multicenter observational registry. J Am Coll Cardiol 2013; 61(2): 176 -184

Additional References § Sherif Iskander and Ami Iskandrian; Risk Assessment Using Single-Photon Emission Computed Tomographic Technetium-99 m Sestamibi Imaging. J Am Coll Cardiol. 1998; 32: 57 -62. § Gary Heller and Robert Hendel, Editors: Handbook of Nuclear Cardiology: Cardiac SPECT and Cardiac PET. Springer-Verlag London © 2013 § Benjamin J. W. Chow et al, Prognostic Value of PET Myocardial Perfusion Imaging in Obese Patients, JACC Cardiovascular Imaging 2014; 7(3) § Vasken Dilsizian and Jagat Narula, Atlas of Nuclear Cardiology, 3 rd Edition, © 2009 Current Medicine Group LLC § Marcelo Di. Carli et al, Long Term Survival of Patients with Coronary Artery Disease and Left Ventricular Dysfunction: Implications for the Role of Myocardial Viability Assessment in Management Decisions. J Thorac Cardiovasc Surg 1998; 116(6): 997 -1004

Additional References § D’Egidio G, et al. Increasing Benefit From Revascularization is Associated With Increasing Amounts of Myocardial Hibernation; A Substudy of the PARR-2 Trial. JACC Cardiovascular Imaging 2009; 2(9) § 2013 ACCF/ACR/ASE/ASNC/SCCT/SCMR Appropriate Utilization of Cardiovascular Imaging in Heart Failure. J Am Coll Cardiol 2013; 61(21) § Ziadi M, et al. Impaired Myocardial Flow Reserve on Rubidium-82 Positron Emission Tomography Imaging Predicts Adverse Outcomes in Patients Assessed for Myocardial Ischemia. J Am Coll Cardiol 2011; 58(7) § Murthy V, et al. Improved Cardiac Risk Assessment with Non-Invasive Measures of Coronary Flow Reserve. Circulation 2011; 124(20): 2215 -2224

Additional References § Skali H, Schulman A and Dorbala S. 18 -F FDG PET/CT for the Assessment of Myocardial Sarcoidosis. Current Cardiology Reports 2013; 15(4): 352 § Einstein AJ. Effects of Radiation Exposure From Cardiac Imaging: How Good Are the Data? J Am Coll Cardiol 2012; 59(6): 553 -565 § Cerqueira MD, et al. ASNC Information Statement: Recommendations for reducing radiation exposure in myocardial perfusion imaging. J Nucl Cardiol doi: 10. 1007/s 12350 -010 -9244 -0. Published online 26 May 2010

Important Safety Information § Image interpretation errors can occur with PET imaging. § Hypersensitivity reactions, including anaphylaxis, may occur in patients who receive PET radiopharmaceuticals. Emergency resuscitation equipment and personnel should be immediately available. § PET/CT imaging contributes to a patient’s overall long-term cumulative radiation exposure, which may be associated with an increased risk of cancer. Safe handling practices should be used to minimize radiation exposure to the patient and healthcare providers. § Adverse reactions, although uncommon, may occur when using PET radiopharmaceuticals. Always refer to the package insert prior to use.