Current Tracers. João V. Vitola, MD, PhD. Cardiologist and Nuclear Medicine Physician Quanta Diagnostico Nuclear Curitiba - Brazil

Transcription

1 Current Tracers João V. Vitola, MD, PhD Cardiologist and Nuclear Medicine Physician Quanta Diagnostico Nuclear Curitiba - Brazil

2 SPECT - Tracer Characteristics

3 TC-99m tracers and protocols One or two day protocols Stress or rest first Stress only ACS imaging

4 Uptake mechanisms

5 Tracers characteristics and Reliability Uptake curve ~ extraction plateau Intracellular dynamics Energy and Resolution

6 Effects of myocardial extraction plateau 0,10 0,08 % Dose.gram tissue 0,06 0,04 99m Tc-Mibi 201 Tl 0,02 0, Coronary flow (ml.min.g -1 )

7 Vasodilator Exercise MIBI Distribution GI uptake

8 GI Uptake Normalized to the gut

9 GI Uptake

10 Time and Food

11 Decreasing Liver Uptake Vitola J et al, J Nucl Cardiol 2001, 8 (6):652-9

12 heart/ liver Dip Exercise (46%) 1.3 ± ± 0.5* Taillefer et al Dip Exer + Dip (23%) 1.3 ± ± 0.6* Vitola et al *p<0.05 Vitola J et al, J Nucl Cardiol 2001, 8 (6):652-9

13 Thallium ~ less GI uptake

14 Thallium Renal extraction Redistributes ~ Better for viability More linear uptake to flow compared to MIBI Where is the Achilles Heel?

15 Typical Effective Doses of Cardiac Studies Effective Dose (msv) Cath 7 Cath CT Angiography SPECT 24 PET Spiral Spiral w. Tube Current Modulation 4 Axial 2 Calcium Score 10 99m Tc Rest- Stress Dual Isotope 4 99m Tc Low-Dose Stress Only Rb Rest- Stress 13 NH 3 Rest- Stress Years of Background Radiation Courtesy Dr Einstein Einstein AJ, JACC 2012; 59: 553

16 Effect of Nuclear Cardiology Scan Protocol on Estimated Cancer Risk Dual Isotope Tc-99m Rest-Stress N-13 ammonia Courtesy Dr Einstein Berrington A. Circulation 2010;122:2403

17 Tc 99m Activities normalized by BMI BMI Injected Activity ~ 2 d protocols mci mci mci mci > 35 15mCi ~ 8 msv

18 PET tracers ATEN. CORRECTION CALCIUM SCORE ANATOMY 64 SLICES PERFUSION (Absolute) VIABILITY LV FUNCT (True Str) Vitola JV, Cerci J, Delbeke D. PET/CT em Cardiologia, Ed. Revinter, Rio de Janeiro, 2010

19 Ammonia Oxygen Rubidium Acetate Unidad PET/CT Ciclotrón UNAM Courtesy of Turku PET Centre Courtesy Erick Alexanderson Courtesy of B&WH Harvard Unidad PET/CT Ciclotrón UNAM

20 Molecular Imaging - flow and metabolism 18 FDG Glucosa 11 C Palmitato IPPA BMIPP Glucógeno ATP ADP AGL K+ ATP ADP Na+ 201 Tl+ 82 Rb+ Misonidazole [O 2 ] 11 C-CGP Glucosa-6-P AGL-CoA Depósitos de lípidos ATP Glucólisis β oxidación Adenosina Piruvato 11 C-HED 18 F Dopamina 18 F NE Lactato Courtesy Erick Alexanderson Krebs 11 C-Acetato Fosforilación oxidativa 15 O 2 11 C-Homocisteína

21 Glycogen Glucose Glucose Hexokinase Glucose-6-P Cell membrane Glycolytic Hexokinase 18- FDG FDG FDG-6-P CELL METABOLISM

22 Cell metabolism using FDG ~ huge in Cancer Pre-therapy Post-therapy CT FDG PET Vitola JV, Delbeke D, et al. Cancer 1996;78:

23 Cyclotron

24 Myocardial Metabolism 80% - Free fatty acid B oxidation...atp +++ Ischemia: increases glycolisis Hiperglicemia...hiperinsul...reduces lipolysis Increases glucose uptake 3-5 x

25 Image Quality and Impact on accuracy Routine AC using PET- CT SPECT 99m Tc-MIBI PET 82 Rb Courtesy of J. Machac-Mt Sinai, NY

26 Future Direction for Cardiac PET Ideal PET MPI Imaging Agent High cardiac uptake with minimal redistribution Near linear myocardial uptake vs. flow up to 5 ml/min/g or more (high first pass extraction fraction) High target to non-target ratio (vs. lung, liver, bowel) Usable for both exercise and pharmacologic stress Usable for quantitation of absolute myocardial flow Available as unit dose ( 18 F-labeled compound) Adapted from: Glover, D and Gropler, R., J. Nucl. Card 14:6 p765-8 Ver. 18Aug 09

27 New PET perfusion tracer labeled with F-18 Chemical Structure of BMS Mitochondrial Complex 1 (MC-1) Inhibitor O N N C l O O 1 8 F 2-tert-Butyl-4-chloro-5-[4-(2- (18F)fluoro-ethoxymethyl)-benzyloxy]-2H-pyridazin-3-one Yu, et al., J Nucl Cardiol. 2007;14(6): Ver. 18Aug 09

28 First Pass Uptake in Isolated Rabbit Hearts 3 BMS (n=4) 201 Tl (n=3) Uptake m Tc-sestamibi (n=3) * * Coronary perfusion flow (ml/min/g) Yu, et al., J Nucl Cardiol. 2007;14(6): * Indicates p<0.05

29 Study Patient BMS SA Stress Rest Stress BMS HLA Stress Rest Rest J. Maddahi, UCLA Stress BMS VLA Rest Ver.18Aug 09

30 What else besides Perfusion and Viability tracers?

31 MIBG (Meta-Iodo-Benzyl-Guanidine) a physiologic analog of the sympathetic nervous system neurotransmitter norepinephrine (NE). OH I NH OH CHCH 2 NH 2 OH CH 2 NH-C-NH 2 NOREPINEPHRINE MIBG

32 Prognostic Significance of 123 I-mIBG Myocardial Scintigraphy in Heart Failure Patients: Results from the Prospective Multicenter International ADMIRE-HF Trial *ADMIRE-HF: AdreView Myocardial Imaging for Risk Evaluation in Heart Failure Jacobson A et al. ACC, 200

33 [ 123 I]mIBG Planar Imaging for Cardiac Assessment Normal innervation NHYA Class II NYHA Class IV H/M ratio:

34 Cardiac Death Event H/M 1.60: 2-year event-free survival 98% Event-free Survival Probability H/M<1.60: 2-year event-free survival 89% Time (days) *p=0.002 vs H/M 1.60

35 Elderly female, stressful event, anterior STEMI normal epicardial vessels 123 MIBG at Rest 99m Tc- MIBI at Rest 90% are women usual post menopausal Villaroel A, Vitola J, Stier A, Dippe T, Cunha C. Expert Rev. Cardiovasc. Ther., 7 (7) 2009

36 Elderly female, stressful event, anterior STEMI normal epicardial vessels 123 MIBG at Rest 99m Tc- MIBI at Rest 90% are women usual post menopausal Villaroel A, Vitola J, Stier A, Dippe T, Cunha C. Expert Rev. Cardiovasc. Ther., 7 (7) 2009

37 Thank you CURITIBA - BRASIL