NUCLEAR CARDIOLOGY- BASICS Dr. THIRUMURTHI CHIEF-NUCLEAR MEDICINE MADRAS MEDICAL MISSION

Nuclear Medicine Specialty in which a wide range of clinical conditions are investigated using radioactive tracers administered to the patient It is completely different process from X-Ray, CT and MRI scan (these look at the anatomy of the body) To look at the function of the body, Nuclear Medicine uses gamma rays

Nuclear Medicine Gamma rays are very similar to X-Rays, but the major difference is that the gamma rays are emitted by pharmaceuticals injected into the bloodstream rather than being produced by machines outside the body. Gamma rays are detected by the gamma camera

Gamma Rays (from Doe Medical Sciences webpage)

Myocardial Perfusion Imaging Radiopharmaceuticals : 201Thallium Technetium based agents PET * Ammonia

Technetium based agents 99m Technetium T 1/2 - 6 Hrs Pharmaceuticals : SestaMIBI, Tetrofosmin SestaMIBI: Methoxy Iso Butyl Isonitrile Passive diffusion Uptake proportional to blood flow & no redistribution Good quality images, gating, easy availability & Cost effective

Exercise stress testing Treadmill or bicycle ergometer Protocols vary - symptom limited Bruce most popular 8 stages Incline and speed increment every 3 minutes Target 85-100% maximum age predicted HR Achieve at least 6 METS for diagnostic accuracy © Continuing Medical Implementation …...bridging the care gap

MPI Stress Procedure Treadmill Pharmacological stress IV Dobutamine / Adenosine DOBUTAMINE Max.Dosage: 40 ug / kg / min + Inj.Atropine 0.6 mg IV ADENOSINE Dose : 140 ug / kg / min - 6 min

Indications Screening of IHD Physiological significance of lesions post CAG Post PTCA & post CABG evaluation Risk stratification Myocardial viability detection

Diagnostic Accuracy % % Sensitivity % Specificity P r e d i c t v A u Exercise Stress ECG1 6 7 7 4 6 9 Exercise Stress Echo1 8 5 7 9 8 3 MPI1 8 9 80 8 9 1. O’Rourke RA, et al. Circulation. 2000;102:126-140. 2. Wackers FJ, et al. Nuclear cardiology. In: Braunwald E, ed. Heart Disease: A Textbook of Cardiovascular Medicine. 5th ed. Philadelphia, Pa: WB Saunders; 1997.

PET Myocardial Imaging PET Perfusion Imaging PET Metabolic Imaging

Flow tracers Rb-82 0-15 N-13 Tc-99m MIBI Tl-201

Metabolic tracer F-18 – fluorodeoxyglucose(FDG) F-18 –BMS 747158 I-123 BMIPP

                                                                                                                           

Stunning Hibernation Scar Perfusion Metabolism Dysfunction Condition Reversible Stunning Reversible Hibernation Irreversible Scar

30% OF NO PERFUSION SEGMENT SHOWS FDG UPTAKE MIBI & FDG 30% OF NO PERFUSION SEGMENT SHOWS FDG UPTAKE

Influence of Viability Testing on Outcomes With Revascularization 20 -80% p<0.0001 16 16 p=NS 12 Annual Cardiac Death Rate (%) 7.7 8 6.2 3.2 4 Revasc Med Rx Revasc Med Rx Viable Non-viable (Allman, JACC 2002; 39: 1151-1158)

ACC/AHA Recommendations for the Use of Radionuclide Techniques to Assess Myocardial Viability Indication Test Class Level of Evidence Predicting improvement in regional and global LV function after revascularization Stress /redistribution/reinjection 201T II B Rest-redistribution imaging I Perfusion plus PET FDG imaging Resting sestamibi imaging Late 201Tl redistribution imaging (after stress) IIb Class I: Conditions for which there is evidence and/or general agreement that a given procedure or treatment is useful and effective LOE B: Data derived from a single randomized trial, or from nonrandomized studies

First-Pass Radionuclide Angiography (RNA)

Indications Coronary artery disease (CAD) Valvular heart disease Congenital heart disease

Equilibrium Gated Radionuclide Ventriculogram MUGA

Purpose Examine the function of the pumping chambers of the heart Left ventricle measurements are more accurate than the right because of the heart’s anatomy (gated first-pass study with radionuclides that do not pass the lungs maybe used for the right ventricle)

BPGS - Blood Pool Gated SPECT Analysis:                                                                                        BPGS - Blood Pool Gated SPECT Analysis BPGS is an interactive standalone application for the automatic segmentation & quantification of gated short axis blood pool (red blood cells, RBC) SPECT.

                   

Imaging CTPA is now the recommended initial lung imaging modality for non-massive PE. [B] Patients with a good quality negative CTPA do not require further investigation or treatment for PE. [A] Isotope lung scanning may be considered as the initial imaging investigation providing (a) facilities are available on site, and (b) chest radiograph is normal, and (c) there is no significant symptomatic concurrent cardiopulmonary disease, and (d) standardised reporting criteria are used, and (e) a non-diagnostic result is always followed by further imaging. [B]