An IntroductiontoNuclear Cardiology :An IntroductiontoNuclear Cardiology


Anatomy & Physiology :Anatomy & Physiology Four cardiac chambers left ventricle of importance in NM Coronary arteries supply myocardium with blood NM detects quality of perfusion to myocardium, an indirect assessment of the coronary arteries


CLINICAL INDICATIONS :CLINICAL INDICATIONS Coronary artery disease causes myocardial ischemia and infarction. Ischemia is reversible condition, caused by temporary deficiency of oxygen to the myocardium Infarction is irreversible condition, that leads to death of a portion of the myocardium.


Clinical indications :Clinical indications During a stress test (exercise) or when certain drugs are administered, the demand for blood flow (oxygen) through the coronary arteries increases.\ If the increase in the demand cannot be met the myocardium becomes ischemic. Ischemia can cause decreased tissue perfusion, and contraction in affected area.


Mechanical activity :Mechanical activity Each cardiac cycle (each beat) consists of systole (ventricular contraction) and diastole (ventricular relaxation) Both sides of heart contract in unison Left ventricular contraction is most important to NM.


Radiopharmaceuticals :Radiopharmaceuticals Evaluation of myocardial perfusion: Single photon emitters, thallium-201 chloride (201-Tl), Technitium 99m sestamibi, (tc99m tetrafosmin) (tc99m teboroxime) Positron emitting tracer, Rubidium-82 (Rb82)


Radiopharmaceuticals :Radiopharmaceuticals Evaluation of ventricular function: Tc99m labeled red blood cells Tc99m albumin Detection of acute myocardial necrosis: Tc99m pyrophospate (PYP) Indium 111 antimyosin


Types of Procedures :Types of Procedures Gated cardiac blood pool typically a rest study MUGA or NVG are common names First pass cardiac stress or rest Myocardial perfusion SPECT images stress/rest or rest only frequently gated


Gated Blood Pool :Gated Blood Pool Gating process Functional assessment ventricular wall motion ES and ED ventricular volumes LV ejection fraction normal = 64% +/- 12%


Gated Blood Pool :Gated Blood Pool Radiopharmaceutical Tc-99m labeled red blood cells in-vitro and in-vivo labeling Images anterior left lateral left anterior oblique (best LV separation)


Gated Blood Pool :Gated Blood Pool Exercise assessment stress done with bicycle rest EF to compare stress EF Primary uses of test congestive heart failure cardiomyopathy chemo cardiotoxicity


First Pass Cardiac Study :First Pass Cardiac Study What’s ‘first pass’? temporal separation of chambers Functional assessment ventricular wall motion ES and ED ventricular volumes LV and RV ejection fractions pulmonary transit time


First Pass Cardiac Study :First Pass Cardiac Study Radiopharmaceuticals via bolus Tc-99m DTPA Tc-99m sestamibi Images one anterior image for 60 seconds acquisition is divided into many millisecond frames for temporal resolution


First Pass Cardiac Study :First Pass Cardiac Study Can be performed with exercise stress done with bicycle rest EF to compare to stress EF Primary uses of test same as gated cardiac study better than gated at right ventricle assessment and cardiac shunts


First Pass Cardiac Study :First Pass Cardiac Study Primary limitation: This procedure requires a special nuclear imaging camera that cannot be used to perform any other type of nuclear procedures. Many clinics cannot justify the cost, so a gated study is used instead.


Myocardial Perfusion Study :Myocardial Perfusion Study Assess coronary blood flow Demonstrate blood perfusing the LV myocardium Software allows gating for EF 3D reconstruction of heart


Myocardial Perfusion :Myocardial Perfusion Radiopharmaceuticals Thallium-201 chloride Tc-99m sestamibi SPECT acquisition provides cross-sectional images of the myocardium in the short axis, horizontal long axis and vertical long axis planes


Myocardial Perfusion :Myocardial Perfusion Performed at rest & stress Stress study options treadmill exercise pharmacologic stress agents adenosine persantine (dipyridamole) dobutamine


Myocardial Perfusion :Myocardial Perfusion Percentage of LV myocardium receiving decreased perfusion Differentiate ischemia from MI 24 hour delayed images demonstrate myocardial viability (hibernating) Rest-only studies can provide information on acute MI’s


Patient Prep :Patient Prep Any stress procedure NPO midnight off beta-blocker medications Chemical stress procedure off caffeine and asthma medications for adenosine/persantine chemical stress Any rest procedure requires no patient prep


Acquisition :Acquisition Inject first dose and acquire resting SPECT study Prepare patient for stress At maximal stress inject radio-pharmaceutical Acquire stress SPECT study (gated) *variations in procedure sequence may occur


Exam Results :Exam Results Myocardial Infarction perfusion defect on rest & stress Myocardial Ischemia perfusion defect on stress only


Time Comparison :Time Comparison Gated study rest 40 minutes First pass study rest 15 minutes stress 60 minutes Myocardial perfusion study 60 minutes stress & 30 minutes rest