nuclear cardiology methods in routine clinical practice n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Nuclear cardiology methods in routine clinical practice PowerPoint Presentation
Download Presentation
Nuclear cardiology methods in routine clinical practice

play fullscreen
1 / 95

Nuclear cardiology methods in routine clinical practice

251 Views Download Presentation
Download Presentation

Nuclear cardiology methods in routine clinical practice

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Nuclear cardiology methods in routine clinical practice Materials for medical students Lang O., Kamínek M. Dept Nucl Med, School of Medicine, Praha, Olomouc

  2. Nuclear cardiology • Set of non-invasive mostly imaging diagnostic methods of the cardiovascular system • Huge expansion during last 30 years, in Czech rep. during last 10 years • Examination of venous system of lower extremities and lung perfusion are included

  3. Seminar includes • Imaging in nuclear cardiology (NC) • NC methods • Myocardial perfusion • Myocardial viability • Heart function • Examination of pulmonary embolism • New trends

  4. Ways of imaging in NC • Detectors of ionizing radiation – gamma cameras • Source of radiation inside the patient body - radiopharmaceutical, tracer • Ways of distribution - perfusion, metabolic process, receptors, etc. • Source of information - ionizing photon (gamma) • Digital images - processing, archiving, transfer • planar, tomographic • SPECT (transversal), PET (coincidence)

  5. Data collection by gamma cameras

  6. PET camera

  7. Way of tomography - SA slices

  8. Other tomographic slices

  9. Parts of left ventricle myocardium Legenda: 1 - apex 2 - anterior wall 3 - lateral wall 4 - inferior wall 5 – septum SA VLA HLA Pollar map

  10. Heart examination • Myocardium imaging • perfusion during stress and rest (80%) • viability • necrosis, innervation, ischemia • Mechanical function assessment • steady-state ventriculography (multigated - MUGA) • Angiocardiography (first-pass) • non-imaging systems

  11. Myocardial perfusionrate of NC examinations

  12. Why stress? Pathophysiology of CAD Hemodynamic effect of coronary stenoses Collaterals Ischemic cascade

  13. Rest myocardial perfusion in CAD • Physiological compensatory arteriolar dilatation in the region supplied by narrowed artery • Blood flow remains the same as in the region supplied by normal artery • Radiopharmaceutical distribution remains homogenous

  14. Stress myocardial perfusion in CAD • Arteriolar dilatation in the bed of normal artery for blood flow increase • Blood flow through the normal artery increases • Arteriolae in the bed of narrowed artery are already dilated - no further dilatation can occure, so blood flow remains as in the resting state • Non-homogenous perfusion (radiopharmaceutical distribution) as a result

  15. Ischemic cascade

  16. Type of stress • Mechanical dynamic stress • ergometer (bicycle), tread-mill • Pharmacological stress • vasodilators - adenosine, dipyridamole • positively inotropic drugs - dobutamine, arbutamine • atropine • Combined of all mentioned above

  17. Ergometer • Goal is to achieve at least 85% of maximal heart rate (220-age) or double-product more than 25000 • Increase by 50 (25) W after every 3 (2) minutes • Rate of pedalling 40 to 60 per minute • Radiopharmaceutical injection at peak stress • distribution proportional to blood flow at the time of injection • Maintain this stress for at least 1 to 2 minutes • Withdraw betablockers (BB), patient fasting

  18. Dipyridamole stress • Acts indirectly via the adenosin (block its removal) • Dilates coronary resistant arteries - it makes possible to assess coronary flow reserve • Maximal effect is achieved 3 to 4 minutes after stopping the 4 minutes infusion • Its effect can be stopped with theophyllines • withdraw them before the test • Usually used in patients using BB, unable to exercise, with LBBB

  19. Contraindications to perform dipyridamole stress • Patients with chronic obstructive pulmonary disease treated by theophyllines (dobutamine can be used) • Patients should avoid tee, cofee, cola before the test to prevent false negative results (insuficient or no vasodilation)

  20. Dipyridamole stress

  21. Side effects of dipyridamole • They occures in approximately 30% of patients • headache • neck tension • warm feeling • dizziness • nausea, hypotension • chest pain (very seldom)

  22. Performance of dipy stress • Dipyridamole applied by intravenous infusion • Usual dosage is 0.56 (0.75; 0.84) mg/kg • Dose is diluted with saline to 50 ml • to prevent local side effects (arm pain) • Duration of infusion is 4 minutes • If the patient is unable of any physical stress, tracer is injected 3-5 min. after stopping infusion

  23. Combined stress • Dipyridamole is infused according to previous rules to sitting or lying patient • 3 to 6 min. bicycle stress follows • better image quality • lower frequency of side effects • can be performed even in patients with hypotension • 1 to 2 min. before stopping bicycle stress radiopharmaceutical is injected

  24. Test arrangement • Right arm - tourniquet of tonometer • Left arm - infusion through the cannula • Saline is connected after stopping dipyridamole for venous link for the case of any complication • Patient is sitting on the ergometer, ECG electrodes according to Mason and Likar

  25. Dobutamine stress • If dipyridamole is contraindicated • Dobutamine intravenously in the dose of 5 to 10 g/kg/min., increase every 3 min. up to dose of 40 g/kg/min. • Monitore ECG, HR and BP, if 85% of maximal HR is not achieved, add Atropine • Radiopharmaceutical is injected 1 to 2 min. before stopping stress • Contraindications: ventricular tachycardia, severe hypertension, hypertrophic cardiomyopathy

  26. Myocardial perfusion protocols • One-day (Tl, Tc, FDG) - two-days (Tc, FDG, Tl) • Stress - rest or rest - stress (Tc, Tl-Tc) • Stress - (redistribution) - reinjection (Tl) • Stress - metabolism (Tc - FDG) • Stress - rest - metabolism (Tc, FDG) • Rest - redistribution - (late redistribution) (Tl) • Rest - metabolism (Tc - FDG)

  27. Radiopharmaceuticals for perfusion Tl-201 chlorid or Tc-99m MIBI for SPECT, N-13H3 or H2O-15 for PET Distribution in the myocardium rely on cells perfusion Tl-201 has redistribution Tc-99m MIBI does not have redistribution

  28. Data processing • Quantitative analysis of myocadial perfusion distribution • CEqual™ - uses pollar maps for standardization and comparison with „normals“ • Gated (synchronized) tomography (QGSPECT) • divides cardiac cycle into 8 periods • makes possible to evaluate mechanical function of the heart (ejection fraction - EF)

  29. Quantification of perfusion

  30. QGSPECT

  31. Basic patterns of myocardial perfusion imaging (MPI) • Normal finding • homogenous perfusion during stress as well as rest • Sign of ischemia • perfusion defect during stress which disappears on rest (reversible defect) • Sign of scar • perfusion defect on stress and rest (fixed defect) • Sign of ischemia and scar • combination of both mentioned above

  32. Main clinical indication of MPI • Detection of ischemic heart disease • Hemodynamic effect of coronary stenoses • Prognosis of patients with konwn CAD • Evaluation of revascularization effect and detection of restenosis • Risk stratification of patients after MI • Myocardial viability • Acute coronary syndromes • Cardiac risk in non-cardiac surgery

  33. Detection of CAD

  34. 66y old pt, atypical chest pain, ECHO difuse wall motion abnormality, Ao+mi reg, sci isch. of inferior wall, EF 40%

  35. Detection of CAD basic parameters • Planar Tl-201 scintigraphy - qualitative evaluatioin • Group of 4.678 pts - sens. 82%, spec. 88% • pts without MI - sens. 85% • pts after MI - sens. 99% • one-vessel disease - sens. 79% • two-vessel disease - sens. 88% • three vessel disease - sens. 92%

  36. Detection of CADbasic parameters • Referral bias • only patients with positive scintigraphy are referred to coronarography • patients with normal scintigraphy are not catheterized • higher sensitivity but decline of specificity • Normalcy rate (used instead of specificity) • negative scintigraphy in patients with very low pretest probabilty of CAD based on history, symptoms, stress ECG

  37. Detection of CAD basic parameters • SPECT Tl-201 scintigraphy • Group of 1.527 pts - sens. 90%, spec. 70% (more false positives due to artefacts), normalcy rate 89% • pts without MI - sens. 85% • pts after MI - sens. 99% • one-vessel disease - sens. 83% • two-vessel disease - sens. 93% • three-vessel disease - sens. 95%

  38. Detection of CAD basic parameters • SPECT Tl-201 scintigraphy • Group of 704 pts • stenosis of 50 to 70% - sens. 63% • stenosis of 75 to 100% - sens. 88% • Dipyridamole stress (1.272 pts) • sens. 87% • spec. 81%