1 / 34

Nuclear Cardiology: Myocardial Perfusion Studies and Ventriculography

Nuclear Cardiology: Myocardial Perfusion Studies and Ventriculography . Croft Stone Nuclear Medicine. Basics of MPI. Radionuclide injected at rest and/or stress Radionuclide taken up by myocardium and gamma rays emitted Rest images compared with stress images

alia
Télécharger la présentation

Nuclear Cardiology: Myocardial Perfusion Studies and Ventriculography

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Nuclear Cardiology:Myocardial Perfusion Studies and Ventriculography Croft Stone Nuclear Medicine

  2. Basics of MPI • Radionuclide injected at rest and/or stress • Radionuclide taken up by myocardium and gamma rays emitted • Rest images compared with stress images • Decreased perfusion stress and rest – MI • Decreased perfusion at stress, normal with rest – ischemia • Area indicates the coronary artery, size correlates with severity of CAD

  3. Basics • Two conditions necessary for blood flow deficit measurement: • 1) coronary flow must be elevated to near maximal levels • 2) radiotracer whose myocardial extraction is proportional to coronary artery blood flow must be used

  4. Stress • Exercise and pharmacologic agents are used to achieve maximal coronary dilation and flow. • Exercise stress gives additional information: • Degree of exercise tolerance • Time to maximal heart rate • Blood pressure response

  5. Pharmacologic stress • Agents: • Dipyridamole (persantine) • Dobutamine • Adenosine

  6. Indications for Pharmacologic Stress Imaging • Inability to perform adequate exercise • Left bundle branch block • Ventricular pacemaker • CCB’s or Beta blockers • Evaluation of patients very early after acute MI (<3 days) or very early after stenting (<2 weeks)

  7. Physics • Radioactive decay • Alpha particles (ionized helium nuclei) • Beta particles (high energy electrons or positrons) • Gamma rays (photons) • Electron capture (x-rays)

  8. Gamma Camera

  9. Camera • Multiple images taken at different rotation angles to obtain 3-D information • Lead collimator excludes photons not traveling in direction of holes in the collimator • 3-D picture can be reconstructed using a mathematical model • Projection system modeled as system of simultaneous linear equations; matrix is then inverted to reveal the source distribution.

  10. Protocols

  11. Radionuclide Properties

  12. Comparison of 201Tl and 99mTc for Myocardial Perfusion Imaging

  13. Tc-99m • Technetium chelated to to a molecule that will be absorbed by the myocardium • Tc-99m-methoxyisobutyl (setamibi) • Tc-99m 1,2bis[bis (2-ethoxyethyl)phosphinoethane (tetrofosmin) • During stress, metabolism changes polarization of cell membrane, driving agent into cell • Also readily absorbed by liver and bowel

  14. Tc-99m preparation

  15. Tc-99m

  16. Quality control • 1.Motion -- There is no evidence of patient motion.2.Alignment --The alignment is very good.3.Count Increase --The myocardial max counts increases in the stress study as expected.4.Normalization --Both studies are normalized to the portion within the myocardium with the highest uptake.5.Extra-Cardiac Activity --There is no significant extra cardiac activity.6.Soft tissue attenuation– minimized • 7. Protocol consistency

  17. Simultaneous assessment of perfusion and function in a single injection, single acquisition sequence. Tc-99m permits evaluation of regional myocardial wall motion and wall thickening throughout the cardiac cycle Quantitates LV volume and EF ECG Gated SPECT imaging(MUGA: multi gated acquisition)

  18. Technique • Stannous pyrophosphate injected • Tc-sodium pertechnetate injected • Pertechnetate enters RBC’s, becomes reduced by the intracellular stannous ion, and is bound to hemoglobin • RBC’s now “tagged” with radioisotope: hence “blood pool” image

  19. Technique • Images of heart are triggered (gated) on the R wave of the ECG • 32 or more frames taken per cardiac cycle • Many cardiac cycles imaged and stored for statistical significance • Total amount of activity stored in frames at each gated time point plotted vs. total time cycle

  20. Technique • Heart rate variations can result in temporal blurring (mixing of counts in adjacent frames). • Beat rejection window usually set at 20%

  21. Sources • Cerqueira, Manuel D. Nuclear Cardiology, 1994, pp 93 – 100, 103-109. • Crean, Andrew and Coulden, Richard. Cardiac Imaging using nuclear medicine and positron emission tomography. Radiologic Clinics of North America, 42 (2004) 619-634 • Heller,Gary V. and Hendel, Robert C. Nuclear Cardiology: Practical Applications, 2004. pp 1-312. • Kowalsky, Richard J. and Falen, Steven W. Radiopharmaceuticals in Nuclear Medicine and Nuclear Pharmacy, 2004: pp 515 – 555.

More Related