This document discusses myocardial perfusion imaging (MPI), a nuclear imaging technique used to detect coronary artery disease. It describes the indications for MPI, including detecting CAD, assessing stenosis, evaluating prognosis, and assessing medical therapy. Risk factors for CAD like smoking, obesity, and high cholesterol are outlined. The document details how CAD causes reduced blood flow and describes associated symptoms. Treatment options for CAD include drugs, angioplasty, stents, and bypass surgery. Imaging protocols and reconstruction techniques for MPI are also summarized.

1. Myocardial Perfusion Imaging SPECT
Basics
Imaging and Protocol Basics

2. Indications of MPI
 Detection of CAD
 Assessing functional significance of coronary
stenosis
 Evaluating prognosis and risk stratification
 Assessing medical therapy of CAD
 Assessing cardiac viability

3. Coronary Artery Disease
 Cardiovascular disease is the leading cause of death
in the United States
 Accounts for nearly 1 million deaths, half of which are the
result of CAD
 CAD is a condition in which the heart does not
receive enough blood
 Caused by accumulation of plaques in the coronary
arteries
 Causes stenosis of the lumen of the vessels
 Decreases ability of the walls of the affected vessels to
contract which inhibits cardiac function
 Occlusion of the vessels can also be caused by thrombus
or embolus in a coronary artery or an artery spasm

4. Risk Factors CAD
 High cholesterol
 High blood pressure
 Cigarette smoking
 Obesity
 Diabetes
 Sedentary lifestyle
 Family history of CAD
 Gender (more prevalent in males)

5. Symptoms of CAD
 Angina pectoris
 Transient pain or discomfort resulting from a temporary lack of
oxygen and nutrients to the heart muscle
 Myocardial Infarction
 A portion of the heart muscle dies resulting from inadequate
blood flow
 Changes the electrical activity of the heart
 Decreases contractility of heart in fibrous area
 Difficulty breathing
 Weakness
 Dizziness
 Perspiration
 CAD progresses over time and a person may be
asymptomatic in the early stages of the disease

6. Manifestations of CAD
 Before reaching > 70-80% vessel occlusion CAD
may have little or no effect on resting heart function
 When demands of the heart muscle are increased
diseased vessels cannot produce adequate blood
flow
 Coronary reserve: the ability to increase coronary
blood flow when needed
 Decreases in CAD due to increased metabolic demands
of the diseased vessels
 Patients with severe CAD will usually have
homogeneous resting regional myocardial blood flow
 Diminished blood flow at stress because of the
inability to increase blood flow when needed

7. Treatment of CAD
 Drug therapy
 Nitroglycerin
 Relaxes smooth muscle causing blood vessels to dilate
 Beta blockers
 Depress cardiac function and decrease cardiac output
 Cholesterol-lowering drugs
 Clot-dissolving agents
 Low-fat diet
 Exercise

8. Treatment of CAD
 CABG (coronary artery bypass graft)
 Blood vessels from one part of the body are used to
bypass a blocked region of a coronary artery to improve
blood supply to the affected area of the heart muscle
 PTCA (percutaneous transluminal coronary
angioplasty)
 Lumen of a stenotic vessel is dilated
 Atherectomy
 Obstructive plaque or thrombus is removed sing lasers or
mechanical devices
 Intracoronary stents

9. Patient Prep MPI Stress Test
 NPO 4 hours prior to test
 No caffeine within 24 hours
 Restrict cardiac medication if possible
 Consent for stress
 Pregnancy consent
 Skin prep/lead placement 12 lead EKG
 IV placement

10. Contraindications
 Pregnancy
 Food within 4 hours of stress study
 Caffeine within 24 hours (for pharmaceutical stress)
 Bronchospasm or severe obstructive lung disease
(for pharmaceutical stress)
 Hypotension (BP < 90)
 Xanthine-containing drugs

11. Protocols
 One-day
 Rest Thallium 3-5mCi/Stress Sestamibi or Tetrofosmin 20-
40mCi
 Rest Sestamibi or Tetrofosmin 10-15mCi/Stress
Sestamibi or Tetrofosmin 30-45mCi
 Two-day
 Stress Day 1
 25-45mCi Sestamibi or Tetrofosmin
 Rest Day 2 (if needed)
 25-45mCi Sestamibi or Tetrofosmin

12. Imaging Protocols maiCAM180
 Rest 30-40 seconds/step
 Stress 20-30 seconds a step
 16/32 steps 32/64 projections
 64x64 matrix
 Non-circular orbit
 Limiting patient motion is essential during acquisition
for quality images
 Movement can appear differently on upright imaging
systems than supine

13. Processing
 Set reconstruction limits on both
Rest and Stress cine data
Segami Mirage 5.715b is used for
demonstration purposes

14. Processing
 Reorient slices to appropriate angles

15. Processing
 Apply mask and post filtering if necessary

16. Reconstruction and Review Basics: Slice
Display
Planes of the heart that are
reconstructed in MPI are:
Horizontal Long Axis (HLA)
Short Axis (SA)
Vertical Long Axis (VLA)
Reconstructed data is viewed at
rest and stress, and the
corresponding planes and slices
are compared.
Intensity/color changes between
the two can represent ischemic
changes.
Count deficient areas that are
shared between the two can
represent fixed defects.

17. Reconstruction and Review Basics: Slice
Display

18. Reconstruction and Review Basics: Volume
Data
 3-D view of the heart that can be viewed from all
angles
 Gated data can be viewed as cine volume data to
assess wall motion
 Surface of the heart can be viewed separately or
simultaneously in both systole and diastole

19. Reconstruction and Review Basics: Volume
Data

20. Reconstruction and Review Basics:
Quantification
 Largely developed by Cedars Sinai Medical Center
(Los Angeles, CA) and Emory University (Atlanta,
GA)
 Polar Map or Bull's-eye of the left ventricle of the
heart
 Left ventricle is sliced from apex to base and
displayed in concentric ring; this allows the
visualization of the left ventricle in a comprehensive
image, rather than multiple images as with slice
displays

21. Reconstruction and Review Basics:
Quantification

22. References
 Nuclear Cardiac Imaging: Terminology and Technical
Aspects; Crawford and Husain; 2003; SNM
 Diagrams taken from Nuclear Cardiac Imaging:
Terminology and Technical Aspects; Crawford and
Husain; 2003; SNM
 Nuclear Cardiac images taken from MAI Demo
database using Cedars Sinai and Segami Mirage
processing applications