CARDIOLOGY IMAGING Flashcards
What are the advantages of Myocardial Perfusion studies?
A: Myocardial Perfusion studies are non-invasive, safe, and cheaper than an angiogram.
Q: What two main types of information does a Myocardial Perfusion study provide?
A: It provides information on 1) Myocardial perfusion and 2) the function of the left ventricle (LV).
Q: What are the two parts of a Myocardial Perfusion study?
A: The study consists of 1) the Myocardial Perfusion part and 2) the Ventriculogram part.
Q: Which medications can influence heart rate in a Myocardial Perfusion study?
A: β-blockers and ACE inhibitors (Angiotensin-Converting Enzyme Inhibitors) can influence heart rate.
What happens to the calculation of Left Ventricular Ejection Fraction (LVEF) in the presence of atrial fibrillation (AF) or dysrhythmia?
A: The LVEF calculation becomes inaccurate because data collection uses an ECG with the R-wave as a trigger, which AF or dysrhythmia disrupts. However, visual evaluation can still provide information.
Q: Does atrial fibrillation (AF) or dysrhythmia affect the perfusion part of a Myocardial Perfusion study?
A: No, AF or dysrhythmia does not affect the perfusion part; it only influences the LVEF calculation.
What radionuclide and carrier are used in Myocardial Perfusion studies?
A: Technetium (99mTc) is used as the radionuclide, and Isonitrile compound (sestaMIBI) acts as the carrier, specifically 99mTc-sestaMIBI.
Q: What two factors determine the uptake of radionuclide into myocardial cells in Myocardial Perfusion studies?
A: Blood flow and the viability (metabolism) of myocardial cells.
What is attenuation in Myocardial Perfusion studies?
A: Attenuation is the interference of overlying soft tissue or nearby organs that may cause false positive or negative defects, commonly affecting the inferior wall.
Q: Which organs commonly cause attenuation defects in Myocardial Perfusion studies?
A: The breast (in females and obese males), diaphragm (mainly in men), gastrointestinal tract (GIT), and liver.
Q: How can attenuation defects be corrected in Myocardial Perfusion studies?
A: - Patient: Drinking two glasses of water or eating a “fatty meal”
Radiographer: Binding the breast
Equipment: Using CT attenuation correction.
Q: What is the purpose of CT in Myocardial Perfusion studies?
A: CT is used for attenuation correction rather than anatomical imaging.
What are the indications for Myocardial Perfusion studies?
.
A: - Redistribution indicates ischemia
Fixed defect indicates a previous myocardial infarction.
Q: Why is only the left ventricle (LV) imaged in Myocardial Perfusion studies?
A: Because of the thickness of the left ventricular muscle wall. If the right ventricle is visible, it may indicate right ventricular hypertrophy.
Q: What does a “cold” area on stress images in Myocardial Perfusion studies indicate?
A: A cold area (decreased radionuclide uptake) indicates a perfusion defect. If it fills in during the “at rest” study, it shows redistribution (ischemia). If it remains the same, it indicates a fixed defect (previous myocardial infarction).
Q: What is evaluated in the ventriculogram part of a Myocardial Perfusion study?
A: The ventriculogram part evaluates heart muscle movement dynamically to calculate left ventricular ejection fraction (LVEF) by assessing volumes during end-diastole and end-systole.
Q: What is the purpose of visually evaluating the ventriculogram images in Myocardial Perfusion studies?
A: Visual evaluation helps confirm the findings from the perfusion images.
What are relative contraindications for the perfusion and ventriculogram parts of a Myocardial Perfusion study?
A:
Perfusion part: β-blocker and ACE inhibitors (ACEI)
Ventriculogram part: Atrial fibrillation (AF) or dysrhythmia