CARDIOLOGY IMAGING Flashcards
(47 cards)
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
Q: How long does a patient lie with their hands above their head during the perfusion part of a Myocardial Perfusion study, and why?
A: The patient lies with their hands above their head for about 20 minutes to prevent attenuation, which is corrected with CT attenuation correction.
Q: How is the Left Ventricular Ejection Fraction (LVEF) calculated in the ventriculogram part of a Myocardial Perfusion study?
A: The computer calculates LVEF using heart wall movement to determine end-diastolic and end-systolic volumes, provided there is no AF.
Q: What is the normal flow of blood and radioactivity through the central circulation?
A: Superior vena cava (SVC) → Right atrium (RA) → Right ventricle (RV) → Pulmonary artery → Lungs → Left atrium (LA) → Left ventricle (LV) → Aorta → Systemic circulation.
Q: What are examples of central shunts that can affect blood and radioactivity flow in the heart?
Patent Ductus Arteriosus (PDA)
Atrial Septal Defect (ASD)
Ventricular Septal Defect (VSD)
Q: How does a Ventricular Septal Defect (VSD) affect the flow of radioactivity in the heart?
A: Radioactivity flows normally through the central circulation, but part recirculates back to the RV and pulmonary artery instead of fully moving into systemic circulation.
part of the radio-activity to system
Q: How does an Atrial Septal Defect (ASD) affect the flow of radioactivity in the heart?
A: With an ASD, radioactivity flows normally from the SVC to the RA, RV, and lungs, then to the LA. However, part of the radioactivity flows to the LV, while another part recirculates back to the RA, RV, and pulmonary arteries.
