Doctors order a cardiac perfusion scan to examine the cause of chest pain or chest pressure, diagnose coronary artery disease, determine appropriate treatment for a coronary artery disease patient or detect a congenital heart defect, explains WebMD. Doctors also order the test to assess proper blood flow to the heart and determine the extent of heart muscle damage following a heart attack. Another reason to perform a cardiac perfusion scan is to check the blood flow following heart surgery.
A cardiac perfusion scan involves intravenously administering a radioactive tracer, which enters the heart through the blood, and taking images of the patient's heart after absorption of the tracer by heart regions with adequate blood circulation, states WebMD. Heart areas with insufficient blood flow cannot absorb the tracer. Improper blood flow sometimes results from damage due to a heart attack.
The scan produces one set of images while the patient rests and creates another set after after exercise or medication intake stress the patient's heart, notes WebMD. The doctor compares both sets to evaluate the condition of the heart.
Preparation for a cardiac perfusion scan involves not eating or drinking at least three hours before the test, reports WebMD. Patients should also avoid over-the-counter medications, caffeinated drinks, alcoholic beverages and tobacco 24 hours prior to a cardiac perfusion scan that involves a stress scan.