Which test is performed to detect reversible myocardial ischemia?

Ans. is 'c' i.e. Thallium scan Assessment of myocardial perfusion using nuclear imaging techniques is being widely used for evaluation of Ischemic heart disease. The radioisotopes injected are thallium, sestamibiProcedureRadioisotopes are injected at rest and during stress (exercise) to produce images of myocardiumThe degree of uptake is directly proportional to blood flow.Principle - The images of myocardium is produced proportional to the uptake of regional blood flow. During stress the blood flow to an area is increased upto five times above the resting condition. But in the case of coronary artery stenosis the blood supply to the area supplied by the stenosed artery will not increase proportionately so the isotope uptake will be low and an area of hypoperfusion appear.In case of thallium what happens is that over the next several hours a complex process occurs that is known as redistribution'. Due to this process thallium continues to pour in the hypoperfused area and the final result is that an area which initially appeared as an area of reduced uptake becomes apparently normal over time.Note - In region of fibrosis (infarction or dead tissue) there will be no redistribution on delayed imaging.