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What is Best scan for assessing myocardial viability: and explain in detail?
Ref: Harrison's Principles of Internal Medicine, 18th edition,, pg 1846Explanation:* Nuclear (or radionuclide) imaging requires intravenous administration of radiopharmaceutical s which undergoes uptake in specific organs & radiation is emitted in the form of photons (gamma rays). The two most commonly used technologies in clinical nuclear cardiology are single- photon emission computed tomography (SPECT) and positron emission tomography (PET). (See the following table)The PET FDG (positron emitting tracer F-18 flurodeoxyglucose) asseses myocardial viabilityUses Rubidium 82, N-13 ammoniaIt measures myocardial glucose metabolism after oral glucoseIschemic/hibernating myocardium show increased FDG uptake - 'flow/metabolism mismatchIdentifies areas of myocardium likely to improve after revascularizationCan calculate LV systolic function & volumesBetter image quality compared to SPECT (Single photon emission computed tomography)SPECT with ThaI201/ Tc99m needs viable myocardial cells for uptake, does not identify hibernating myocardium.'