Reversed mismatch on PET scan – Cardiology MCQ

Reversed mismatch on PET (Positron Emission Tomography) scan is seen in:

a) Left bundle branch block

b) Right ventricular pacing

c) Non ischemic cardiomyopathy

d) All of the above

Correct answer: d) All of the above

‘Reversed mismatch’ means normal perfusion, with reduced uptake of 18-fluoro-deoxy-glucose (FDG).

In addition to the above conditions, this situation can also be seen in the setting of revascularization early after myocardial infarction and sometimes in diabetes mellitus.

Usual perfusion-metabolism mismatch is reduced myocardial perfusion and contractile function in with relatively preserved or increased FDG uptake. It may be noted that ischemic myocardium switches over to glucose utilization instead of the usual fatty acid metabolism as glucose metabolism gives more ATP (adenosine tri phosphate) per oxygen molecule used. Tracers used to assess perfusion during PET scan include rubidium 82 and N-13 ammonia.


  1. Anavekar NS et al. Revascularization in Patients With Severe Left Ventricular Dysfunction. Is the Assessment of Viability Still Viable?J Am Coll Cardiol. 2016;67(24):2874-2887.