u/ScaleBlind

Approximate effective doses, and they are far enough apart to change what u order.

Tc-99m sestamibi rest and stress, one day protocol: roughly 8 to 12 mSv
Thallium-201: roughly 15 to 20 mSv, the highest of the common studies, because the photon energy is low and the half life is long
Rubidium-82 PET: roughly 3 to 5 mSv
N-13 ammonia PET: roughly 2 mSv

A stress first strategy, imaging only if the stress images are abnormal, removes the rest injection entirely in the pts who need it least.

Thallium carries the highest dose and gets reserved for the question only it answers, which is viability through redistribution.

E wave alone moves with preload, so it tells u very little on its own.

Septal e prime under 7 cm/s or lateral under 10 cm/s says the myocardium relaxes poorly. That is the abnormality. E over e prime then estimates filling pressure on top of it.

Average E over e prime above 14 points to raised LA pressure. Under 8 argues against it. Between them the study needs the other three: TR velocity over 2.8 m/s, LA volume index over 34 mL/m2, and the mitral inflow pattern.

Two of three abnormal means raised filling pressures. One of three is indeterminate and stays indeterminate on the report.

The algorithm breaks in atrial fibrillation, significant mitral disease, heavy annular calcification and after a mitral valve procedure.

A place to discuss interesting cases, echocardiography, nuclear cardiology, cardiac CT, CMR, imaging guidelines, new research, and real-world interpretation challenges. I’d also like it to be useful for board preparation, with practice questions, exam-focused discussions, educational resources, and teaching points.