Table 3.

Potential causes of inconsistencies between planar ^99mTc‐PYP scintigraphy and biopsy findings in suspected ATTR‐CM

Planar 99mTc‐PYP scintigraphy	Biopsy	Potential causes of inconsistencies
Positive	Negative	Sampling errors in biopsy Errors in scintigraphy imaging time or evaluation Errors in pathological diagnosis Cardiac pools Deposit of proteins other than transthyretin (e.g. AL)
Negative	Positive	Errors in scintigraphy evaluation Errors in pathological diagnosis Deposit of proteins other than transthyretin (e.g. AL) ATTRv‐CM with a low sensitivity in 99mTc‐PYP scintigraphy (Ser77Tyr or Phe64Leu mutation)