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. 2022 Jun 6;9(4):2764–2765. doi: 10.1002/ehf2.14007

Table 2.

Typical false‐positive and false‐negative cases in planar 99mTc‐PYP scintigraphy for the diagnosis of ATTR‐CM

Planar 99mTc‐PYP scintigraphy results Potential causes of false results
False positive

  • Recent myocardial infarction (<4 weeks)

  • Rib fractures and valvular/annular calcifications

  • AL amyloidosis

  • AApoAI, AApoAII, AApoAIV, and Aβ2M

  • Hypertrophic cardiomyopathy

  • Hydroxychloroquine toxicity

  • Cardiac blood pool

  • Intravenous iron injections
False negative

  • Insufficient amount of amyloid deposits

  • Delayed or premature acquisition in 99m Tc‐PYP scintigraphy

  • ATTRv‐CM with a low sensitivity in scintigraphy (Ser77Tyr or Phe64Leu mutation)

  • Initial diagnosis of cardiac pools with myocardial deposits