Cardiac amyloidosis nuclear cardiac scans

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]; Aarti Narayan, M.B.B.S [3]

Overview[edit | edit source]

The initial imaging modality imaging in patients with suspected cardiac amyloidosis is echocardiography. The diagnosis of ATTR cardiac amyloid can then be confirmed with a nuclear scan (99mTc-PYP imaging), which can then guide management.^[1]

Nuclear Cardiac Scans[edit | edit source]

99mTechnetium-pyrophopshate (99mTc-PYP) is a widely available radiotracer. In conjunction with a cardiac or chest SPECT, 99mTc-PYP is infused and then the images are examined for visual interpretation and quantification of the degree of myocardial uptake. Qualitatively, myocardial uptake patterns are either absent, focal, diffuse, or focal on diffuse. A diffuse pattern is suggestive of ATTR cardiac amyloid. Quantitatively, radiotracer uptake in the the region of interest (ROI) in the heart (H) is compared to uptake in the contralateral lung (CL) at 1 hour after tracer injection, which yields an H/CL ratio. A ratio of ≥1.5 is suggestive of ATTR cardiac amyloid. Alternatively, uptake in the ROI can be visually compared to the rib at 3 hours after tracer injection, with a visual score grade of >2 (indicating uptake equal to that of the rib) suggestive of ATTR cardiac amyloid.^[2]

References[edit | edit source]

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