Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Cardiac amyloidosis other imaging findings
Introduction
Overview
Overview
The initial imaging modality used 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 the management.
Other Imaging Findings
Other Imaging Findings
Nuclear Cardiac Scanning
- 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.[1]
- 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 the uptake in the contralateral lung (CL) at 1 hour after tracer injection, which yields an H/CL ratio.
- A H/CL 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]
Targeted imaging
- Direct detection of amyloid fibrils is possible using molecular imaging using amyloid-binding PET tracers, such as:
- 11-Pittsburgh compound-B
- F-18-florbetapir
- F-18-florbetaben
- Using these PET tracers enables to:
- Measure global and regional amyloid burden deposited in the myocardium
- Detect molecular changes in the fibril composition
- Tracer uptake can be assessed visually or using a number of indexes such as: target to-background ratio, myocardial retention index, and myocardial standardized uptake value.
- These tracers might provide the opportunity to evaluate cardiac and systemic amyloid deposits throughout the whole body (for example in AL amyloidosis)
References
References
- ↑ Falk, RH (May 2014). “How to image cardiac amyloidosis”. Circulation: Cardiovascular Imaging. 7: 552–562.
- ↑ “ASNC Practice Points: 99mTechnetium-Pyrophosphate Imaging for Transthyretin Cardiac Amyloidosis” (PDF).
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mandana Chitsazan, M.D. [2] Raviteja Guddeti, M.B.B.S. [3] Aarti Narayan, M.B.B.S [4]