Cardiac amyloidosis other imaging findings: Difference between revisions
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* Quantitatively, [[radiotracer]] uptake in the the region of interest (ROI) in the heart (H) is compared to the uptake in the [[Anatomical terms of location|contralateral]] [[lung]] (CL) at 1 hour after [[Radiotracer|tracer]] [[Injection (medicine)|injection]], which yields an H/CL ratio. | * Quantitatively, [[radiotracer]] uptake in the the region of interest (ROI) in the heart (H) is compared to the uptake in the [[Anatomical terms of location|contralateral]] [[lung]] (CL) at 1 hour after [[Radiotracer|tracer]] [[Injection (medicine)|injection]], which yields an H/CL ratio. | ||
* A H/CL ratio of ≥ 1.5 is suggestive of ATTR cardiac amyloid. | * 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 [[Radiotracer|tracer]] [[Injection (medicine)|injection]], with a visual score grade of > 2 (indicating uptake equal to that of the [[rib]]) suggestive of ATTR cardiac amyloid.<ref>{{Cite web|url=https://www.asnc.org/Files/Practice%20Resources/Practice%20Points/ASNC%20Practice%20Point-99mTechnetiumPyrophosphateImaging2016.pdf|title=ASNC Practice Points: 99mTechnetium-Pyrophosphate Imaging for Transthyretin Cardiac Amyloidosis|last=|first=|date=|website=|archive-url=|archive-date=|dead-url=|access-date=}}</ref> | * Alternatively, uptake in the ROI can be visually compared to the [[rib]] at 3 hours after [[Radiotracer|tracer]] [[Injection (medicine)|injection]], with a visual score grade of > 2 (indicating uptake equal to that of the [[rib]]) suggestive of ATTR cardiac amyloid.<ref>{{Cite web|url=https://www.asnc.org/Files/Practice%20Resources/Practice%20Points/ASNC%20Practice%20Point-99mTechnetiumPyrophosphateImaging2016.pdf|title=ASNC Practice Points: 99mTechnetium-Pyrophosphate Imaging for Transthyretin Cardiac Amyloidosis|last=|first=|date=|website=|archive-url=|archive-date=|dead-url=|access-date=}}</ref> | ||
===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== | ||
{{reflist|2}} | {{reflist|2}} | ||
Revision as of 17:33, 31 October 2019
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Cardiac amyloidosis Microchapters |
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Cardiac amyloidosis other imaging findings On the Web |
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American Roentgen Ray Society Images of Cardiac amyloidosis other imaging findings |
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Risk calculators and risk factors for Cardiac amyloidosis other imaging findings |
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
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
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
- ↑ 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).