![Quantification of Atherosclerotic Plaque Activity and Vascular Inflammation using [18-F] Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography FDG-PET/CT](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F3777.jpg&w=3840&q=50)
18F-fluoride PET/MR in cardiac amyloid: A comparison study with aortic stenosis and age- and sex-matched controls
Jack P M Andrews1, Maria Giovanni Trivieri2,3, Russell Everett4
1British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Room SU.305, Chancellor's building, 51 Little France Crescent, Edinburgh, EH16 4SB, UK. jack.andrews@ed.ac.uk.
Objectives:
Cardiac MR is widely used to diagnose cardiac amyloid, but cannot differentiate AL and ATTR subtypes: an important distinction given their differing treatments and prognoses. We used PET/MR imaging to quantify myocardial uptake of 18F-fluoride in ATTR and AL amyloid patients, as well as participants with aortic stenosis and age/sex-matched controls.
Methods:
In this prospective multicenter study, patients were recruited in Edinburgh and New York and underwent 18F-fluoride PET/MR imaging. Standardized volumes of interest were drawn in the septum and areas of late gadolinium enhancement to derive myocardial standardized uptake values (SUV) and tissue-to-background ratio (TBRMEAN) after correction for blood pool activity in the right atrium.
Results:
53 patients were scanned: 18 with cardiac amyloid (10 ATTR and 8 AL), 13 controls, and 22 with aortic stenosis. No differences in myocardial TBR values were observed between participants scanned in Edinburgh and New York. Mean myocardial TBRMEAN values in ATTR amyloid (1.13 ± 0.16) were higher than controls (0.84 ± 0.11, P = .0006), aortic stenosis (0.73 ± 0.12, P < .0001), and those with AL amyloid (0.96 ± 0.08, P = .01). TBRMEAN values within areas of late gadolinium enhancement provided discrimination between patients with ATTR (1.36 ± 0.23) and all other groups (e.g., AL [1.06 ± 0.07, P = .003]). A TBRMEAN threshold >1.14 in areas of LGE demonstrated 100% sensitivity (CI 72.25 to 100%) and 100% specificity (CI 67.56 to 100%) for ATTR compared to AL amyloid (AUC 1, P = .0004).
Conclusion:
Quantitative 18F-fluoride PET/MR imaging can distinguish ATTR amyloid from other similar phenotypes and holds promise in improving the diagnosis of this condition.
Insights
18F-fluoride PET/MR imaging can differentiate transthyretin amyloid cardiomyopathy (ATTR) from light-chain amyloidosis (AL). This quantitative imaging approach shows promise for improving the diagnosis of cardiac amyloidosis.
Area of Science:
- Cardiovascular Imaging
- Nuclear Medicine
- Radiochemistry
Background:
- Cardiac magnetic resonance (MR) is used for cardiac amyloid diagnosis but cannot distinguish between AL and ATTR subtypes.
- Accurate differentiation is crucial due to differing treatments and prognoses for AL and ATTR amyloidosis.
Purpose of the Study:
- To evaluate the utility of 18F-fluoride PET/MR imaging in quantifying myocardial uptake and differentiating cardiac amyloid subtypes.
- To assess the diagnostic performance of 18F-fluoride uptake in distinguishing ATTR amyloid from AL amyloid and other cardiac conditions.
Main Methods:
- A prospective multicenter study involving 53 patients (18 cardiac amyloid, 13 controls, 22 aortic stenosis) who underwent 18F-fluoride PET/MR imaging.
- Myocardial standardized uptake values (SUV) and tissue-to-background ratio (TBRMEAN) were derived from the septum and late gadolinium enhancement (LGE) regions.
- Blood pool activity was corrected using the right atrium to calculate TBRMEAN.
Main Results:
- Mean myocardial TBRMEAN was significantly higher in ATTR amyloid patients (1.13 ± 0.16) compared to controls (0.84 ± 0.11), aortic stenosis (0.73 ± 0.12), and AL amyloid (0.96 ± 0.08).
- TBRMEAN values within LGE regions further discriminated between ATTR (1.36 ± 0.23) and AL amyloid (1.06 ± 0.07).
- A TBRMEAN threshold >1.14 in LGE areas achieved 100% sensitivity and specificity for differentiating ATTR from AL amyloid.
Conclusions:
- Quantitative 18F-fluoride PET/MR imaging effectively distinguishes ATTR amyloid from other cardiac phenotypes, including AL amyloid.
- This imaging modality holds significant promise for improving the diagnostic accuracy of transthyretin amyloid cardiomyopathy.
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