Hybrid PET/MRI Detects Arterial Inflammation in Subclinical Atherosclerosis

Inflammation may occur prior to plaque formation in middle-age individuals with heart disease or heart disease risk factors, the results of a new study suggest. The study also identified ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/magnetic resonance imaging (PET/MRI) as an effective method for identifying arterial inflammation in these patients. The study findings were published in the Journal of the American College of Cardiology.

A total of 755 individuals with known subclinical atherosclerosis and between the age of 40 and 54 underwent carotid, aortic, and ilio-femoral 18F-FDG PET/MRI.

Participants were enrolled from the observational PESA-CNIC (Progression of Early Subclinical Atherosclerosis–Centro Nacional de Investigaciones Cardiovasculares)-Santander study. Measurements were taken at baseline and at 3 and 6 years. At each follow-up visit, investigators examined the presence, distribution, and number of arterial inflammatory plaques and foci in the presence of or without inflammation.

Almost half (48.2%) of PESA-CNIC participants had arterial inflammation, which was present in femoral arteries (24.4%), aorta (19.3%), carotid arteries (15.8%), and iliac arteries (9.3%). Approximately 90% of participants had plaques (femoral arteries [73.9%], iliac arteries [55.8%], and carotids [53.1%]).

The presence of cardiovascular risk factors was associated with increases in ¹⁸F-FDG arterial uptakes and plaques, demonstrating an increase in arterial inflammation (P <.01).

Up to 11% of plaques did or did not demonstrate inflammation, and 61.5% of coincident ¹⁸F-FDG arterial uptakes were identified in plaque-free arterial segments. In addition,  a higher plaque burden was observed in participants with vs without arterial inflammation (P <.01).

There was also a positive correlation between the number of plaques and ¹⁸F-FDG arterial uptakes (P <.001).

Limitations of the analysis include the cross-sectional design, as well as the inclusion of relatively young patients.

“These findings demonstrate the potential for in vivo imaging of systemic atherosclerosis-related inflammation, its study at early stages, and the identification of individuals likely to benefit from early intervention,” the researchers wrote.

Reference

Fernández-Friera L, Fuster V, López-Melgar B, et al. Vascular Inflammation in subclinical atherosclerosis detected by hybrid PET/MRI. J Am Coll Cardiol. 2019;73(12):1371-1382.