Metabolic and densitometric correlation between atherosclerotic plaque and trabecular bone: an ¹⁸F-Natrium-Fluoride...

Increasing evidence links atherosclerosis to a decreased bone thickness. This correlation could reflect a bone/plaque interaction. Hereby we analyzed Hounsfield density (HU) and mineral turnover in bone and in the arterial calcifications (AC), using a computational method applied to PET/CT data. 79 ¹⁸F-NaF PET/CT from patients with AC were retrospectively analyzed. Mean AC density and background-corrected uptake (TBR) were estimated after semi-automatic isocontour segmentation. The same values were assessed in the trabecular bone, using an automatic adaptive thresholding method. Patients were then stratified into terciles, according to their mean HU plaque density ("light", "medium" or "heavy" calcifications"). 35 ¹⁸F-NaF PET/CT from patients without AC served as controls. Vertebral density and TBR were lower in patients than in controls (137±25 vs. 160±14 HU, P<0.001); (6.2±3.9 vs. 8.4±3.4, P<0.05). Mean trabecular TBR values were 8.3±4, 4.5±2.1 and 3.5±1.8 in light, medium and heavy AC groups, respectively (P<0.05 for light vs. medium and P<0.01 for light vs. heavy). Similarly, mean trabecular HU was 143±19, 127±26 and 119±18 in the three groups, respectively (P<0.01 for light vs. heavy). Mean AC density was inversely associated with the trabecular HU (R=-0.56, P<0.01). Conversely, plaques' TBR directly correlated with the one in trabecular bone (R=0.63, P<0.001). At multivariate analysis, the sole predictor of vertebral density was plaque HU (P<0.05). Our data highlight a correlation between plaque and bone morpho-functional parameters and suggest that observing skeletal bone characteristics could represent a novel window on atherosclerosis pathophysiology.