Fibromuscular dysplasia (FMD) is a non-atherosclerotic non-inflammatory arterial disease of unknown origin. We previously showed the presence of triple signal (TS) at ultrasound within common carotid artery (CCA) wall. We aimed at coupling TS presence with microconstituents of the vessel wall. We included 50 patients with multifocal FMD, 50 essential hypertensive (HT) patients and 50 healthy subjects (HS) matched for age, sex, ethnicity and BP (HT and FMD). TS score from the right and left CCA were assessed from 15-MHz echotracking system coupled with aplanation tonometry. 14 microconstituents of the CCA, representing geometry, perivascular tethering, and wall material coefficients were derived from fitting of the pressure-diameter curve. In multivariate analysis, age, hypercholesterolemia and IMT were significantly associated with TS, explaining 9.5% of its variance. TS was more frequent in FMD than HS (49% vs 16%, p