A combined “in vivo” noninvasive evaluation of carotid plaques using ultrasonography and high-resolution magnetic resonance - new insight into plaque burden and vulnerability

Abstract. Background: Qualitative change in carotid plaques was prospectively evaluated by Gray Scale Median (GSM) analysis at repeated examinations “in vivo”, in relation to quantitative change in carotid arterial geometry, as assessed by high-resolution magnetic resonance imaging (HR-MRI). Patients and methods: Duplex ultrasound with GSM analysis and HR-MRI at the carotid level were performed at baseline and 1- and 2-year follow up in 30 patients with < 70% carotid stenosis. Changes in GSM values (ΔGSM) were evaluated as the intra-individual difference between 2-year and baseline values. HR-MRI studies were evaluated for lumen area (LA), total vessel area (TVA), vessel wall area (VWA = TVA-LA) and normalized wall index (NWI = VWA/TVA). Results: ΔGSM value distribution was divided into quartiles. Predominantly echolucent plaques with ΔGSM value in the lowest quartile (ΔGSM ≤- 8) showed a significantly greater mean 2-year LA (28.62 ± 10.9 mm2 vs. 17.88 ± 4.8 mm2, p = 0.04) and a greater mean 2-year TVA (8...