Objective: two ultrasound systems (QAS, Esaote; and E-Track, Aloka) provide radio-frequency (RF)-based tracking of carotid wall, allowing real-time determination of vessel diameter, distension, and stiffness (CS). Measurement is performed in a single line by E-Track and in 16 equidistant lines by QAS.

Aim: to evaluate whether measures of CS with the two systems are comparable and to assess intra- and interoperator variability.

Methods: MyLab 70 (Esaote) and Alpha 7 (Aloka) were used in random order to measure right CCA diameter and distension, and to calculate distensibility coefficient (DC) in 173 subjects (5 groups: 21 controls (NL), 35 prehypertensives (PHBP), 23 hypertensives (HBP), 27 type 2 diabetics (DM) and 67 HIV-positive patients. In 30 subjects, the study was repeated after 60-min, both by the same and by another operator.

Results: correlation coefficients between the two systems for CCA diameter, distension and DC were high (r=0.84, 0.90 and 0.87, p<0.0001). QAS provided significantly (P<0.001) higher CCA diameter and lower distension and DC than E-track (7.58±1.07 vs. 7.35±1.00 mm; 378±146 vs. 447±154 μm; and 0.35±0.17 vs. 0.44±0.19 kPa). In the 5 study groups, DC obtained with QAS and E-Track discriminated among them with similar statistical significance. Intra- and inter-operator variability for CCA distension was 7.5±4.6% and 9.0±6.9% with QAS and 9.8±8.5% and 12.4±649% with E-Track.

Conclusions: measures of CS with QAS and E-Track are correlated and equally effective to discriminate diseased populations. Yet, CS values are higher with QAS, and therefore the systems are not interchangeable