CAROTID INTIMA-MEDIA THICKNESS MEASUREMENT: ARE THERE DIFFERENCES BETWEEN AUTOMATIC VS. MANUAL MEASUREMENTS?

Objective: Increased carotid intima-media thickness (IMT) is a recognized early marker of atherosclerosis and cardiovascular risk, as well as a predictor of events. Manual or automatic measurements are the method used to assess wall thickness. Objective: To evaluate whether there were differences between both measurements for determining the IMT. Design and method: 1321 carotid ultrasounds of patients were analyzed; mean age: 66.8 years and 51% women. The average number of measurements made by the automatic measurements (AIMM) was 315 using the VIVIS 5 GE ultrasound software, while the manual measuremets (MIMM) were six (6) using the same probe. The posterior wall of both common carotid arteries was scanned 1 cm from the bifurcation and in a segment of 20 mm extension, taking as valid the highest average value obtained in any of the carotid arteries. A normal maximum thickness was considered up to a value of 0.10 mm. Statistical analysis: A descriptive analysis was performed through frequency tables and summary measurements. Univariate and multivariate linear models were applied. Results: The mean AIMM was 0.766 and the MIMM was 0.761, p < 0.001, indicating that AIMM are mild but significantly higher than MIMM. (p = 0.001) Regarding abnormal values, 96 (7.3%) were detected using AIMM, while 86 (6.5%) were using MIMM (p = 0.033) Differences were also observed in relation to sex, where AIMM were significantly higher in men (p = 0.0164) and with increasing age (p = 0.0062). The average IMT performed using AIMM was significantly higher than that performed using MIMM, as well as for detecting abnormal values, > 0.10 mm, and in turn, they identified a greater thickness in men in relation to women and with increasing age. The differences could be explained by the greater number of measurements performed with AIMM, while MIMM very operator-dependent. Conclusions: If possible, the automatic measurements should be used to assess carotid intima-media thickness.