Comparison of automatic intima media thickness measurement and eye balling.

摘要

Compound Imaging is an ultrasound technique that scans up to 9 lines of sight and combines them in real time. This technique may improve ultrasound evaluations of intima media thickness (IMT) and carotid plaque echomorphology due to less shadowing and reverberations [1, 2]. Automated programs to assess IMT are used to make the measurements more objective and reproducible, as compared to human observers. Ultrasound settings significantly alter IMT measurements [3]. We wanted to compare different manual and semi-automated ultrasound techniques of IMT assessment, including compound imaging.We investigated both end-diastolic far wall IMT of the common carotid arteries of 163 ischaemic stroke/TIA patients from our stroke unit (102 men, 61 women, mean age 62 years) using the HDI 5000 (Philips, The Netherlands) colour duplex and the software version HDI Lab 2.0. The following modalities were used: (1) the arithmetic mean of 3 measurements (1.0,1.5 and 2 cm proxi-mally to the bifurcation) using the cursors of the software. (2) As in '1' but using the compound imaging function. (3) The software itself calculated (offline) the IMT over the above-mentioned segment of 1 cm, transposing the longitudinal picture into a cross-sectional 2-dimensional picture of ultrasound intensities. On this latter picture, the software automatically put cursors at the points of interest. (4) As in '3' using compound imaging. (5) Using the same frame as in '3', the cursors were adjusted if the investigator felt they were not placed correctly. (6) As in '5' using compound imaging. The second investigator used the identical frozen picture for '1' and '2'; however, for '3-6' he could also choose a different end-diastolic position.