Evaluation of off-line automated intima-media thickness detection of the common carotid artery based on M-line signal processing

Intima-media thickness (IMT) measurements have gained increasing attention, because IMT is assumed to represent the endothelial adaptive response to p hysiological and pathophysiological processes, The main aim of the present study was to assess the intrasubject intrasession variability of a new off- line automated radio frequency (RF) IMT method in comparison with an alread y established off-line manual B-mode IMT method. IMT also was assessed by m eans of an on-line manual B-mode and an on-line manual RF IMT method. We in vestigated posterior wall IMT 0-1 cm proximal to the bulb in both common ca rotid arteries of 16 young (20-31 y; mean 25 y) female and male and 13 elde rly (51-65 y; mean 56 y) female volunteers. Two commercially available ultr asound devices (Pie Medical Scanner 200 and Ultramark 9) were used to asses s the effects of signal processing on the off-line automated RF IMT method. Intrasubject intrasession variability was determined using the standard de viation to evaluate and compare the various methods, Spearman rank correlat ion coefficients and Bland and Altman bias and limits of agreement were cal culated to objectivate the comparability between the various methods, Intra subject intrasession variation of IMT estimates was not statistically diffe rent between any of the methods. We observed a good comparability between t he commonly used off-line manual B-mode IMT method and the off-line automat ed RF IMT method at the level of the common carotid artery. (C) 1998 World Federation for Ultrasound in Medicine & Biology.