PurposeThe aim of this study was to introduce and implement a noninvasive method to derive the carotid artery pressure waveform directly by processing diagnostic sonograms of the carotid artery.MethodsUltrasound image sequences of 20 healthy male subjects (age, 36±9 years) were recorded during three cardiac cycles. The internal diameter and blood velocity waveforms were extracted from consecutive sonograms over the cardiac cycles by using custom analysis programs written in MATLAB. Finally, the application of a mathematical equation resulted in time changes of the arterial pressure. The resulting pressures were calibrated using the mean and the diastolic pressure of the radial artery.ResultsA good correlation was found between the mean carotid blood pressure obtained from the ultrasound image processing and the mean radial blood pressure obtained using a standard digital sphygmomanometer (R=0.91). The mean absolute difference between the carotid calibrated pulse pressures and those measured clinically was -1.333±6.548 mm Hg.ConclusionThe results of this study suggest that consecutive sonograms of the carotid artery can be used for estimating a blood pressure waveform. We believe that our results promote a noninvasive technique for clinical applications that overcomes the reproducibility problems of common carotid artery tonometry with technical and anatomical causes.

No abstract

No abstract

No abstract

Clarifying the complex interaction between mechanical and biological processes in healthy and diseased conditions requires constitutive models for arterial walls. In this study, a mathematical model for the displacement of the carotid artery wall in the longitudinal direction is defined providing a satisfactory representation of the axial stress applied to the arterial wall. The proposed model was applied to the carotid artery wall motion estimated from ultrasound image sequences of 10 healthy adults, and the axial stress waveform exerted on the artery wall was extracted. Consecutive ultrasonic images (30 frames per second) of the common carotid artery of 10 healthy subjects (age 44 ± 4 year) were recorded and transferred to a personal computer. Longitudinal displacement and acceleration were extracted from ultrasonic image processing using a block-matching algorithm. Furthermore, images were examined using a maximum gradient algorithm and time rate changes of the internal diameter and intima-media thickness were extracted. Finally, axial stress was estimated using an appropriate constitutive equation for thin-walled tubes. Performance of the proposed model was evaluated using goodness of fit between approximated and measured longitudinal displacement statistics. Values of goodness-of-fit statistics indicated high quality of fit for all investigated subjects with the mean adjusted R-square (0.86 ± 0.08) and root mean squared error (0.08 ± 0.04 mm). According to the results of the present study, maximum and minimum axial stresses exerted on the arterial wall are 1.7 ± 0.6 and -1.5 ± 0.5 kPa, respectively. These results reveal the potential of this technique to provide a new method to assess arterial stress from ultrasound images, overcoming the limitations of the finite element and other simulation techniques.