Automated intima-media thickness: the Los Angeles Atherosclerosis Study

Area of Science:

• Cardiovascular Imaging
• Medical Ultrasound Technology
• Atherosclerosis Research

Background:

• Common carotid artery (CCA) intima-media thickness (IMT) is a key indicator of early atherosclerosis.
• Automated edge-tracking offers potential for standardized IMT assessment.
• Reproducibility of IMT measurements is crucial for clinical and research applications.

Purpose of the Study:

• To evaluate the within- and between-sonographer reproducibility of automated edge-tracking IMT.
• To assess the performance of a low-cost mobile ultrasound scanner for IMT measurements.
• To compare the reproducibility of the proposed IMT protocol with existing methods.

Main Methods:

• B-mode ultrasound images of the CCA were acquired from 38 subjects (aged 31-75 years) on two separate occasions.
• Two sonographers performed measurements using automated edge-tracking on a mobile scanner.
• Reproducibility error was quantified using mean absolute difference (MAD) and standard deviation of differences (SDdelta).

Main Results:

• Within-sonographer error for IMT was small (MAD=0.027+/-0.006 mm; SDdelta=0.044 mm).
• Between-sonographer error was also low (MAD=0.041+/-0.008 mm; SDdelta=0.064 mm).
• Averaging measurements across arteries and positions reduced inter-sonographer error by 47% (MAD=0.022+/-0.003 mm; SDdelta=0.029 mm).

Conclusions:

• The automated edge-tracking IMT protocol demonstrates high reproducibility for CCA measurements.
• The proposed method using a low-cost mobile scanner significantly reduces reproducibility error.
• This protocol offers a reliable and potentially more accessible tool for early atherosclerosis detection.