Objectives: Artery distension, the difference between diastolic and systolic diameter, is an important measure in stiffness evaluation. Distension can be extracted with high precision and accuracy from radio-frequency ultrasound (US) measurements at a high frame-rate using phase-tracking. However, in daily practice processed B-mode images are collected with a lower frame-rate, but higher line density, and distension may only be assessed using echo-tracking. Therefore, the aim of this study is to evaluate the accuracy and precision of echo-tracking distension as compared to that of phase-tracking distension.

Methods: Longitudinal B-mode (40mm, 37fps) US-measurements (video clips 3–6 heartbeats) of the left common carotid artery were performed with a Philips IU22 scanner on 21 patients (age 45–88y) with a recent cerebrovascular accident. In addition, unprocessed radio-frequency US-measurements were performed with a Mylab70 scanner operating in Fast B-mode (31 lines covering 29mm, 300fps, 3–6 heartbeats). To extract the diameter waveform, semi-automatic wall echo-tracking and phase-tracking methods were applied to B-mode and Fast B-mode measurements respectively.

Results: One patient was excluded due to large out of plane motion. Although phase-tracking diameter waveforms showed more detail, both methods exhibit similar intra-subject precision (SD=34μm and SD=33μm, F-test: p-value=0.4). Echo-tracking and phase-tracking systolic-diastolic distension were similar (bias is 25±90μm, paired t-test: p-value=0.18).

Conclusion: Clinical scanners operating in B-mode can be used to measure distension with reasonable precision and accuracy in a relevant stroke population, although waveform details may be masked at lower frame-rates.

This research was supported by the Center for Translational Molecular Medicine and the Dutch Heart Foundation.