Ying‑An Chena, Pei‑Ya Chena,b, Shinn‑Kuang Lina,b*
aStroke Center and Department of Neurology, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei, Taiwan; bSchool of Medicine, Tzu Chi University, Hualien, Taiwan
Open Access funded by Buddhist Compassion Relief Tzu Chi Foundation
Abstract
Objectives: The intima–media thickness (IMT) of the carotid artery can now be detected on a three‑dimensional (3D) plane. The 3D vessel wall volume (VWV) more accurately represents vascular conditions. Through 3D ultrasound, we established a standardized method for carotid VWV measurement. Materials and Methods: A total of thirty patients without stroke or cardiovascular disease who received carotid duplex sonography were retrospectively reviewed. Gray‑scale 3D images from the distal common carotid artery (CCA) to internal carotid artery on both sides were acquired using a single‑sweep 3D transducer and analyzed offline by using the vascular plaque quantification function of the Philips QLAB software. Then, the 3D IMT (QLAB intima–media thickness [QIMT]), total plaque volume (TPV), and VWV were measured by a neurologist and a technician, and the interobserver variability was assessed. Results: The mean two‑dimensional (2D) carotid IMT was 0.65 ± 0.12 mm. The mean QIMT, TPV, and VWV measured by observer 1 were 0.68 ± 0.18 mm, 26 ± 12 mm3, and 94 ± 10 mm3, respectively. The Bland–Altman plot of the mean differences between the QIMT, TPV, and VWV values measured by observers 1 and 2 showed that those of observer 2 were within two standard deviations of those of observer 1. Intraclass correlation coefficients (ICCs) indicated strong correlations in QIMT (ICC = 0.76), TPV (ICC = 0.85), and VWV (ICC = 0.90; P < 0.001) between observers 1 and 2. Both 2D IMT and 3D QIMT exhibited a positive linear correlation with age. Conclusion: This study established a standardized VWV measurement through 3D ultrasound. Reasonable interobserver differences were obtained within a 95% limit of agreement and high reliability (ICC = 0.90). The VWV 1 cm from the CCA bifurcation was quantified with a mean value of 94.2 mm3. Further studies on the 3D ultrasound quantification of carotid arteries are warranted.
Keywords: Interobserver reliability, Intima–media thickness, Three‑dimensional ultrasound, Total plaque volume, Vessel wall volume
