Evaluation of Carotid Artery Stenosis Using 3D/4D Vessel Cast

Screening for carotid artery stenosis (CAS) is vital in symptomatic patients as stenosis related to atherosclerotic plaque can cause neurological ischemia and potentially stroke. Imaging options for CAS includes carotid duplex ultrasonography (DUS), CT angiography (CTA), and MR angiography (MRA); however, accurate estimation of stenosis is limited. Catheter angiography (CA) is regarded as the reference standard for quantifying the exact severity of CAS. Though very effective, CA is invasive and thus only used in select patients, specifically, those who are suspected to require treatment. 3D/4D vessel cast is an ultrasound technique that provides an accurate map of the carotid artery lumen. The purpose of this study is to validate 3D/4D vessel cast as a useful tool in the evaluation of CAS and compare its accuracy to CA, CTA, MRA, and carotid DUS.

Materials and Methods:

This single-center, retrospective cohort study consisted of 63 events among 36 patients with CAS from 2018 to 2022. Patients with a carotid DUS, associated 3D/4D vessel cast, and a carotid CA, CTA, or MRA within a 1-year time frame were included. All vessel casts were obtained with the XL14-3 workflow (Philips, Amsterdam, Netherlands). Measurements of the stenotic vessel were acquired on the vessel cast image. The primary endpoint assessed absolute difference in percent stenosis determined by vessel cast between that of CA, CTA, and MRA. Statistical analysis included paired t-tests and Spearman correlation coefficients.

Results:

The 63 events were composed of 18 CAs, 29 CTAs, and 16 MRAs. The mean stenosis in vessel cast was 73.8 ± 6.7% and in CA was 77.8 ± 10.1% (p=0.2). The mean difference was 7.4 ± 2.5% and the two modalities yielded a correlation coefficient of 0.55 (p=0.02). For the CTA group, the average stenosis for vessel cast was 64.3 ± 20.1% and in CTA 65.4 ± 21.7% (p=0.8). The average difference was 17 ± 5.9% and the correlation coefficient was 0.39 (p=0.04). In the MRA analysis, mean stenosis in vessel cast was 55.8 ± 24.7% and in MRA 69.0 ± 13.9% (p=0.07). The average difference between vessel cast and MRA was 20 ± 11% and produced a correlation coefficient of 0.31 (p=0.2).

Conclusion:

3D/4D vessel cast demonstrates moderate correlation to carotid CA. Further studies with larger sample sizes are needed to assess the clinical validity of vessel cast in comparison to CTA and MRA. Given that it is a safe and effective technique, 3D/4D vessel cast should be considered in the diagnostic armamentarium to obtain estimates of stenosis.