Background

Multi-sequence magnetic resonance imaging (MRI) is commonly used for the quantification of carotid atherosclerotic plaque composition (1). Limitations are long scan time and image misregistration errors. Multi-contrast Atherosclerosis Characterization (MATCH) was developed to overcome these limitations (2).

Aim

To compare MATCH with multi-sequence MRI for the quantification of carotid plaque components.

Methods

Twenty symptomatic patients with ≥2 mm carotid plaque underwent 3.0 Tesla multi-sequence and MATCH MRI. Image quality was scored on a 5-point scale based on vessel wall signal-to-noise ratio (SNR) and visibility of vessel wall and substructures (1, poor and 5, excellent) (3). The effective vessel wall SNR and contrast-to-noise ratio (CNR) between IPH and the muscle were calculated by dividing SNR and CNR by the acquisition time. Image analysis of the MATCH images was performed independently of that of the multi-sequence images (Figure 1). A Cohen’s kappa test was used to determine agreement in the detection of plaque components using multi-sequence versus MATCH MRI. The sensitivity and specificity of MATCH in identifying plaque components were calculated using multi-sequence MRI as the reference standard.

Results

One total or nearly occluded artery was excluded. The mean quality scores of the MATCH images were lower than multi-sequence images (2.4±0.5 versus 3.7±0.4; p<0.05), respectively. The overall effective SNR of MATCH was higher than the multi-sequence protocol except for the hyper T1w images (Figure 3 1). The mean effective CNR of intraplaque hemorrhage (IPH) on MATCH was significantly higher than that of magnetization prepared rapid acquisition gradient echo (MPRAGE) (7.2 ±4.3 versus 4.7±2.8; p=0.007). The scan time for MATCH and multi-sequence MRI was 7 and 39 minutes, respectively. Excellent intraobserver agreement was obtained for scoring a Lipid-rich necrotic core (LRNC) (k=0.89) and IPH (k=0.91) on the MATCH images while fair intraobserver agreement was observed for calcifications (k=0.32). The sensitivity and specificity of scoring LRNC and IPH were >83% and >96% while for calcifications the sensitivity and specificity were 76% and 50%, respectively (Figure 4). No significant differences between MATCH and multi-sequence MRI were found in the volume of LRNC, IPH, and calcifications. There was a small but significant difference in the total volume of the vessel wall and total volume of fibrous tissue (Figure 2).

Conclusion

We demonstrated excellent agreement between MATCH and multi-sequence MRI for the identification and quantification of LRNC and IPH. There was only fair agreement for scoring the presence of calcifications. Although MATCH images showed a lower mean image quality score, short scan time and perfect co-registration are major advantages of MATCH.

Acknowledgements

No acknowledgement found.

References

1. Saba L, Yuan C, Hatsukami TS, et al. Carotid Artery Wall Imaging: Perspective and Guidelines from the ASNR Vessel Wall Imaging Study Group and Expert Consensus Recommendations of the American Society of Neuroradiology. AJNR Am J Neuroradiol 2018;39:E9-E31. 2. Fan Z, Yu W, Xie Y, et al. Multi-contrast atherosclerosis characterization (MATCH) of carotid plaque with a single 5-min scan: technical development and clinical feasibility. J Cardiovasc Magn Reson 2014;16:53. 3. Yuan C, Mitsumori LM, Ferguson MS, et al. In vivo accuracy of multispectral magnetic resonance imaging for identifying lipid-rich necrotic cores and intraplaque hemorrhage in advanced human carotid plaques. Circulation 2001;104:2051-6.