Vulnerable plaque: detection of agreement between multi-detector-row CT angiography and US-ECD

Objectives: The purpose of this work was to evaluate the agreement between ultra-sound echo-color Doppler (US-ECD) and multi-detector-row CT angiography (MDCTA) in the characterization of vulnerable plaque.

Methods: From January 2004 to January 2007 658 patients who underwent both MDCTA and US-ECD for the study of carotid arteries, were retrospectively evaluated (453 males, 205 females). For all subjects the following parameters were analysed: plaque morphology (regular versus irregular), type of the plaque (fatty, mixed and calcified) and presence of ulcerations. Statistical analysis was performed to calculate concordance between the two techniques employed.

Results: In the definition of the type of plaque, the observed agreements were 77.2% and the kappa value was 0.657 (95% confidence interval: 0.615-0.699). The weighted kappa resulted 0.644. In the definition of ulceration plaque, the observed agreements were 88.4% but the kappa value was only 0.325 (95% confidence interval: 0.201-0.449). Agreement observed in the evaluation of plaque morphology was 78.3% with a kappa value of 0.513 (95% confidence interval: 0.452-0.574).

Conclusion: We observed a good agreement between US-ECD and MDCTA in the assessment of plaque type whereas a poor agreement resulted in the evaluation of plaque ulceration. The use of US-ECD and MDCTA provides different results in the evaluation of plaque. Our results suggest that information deriving from US-ECD should be always critically compared with other diagnostic techniques.