Objective: To investigate the correlation between duplex scanning, magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) in the evaluation of extracranial internal carotid artery (EICA) stenosis.
Methods: All the examinations mentioned-above were performed on 32 patients. According to NASCET, EICA stenosis were classified into four grades: mild (the diameter reduction < 30%), moderate (31% approximately 69%), severe (70% approximately 99%), and total occlusion.
Results: One (3.1%) patient suffered from acute brain infarction after DSA. To compare duplex with DSA, Kappa = 0.78, and by the use of a severe or a greater than 30% stenosis as a positive study, the sensitivity, specificity and accuracy were 78%, 95%, 92% and 97%, 91%, 94%, respectively. To compare MRA with DSA, Kappa = 0.73, and with the same criteria, the sensitivity, specificity and accuracy were 78%, 90%, 89% and 97%, 91%, 94%, respectively. In the evaluation where the results of duplex and MRA were in agreement, to compare duplex + MRA with DSA, Kappa = 0.93, and the sensitivity, specificity and accuracy in the diagnosis of severe stenosis were 100%, 95% and 96%, and the accuracy in the diagnosis of > 30% stenosis was 100%.
Conclusions: There is good correlativity between duplex scanning, MRA and DSA in the examination of EICA stenosis. A combination of duplex and MRA with their results in agreement may ultimately eliminate the need of DSA in the evaluation of EICA stenosis.