MDCTA of carotid plaque degree of stenosis: evaluation of interobserver agreement.
OBJECTIVE
Atherosclerotic disease of the carotid arteries is one of the most important causes of stroke. Our objective was to evaluate the interobserver agreement in the measurement of the degree of carotid plaque stenosis by using MDCT angiography (MDCTA) and the effects produced using different window parameters and by the different types of plaque.


METHODS
From June 2005 to June 2006, we retrospectively evaluated 215 patients (151 men, 64 women) who underwent MDCTA for the study of carotid arteries. In all patients we measured degree of stenosis, applying the criteria of the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Each patient was studied independently by two observers. We used three window settings for the measurements. We grouped the measurements according to the type of plaque. Obtained data were then analyzed to calculate the interobserver agreement and the kappa value.


RESULTS
Kappa values for the degree of stenosis evaluation were 0.696, 0.79, and 0.775 for window settings 1, 2, and 3, respectively. The best agreement was observed in the assessment of fatty plaque, whereas the presence of calcification produced disagreement.


CONCLUSIONS
We observed a very good interobserver agreement in the evaluation of degree of stenosis using MDCTA with the application of specific visualization parameters. Our data suggested that MDCTA can provide reproducible values.
Saba
Luca
L
Department of Science of the Images, Policlinico Universitario, s.s. 554 Monserrato, Cagliari 09045, Italy. lucasaba@tiscali.it
Mallarini
Giorgio
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011856:Radiographic Image Enhancement; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media