CAROTID STENOSIS - A COMPARISON BETWEEN MR AND SPIRAL CT ANGIOGRAPHY

We performed a preliminary study comparing three-dimensional time-of-f light (3 D TOF) magnetic resonance angiography (MRA) and spiral CT ang iography (SCTA) in the detection and assessment of internal carotid ar tery stenosis. Digital subtraction angiography (DSA) was the reference examination. We examined 20 patients with signs of cerebrovascular in sufficiency, who underwent MRA, SCTA and DSA within a 3 day period. Bo th internal carotid arteries were assessed by three blinded readers fo r degree of stenosis at two different levels (bulb and remaining secti on) giving a total of 80 assessments. Interobserver variability, sensi tivity, specificity, diagnostic accuracy, concordance, overestimation and underestimation were assessed. Interobserver variability was not s tatistically significant. MRA showed higher sensitivity, specificity, diagnostic accuracy and concordance than SCTA (92.0% vs 80.8 %, 98.2 % vs 96.4 %, 96.3 % vs 91.3 % and 96.0 % vs 88.0%,respectively). MRA ga ve rise to a 5.0 % overestimation rate, whereas SCTA occasioned a 7.5 % underestimation rate. These differences are not statistically signif icant. These results suggest that MRA is a more useful, noninvasive mo dality for assessment of the internal carotid artery with a more than 70% stenosis.