Semi-automatic quantitative measurements of intracranial internal carotid artery stenosis and calcification using CT angiography

Abstract

IntroductionIntracranial carotid artery atherosclerotic disease is an independent predictor for recurrent stroke. However, its quantitative assessment is not routinely performed in clinical practice. In this diagnostic study, we present and evaluate a novel semi-automatic application to quantitatively measure intracranial internal carotid artery (ICA) degree of stenosis and calcium volume in CT angiography (CTA) images.MethodsIn this retrospective study involving CTA images of 88 consecutive patients, intracranial ICA stenosis was quantitatively measured by two independent observers. Stenoses were categorized with cutoff values of 30% and 50%. The calcification in the intracranial ICA was qualitatively categorized as absent, mild, moderate, or severe and quantitatively measured using the semi-automatic application. Linear weighted kappa values were calculated to assess the interobserver agreement of the stenosis and calcium categorization. The average and the standard deviation of the quantitative calcium volume were calculated for the calcium categories.ResultsFor the stenosis measurements, the CTA images of 162 arteries yielded an interobserver correlation of 0.78 (P < 0.001). Kappa values of the categorized stenosis measurements were moderate: 0.45 and 0.58 for cutoff values of 30% and 50%, respectively. The kappa value for the calcium categorization was 0.62, with a good agreement between the qualitative and quantitative calcium assessment.ConclusionsQuantitative degree of stenosis measurement of the intracranial ICA on CTA is feasible with a good interobserver agreement ICA. Qualitative calcium categorization agrees well with quantitative measurements.

Feasibility of assessment of conjunctival microvascular hemodynamics in unilateral ischemic stroke

“…A common cause of ischemic stroke is insufficient blood supply from the internal carotid artery (ICA) to one side of the brain. Currently, vascular imaging techniques are available for evaluation of ICA stenosis and blood velocity in subjects with ischemic stroke (Bleeker et al, 2012; Gough, 2011; Marquering et al, 2012; Rodriguez et al, 2011; Zachrisson et al, 2012). Since oxygenated blood is supplied to the eye and brain by the ICA, assessment of the ocular microcirculation may provide useful information about the cerebral blood supply.…”

Association between Intracranial Atherosclerotic Calcium Burden and Angiographic Luminal Stenosis Measurements

“…Our findings of a weak correlation between the degree of intracranial stenosis and the intracranial atherosclerotic calcium burden 15 and a strong correlation between qualitative and quantitative measures of intracranial atherosclerotic calcium burden are similar to the existing literature. 16 Our work uniquely builds upon this knowledge by using NCCTs to measure calcium burden and adapting a commonly used method for coronary calcium scoring (Agatston score) to the intracranial ICA.…”

Intracranial Carotid Calcification on Cranial Computed Tomography

“…Several previous studies tested correlations between intracranial calcification and systemic diseases, 11 , 14 , 24 , 25 brain ischemic changes, 13 , 17 , 20 , 21 , 25 – 27 and carotid stenosis. 15 , 16 , 19 , 22 , 28 Only 2 studies compared visual calcium scoring and semiautomatic calcium volume measurement. 19 , 23 Bleeker et al 19 used CT angiography and categorized intracranial calcification visually into absent, mild, moderate, or severe (similar to Woodcock approach) and found good interobserver agreement for visual calcium score (linear-weighted κ=0.62; 95% confidence interval, 0.54–0.70), excellent interobserver agreement for semiautomatic quantitative calcium volume (Pearson correlation coefficient, 0.99; P <0.01; 95% limit of agreement 0.3±8.5 mm 3 ).…”