The Feasibility Evaluation Of Carotid Artery Vulnerable Plaque By DECT

Background and purpose:The carotid artery plaque is major risk factor for ischemic strokes. The vulnerable carotid artery plaque is defined by its CT density value and plaque surface morphology in CT. The new concept of DE spectral curve introduced by DECT in recent years have also been a tool for defining plaque vulnerability. So, hence in this study, firstly we analyze the vulnerable plaques by using CT density value, plaque surface morphology and DE spectral curve and then secondly we correlate all three parameters including DE-curve for feasible evaluation of the plaque vulnerability in respect to ischemic strokes and establishing its superiority.Methods:Among total of 159 cases of carotid artery plaques found between year 2012 to 2014 from First Affiliated Hospital of Kunming Medical University, we only included 50 segments of carotid artery plaque from 50 cases in respect to low density in CT and transverse diameter more than 2mm and with exclusion of calcified plaques. All the patients included for study of plaque underwent DE carotid artery angiogram and respectively CT/MRI of the Head in two weeks.We used DE-DSCT imaging (SOMATOM Definition Flash, Siemens Medical Solutions, Forchheim, Germany). A dual energy protocol was used with tube A (140 kV,51 mA) and tube B (80 kV,213 mAs) with 128X 0.6-mm collimation, pitch 0.7 and rotation time of 0.28 s.. All those soft and mixed plaques were only analyzed for its morphology, CT density value and DE spectral curve and established the correlation between them. We also included the CT/MRI head of all patients whose plaques were analyzed to find out the correlation with the ischemic strokes.Results:1. In total of 159 cases found during our retrospective cases analysis we only included 50 segments of 50 cases of with 17 females and 33 males were found.21 segments of plaque were in trunk of common carotid arteries just below the bifurcation and 22 were in the bifurcation. Others 5 were in internal carotid arteries and 2 in external carotid. Out of 50,21 were found in right side while 29 were in left side.2. In total of 50 cases, according to CT density value,24 fatty plaques and 26 mixed plaques were found. According to DE-curve,21 showed ascending curve representing fatty plaques while 29 showed descending curves. According to surface morphology,10 plaques showed irregular surface morphology and 3 showed ulcerated plaque representing vulnerable plaques.3. Out of 50 cases, only 16 showed ischemic strokes.Out of 16 ischemic strokes, according to CT density value,12 strokes were caused by fatty plaques and 4 from mixed plaque. According to DE curve,13 ascending curves showed strokes positives and 3 descending curve showed stroke positive. According to plaque surface morphology,10 irregular surface showed positive strokes whereas 3 regular surface morphology and 3 ulcerated showed stroke. Out of 16 ischemic strokes,9 were seen on MRI head,while 7 were found in unenhanced CT head.4.50% of positive predictive value with 75% sensitivity of fatty plaques with CT density value,67% of positive predictive value with 62.5% of sensitivity of irregular surface morphology and,61% of positive predictive value with 81.25% of sensitivity was found with DE curve ascending slopes in respect to strokes 5. The statistical analysis, non-parametric bivariate kendalls tau_b test was carried out. There was significant correlation between CT density value,morphology, DEcurve and stroke. The kendalls tau_b value of ct density value, de curve and plaque surface morphology is-.37,-.54,-.30 respectively,which shows the strong negative relationship between strokes and these parameters.Conclusions:1.50% of positive predictive value with 75% sensitivity of fatty plaques with CT density value was shown with related to stroke.67%of positive predictive value with 62.5% of sensitivity of irregular surface morphology was shown with related to stroke.61% of positive predictive value with 81.25% of sensitivity was found with DE curve ascending slopes in respect to strokes. The sensitivity with DE spectral curve in overall three parameters in relation to ischemic strokes was high. 2. Overall correlation value of three parameters with respect to ischemic strokes shows strong negative correlation which is statistically significant.so hence We found the good and strong coorelation between all three parameters with high affinity for predicting ischemic strokes,which establishes the superior feasibility for study of plaque vulnerability with DE DSCT.