Research The Rationality Of Transcranial Doppler And Standardized Stenosis Index In Clinical Application To Diagnosis Carotid Stenosis

Objectives: Stroke is the highest morbidity and mortality in one of the three diseases in the world, of which 30% of ischemic stroke is caused by the carotid artery disease. Not only the level and parts of carotid artery stenosis but also early to diagnosis and treatment is very important for prevention ischemic cerebrocascular disease. In this study, by using of sonography, Transcranial Doppler(TCD), the standard stenosis index(Fsti), general stenosis index(Wsti) and Clinical-sonographic index(CSI) were calculated. Through compared the relationship among the three data, prove the rationality of Fsti in carotid stenosis in clinical practice. Try to develop a new diagnostic method which can filter and early treat carotid artery disease .Methods:1 Case Selection83 patients were selected randomly from the neurolog department of Bethune International Peace Hospital during June 2009-June 2010, a total of 166 vessels, of which 48 male and 35 female. The mean age was 68.4±9.4 years(rang from 45-88 years old) . Among them 7 patients with hypertension, 36 with diabetes mellitus and 16 with hypertension conbine diabetes mellitus. 23 main sympotoms were dizziness, 43 main symptoms were limb weakness, 9 main sympotoms were dizziness combine limb weakness, the remaining 7 were blurred vision or speech not clear. All the 83 patients underwent sonography and transcranial Doppler ultrasound examination and recorded relevant data. 45 patients underwent CTA and 13 patients underwent DSA examination.2 The data recorded by TCD:systolic velocity(Vs), diastolic velocity(Vd), mean velocity(Vm), pulsitility index(PI). Based on TCD diagnostic criteria of stenosis the vessels were divided into normal, mild stenosis, moderate stenosis, severe stenosis and occlusion.According to standard stenosis index formula (Fsti), general stenosis index formula (Wsti), stenosis index was calculated respectively. Fsti=1-2/(2+ (Vm-Vm0)/Vms-(PI-PI0)/PIs), Wsti=1-Vm1/Vm0×PI1/PI0. At the same time,calculated using the formula of Clinical-sonographic index (CSI), CSI = MFV (cm/sec)+3×AI (%)+180×?PI+90×CS(presence=1, absence=0)+30×DM (presence=1, absence=0).3 The data recorded by vascular sonography:The most carotid artery stenosis was found by multi-site observations at the most narrow lumen, and measured by using the method of North American symptomatic carotid endarterectomy trial method (NASCET). The formula for the diameter of the stenosis was〔(narrow distal normal diameter values - the narrowest section of the narrow diameter of the blood value)/value of the narrow diameter of distal normal〕×100%. The degree of stenosis was divided into normal, mild stenosis, moderate stenosis, severe stenosis and occlusion.4 Stenosis of DSA and CTA was calculated by using the method of NASCET.5 StatisticsThe results would be dealt with SPSS17.0 statistical software package. For stenosis of TCD and vascular sonography were measured by counting compared using the chi-square classification test. Fsti, Wsti and vascular sonography measured stenosis were compared using the paired Wilcoxon test, and the linear correlation analysis. Bland-Altman plot analysis for consistency analysis, and curve fitting. ROC curves were produced for Fsti, Wsti and CSI, observed the area under the curve. To P <0.05 was considered statistically significant.Results:1 Using TCD examination there were 73(44%) normal vessels, 50 (30.1%) mild stenosis, 22(13.3%) moderate stenosis, 20(12.0%) severe stenosis , 1 (0.6%) occlusion. Using vascular sonography there were 77(46.4%) normal vessels, 35(21.1%) mild stenosis, 31(18.7%) moderate stenosis, 20(12.0%) severe stenosis, 3(1.80%) occlusion. After the application of chi-square test it concluded that there was no statistical difference between the two methods(X2=6.259,P=0.181> 0.05).2 There were 13 patients who underwent DSA examination., a total of 26 vessels. There were 24 vessels which had the similar results after DSA and sonography. The consistency was 92.3%. There were 20 vessels which had the similar results after DSA and TCD. The consistency was 76.9%.3 There were 45 patients who underwent CTA examination, a total of 90 vessels. The stenosis detection rate of sonography is 77.7%. Compared to CTA of stenosis≥50%, sensitivity was 91.1% and specificity was 80.3%. The stenosis detection rate of TCD was 76.7%. Compared to CTA of stenosis≥50%, sensitivity was 85.2% and specificity was 59.0%.4 Stenosis which using the three methods of Fsti, Wsti and sonography were compared by Wilcoxon rank test. It concluded that there was significant difference among the three methods(P=0.000 <0.05). Through the spearman correlation analysis, they had a linear correlation with the correlation coefficient of 0.861 and 0.620(P = 0.000<0.05) , with statistical significance. In the vessels stenosis≥50%, sonography compared with Wsti and Fsti respectively by using the spearman linear correlation analysis. Correlation coefficient of Fsti and Wsti was 0.736 and 0.610(P=0.000 <0.05), with statistically significant.5 For the vessels of stenosis≥50% by sonography and Fsti, Bland-Altman plot analysis was used. According to the result, 1.67% (1/60) of the points outside the 95% limits of agreement. Within 95% limits of agreement, the maximum of the stenosis difference was 23% in the two methods, an average of the two methods was 68%. The same analysis applied to Wsti, 3.3% (2/60) of the points outside the 95% limits of agreement. Within 95% limits of agreement, the maximum of the stenosis difference was 42% in the two methods, an average of two methods was 64%.6 Done ROC curve for Fsti, Wsti and CSI respectively. The areas under the curve were 0.950, 0.792 and 0.800 for Fsti, Wsti and CSI.7 Fitting curve to stenosis rate of sonography and Fsti, the result of the cubic model was the best, with statistical significance (R~2=0.788, P=0.000<0.05). The equation is-0.005-0.270 Fsti+2.800 Fsti~2-1.563 Fsti~3Conclusions:1 Thought TCD blood flow velocity examination, the judgement of vessel stenosis is relaticely accurate .2 Tthe vessels of stenosis rate≥50% which judged by Fsti and sonography are in good agreement.3 Comparing three motheds of Fsti, Wsti and CSI, Fsti for judging vessels stenosis is more accurate in clinical.4 There is a good fit cubic equation for Fsti and the diagnosis of sonography. It have a positive correlation with the middle and serious stenosis on the curve. It concluded that Fsti has rationality and practical in clinical but there is a range of application for Fsti.