Study Of Multislice Spiral Computed Tomography In Coronary Artery Disease Diagnosis

OBJECTIVE: To evaluate image quality of Multi-slice Spiral CT (MSCT) in the coronary artery imaging and the diagnostic accuracy in determining coronary lesions.MATERIALS AND METHODS: 65 patients( 47 male, 18 female, aged 63.6 + 11.5 years) who were suspected of the stenosis of the coronary arteries were examined with MSCT . The CT data were aquired within a single breathhold .45 out of 65 cases underwent conventional coronary angiography. ECG was given conventional before MSCT examination, receptor-blocking medication were given to patients whose heart rate was fast. From MSCT data-sets, all axial image series were reconstructed during every 10% of the R-R interval to search for an optimum reconstruction window by means of retrospective electrocardiographic gating; Sensitivity and specificity of diagnosing stenosis was studied after comparing the results of conventional coronary angiography with Coronary calcium scoring with plain scan images at 70% of the R-R interval. Every coronary artery [left main(LMA), left anterior descending(LAD), left circumflex(LCA), right coronary artery(RCA) and side branches] was reconstructed in its optimum reconstruction window to evaluate the demonstration of them. The result of conventional coronary angiography was regarded as a gold standard to study sensitivity and specificity after comparing the results of two experiments.RESULTS: Sensitivity and specificity of diagnosing stenosis of coronarycalcium score to identify >50% obstructed branches was 79.2%, 84.9% respectively .The rate of demonstration of every artery (LAD96% LCA92% RCA86% ) was highest in 70% reconstruction window and relatively higher in RCA (74% ) in 40% reconstruction window .When CT mean of the root of the arota is 309 28HU,image quality was better. 260 arteries of 65 cases with MSCT examinations, there were 228 arteries(87.7%)which could be analysed for diagnosis and 32 arteries(12.3%) which could not be analysed correctly . The demonstration of LAM and the proximal-middle segments of LAD was best in reconstruction images. 49 arteries were diagnosed as the stenosis of coronary arteries in conventional angiography such as 3 LMA, 21 LAD, 12 LCA and 13 RCA.Meanwhile 44 arteries,by means of MSCT investigation, were found to be stenosis including 3 LMA, 17 LAD , 12 LCA and 12 RCA. The total sensitivity of MSCT is 83.7%(41/49),specificity is 97.7% (128/131). CONCLUSION: With the heart rate controlled ,MSCT could be used as a non-invasive screening method for the patients with suspected of the stenosis of coronary artery.