A Comparative Study Of 64-slice Spiral CT Coroary Angiography With Prospective And Retrospective ECG-Gating

Objective1. To compare radiation dose and image quality between prospective and retrospective ECG gating CT coronary angiography (CTCA) with 64-slice CT scanner.2. To compare diagnosis coronary artery narrow accuracy between prospective and retrospective ECG gating CT coronary angiography with 64-slice CT scanner.Material and Methods1. Sixty patients with suspected coronary artery disease were selected, and randomly devided into two groups. Thirty patients in research group (average body-mass index [BMI]:25.30±3.15kg/m2, heart rate≤65 beats per minute [bpm]) underwent CTCA using prospective ECG-gating (120 kV,650mA), while the rest 30 patients in control group (average BMI:25.40±3.00kg/m2, heart rate≤65 bpm) underwent CTCA using retrospective ECG-gating (120kV,650mA). The average effective dose (ED) and standardizing radiation dose (EDsd) which was standardized by 12 cm length were respectively calculated, and statistical analysis was then conducted, whereas image quality was evaluated.2.35 patients, who underwent the CTCA and the X-ray coronary angiography, were divided into two groups. Prospective ECG gating scan group,13 patients (male 12, female= 1), aged 54-75 years, mean 63±6.9 years; retrospective ECG gateing scan group,22 patients (male 19 cases,3 females), aged 50-83 years, mean 63±10.2 years. X-ray coronary angiography as the gold standard for diagnosis of coronary artery stenosis, the degree of stenosis divided into 5 levels:normal lumen; mild stenosis (<50%), moderate stenosis (50%-75%), severe stenosis (76%-99%) and vascular occlusion (100%). prospective and retrospective ECG gating CTCA diagnosis of stenosis of the sensitivity, specificity, positive predictive value, negative predictive value and accuracy respectively. Compare the diagnosis accuracy between prospective and retrospective ECG gating coronary angiography.Results 1. The average ED of research group and control group was (5.97±1.04) mSv and (26.25±2.36) mSv, respectively (tA,B=43.13, P<0.05). The EDSd of two groups was (5.49±0.45) mSv and (23.77±1.64) mSv (tSd=59.00, P<0.05). EDSd decreased by 77% in research group compared with control group. No significant difference of image quality was found between two groups (%=0.426, P=0.235).2. Prospective and retrospective ECG gating CTCA diagnosis of coronary artery stenosis were excellent consistency with X ray coronary angiography(Kappa values were 0.844,0.849). There was no significant difference between prospective and retropective ECG gating CT coronary angiography in diagnosis capacity on coronary artery stenosis (χ2=0.314, P=0.957).ConclusionProspective ECG gating CTCA can effectively reduce radiation dose without compromising image quality. Prospective and retrospective ECG gating CTCA have good diagnostic capabilities of singificant coronary stenoses, and there is no difference between the two scan methods.