| Backgrounds 64-detector row helical CT coronary angiography has been widely put into use in clinic, and it is an important method to diagnose coronary heart disease. Howerver, its imaging quality was affected by many factors such as respiration, heart rate, cardiac rhythm, contrast medium and reformation method, et al, among which the heart rate and contrast medium are most important. With the mass research, acute coronary syndrome related significantly with the stability and composition of plaque, and it also resulted in the main dead cause of coronary heart disease. At present, there are few reporters about the evaluation of measurement accuracy on coronary artery caliber. The purpose of this study is to explore the accuracy and influence of different heart rate on measuring coronary artery with 64-detector row helical CT in using Osiris419 software and the heart package of measuring diameter value in AW4.2 in a pulsating cardiac phantom, also to explore the effect of heart rate and different enhanced levels on the accuracy of measuring plaque. Part one: Accuracy and influence of different heart rate on measuring different coronary artery with 64-detector row helical CTObjective To explore the accuracy and influence of different heart rate on measuring coronary artery with 64-detector row helical CT in using Osiris419 software and the heart package of measuring diameter value in AW4.2 in a pulsating cardiac phantom. Methods An adjustable pulsating cardiac phantom (GE) was scanned using a 40mm VCT (GE Light Speed CT) with cardiac pulsating rates of 0, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 and 105 beats per minute (bpm). The lumens of coronary artery was 4mm and was made with stenosis of 0%,25%,50%,75%. The variable rotation speeds technique of 0.35s was used. The raw data were reconstructed using two--sector reconstruction algorithm at 90% R-R interval. First the images of coronary artery were evaluated using Osiris419 software. Then these images were evaluated by the heart package of measuring diameter value in AW4.2.Results Picture quality cut down and the caliber became bigger with the heart rate speeding up by Osiris419 software. The measured values of no stenosis were 4.20,4.20,4.22,4.26,4.30,4.24,4.08,4.33,4.18,4.22,4.29,3.97,4.33,4.15,4.23mm;The measured values of 25% stenosis were 2.30,2.31,2.29,2.30,2.38,2.32,2.40,2.30,2.29,2.38,2.36,2.39,2.50,2.33,2.47mm;The measured values of 50% stenosis were 2.00,2.00,2.01,2.02,2.03,2.05,2.02,2.06,2.08,2.09,2.04,2.05,2.14,1.85,2.10mm;The measured values of 75% stenosis were 1.60,1.58,1.60,1.61,1.63,1.57,1.66,1.60,1.66,1.77,1.66,1.63,1.69,1.73,1.73mm. By using one-factor analysis of variance, we can conclude that heart rate plays no statistical significance in measuring coronary artery of 0%,25%,50%,75% by Osiris419 software (p>0.05). With the heart package of measuring diameter value in AW4.2,picture quality cut down obviously and the caliber became no regularity . With the heart rate increasing, the measured values of no stenosis were 4.38,4.25,4.33,4.72,4.20,4.13,4.30,4.23,4.52,4.30,4.48,4.40,4.28,3.85,4.40mm;The measured values of 25% stenosis were 3.50,3.12,3.53,3.02,3.32,2.93,3.23,3.13,3.25,2.93,3.00,3.57,3.77,3.27,3.27mm;The measured values of 50% stenosis were 2.65,2.70,2.87,2.57,2.47,2.78,2.60,2.50,2.50,2.95,2.58,2.50,2.62,2.32,3.16mm;The measured values of 75% stenosis were 2.30,2.15,2.10,1.98,2.03,2.33,2.43,1.88,3.60,3.85,2.10,2.02,2.43,2.27,3.00mm.By using one-factor analysis of variance, we can conclude that heart rate plays statistical significance in measuring coronary artery of 25%,50%,75%(P<0.01)and heart rate plays no statistical significance in measuring coronary artery of 0%(P>0.05). By using paired samples test we can conclude that statistical significance exists between the two methods and the method of Osiris419 surpasses the other one.Conclusion With Osiris419 software the measured values can relate less with heart rate. It can raise accuracy and plays more objectivity using Osiris419 software in a pulsating cardiac phantom to evaluate diameter of different coronary artery. It plays an important role in clinical research and application. By the heart package of measuring diameter value in AW4.2 the measured values relate more with heart rate and lack accuracy. Part two: Influence of different enhancement on measuring coronary artery plaque with 64-detector row helical CTObjective To explore the accuracy and influence of different heart rate and enhancement on measuring coronary artery plaque with 64-detector row helical CT in using Osiris419 software.Methods An adjustable pulsating cardiac phantom (GE) was scanned using a 40mm VCT (GE Light Speed CT) with cardiac pulsating rates of 0, 45, 55, 65 and 75 beats per minute (bpm). The lumens of coronary artery was 5mm and was made with stenosis of 25%,50%,75%. The enhanced values were made to 250,370,430,500,600HU and group A,B,C,D,E. The variable rotation speeds technique of 0.35s was used. The raw data were reconstructed using two--sector reconstruction algorithm at 90% R-R interval. The images of coronary artery were evaluated using Osiris419 software.All dates were analyzed by SPSS 16.0 statistical software package and expressed by mean±standard deviation. One-way ANOVA was performed among groups. Difference with P<0.05 was considered as significa.Results Picture quality cut down and the caliber became bigger with the heart rate speeding up by Osiris419 software. When the heart rate smaller than 75bpm, the measured values varied un-obviously. By using one-factor analysis of variance, we can conclude that heart rate plays no statistical significance in measuring coronary artery of 25%,50%,75% by Osiris419 software (p>0.05). By using one-factor analysis of variance, we can conclude that enhancement plays statistical significance in measuring coronary artery of 25%,50%,75%(P<0.01). If the CT value was 250HU, the measured values obviously exceeded other values.Conclusion With Osiris419 software the measured values can relate less with heart rate. It can raise accuracy and plays more objectivity using Osiris419 software in a pulsating cardiac phantom to evaluate diameter of different coronary artery. It plays an important role in clinical research and application. Constrast medium's different enhancement effect impacts the measuremtnt of different coronary artery. |
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