ABSTRACT
Objective To explore the main influence factors(heart rate,rotation speed,and reconstruction algorithm)on the image quality of coronary artery with 40 mm VCT(64-detector row helical CT)using a pulsating cardiac phantom.Methods An adjustable pulsating cardiac phantom(GE) containing predetermined simulated coronary arteries was scanned using a 40 mm VCT(GE LightSpeed CT) with cardiac pulsating rates of 40,45,50,55,60,65,70,75,80,85,90,95,100,105,110,and 115 beats per minute(bpm).The variable rotation speeds technique of 0.35 s,0.40 s,and 0.45 s were used, respectively.The raw data were reconstructed using both one-sector and multi-sector reconstruction algorithm at optimal window of the R-R interval.The image quality score(IQS)was evaluated by two radiologists according to the same evaluation standard of reformated image.The correlation between heart rate(HR), roation speed,reconstruction algorithm,and IQS were analyzed.The IQS as independent variable and the HR,rotation speed,reconstruction algorithm as dependent variables were analyzed by multiple linear regression analysis.Restllts The heart rate and the reconstruction algorithm had significant influence on IQS.The rotation speed(0.35s,0.40s,and 0.45s)didn't have significant influence on IQS.There was linear regression relationship between heart rate,reconstruction algorithm and IQS(P
ABSTRACT
Objective To evaluate the diagnostic accuracy and reliability for coronary artery stenosis and in-stent restenosis detection using 64-slice spiral computed tomography(multislice CT,MSCT) angiography and digital subtraction angiography(DSA).Methods A pulsating cardiac phantom with two simulated coronary arteries was scanned on a 64- slice CT scanner and underwent DSA at static state,at 4 different sinus rhythms of 0,50,70,and 90 beats per minute(bpm).One simulated artery was 3 mm in lumen diameter with 3 segments of 25%,50%,and 75% stenoses.A stent with 2 segments of 50% and 75% stenoses was placed into the other artery with 4mm in lumen diameter.Images from MSCT were analyzed and compared with those from DSA.Results(1)The mean values of the 25%,50%,and 75% stenoses measured with MSCT were(30.0?1.4)%,(49.5?1.3)%,and(72.9?3.9)%,respectively (P values were 0.005,0.531,and 0.369 respectively).The mean values of the 25%,50%,and 75% stenoses measured with DSA were(24.8?2.0)%,(48.2?2.1)%,(75.3?2.4)% respectively (P values were 0.883,0.180,and 0.796,respectively).(2)MSCT was susceptible to heart rate,with artifact increasing as heart rate increasing,especially when the heart rate were ≥70 bpm.(3)There was a good correlation between 64-slice MSCT and DSA(r=0.995,P=0.000).(4)64-slice MSCT could show the stent and in- stent restenosis simutaneously.Its capability to depict in-stent restenosis was limited.The depiction rate of 50% in- stent restenosis were(46.4?4.5)%(0 bpm)and(43.6?5.7)%(50 bpm) respectively(P