The Assessment Of High Definition CT In The Image Quality Of The Segment Coronary Artery Calcified And Stent

Objective Comparing the imaging quality of the segment coronary calcium andcoronary stent between64multi-slice computed tomography with GE light Speed VCTand GE Light Speed HDCT, to approach the practical value of HDCT(High DefinitionCT, HDCT) in reducing beam hardening artifact and partial volume effect of thesegment coronary calcium and coronary stent.Materials and Methods Patients having multi-slice CT angiography performedfrom2009August to2012February were enrolled and divided into one calcium groupand one stent group.(1) The Calcium Group:64patients underwent HDCT scan andthe images of coronary artery calcification were reconstructed by HD standardreorganization algorithm..64patients underwent64-VCT scan and the images ofcoronary artery calcification were reconstructed by standard reorganization algorithm.Coronary artery calcification score of each segment coronary calcification wasmeasured with Agatston method. Coronary artery calcification score value from10to100was mild calcification. Moderate calcification score value was from100to400.Coronary artery calcification score value above400was severe calcification.(2) TheStent Group:34patients underwent HDCT scan and the images of coronary stent werereconstructed by HD standard reorganization algorithm.47patients underwent64-VCT scan and the images of coronary stent were reconstructed by standardreorganization algorithm. Diameters of the coronary stent were respectively measuredwith Osiris419Software. CPR images through coronary artery calcification and stentwere respectively evaluated for image quality on a5-point scale. The results were analyzed by two independent samples t-test.Result （1）The Calcium Group: The clinical data of the patients on HDCT and64-VCT was well matching and consistent. There were220segments coronary calciumon HDCT. There were225segments coronary calcium on64-VCT. The image qualityscores of mild, moderate and severe calcification of the segments coronary arterycalcium on HDCT and64-VCT were respectively3.83±0.79,3.36±1.45,3.25±1.37and3.17±0.71,2.72±0.90,2.45±1.18. The image quality on HDCT was better than that on64-VCT. The difference was statistically significant (all P＜0.05).（2）The StentGroup: The clinical data of the patients on HDCT and64-VCT was well matching andconsistent. There were41stents on HDCT and69stents on64-VCT. The diameter ofthe stents was range from2.5mm to4mm. For2.5mm,3.0mm,3.5mm and4mm of thestent，diameter of coronary stent measured on HDCT was respectively higher than thatmeasured on64-VCT. The difference is statistically significan（tt＝9.33，8.54，7.04and3.78, all P0.05）. For diameter of the stent was2.5mm and3.0mm, the scores of theimaging quality on HDCT were respectively4.36±0.67and4.08±0.76, which wasbetter than that on64-VCT(2.65±0.83and3.20±0.52).The difference was statisticallysignificant（t＝5.94and3.94, all P＝0.000）. For diameter of the stent was3.5mm and4mm, the scores of the imaging quality on HDCT and64-VCT were respectively3.75±0.46,4.13±0.35and3.69±0.75,3.75±0.45. The difference was no statisticallysignificant（t＝0.20and1.97，P＝0.850and0.060）.Conclusion Images of coronary calcium and stent on HDCT with high definitiontechnology can demonstrate the local lumen of coronary calcium and the stent internalstructure more clearly. The beam hardening artifact and partial volume effect ofcoronary calcium and stent was reduced by HDCT. The image quality of segmentcoronary artery calcification and the stent on HDCT have been significantly improved than that on64-VCT.