双源双能CT使用单能量或双能量扫描及不同重建方法在肝动脉相成像中的优化  

Optimization of the scan protocol of single energy or dual energy and reconstruction method in hepatic arterial phase

作　　者：杜美美[1] 陈博[1] 严志汉[1] 陈拓荣 田雨生[2] DU Meimei CHEN Bo YAN Zhihan CHEN Tuorong TYAN Yeusheng(Department of Radiology, the Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325027 Chung Shan Medical University, Taichung, 40201)

机构地区：[1]温州医科大学附属第二医院放射科,浙江温州325027 [2]台湾中山医学大学,台湾台中40201

出　　处：《温州医科大学学报》2017年第8期576-579,584,共5页Journal of Wenzhou Medical University

摘　　要：目的:比较双源双能CT双能量扫描标准融合图像与单能量扫描图像的图像质量和辐射剂量,对比滤波反投影(FBP)法和迭代(IR)法进行图像重建后的图像质量,为临床选择最佳的扫描和重建方式提供依据。方法:使用2种体型含高、低密度病灶的动脉期肝脏假体,采用第二代双源双能CT分别行单能量(120kVp)和双能量(100kVp/Sn140kVp)扫描,随后均采用FBP和IR方法进行图像重建。记录单能量和双能量扫描的辐射剂量。对图像进行感兴趣区圈选、定量分析,计算病灶的对比噪声比(CNR)和质量因数(FOM)。结果:在瘦体型假体,FBP法和IR法高密度病灶双能量扫描图像的CNR较单能量扫描高,差异有统计学意义(P<0.05),而低密度病灶双能量扫描和单能量扫描图像的CNR差异无统计学意义(P>0.05)。在肥胖体型假体,FBP法和IR法所有病灶双能量扫描图像的CNR均较单能量扫描高,差异有统计学意义(P<0.05)。双能量CT扫描剂量较单能量扫描剂量高。在瘦体型假体IR法低密度病灶双能量扫描的FOM较单能量扫描低,差异有统计学意义(P<0.05)。其余病灶IR法和FBP法单能量和双能量扫描图像间FOM差异无统计学意义(P>0.05)。IR图像的CNR均较FBP图像佳(P<0.05)。结论:综合考虑图像质量和扫描辐射剂量,双能量CT扫描标准融合图像与单能量扫描图像无明显差异,IR图像比FBP图像CNR高,建议肝动脉相扫描图像以IR重建影像,根据是否需要物质分离信息选择是否进行双能量扫描。Objective： To Compare the image quality and radiation dose of image acquired from a dual energy CT scan with image obtained from a single energy scan in the second dual-source generation system abdominal CT combined with iterative reconstruction. To determine the optimal scan methods and reconstruc- tion methods for clinical work, Methods： Two size arterial phase liver phantoms containing two density lesions （low and high） was scanned using a second generation dual source dual energy CT （DSCT） scanner in the single energy mode （120 kVp） and the dual energy mode （100 kVp/Sn 140 kVp）. Images were reconstructed with both filtered back-projection （FBP） and iterative reconstruction （IR） algorithms. Volume CT dose index （CTDIvot） and the dose length product （DLP） recorded from all protocols were used to dose evaluation. For quantitative analyses of the phantom, the contrast-to-noise ratio （CNR） and figure of merit （FOM） were measured. Results： For small size phantom, CNR of high density lesions in the mixed images derived from a dual energy CT scan was significantly higher than that in images acquired with a single-energy scan （P〈0.05）, while there was no statistically significant difference existed in low density lesions （P〉0.05）. For big size phantom, CNR of both high and low density lesions in dual-energy mixed images showed a higher CNR in comparison to single-energy images （P〈0.05）. Dose of dual energy CT scan was higher than that of single energy scan. As to FOM, except in the low density lesions group IR images of small size phantom, there was no significant difference between all lesions of the dual energy scanning standard fusion image and single energy scanning image （P〉0.05）. Compared with FBP images, CNR of IR images was significantly better than that of FBP images （P〈0.05）. Conclusion： Take both the image quality and radiation dose to consider, there is no obvious difference between the dual energy scanning standard fusion image

关 键 词：双源双能CT 放射摄影术 腹部 辐射剂量 影像质量 

分 类 号：R814[医药卫生—影像医学与核医学]