摘要
目的观察双能量CT心肌灌注成像中线束硬化伪影(beam-hardening,BH)的好发部位,比较不同单能量成像对线束硬化伪影的校正效果和图像质量。方法对84例需行心脏CT增强检查的拟诊或确诊冠心病患者进行双源双能量CT(100 k Vp/Sn 140 k Vp)心肌灌注扫描,特殊软件后处理得到心肌碘分布图和65、75、85、95、105 ke V单能量图像,以自动生成的M图像(平均加权混合120 k V)为对照,观察线束硬化伪影的发生部位和数量,根据心肌碘含量、CT值、图像背景噪声(SD)、信噪比(SNR)、对比噪声比(CNR)和图像质量评分综合评价心肌单能量成像价值。结果 65 ke V单能量图像伪影计数为274,随着能量增加,伪影计数逐渐减少(P<0.05);左心室的基底段伪影最明显(36.5%,100/274),其次为间隔壁(25.91%)、上腔静脉旁段(24.82%)、后壁(12.77%)(P<0.05);心肌伪影区碘含量(-2.37±0.84)mg/g低于非伪影区碘含量(3.5±0.92)mg/g(t=-19.36,P<0.01);85 ke V的非伪影心肌CT值(93.52±18.52)HU与120 k V[(96.06±16.32)HU]最接近,CT值的组间差异有统计学意义(P<0.01);85 ke V的SD最小(12.98±3.16,P<0.01),非伪影心肌的SNR:75 ke V(6.89±1.79)与85 ke V(6.5±1.7)较高,二者无明显差别(t=1.5,P=0.14),CNR:75 ke V最高(18.79±6.76,P<0.01),85 ke V(15.4±5.67)与65 ke V(15.53±4.56)之间无明显差别(t=0.27,P=0.79);图像质量评分:85 ke V最高,两名诊断医师对六组图像进行评分,结果高度一致(Kappa=0.79,P<0.01)。结论左心室的基底段、间隔壁和上腔静脉旁易出现线束硬化伪影;正常心肌密度在85 ke V与混合能量120 k V最接近,85 ke V能在最有效纠正线束硬化伪影的同时保证较好的图像质量。
Objective To observe the sites with high incidences of beam-hardening （BH） artifacts in dual-energy CT myocardial perfusion images, and compare the image quality and effect for BH correcting in different monochromatic energy images via dual-source dual-energy CT myocardial perfusion imaging. Methods Eighty-four patients requiring cardiac enhancement-CT examination with suspected or definite coronary artery disease underwent dual-energy （100 kVp/Sn 140 kVp） myocardial perfusion imaging with dual-source CT in our department, and were enrolled in this study. Iodine maps and monoenergetic images under 65, 75, 85, 95 and 105 keV were obtained after the process of specialized post-processing software. M image （weighted polychromatic 120 kV） was generated by the system automatically and served as control. The sites and numbers of beam-hardening artifacts were observed and counted. The rate of artifacts, objective measurements of myocardial iodine content, CT value, signal-to-noise ratio （ SNR）, contrast to noise ratio （CNR） and subjective image quality grades were used to comprehensively assess the value of monoenergetic images. Results The number of artifacts was 274 on 65 keV images, and was reduced gradually with the increase of keV （ P 〈 0. 05）. The sites with high incidence of artifacts were the left ventricular basal segment 36.5 % （ 100/274）, followed by ventricular septal segment 25.91% （ 71/274 ）, superior-vena-cava-besides segment 24.82% （68/274） and posterior segment 12.77% （35/274）（P 〈 0. 05）. The iodine content of myocardium was - 2.37 ＋ 0.84 mg/g under artifacts, significantly lower than non-under artifacts [ 3.5 ±0.92 rag/g, t = - 19.36, P 〈0.01 ]. The non-artifact myocardial CT number of 85 keV was 93.52± 18.52 HU for non-artifact, which was the closest to polychromatic 120 keV （96.06 ±16.32 HU）, and significant difference was seen between them （P 〈 0.01 ）. SD of 85 keV was the lowest （ 12.98 ±3. 16）. SNR of non-under artifacts in the
出处
《第三军医大学学报》
CAS
CSCD
北大核心
2015年第16期1662-1667,共6页
Journal of Third Military Medical University
基金
国家临床重点专科建设项目(国卫办医函[2013]544号)~~
