CAJ | 학술논문

目的探讨宝石能谱计算机断层扫描(computed tomography,CT)70 keV单能量图像在后颅窝成像中提高图像质量及去除硬化伪影的价值.方法①将2011年6月至2012年10月在首都医科大学附属北京天坛医院进行头部宝石能谱CT 70 keV单能量模式平扫的87例以及同期头部宝石能谱CT常规混合能量CT平扫400例患者影像学资料分别建立数据库.②从上述两个数据库中采用随机序数法分别抽取20例患者资料,测定双侧内听道中点、四脑室最大层面桥脑中心及小脑白质20 mm2感兴趣区CT值及其标准差,图像质量用噪声水平(CT值标准差)衡量,比较两组图像质量.另外,从上述两个数据库中采用随机序数法分别抽取30例患者资料,进行后颅窝伪影评分,比较两组评分差异.结果能谱扫描模式下70 keV单能量图像所测得两组双侧内听道中点、四脑室最大层面桥脑中心及小脑白质的噪声水平中位数(四分位数)分别为(单位:HU):70 keV单能量图像3.96(3.60,4.24)、3.66(3.40,3.92)、3.37(3.06,3.65),混合能量图像5.52(5.16,5.80)、4.52(4.15,5.36)、4.26(3.95,4.74),与混合能量组比较,70 keV单能量组图像后颅窝脑组织不同位置噪声水平均降低,差异有显著性,P均<0.001.后颅窝伪影方面,70 keV单能量组图像评分高于混合能量组,两组中位数和四分位数分别为单能量组4(3,4)和混合能量组3(2,3),差异有显著性(P<0.001).结论能谱扫描模式下70 keV单能量图像经初步研究显示,能够满足后颅窝诊断需要,并且与常规混合能量图像相比较,能够显著降低后颅窝脑实质图像噪声,提高后颅窝图像质量、抑制后颅窝伪影.
목적탐토보석능보계산궤단층소묘(computed tomography,CT)70 keV단능량도상재후로와성상중제고도상질량급거제경화위영적개치.방법①장2011년6월지2012년10월재수도의과대학부속북경천단의원진행두부보석능보CT 70 keV단능량모식평소적87례이급동기두부보석능보CT상규혼합능량CT평소400례환자영상학자료분별건립수거고.②종상술량개수거고중채용수궤서수법분별추취20례환자자료,측정쌍측내은도중점、사뇌실최대층면교뇌중심급소뇌백질20 mm2감흥취구CT치급기표준차,도상질량용조성수평(CT치표준차)형량,비교량조도상질량.령외,종상술량개수거고중채용수궤서수법분별추취30례환자자료,진행후로와위영평분,비교량조평분차이.결과능보소묘모식하70 keV단능량도상소측득량조쌍측내은도중점、사뇌실최대층면교뇌중심급소뇌백질적조성수평중위수(사분위수)분별위(단위:HU):70 keV단능량도상3.96(3.60,4.24)、3.66(3.40,3.92)、3.37(3.06,3.65),혼합능량도상5.52(5.16,5.80)、4.52(4.15,5.36)、4.26(3.95,4.74),여혼합능량조비교,70 keV단능량조도상후로와뇌조직불동위치조성수평균강저,차이유현저성,P균<0.001.후로와위영방면,70 keV단능량조도상평분고우혼합능량조,량조중위수화사분위수분별위단능량조4(3,4)화혼합능량조3(2,3),차이유현저성(P<0.001).결론능보소묘모식하70 keV단능량도상경초보연구현시,능구만족후로와진단수요,병차여상규혼합능량도상상비교,능구현저강저후로와뇌실질도상조성,제고후로와도상질량、억제후로와위영.
Objective To discuss the value of improving the quality of the image and the removal of hardening artifact for the usage of GE Discovery computed tomography(CT)750 HD 70 keV monochromatic image in the posterior cranial fossa imaging. Methods ①From June 2011 to October 2012, 87 patients were taken spectrum scan mode head CT scan in our hospital, 400 patients were taken conventional mixed energy head CT scan using GE Discovery CT750 HD, their image informations were used to create database respectively.②From each database, 20 cases were extracted using random number method at random respectively. CT value and its standard deviation(SD) of 20 mm2 region of interest(ROI) were measured for different position of brain tissue inside posterior cranial fossa in the cases selected, including:midpoint of the bilateral internal auditory meatus, pons center and cerebellar white matter in the level with maximum 4th ventricle. Image quality was measured by the noise level(CT value standard deviation SD), and statistical analysis between the 2 groups was taken. In addition, from each database, 30 cases were extracted using random number method at random respectively. Then for the cases selected, score for the posterior fossa artifact was taken and a statistical analysis was made. Results All cases of spectrum scan mode 70 keV monochromatic image in our study can meet the diagnosis need of posterior cranial fossa. Median noise level of bilateral internal auditory meatus midpoint, pons center and cerebellar white matter in the level with maximum 4th ventricle are(unit:HU):70 keV monochromatic image group3.96(3.60, 4.24)、3.66(3.40, 3.92)、3.37(3.06, 3.65), mixed energy head CT group 5.52(5.16, 5.80)、4.52(4.15, 5.36)、4.26(3.95, 4.74), respectively. Compared to mixed energy head CT, noise index of different brain tissue position inside the posterior fossa is decreased significantly, there are significant statistical differences, all P<0.001. As to posterior cranial fossa artifact, median score of 70 keV monochromatic image(4, 3-4) is higher than the mixed energy CT image(3, 2-3), and there are significant statistical differences, P<0.001. Conclusions Spectrum scan mode 70 keV monochromatic image can meet the diagnosis need of posterior cranial fossa after initial studies. Compared with conventional mixed energy CT image, 70 keV monochromatic image can significantly reduce image noise of the posterior fossa brain parenchyma, improve image quality, and inhibit the artifact of posterior cranial fossa.