能谱CT单能成像对乏血供肝癌的诊断价值

Preliminary application of gemstone spectral imaging in the diagnosis of hypovascular liver neoplasms

目的探讨宝石能谱CT单能量成像在显示乏血供肝癌病灶中的使用价值。方法运用宝石能谱CT对34例乏血供肝癌患者进行能谱扫描,对原始数据进行常规混合能量重建(140 kVp)和单能量重建(65 keV),在GE AW4.4工作站上通过能谱浏览器(GSI Viewer)分别选用混合能量图像和单能量图像对同层面病灶进行观察,观察病灶的数目、病灶与周边正常肝组织的对比(CT值差值)、背景噪声、对比噪声比和主观评分,并做配对t检验。结果在同一层面上单能图像发现的病灶数目明显多于混合能量图像。34例患者中仅有12例结果一致,22例单能图像显示病灶数目多于混合能量图像。单能与混合能图像中病灶与正常肝组织间的对比、对比噪声比及主观评分分别为(21.19±15.23)和(11.13±10.09)、(1.53±0.88)和(0.88±0.68)、(4.32±0.65)和(3.7±0.53),各项指标间的差异有统计学意义(P<0.01),图像背景噪声为(14.02±2.08)和(13.64±2.07),差异无统计学意义。结论宝石能谱CT GSI模式扫描重建65 keV单能图像可明显提高乏血供肝癌的检出率。

Objective To evaluate the value of gemstone spectral imaging（GSI） in the diagnosis of hypovascular liver neoplasms.Methods 34 cases hypovascular liver neoplasms of GSI CT data were retrospectively studied.GSI Viewer was applied to acquire iodine-based image,65 keV monochromatic images and 140 kVp conventional polychromatic images.The number of lesions,contrast ratio（CR）,singal-to-noise ratio（SNR）,contrast-to-noise ratio（CNR） and subjective image quality were calculated in the same slice,Paired t tests were used to compare differences between the two modes.Results Only 12 lesions could be found in conventional polychromatic images while monochromatic images revealed 34 lesions.Compared with polychromatic images,the CR,CNR and subjective image quality were higher in monochromatic images,（21.19±15.23） vs（11.13±10.09）;（1.53±0.88） vs（0.88±0.68）;（4.32±0.65） vs（3.7±0.53）.SNR was no statistical difference between monochromatic images and conventional polychromatic images,（14.02±2.08） vs（13.64±2.07）.Conclusion GSI 65 keV monochromatic images could increase significantly the detection of hypovascular liver neoplasms.