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目的评估能谱CT单能量成像对小肝癌(≤3cm)的显示能力及诊断准确率。方法对27例病人的31个HCC病灶行动脉晚期(LAP)和门静脉期(PVP)能谱CT扫描,采用两种扫描方案,A组采用常规140kV混合能量成像(A组),B组采用40～140keV单能量成像。比较两组肿瘤-肝脏信噪比(CNR)及平均影像噪声,并进行t检验。记录动脉晚期影像对病灶显示能力、阅片者信心及对病灶的主观评价。结果 B组中最高CNR分布在40、50和70keV。B组CNR值和病变醒目分数(lesionconspicuityscores,LCS)高于A组[两组CNR值:LAP,(3.36±2.07):(1.47±0.89);PVP,(2.29±2.26):(1.58±1.75);40～70keV的LCS为2.82、2.84、2.63、2.53,分别对应140keV的LCS为1.95;P<0.001]。B组在70keV水平获得最低影像噪声,B组影像质量高于A组(4.70:4.07,P<0.001)。结论能谱CT40～70keV单能量成像能提高小肝癌的检出能力,不会降低影像质量。要点①能谱CT扫描有助于提高小肝癌检出能力。②40～70keV单能量水平成像能够提高检测灵敏度。③前瞻性研究表明,单能量成像能提高诊断信心。
Objective To evaluate the ability of single-energy tomography (CT) imaging and its diagnostic accuracy for small hepatocellular carcinoma (≤3cm). Methods CT scan of LAP and PVP in 27 HCC lesions of 27 patients was performed by two kinds of scanning schemes. Group A received routine 140 kV mixed energy imaging (group A), while group B received 40 ~ 140keV single energy imaging. The tumor-liver signal-to-noise ratio (CNR) and mean image noise were compared between two groups and t-test was performed. Late arterial imaging records the ability of the lesion, the reader’s confidence and the subjective evaluation of the lesion. Results The highest CNR in group B was distributed at 40, 50 and 70 keV. CNR and lesionconspicuityscores (LCS) in group B were higher than those in group A [CNR values of two groups: LAP, (3.36 ± 2.07) :( 1.47 ± 0.89); PVP, (2.29 ± 2.26) :( 1.58 ± 1.75) ; The LCS of 40-70 keV was 2.82, 2.84, 2.63 and 2.53, corresponding to an LCS of 140 keV of 1.95; P <0.001]. Group B received the lowest image noise at 70 keV, and the quality of group B was higher than that of group A (4.70: 4.07, P <0.001). Conclusion The single-energy imaging of CT40 ~ 70 keV can improve the detection ability of small hepatocellular carcinoma without reducing the image quality. Essentials ① spectral CT scan can help improve the detection of small liver cancer. ②40 ~ 70 keV single energy level imaging can improve the detection sensitivity. Prospective studies have shown that single-energy imaging can improve diagnostic confidence.