双能CT虚拟平扫技术在胰腺癌中的应用评估

Evaluaion of Application with Dual-Energy CT:Virtual Non-Contrast Images of the Pancreatic Carcinoma

目的探讨双能CT虚拟平扫(VNC)技术在胰腺癌评估中替代常规真实平扫(TNC)的可行性及临床价值。方法搜集经手术病理证实的33例胰腺腺癌患者的病例资料。所有患者均行双能CT平扫和双期增强扫描,增强图像经双能软件处理得到VNC图及碘分布图(碘图)。比较TNC、动脉期虚拟平扫(AVNC)、实质期虚拟平扫(VVNC)三组图像中胰腺癌组织的CT值、标准差值(SD)、信号噪声比(SNR);比较三组图像主观质量评分以及对胰腺癌的检出敏感性差异。结果胰腺癌组织AVNC及VVNC的CT值与TNC的CT值呈正相关(动脉期r=0.793,实质期r=0.555);TNC、AVNC和VVNC三组图像中胰腺癌组织的CT值由大到小依次为TNC、AVNC、VVNC,SD值由大到小依次为TNC、VVNC、AVNC,SNR值由大到小依次为AVNC、VVNC、TNC,分别两两比较三组病灶的CT值、SD及SNR值,三者TNC与AVNC及VVNC之间均有统计学差异(P<0.05),AVNC与VVNC之间无统计学差异(P>0.05);三组图像质量均满足临床诊断要求,主观质量评分无统计学差异(P>0.05);三组图像对胰腺癌检出敏感性差异无统计学意义(P>0.05)。结论双能CT所得VNC图像质量完全能满足诊断要求,可以代替以往动态增强扫描中作为基线的常规平扫,碘图具有额外的价值。

Objective To explore the feasibility of use of virtual non-contrast images in te place of conventional non- contrast images of dual-energy computed tomography（DECT） in evaluating pancreatic carcinoma. Methods Thirty-three patients with pancreatic carcinoma proved by pathological diagnosis underwent abdominal DECT using a triphasic protocol consisting of true non-contrast（ TNC）, arterial-phase（AP） and venous-phase（VP） acquisitions. The virtual non-contrast CT images and iodine images were reconstructed based on the enhanced imaging data. The average CT value, image noise（ SD）, signal-noise ratio（SNR） of pancreatic carcinoma tissue, score of subjective diagnosis and the detection sensitivity of pancre- atic carcinoma were compared among TNC,AVNCand VVNC. Results The CT value of AVNC and VVNC in pancreatic carcinoma tissue was positively correlated with that of TNC（ AVNC r = 0. 793, VVNC r = 0.555）. The average CT value of pancreatic carcinoma tissue from large to small was TNC 〉 AVNC 〉 VVNC, the SD of lesion obtained from AVNC, VVNC and TNC was TNC 〉 VVNC 〉 AVNC, and the SNR was AVNC 〉 VVNC 〉 TNC. By respective pairwise comparison of the CT value, SD and SNR of the lesion among three groups , there were significant difference between TNC and AVNC, TNC and VVNC （ P 〈 0.05 ）, and there was no significant difference between AVNC and VVNC （ P 〉 0.05 ）. All three groups of image quality could meet the clinical diagnostic requirements. There was no significant difference in subjective quality scores a- mong the three groups （ P 〉 0.05 ）. The detection sensitivities of pancreatic carcinoma were not significantly different among the three groups （P 〉 0.05）. Conclusion Image quality of VNCT derived from dual-energy CT can meet the diagnostic requirements. VNCT could be obtained with similar image quality as TNCT. Iodine images can provide additional diagnostic value.