中文摘要：

目的 评估CT能谱成像在胰腺癌病灶显示中的价值.方法 选取本院行CT能谱检查,且病理证实为胰腺导管腺癌的113例患者.CT扫描期相分平扫、动脉晚期（AP）、门脉期（PP）;增强采用能谱扫描（GSI）模式.将感兴趣区（ROI）分别放置于病灶和胰腺实质处,重复测量3次,求得3次的平均值,计算病灶及胰腺实质AP和PP 40~140 keV的单能量CT值（CTmono值）、归一化CTmono值（以胰腺实质为标准）、对比噪声比（CNR）值及最佳单能量keV值,比较胰腺癌与胰腺组织间的差异,并将最佳单能量与70 keV单能量（相当于常规CT 120 kVp能量水平）进行比较.统计方法为配对t检验和符号秩和检验.结果 胰腺导管腺癌在AP及PP的最佳单能量为40 keV,AP和PP的最佳CNR平均值为2.31±1.02和2.38±1.02,70 keV CNR值为2.08±0.98和2.12±0.96,2期最佳CNR值均高于70 keV的CNR值.胰腺癌在70 keV时AP和PP的CTmono值分别为（58±13） HU和（71±19） HU,PP高于AP,40 keV 时AP和PP的CTmono值分别为（111±44） HU和（155±57） HU;胰腺癌在40 keV 时AP和 PP的归一化CTmono值的中位数分别为47.0%和53.9%,70 keV时分别为57.7%和61.8%,40 keV归一化CTmono值低于70 keV,有显著性差异.结论 CT能谱成像显示胰腺癌为相对乏血供、进行性强化的病灶;最佳单能量成像能够提高胰腺癌病灶的显示效果.

英文摘要：

Objective To explore the value of CT spectral imaging in the demonstration of pancreatic ductal adenocarcinoma （PDAC）.Methods 113 patients were scanned by CT spectral,and gemstone spectral imaging （GSI） was performed in late arterial phase （AP） and portal venous phase （PP）.All diagnosis were pathologically confirmed.The ROIs were placed on the lesion and on the pancreatic parenchyma.The ROI files including the CTmono values and the normalized CTmono values （normalized to pancreatic parenchyma） were saved.The works were performed three times repeatedly.CNR values ranged from 40 keV to 140 keV and the optimal keV in AP and PP were calculated.The differences of CTmono values, normalized CTmono values,and CNR were compared between the optimal keV and 70 keV（equivalent to conventional 120 kVp energy level）.Paired t-test and Wilcoxon signed rank test were performed.P〈0.05 was considered statistically significant.Results The optimal monochromatic energy of PDAC were 40 keV in both AP and PP.The optimal CNR values（mean±standard） were 2.31±1.02 and 2.38±1.02 in AP and PP,while the corresponding values of 70 keV were 2.08±0.98 and 2.12±0.96.The CNR of 40 keV was higher than that of 70 keV in both AP and PP.The CTmono values of PDAC were （58±13） HU and （71±19） HU at 70 keV and were （111±44） HU and （155±57） HU at 40 keV in AP and PP.The CTmono value in PP was higher than in AP.The median of normalized CTmono values of PDAC at 40 keV were 47.0% and 53.9% in AP and PP, and were lower than those of 70 keV,which were 57.7% and 61.8%.The differences of normalized CTmono values between 40 keV and 70 keV were significant.Conclusion CT spectral imaging manifests that PDAC is hypovascular both in AP and PP and is progressively enhanced form AP to PP.There is maximal conspicuity of tumor in AP, and the optimal monochromatic imaging can improve the conspicuity of PDAC lesion.