【摘要】 目的 探讨双能量CT(DECT)获得的虚拟非对比增强（VNC）图像在评估肺内部分实性结节（PSN）方面的可行性，并与真实非增强（TNC）图像质量进行比较。方法 回顾性收集我院2022年1月～2023年1月46例孤立性肺结节患者，同时行TNC扫描和增强DECT扫描（动脉期和静脉期），并根据双期DECT重建双期VNC图像。在双期VNC和TNC图像中测量PSN和同侧竖脊肌的CT值、噪声及病变直径，计算PSN的信噪比和对比度噪声比。记录TNC和VNC模式下的有效辐射剂量。由2位经验丰富的放射科医生使用5分量表进行主观评分。采用非参数检验比较不同扫描阶段图像的主观、客观参数和有效辐射剂量，采用Kappa检验用于评估两位医生主观评分的一致性。结果 动、静脉期VNC与TNC图像的客观评价指标（直径、CT值、噪声、信噪比、对比度噪声比）的差异无统计学意义(P>0.05)。TNC图像主观评分均值最高，静脉期VNC图像次之，动脉期主观评分最低，3组评分差异有统计学意义（P<0.001），但双期VNC均满足诊断要求。2位医生主观评分一致性较强(0.63～0.73)。VNC代替TNC约降低30%的辐射剂量。结论 双瞬切能谱增强静脉期虚拟平扫技术能够提供与常规平扫相似的图像质量，且能显著减少患者辐射剂量，尤其适用于需要多次复查的患者。更多还原

【Abstract】 Objective To investigate the feasibility of utilizing virtual non-contrast enhanced(VNC) images derived from dualenergy computed tomography(DECT) for the assessment of part-solid nodules(PSN) within the lung, and compare the image quality with that of true non-enhanced(TNC) images. Methods A retrospective analysis was conducted on 46 patients with solitary pulmonary nodules at our institution from January 2022 to January 2023. Patients underwent both TNC scanning and contrast-enhanced DECT scanning during the arterial and venous phases, with dual-phase VNC images reconstructed from the dual-phase DECT data. CT values, noise(standard deviation), and lesion diameters of PSN and the ipsilateral erector spinae muscle were measured on both dual-phase VNC and TNC images. The signal-to-noise ratio and contrast-to-noise ratio for PSN were calculated. Effective radiation doses in TNC and VNC modes were recorded. Subjective scoring was performed by two experienced radiologists using a 5-point scale. Non-parametric tests were employed to compare the subjective and objective parameters, as well as the effective radiation doses, of images obtained at different scanning phases. Kappa tests were utilized to evaluate the inter-rater agreement of the subjective scores provided by the two radiologists. Results The objective evaluation metrics(diameter, CT value, standard deviation, signal-to-noise ratio, contrast-to-noise ratio) between arterial and venous phase VNC and TNC images were not statistically significant(P>0.05). The mean subjective score for TNC images was the highest, followed by venous phase VNC images, with arterial phase scores being the lowest. There was a statistically significant difference in the scores among the three groups(P<0.001), yet both phases of VNC met diagnostic requirements.The inter-rater agreement for the subjective scores between the two radiologists was strong, with a range of 0.63 to 0.73. The use of VNC in place of TNC resulted in an approximate 30% reduction in radiation dose. Conclusion The dual-phase spectral CT with virtual non-contrast venous phase imaging provides image quality comparable to conventional non-contrast imaging and significantly reduces patient radiation exposure, making it particularly suitable for patients requiring multiple follow-up examinations.更多还原