ISSN 1004-4140
CN 11-3017/P

双层探测器光谱CT虚拟平扫在儿童胸部CT增强扫描中的应用

Application of Dual-layer Detector Spectral Computed Tomography Virtual Non-contrast Scanning in Enhanced Chest Computed Tomography for Children

  • 摘要: 目的:讨论双层探测器光谱CT(DLCT)虚拟平扫(VNC)技术在儿童胸部CT增强检查中应用的可行性。方法:回顾性分析我院在双层探测器光谱CT上扫描的51例儿童增强胸部CT影像数据及临床资料。对每例原始图像采取相同方案进行处理:分别利用静脉期光谱基数据(SBI)进行投影空间光谱重建得到VNC图像,并和常规真实平扫(TNC)图像从图像质量和辐射剂量两方面进行比较:选用两位高年资影像诊断医生分别在两组影像上测量肺动脉干、胸主动脉干、竖脊肌、肺部组织、胸壁下皮下脂肪的CT值和SD值,计算相应影像的信噪比(SNR)和对比度噪声比(CNR),分别记录平扫期、动脉期、静脉期的辐射剂量;对两组图像运用5分法进行主观评分,采用Kappa检验分析两位医师对两种图像主观评价的一致性,采用Mann-Whitney U检验比较两种图像的图像质量的主观评分;运用配对样本t检验对组间图像质量和辐射剂量进行客观统计学分析。结果:图像质量客观评价中各结构的SNR、CNR及主观评分组两组之间无明显统计学差异,TNC组和VNC组的主观图像评分中位数均为4分;VNC组有效剂量长度乘积(DLP)(298.14±119.40)mGy·cm和有效辐射剂量(ED)(4.27±1.34)mSv均显著低于TNC组的DLP(437.31±178.28)mGy·cm和ED(6.26±2.00)mSv,VNC组两期扫描相比TNC组3期扫描DLP降低了31.82%,ED降低了31.79%。结论:将光谱CT虚拟平扫VNC图像用于儿童胸部增强扫描中以替代常规平扫期TNC图像,有较好的图像质量用于诊断,并能够显著降低辐射剂量。

     

    Abstract: Objective: This study aimed to explore the feasibility of applying dual-layer detector spectral computed tomography (DLCT) virtual non-contrast (VNC) technology in pediatric enhanced chest CT examinations. Methods: Retrospective analysis was conducted on the enhanced chest CT imaging data and clinical information of 51 children who underwent DLCT scanning at Wuhan Union Hospital. The same processing protocol was applied to each original image. VNC images were obtained using projection space spectral reconstruction from the venous phase spectral base images (SBI) and compared with true non-contrast (TNC) images regarding image quality and radiation dose. Two radiologists measured the CT and SD values of the pulmonary artery trunk, aorta trunk, erector spinae, lung tissue, and subcutaneous fat of the chest wall on image sets, calculating the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Non-contrast, arterial, and venous phase radiation doses were recorded. Subjective image quality scores were assigned using a 5-point Likert scale, and inter-observer consistency was assessed with the Kappa test. The Mann–Whitney U test compared subjective scores, while the paired t-test was used for objective image quality and radiation dose analyses. Results: Objective evaluation of image quality showed no significant statistical differences between the SNR, CNR, and subjective scores of both groups. The median subjective image scores for TNC and VNC were 4 points. The DLP and ED values of the VNC group (298.14±119.40) mGy·cm, (4.27±1.34) mSv were significantly lower than those of the TNC group (437.31±178.28) mGy·cm, (6.26±2.00) mSv. The DLP and ED of the VNC group reduced by 31.82% and 31.79%, respectively, compared to the TNC group. Conclusion: Spectral CT virtual non-contrast (VNC) images as a substitute for conventional non-contrast (TNC) images in pediatric enhanced chest scans offers satisfactory diagnostic image quality and can significantly reduce radiation dose.

     

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