双层探测器光谱CT虚拟平扫联合40keV虚拟单能量成像用于降低小肠CT造影辐射剂量

目的 观察双层探测器光谱CT(DLCT)虚拟平扫(VNC)联合40 keV虚拟单能量成像(VMI)用于降低小肠CT造影(CTE)辐射剂量的价值。方法 回顾性分析63例接受CT真实平扫(TNC)及双期增强扫描的炎性肠病(IBD)患者，测算病变/组织结构在重建TNC,常规动、静脉期，虚拟动、静脉期平扫(VNC_a、VNC_v)及40 keV VMI图像中的CT值和图像噪声(SD)、信噪比(SNR)、对比度噪声比(CNR),以及剂量长度乘积(DLP)、容积CT剂量指数(CTDIvol)及有效剂量(ED);对比TNC及VNC图像、常规动脉期及40 keV VMI图像并进行客观评价；对常规扫描与VNC_v联合40 keV VMI CTE图像进行主观评价，并比较其辐射剂量。结果 TNC、VNC_a及VNC_v图像中，病变累积肠壁、未累及肠壁及腰大肌CT值差异均无统计学意义(P均>0.05)。病变肠壁、腹主动脉及回结肠静脉在40 keV VMI图像中的CT值、SNR及CNR均高于常规动脉期图像(...

Virtual non-contrast images combined with 40 keV virtual monoenergetic images for reducing radiation dose of CT enterography based on dual-layer spectral detector CT

Objective To observe the value of virtual non-contrast (VNC) image combined with 40 keV virtual monoenergetic image (VMI) for reducing radiation dose of CT enterography (CTE) based on dual-layer spectral detector CT (DLCT). Methods Data of 63 patients with inflammatory bowel disease (IBD)who underwent CT true non-contrast (TNC) scanning and dual-phase contrast scanning were retrospectively analyzed. CT values, noise (SD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) of lesion/tissue/structure on TNC, conventional arterial and venous phase, VNC of arterial and venous phase (VNC_a and VNC_v) and 40 keV VMI images were measured, and dose-length product (DLP), volume CT dose index (CTDIvol) and effective dose (ED) were calculated, respectively. Objective evaluation was performed to compare TNC and VNC, also between conventional arterial phase and 40 keV VMI. Subjective score and radiation dose were compared between conventional CT and VNC combined with 40 keV VMI. Results No significant difference of CT values of involved intestinal wall, non-involved intestinal wall nor psoas major muscle was found among TNC, VNC_a and VNC_v images (all P>0.05). CT values, SNR and CNR of involved intestinal wall, non-involved intestinal wall and psoas major muscle on 40 keV VMI images were all higher than those on conventional arterial phase CT images (all P<0.05). The subjective score of conventional CT and VNC_v combined with 40 keV VMI images was 4(4, 5) and 4(4, 5), without significant difference (P>0.05). Compared with conventional CT scanning, radiation dose of CTE using VNC_v combined with 40 keV VMI decreased about 67.53%. Conclusion DLCT VNC combined with 40 keV VMI could reduce radiation dose of CTE.