泪道CT造影中联合三维重建的价值和辐射剂量研究

Value of 3D reconstruction in CT-dacryocystography and its radiation exposure

目的评估及对比泪道CT造影检查中接受平扫与平扫联合三维重建患者所暴露的辐射剂量和获得的有效图像信息数量,探讨三维重建技术在泪道CT造影中的价值和必要性。方法回顾性分析96例因泪道阻塞需行泪道CT造影的患者,其中49例患者进行泪道CT平扫检查(平扫组),47例患者进行泪道CT平扫+三维重建检查(重建组)。对比观察两组患者在检查过程中暴露的射线剂量,获得的总CT图片的数量,统计有泪道相关参考价值的有效CT图片数量,并进行对比分析。结果重建组较平扫组暴露更多辐射剂量[(504.7±405.8)mGy×cm vs(363.8±159.9)mGy×cm,P=0.026],得到更多的总CT数(289±74 vs 230±57,P=0.000)和有效CT数(132±36 vs 112±29,P=0.003),但重建组CT有效率降低(45.67%±0.51%vs48.70%±0.71%,P=0.000)。结论平扫联合三维重建较平扫检查需暴露更多的辐射剂量,虽得到较多有效泪道CT图像,但有效率下降;两种检查方法均应该考虑减少与泪道显影无关的射线暴露。

Objective To evaluate and compare the radiation dose and the number of images with valid data obtained during the plain scan and combined 3D reconstruction in CT-dacryocystography,and explore the necessity of 3D reconstruction for nasolacrimal duct obstruction diagnosis.Methods A retrospective analysis was performed in 96 patients with nasolacrimal duct obstruction requiring CT-dacryocystography,of which 49 patients underwent plain nasolacrimal CT scan(plain scan group),and the other 47 patients underwent plain nasolacrimal CT scan+3D reconstruction(reconstruction group).The dose of radiation exposed during the examination,the number of total CT images obtained,and the number of CT images with valid data of lacrimal tract were compared and analyzed between the two groups.Results The reconstruction group was exposed to more radiation([504.7±405.8]mGy×cm vs[363.8±159.9]mGy×cm,P=0.026)than the plain scan group,and obtained more CT images(289±74 vs 230±57,P=0.000)and CT images with valid data(132±36 vs 112±29,P=0.003),but the proportion of CT images with valid data in the reconstruction group was lower([48.70±0.71]%vs[45.67±0.51]%,P=0.000).Conclusion The combined three-dimensional reconstruction technique in CT-dacryocystography increases radiation exposure risk compared to plain scan.It obtains more CT images of lacrimal ducts,but the efficiency is relatively low.Reducing radiation exposure that is not related to the imaging of the lacrimal duct should be considered in both of the two methods.