第二代双源CT双能量虚拟平扫在直肠癌诊断中的应用评估

Clinical application of virtual non-contrast CT in diagnosing rectal cancer with second-generation dual-source computed tomography: a preliminary study

目的:评价双源CT双能量虚拟平扫(VNCT)技术在临床直肠癌诊断中的可行性。方法:对49例经肠镜活检确诊为直肠癌的患者行盆腔常规平扫及动脉期、门脉期双能量扫描,采用Liver VNC软件分别得到直肠癌病灶、髂腰肌、皮下脂肪、髂外动脉动脉期及门脉期的VNCT图像,分别测量并比较常规平扫及动脉期、门脉期VNCT这3组图像中病灶的平均CT值、图像噪声、图像质量和辐射剂量等方面的差异。结果:常规平扫与VNCT图中所测得的组织平均CT值除髂外动脉、皮下脂肪外差异均无统计学意义(P>0.05),VNCT的图像噪声低于常规平扫而信噪比高于常规平扫(P<0.01),但其图像质量略低于常规平扫(P<0.01),不过仍可达到诊断需求。动脉期VNCT为(3.96±0.46)分,门脉期VNCT为(3.80±0.54)分,省略常规平扫降低的辐射剂量为(31.49±1.47)%。结论:VNCT在直肠癌术前检查中可减低辐射剂量,且不影响诊断,具有潜在临床应用价值。

Objective To evaluate the clinical feasibility of dual-energy virtual non-enhanced CT in rectal cancer patients. Methods Forty-nine patients with rectal cancer proved by biopsy underwent conventional CT scan and pelvic dual-energy scan. The Liver VNC software was used to reform the virtual non-contrast CT （VNCT） at arterial and portal phase. The mean CT value, noise, image quality, and radiation dose for virtual non-contrast CT （VNCT） and true non-contrast CT （TNCT） imaging were compared. Results There was no statistical difference in mean CT value of all tissues except for external iliae artery and subcutaneous fat （P〉0.05）. The noise of VNCT images was lower than TNCT images （P〈 0.01）. The image quality of VNCT was lower than TNCT （P〈0.01） but was still diagnostic. The reduction of radiation dose by omitting the TNCT scan was about （31.49±1.47）%. Conclusions VNCT scan could reduce radiation dose and may potentially replace TNCT for muhi-phase rectum preoperative staging.