低管电压和低对比剂联合IMR技术在椎动脉V3段3DCTA中的可行性研究

Feasibility study of low tube voltage and low contrast medium combined with IMR technology in 3DCTA of vertebral artery V3 segment

目的探讨低管电压自动管电流调节(ATCM)和低对比剂浓度、剂量及注射速率联合全模型迭代重建(IMR)技术在椎动脉V3段三维CT血管成像(3DCTA)中的可行性。方法选取该院2019年11月至2020年5月临床怀疑上颈椎、颅颈交界区病变而行颈部椎动脉V3段3DCTA的患者60例,采用随机数字表法将患者分成A、B两组,每组各30例。A组采用80 kV、平均管电流为50 mAs的ATCM技术,25 mL注射速率为3 mL/s的对比剂碘海醇(碘含量300 mg/mL)联合IMR技术进行检查;B组采用120 kV、150 mAs固定管电流,50 mL注射速率为5 mL/s的对比剂碘帕醇(碘含量370 mg/mL)联合滤波反投影(FBP)重建技术进行检查。测量并比较两组CT值、噪声、信噪比(SNR)、对比噪声比(CNR)、图像敏感度(FOM),并对所得图像的质量进行评价。记录CT容积剂量指数(CTDIvol)及剂量长度乘积(DLP),计算有效剂量(ED)。结果两组图像椎动脉的CT值比较差异无统计学意义(P>0.05);但A组噪声小于B组(P<0.05),A组SNR、CNR及FOM均大于B组(P<0.05)。两组图像质量[(4.78±0.41)分vs.(4.85±0.35)分]均满足临床诊断要求,图像质量主观评价差异无统计学意义(P>0.05)。A组CTDIvol、DLP、ED均低于B组(P<0.05)。A、B组对比剂碘摄入量分别为7.5、18.5 g,对比剂碘流率分别为0.9、1.85 mg/s,与B组比较,A组碘摄入量及碘流率分别下降了59.5%、51.4%。结论低管电压ATCM和低对比剂浓度、剂量及注射速率联合IMR技术不仅可保证椎动脉V3段3DCTA图像质量,也减少了患者所接受的辐射剂量,降低了对比剂碘摄入量及碘流率。

Objective To investigate the feasibility of low-voltage,automatic tube current adjustment(ATCM)and low contrast agent concentration,dose and injection rate combined with full-model iterative reconstruction(IMR)in vertebral artery V3-segment three-dimensional CT angiography(3DCTA).Methods A total of 60 patients with suspected upper cervical spine,craniocervical junction lesions undergoing cervical vertebral artery V3 segment 3DCTA in this hospital from November 2019 to May 2020 were selected and divided into the group A and B by adopting the random number table method,30 cases in each group.The group A adopted the ATCM technology of 80 kV,average tube current of 50 mAs,25 mL of contrast agent iohexol(iodine content 300 mg/mL)combined IMR technology with an injection rate of 3 mL/s,while the group B adopted 120 kV,150 mAs fixed tube current,50 mL injection rate of 5 mL/s contrast agent iopamidol(iodine content 370 mg/mL)combined filter back projection(FBP)reconstruction technology.CT value,noise,signal-to-noise ratio(SNR),contrast noise ratio(CNR)and image sensitivity(FOM)were measured and compared between the two groups and the quality of the resulting images was evaluated.The CT volumetric dose index(CTDIvol)and dose-length product(DLP)were recorded,and the effective dose(ED)was calculated.Results There was no statistically significant difference in the vertebral arterial CT value between the two groups(P>0.05),but the noise of the group A was lower than that of the group B(P<0.05),SNR,CNR and FOM of the group A were greater than those of the group B(P<0.05).The image quality of the two groups met the requirements of clinical diagnosis[(4.78±0.41)points vs.(4.85±0.35)points],and there was no statistically significant difference in the subjective evaluation of image quality(P>0.05).The CTDIvol,DLP and ED levels in the group A were lower than those in the group B(P<0.05).The iodine intakes of contrast medium in the group A and group B were 7.5 g and 18.5 g,respectively,and the iodine flow rates of contrast agent were 0.9 and 1.85 mg/s,respectively,and compared with group B,the iodine intake and iodine flow rate of the group A were decreased by 59.5%and 51.4%,respectively.Conclusion Low tube voltage ATCM and low contrast concentration,dose and injection rate combined with IMR technology can not only ensure the 3DCTA image quality of vertebral artery V3 segment,but also reduce the radiation dose received by the patients,and reduce the iodine intake and iodine flow rate of contrast agent.