膝关节水平小剂量测试技术在大螺距、低千伏下肢动脉CT成像中的应用研究  

Efficacy of test bolus technique for high pitch,low voltage CT angiography of the pelvic and lower extremity vessels

作　　者：胡蓝月[1] 周文珍[1] 王薇[1] 许权[1] 尚晓彤 张娅梅[1] 赵晓静[1] 李同 HU Lan-yue;ZHOU Wen-zhen;WANG Wei;XU Quan;SHANG Xiao-tong;ZHANG Ya-mei;ZHAO Xiao-jing;LI Tong(Department of Radiology,Nanjing First Hospital,Nanjing Medical University,Jiangsu 210006,China)

机构地区：[1]南京医科大学附属南京医院(南京市第一医院)医学影像科,江苏南京210006 [2]南京市江宁区中医院放射科,江苏南京211100

出　　处：《影像诊断与介入放射学》2023年第2期130-134,共5页Diagnostic Imaging & Interventional Radiology

摘　　要：目的评价膝关节水平小剂量测试技术在大螺距、80 kVp下肢动脉CT成像(CTA)中的应用价值,并评价下肢动脉CTA辐射剂量及图像质量。方法将共60例怀疑下肢动脉硬化闭塞症患者分为两组。A组:30例患者,CTA扫描使用大螺距(3.0),80 kVp,重组方法为迭代重组。B组:30例患者,CTA扫描参数为螺距1.0,120 kVp,滤过反投影法重组。所有A组患者利用膝关节水平小剂量测试扫描个体化计算CTA扫描触发时间。比较两组CTA图像平均血管强化CT值、图像信噪比(SNR)、对比噪声比(CNR)、图像质量评级及辐射剂量。结果A组血管平均CT值、SNR及CNR分别为(494.41±89.27)HU,50.12±19.21、43.37±16.83,B组对应值分别为(320.52±73.29)HU、36.71±10.43、26.27±9.54,两组间均存在统计学差异(P均<0.001)。两组间图像质量评级不存在统计学差异(P>0.05)。两组剂量长度乘积具有统计学差异[A组(152.20±10.23)mGy×cm,B组(789.14±96.89)mGy×cm,P<0.001]。小剂量测试扫描中A组30例患者共获得60条膝关节水平动脉时间-密度曲线,其中1条曲线来源于侧支循环,膝关节水平平均动脉峰值时间为33 s。结论大螺距、80 kVp下肢动脉CTA成像可满足诊断需求并大幅降低辐射剂量。采用膝关节水平动脉强化峰值时间个体化计算CTA触发时间可有效保证大螺距下肢动脉CTA成像成功实施。Objective To investigate image quality and radiation dose of high-pitch 80 kVp CT angiography(CTA)of the pelvic and lower extremities and assess the efficacy of test bolus technique at knee level.Methods A total of 60 patients with suspected the pelvic and lower limbs arterial disease were divided into two groups:group A[30 patients,high pitch(3.0),80 kVp,and iterative reconstruction(IR)]and group B[30 patients,standard pitch(1.0),120 kVp,and filtered back projection reconstruction].The scan delay time in group A was determined by test bolus technique at knee level.The radiation dose,mean signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)and image quality were compared.Results There were significant differences between two groups in mean arterial attenuation[80 vs.120 kVp:(494.41±89.27)HU vs.(320.52±73.29)HU,P<0.001],mean SNR(50.12±19.21 vs.36.71±10.43,P<0.001)and CNR(43.37±16.83 vs.26.27±9.54,P<0.001).No difference was found in image quality between two groups(all P>0.05).The mean dose length product was significantly lower in 80 kVp group[(152.20±10.23)mGy×cm vs.(789.14±96.89)mGy×cm,P<0.001].Conclusion The high-pitch 80 kVp CTA of the pelvic and lower extremities using IR yields reduction of radiation exposure as well as acceptable image quality if the delay time of CTA was determined by test bolus technique using monitoring scan at knee level.

关 键 词：小剂量测试 大螺距 血管成像 放射剂量 体层摄影术 X线计算机 

分 类 号：R543.5[医药卫生—心血管疾病] R814.42[医药卫生—内科学]