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目的探讨全模型迭代重建(IMR)技术联合低管电压MSCT扫描在肾动脉成像中降低辐射剂量及控制图像质量的应用价值。方法前瞻性连续搜集行腹盆腔动态增强CT扫描的120例患者,根据患者体质量指数(BMI)分为A组(BMI≤22 kg/m~2)、B组(22 kg/m~20.05),余组间各数据差异有统计学意义(P<0.01)。结论应用IMR较iDose~4可更显著的提高图像SNR、CNR及图像质量。根据患者BMI采用适当的低管电压(80 kV或100 kV)联合IMR重建技术进行肾动脉成像,在降低患者辐射剂量的同时可获得理想的图像。
Objective To investigate the value of IMR combined with low-voltage MSCT in reducing the radiation dose and controlling the image quality in renal artery imaging. Methods A total of 120 consecutive patients undergoing dynamic contrast-enhanced computed tomography (CT) with abdominal atrophy were prospectively studied. Patients were divided into group A (BMI≤22 kg / m ~ 2) and group B (22 kg / BMI≤25 kg / m ~ 2) were divided into three subgroups: A1-FBP group (120 kV, FBP), A2-iDose ~ 4 group B2-iDose ~ 4 group (100 kV, iDose ~ 4), B2-IMR group (100 kV, IMR group) ). The CT value of renal artery in each group was measured. The MIP image quality of each group was scored. CT volume index (CTDIvol) and dose length product (DLP) of each group were recorded. The signal to noise ratio (SNR) Noise ratio (CNR), total iodine, image sensitivity (FOM) and effective dose (ED). A1 and A2, B1 and B2 with iodine total, DLP, ED using independent samples t test; A, B two groups of three subgroups (A1-FBP, A2-iDose ~ 4 and A2-IMR, FBP, B2-iDose ~ 4 and B2-IMR). One-factor analysis of variance (ANOVA) was used to compare the CT value, SNR, CNR and FOM of renal artery, and rank sum test was used to compare the renal artery image quality score. Results CTDIvol, DLP and ED in group A1 and A2 were 16.9 m Gy, (886.1 ± 46.0) m Gy · cm, (13.3 ± 0.7) m Sv, 4.9 m Gy, (261.9 ± 12.5) m Gy · cm, (3.9 ± 0.2) m Sv. The data of B1 and B2 were 16.9 m Gy, (929.6 ± 45.3) m Gy · cm, (14.0 ± 0.7) m Sv, 10.1 m Gy, (559.9 ± 26.4) m Gy · cm, (8.4 ± 0.4) m Sv. The difference between the above data was statistically significant (P <0.01). The SNR, CNR, FOM and image quality scores of A1-FBP, A2-iDose ~ 4 and A2-IMR groups were 10.1 ± 3.0,13.2 ± 3.5, (11.0 ± 5.9) mGy -1, 3.0 ), 14.5 ± 4.1, 15.6 ± 3.9, (52.5 ± 26.8) mGy -1, 3.0 (2.0,3.0), 34.9 ± 13.3, 44.4 ± 12.2, (339.3 ± 237.8) mGy -1, 3.0 (3.0,4.0). The data of B1-FBP, B2-iDose ~ 4 and B2-IMR groups were 9.0 ± 2.4,9.7 ± 2.7 (6.0 ± 3.7) mGy -1, 3.0 (2.0,3.0) and 13.3 ± 3.3,14.9 ± 2.9, (22.8 ± 9.3) mGy -1, 3.0 (2.0, 3.0), 28.4 ± 9.0, 38.5 ± 10.3, (157.0 ± 86.9) mGy -1, 3.0 (3.0, 4.0) respectively. There was no significant difference in image quality scores between A1-FBP and A2-iDose ~ 4, B1-FBP and B2-iDose ~ 4 groups (P> 0.05) . Conclusion The application of IMR can significantly improve the image SNR, CNR and image quality compared with iDose ~ 4. Based on the patient BMI, renal artery imaging was performed with appropriate low-voltage (80 kV or 100 kV) combined with IMR reconstruction to achieve ideal images while reducing the patient’s radiation dose.