超低管电压联合DLIR-H算法在冠脉CT血管成像“双低”扫描中的应用价值

Application Value of Ultra Low Tube Voltage Combined with DLIR-H Algorithm in Reducing both Radiation and Contrast Doses in Coronary CT Angiography

目的探讨超低管电压(70 kVp)联合高权重深度学习图像重建(High-strength Deep Learning Image Reconstruction,DLIR-H)技术降低冠脉CT血管成像辐射剂量与对比剂用量的临床价值。方法收集72例临床拟行冠状动脉CTA检查的患者,随机分为A、B两组,各36例。A组扫描方案:70 kV,智能mA调节技术,噪声指数(Noise Index,NI)为30 HU;对比剂总量16 mgI/(kg·s),DLIR-H重建。B组扫描方案:120 kV,智能mA调节技术,NI为22 HU,对比剂总量32 mgI/(kg·s),50%自适应统计迭代重建。两组均以10 s的对比剂注射持续时间计算对比剂注射流速。对两组图像质量进行主观评分和客观评价。图像质量主观评分采用5分法,图像噪声、信噪比(Signal to Noise Ratio,SNR)和对比噪声比(Contrast to Noise Ratio,CNR)用于图像质量客观评估。结果两组图像质量主观评分满足诊断要求,A组图像质量的主观评分优于B组,差异有统计学意义(P<0.001)。A组的背景噪声标准差值(12.36±2.86)明显低于B组(19.06±2.43),差异有统计学意义(P<0.001);A组右冠状动脉(Right Coronary Artery,RCA)、左冠状动脉前降支(Left Anterior Descending,LAD)与回旋支(Left Circumflex,LCX)的SNR(36.40±11.71、35.01±10.95、35.32±11.33)明显高于B组(20.77±3.76、20.33±3.46、20.15±3.34),差异有统计学意义(P<0.001);A组RCA、LAD和LCX的CNR(48.47±13.61、47.08±12.72、47.38±13.12)明显高于B组(26.25±4.79、25.82±4.54、25.64±4.15),差异有统计学意义(P<0.001)。A组对比剂平均用量(22.87±4.06)mL和辐射剂量(0.82±0.15)mSv较B组(48.64±7.09)mL、(2.23±0.93)mSv分别降低了53%和63.2%。结论与传统扫描方案相比,超低管电压联合DLIR-H算法行CCTA扫描,图像质量优,患者接受的辐射剂量与对比剂总量均明显降低。

Objective To explore the clinical value of 70 kVp tube voltage combined with high-strength deep learning image reconstruction(DLIR-H)technology in reducing both radiation and contrast doses in coronary CT angiography(CCTA).Methods A total of 72 patients required to undergo CCTA were prospectively enrolled and randomly divided into two groups A and B,with 36 cases in each group.Group A(n=36)used the new scan protocol:70 kV,smart mA adjustment technolegy,noise index(NI)of 30 HU,contrast dose of 16 mgI/(kg·s),DLIR-H reconstruction.Group B used the conventional scan protocol:120 kV,smart mA adjustment technolegy,NI of 22 HU,contrast dose of 32 mgI/(kg·s),50%ASIR-V reconstruction.The contrast injection rate was adjusted for 10 s injection duration.The image quality of the two groups were evaluated subjectively and objectively.The subjective image quality was evaluated by 5-point system(5=best).Image noise,contrast-noise-ratio(CNR)and signal-noise-ratio(SNR)for vessels were measured to evaluate the objective image quality.Results The image quality in the two groups fully met the diagnostic requirements.The subjective score of image quality in group A was better than that in group B,and the difference was statistically significant(P<0.001).The standard deviation of background noise in group A(12.36±2.86)was significantly lower than those in group B(19.06±2.43),and the difference was statistically significant(P<0.001).The SNR in right coronary artery(RCA),left anterior descending(LAD)and left circumflex(LCX)in group A(36.40±11.71,35.01±10.95,35.32±11.33)were significantly higher than those in group B(20.77±3.76,20.33±3.46,20.15±3.34).The differences were statistically significant(P<0.001).The CNR of RCA,LAD and LCX in group A(48.47±13.61,47.08±12.72,47.38±13.12)were significantly higher than those in group B(26.25±4.79,25.82±4.54,25.64±4.15),the differences were statistically significant(P<0.001).The average contrast dose were(22.87±4.06)mL and radiation dose was(0.82±0.15)mSv in group A,which were 53%and 63.2%reduction compared with the(48.64±7.09)mL and(2.23±0.93)mSv in group B,respectively.Conclusion The use of 70 kVp tube voltage combined with DLIR-H algorithm for CCTA in normal size patients significantly reduces radiation dose and contrast medium dose while improves image quality compared with the conventional scan protocol.