64层螺旋CT超低管电压肺动脉造影的临床研究

Clinical research of 64-slice CT ultra-low tube voltage pulmonary arteriography

目的通过比较80kV-CTPA与120kV-CTPA的图像质量与辐射剂量,明确80kV-CTPA应用于体质量指数≤26 Kgg/m2、体质量≤80Kg病人的临床价值。方法前瞻性选取我院2014年8月-2014年12月体质量指数≤26 Kg/m2、体质量≤80Kg的病人40例,随机分为A、B两组。A、B两组管电压分别设置为80kV和120 kV。管电流设置基于体质量指数。评价并对比A、B两组图像质量与辐射剂量。计数资料比较采用χ~2检验,计量资料比较采用t检验,等级资料比较采用秩和检验。检验水准α=0.05。结果 A组右肺下叶动脉分支平均显示级数为8.90±1.52,B组为8.55±0.88,t=0.890,P=0.379,差异无统计学意义。A、B两组诸肺动脉节段主观评分差异无统计学意义(3.75±0.47 vs.3.69±0.48,Z=-1.409,P=0.159)。肺动脉干CT值与噪声值A组均高于B组,差异具有统计学意义(P=0.000)。肺动脉干SNR A组略低于B组约19%,差异具有统计学意义(11.41±3.10 vs.14.16±3.22,t=-2.758,P=0.009)。肺动脉干CNR A组与B组相比差异无统计学意义(9.99±2.98 vs.11.75±3.54,t=-1.704,P=0.097)。有效剂量A组显著低于B组(2.28±0.46mSv vs.5.72±2.08mSv,t=-7.225,P=0.000)。结论低管电压CTPA应用于特定病人中可以有效减低辐射剂量,同时保持图像质量,具有临床应用价值。

Objective To confirm the clinical value of 80kV-CTPA on patients BMI≤26 Kg/m^2 and BM 80Kg by comparing the image quality and radiation dose between 80kV-CTPA and 120kV-CTPA protocols. Methods 40 patients with normal body mass index （ ≤26 Kg/m^2） and body mass （≤80Kg） suspected with pulmonary em- bolism（PE） were prospectively enrolled from August 2014 to December 2014. The patients were divided into two groups, and tube voltage was set at 80 KV and 120 KV for the two groups, respectively. The radiation dose and im- age quality were compared between the two groups by X： and t test. Results The display stage of right lower lobe ar- tery was 8.90 ± 1.52 and 8. 55 ± 0. 88 in the group A and B （ t = 0. 890, P = 0. 379）. The mean image quality score was 3.75 ±0. 47 in the group A and 3.69 ±0.48 in the group B （Z = - 1. 409, P =0. 159）. The pulmonary artery trunk showed significantly higher attenuation and noise in the group A than in the group B （P = 0. 000 respectively）. It showed significantly lower SNR in the group A than in the group B （ 11.41 ± 3.10 vs. 14. 16 ± 3.22, t = - 2. 758, P=0.009）. The CNR was 9. 99±2.98 in the group A and 11.75 ±3.54 in the group B （t = -1.704, P= 0. 097 ）. The mean ED was significantly lower in the group A than in the group B （ 2.28 ± 0. 46mSv vs. 5.72 ± 2. 08mSv, t = - 7. 225, P = 0. 000）. Conclusion 80KV CTPA could obtain stable image quality and greatly reduce effective radiation dose for patients with normal body mass index （ ≤26 Kg/m^2 ） and body mass （≤80Kg）.