100 kV管电压下快速迭代重建(iDose)级别对头颈部CTA图像质量的影响

Influence of iDose iterative reconstruction grade on head and neck CTA quality at 100kV tube voltage

为了比较不同的快速迭代重建(iDose)级别在低管电压头颈部CT血管成像(CTA)中降低噪声的程度和对图像的影响,收集拟行头颈部CTA检查患者30例,采用300 mg I/m L的对比剂50m L在100k V下进行iDose-1级到iDose-6级的图像重建,进而进行各重建等级图像的主观评价,并记录各重建等级的左侧大脑中动脉(MA)M1段CT值、左侧颞叶CT值、左侧颞叶标准差(SD),最后计算对比噪声比(CNR)和信噪比(SNR)。结果显示:iDose-1级到iDose-6级重建图像主观评分差异无统计学意义(P>0.05),其中iDose-4级重建图像评分最高;iDose-1级到iDose-6级重建图像中左MA的M1段CT值与左侧颞叶CT值差异无统计学意义(P>0.05);SD随iDose重建等级的增大而减少,其差异有统计学意义(P<0.05);SNR、CNR随重建等级逐渐增大而增大,其差异有统计学意义(P<0.05),其中iDose-5级重建图像SD值最低,SNR和CNR最大,图像质量最佳。由此认为:低管电压下行头颈部CTA成像时,iDose算法能有效降低噪声,改善图像质量,其中iDose-5级图像质量最佳。

To compare the noise reduction and image quality of different iDose construction grade in low tube voltage computed tomography angiography（CTA） in head and neck artery angiography, 30 patients underwent head and neck CTA with 50 m L 300 mg I/ML contrast media at 100 k V tube voltage were selected. All the images were reconstructed from iDose-1 to iDose-6. The CT values of the left middle cerebral artery（M1）,left temporal lobe,standard deviation（SD） were recorded. The contrast to noise ratio（CNR） and signal-to-noise ratio（SNR）were calculated. The results showed that there were no significant statistic differences（P 〉0.05） in subjectively evaluating image quality of CTA in head and neck artery angiography among the construction from iDose-1 to iDose-6, and the score of image quality was the highest in iDose-4 grade construction. Moreover,there were no significant statistic differences（P〉0.05） in the CT value of left middle cerebral artery（M1） and the left temporal lobe. Besides,the value of SD was reduced with the increase of iDose grade,while the values of SNR and CNR were on the contrary. The SD value of the iDose-5 reconstruction reached the lowest and the SNR and CNR values reached the highest, and the quality of image were the best. It is concluded that iDose can reduce the noise effectively and improve the quality of image in the head and neck artery angiography at low tube voltage,and the image quality of iDose-5 were the best.