基于多模型的迭代重建算法在胸部低剂量CT筛查中的应用

目的探讨基于多模型的迭代重建(ASiR-V)算法在胸部低剂量CT筛查中的应用。方法将100名受检者随机分为低剂量组(120kVp/30 mAs)和超低剂量组(120kVp/17.5 mAs),以不同权重ASiR-V(0、30%、50%、70%、100%)重建肺算法和标准算法图像。比较不同权重下ASiR-V图像的主观评分、肺算法图像的结节数量及标准算法图像升主动脉的CT值标准差(SD值),比较ASiR-V50%权重下不同主观评分的SD值。结果 ASiR-V70%肺算法图像主观评分最高,结节检出数量最多;ASiR-V50%标准算法图像主观评分最高,ASiR-V50%条件下主观评分为2、3、4及5分时,SD值分别为(24.20±1.01)HU、(20.99±2.32)HU、(19.54±2.16)HU及(16.90±2.60)HU,两两比较差异均有统计学意义(P均0.05)。结论 ASiR-V70%及50%分别为观察肺及纵隔的最佳权重。ASiR-V50%标准算法图像升主动脉SD值为20.99HU是满足诊断的客观要求。

Application of adaptive statistic iterative reconstruction Veo in low-dose chest CT screening

Objective To discuss the application of adaptive statistic iterative reconstruction Veo (ASiR-V) in low-dose chest CT screening.Methods Totally 100 patients were categorized randomly into low-dose group (120 kVp/30 mAs) and ultra-low-dose group (120 kVp/17.5 mA). Images were reconstructed with different ASiR-V blending percentages (0, 30%, 50%, 70%, 100%). Subjective image score, number of nodules and the standard deviation (SD) of CT value among different ASiR-V blending percentages, SD among different scores in ASiR-V50% were all compared.Results The scores of lung algorithm images with ASiR-V70% were higher than the others. The most nodules were detected with ASiR-V70%. The scores for standard algorithm images with ASiR-V50% were higher than the others. SD values in subjective scoring 2, 3, 4 and 5 of ASiR-V50% were (24.20±1.01) HU, (20.99±2.32) HU, (19.54±2.16) HU and (16.90±2.60) HU respectively, which had statistically significant between any two (all P<0.05).Conclusion 70% is the best blending percentage for lung algorithm and 50% for standard algorithm;20.99 HU of SD at ascending aorta is the criteria of images reconstructed by standard algorithm with ASiR-V50% for low-dose chest screening.