Abstract：
This study aims to investigate the maximum achievable dose reduction for applying a new deep learning-based reconstruction algorithm, namely the artificial intelligence iterative reconstruction (AIIR), in computed tomography (CT) for hepatic lesion detection. A total of 40 patients with 98 clinically confirmed hepatic lesions were retrospectively included. The mean volume CT dose index was 13.66 ± 1.73 mGy in routine-dose portal venous CT examinations, where the images were originally obtained with hybrid iterative reconstruction (HIR). Low-dose simulations were performed in projection domain for 40%-, 20%-, and 10%-dose levels, followed by reconstruction using both HIR and AIIR. Two radiologists were asked to detect hepatic lesion on each set of low-dose image in separate sessions. Qualitative metrics including lesion conspicuity, diagnostic confidence, and overall image quality were evaluated using a 5-point scale. The contrast-to-noise ratio (CNR) for lesion was also calculated for quantitative assessment. The lesion CNR on AIIR at reduced doses were significantly higher than that on routine-dose HIR (all p < 0.05). Lower qualitative image quality was observed as the radiation dose reduced, while there were no significant differences between 40%-dose AIIR and routine-dose HIR images. The lesion detection rate was 100%, 98% (96/98), and 73.5% (72/98) on 40%-, 20%-, and 10%-dose AIIR, respectively, whereas it was 98% (96/98), 73.5% (72/98), and 40% (39/98) on the corresponding low-dose HIR, respectively. AIIR outperformed HIR in simulated low-dose CT examinations of the liver. The use of AIIR allows up to 60% dose reduction for lesion detection while maintaining comparable image quality to routine-dose HIR.
摘要：
本研究旨在探讨应用新的基于深度学习的重建算法可实现的最大剂量减少，即人工智能迭代重构(AIIR)，在计算机断层扫描（CT）检查肝脏病变。回顾性纳入了40例临床证实的98例肝脏病变。常规剂量门静脉CT检查平均容积CT剂量指数为13.66±1.73mGy,其中图像最初是通过混合迭代重建(HIR)获得的。在投影域中进行了40％的低剂量模拟-，20%-,和10%的剂量水平，然后使用HIR和AIIR进行重建。要求两名放射科医生在单独的会议中在每组低剂量图像上检测肝病变。定性指标，包括病变显著性，诊断信心，和整体图像质量使用5分制进行评估。还计算了病变的对比噪声比（CNR）以进行定量评估。降低剂量的AIIR上的病变CNR显着高于常规剂量HIR（均p<0.05）。随着辐射剂量的减少，定性图像质量降低，而40%剂量的AIIR和常规剂量的HIR图像之间没有显著差异。病变检出率100%,98%（96/98），和73.5%（72/98）对40%-，20%-,和10%剂量的AIIR，分别,而它是98%(96/98)，73.5%（72/98），40%(39/98)在相应的低剂量HIR上，分别。在模拟的低剂量肝脏CT检查中，AIIR优于HIR。AIIR的使用允许用于病变检测的剂量减少高达60%,同时保持与常规剂量HIR相当的图像质量。
