AI 中文总结
研究评估retroOpt新型器官水平管电流调制方法用于肝脏转移灶检测，通过对患者CT检查生成不同剂量系列，比较病灶检测敏感性和图像质量，发现该方法在低剂量下能有效检测转移灶，优于均匀剂量降低，可实现更大剂量 reduction。
AI 中文摘要
目的：评估retroOpt，一种新型器官水平管电流调制（TCM）方法，该方法在保留肝脏转移灶检测诊断图像质量的同时将有效辐射剂量降至最低。方法：在这项经IRB批准的回顾性研究中，22例有68个肝脏病灶（38个恶性，30个良性）的患者接受了门静脉期胸部-腹部-盆腔CT检查。利用投影域噪声仿真，为每位患者生成五个系列：原始全剂量（Orig-100）、有效剂量均匀降低至原始剂量的40%（UD-40）和60%（UD-60），以及相同水平的器官水平TCM（Opt-40、Opt-60）。三位腹部放射科医生独立检测并分类病灶，并对图像质量进行评分（5分制李克特量表）。通过McNemar检验比较每个病灶的敏感性。通过逻辑回归估计50%和90%敏感性的恶性病灶大小阈值（x50、x90）。通过Wilcoxon符号秩检验比较图像质量。结果：在60%剂量水平时，Opt-60的平均恶性病灶敏感性与全剂量CT相当（82%对80%），且超过均匀剂量降低（67%）。在40%剂量水平时，Opt-40的平均敏感性从UD-40的52%提高到68%。所有病灶的平均敏感性从UD-40的54%提高到Opt-40的64%，从UD-60的65%提高到Opt-60的77%，与全剂量（76%）相当。所有优化与均匀剂量的差异均具有显著性（p<=0.003）。Opt-60的病灶大小阈值与Orig-100紧密匹配（x50为3.3对3.7mm；x90为15.7对16.8mm）。Opt-60的图像质量中位数在不同读者中为3至4.5。结论：器官水平TCM在原始有效剂量的60%时保留了肝脏转移灶检测能力，优于均匀剂量降低。针对特定任务的器官水平剂量优化可能比均匀策略使需要重复转移灶监测的患者的CT剂量降低更多。
英文摘要
Objective: To evaluate retroOpt, a novel organ-level tube current modulation (TCM) method that minimizes effective radiation dose while preserving diagnostic image quality for liver metastasis detection. Methods: In this retrospective, IRB-approved study, 22 patients with 68 liver lesions (38 malignant, 30 benign) underwent portal venous phase contrast-enhanced chest-abdomen-pelvis CT. Using projection-domain noise emulation, five series were generated per patient: original full dose (Orig-100), uniform dose reduction to 40% (UD-40) and 60% (UD-60) of the original effective dose, and organ-level TCM at the same levels (Opt-40, Opt-60). Three abdominal radiologists independently detected and classified lesions and rated image quality (5-point Likert). Per-lesion sensitivity was compared by McNemar test. Malignant lesion-size thresholds for 50% and 90% sensitivity (x50, x90) were estimated by logistic regression. Image quality was compared by Wilcoxon signed-rank test. Results: At the 60% level, Opt-60 achieved mean malignant lesion sensitivity comparable to full-dose CT (82% vs 80%) and exceeded uniform reduction (67%). At the 40% level, Opt-40 improved mean sensitivity over UD-40 from 52% to 68%. Mean all-lesion sensitivity rose from 54% (UD-40) to 64% (Opt-40) and from 65% (UD-60) to 77% (Opt-60), remaining comparable to full dose (76%). All optimized-versus-uniform differences were significant (p <= 0.003). Opt-60 lesion-size thresholds closely matched Orig-100 (x50 3.3 vs 3.7 mm; x90 15.7 vs 16.8 mm). Median Opt-60 image quality ranged from 3 to 4.5 across readers. Conclusions: Organ-level TCM preserved liver metastasis detection at 60% of the original effective dose, outperforming uniform dose reduction. Task-specific organ-level dose optimization may enable greater CT dose reduction than uniform strategies for patients requiring repeated metastasis surveillance.
