Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
Siemens Healthineers, Malvern, PA, 19355, USA.
Abdom Radiol (NY). 2019 Oct;44(10):3350-3358. doi: 10.1007/s00261-019-02150-9.
Prior iterative reconstruction (PIR) uses spatial information from one phase of enhancement to reduce image noise in other phases. We sought to determine if PIR could reduce radiation dose while preserving observer performance and CT number at multi-phase dual energy (DE) renal CT.
CT projection data from multi-phase DE renal CT examinations were collected. Images corresponding to 40% radiation dose were reconstructed using validated noise insertion and PIR. Three genitourinary radiologists examined routine and 40% dose PIR images. Probability of malignancy was assessed [from 0 to 100] with malignancy assumed at probability ≥ 75. Observer performance was compared on a per patient and per lesion level. CT number accuracy was measured.
Twenty-three patients had 49 renal lesions (11 solid renal neoplasms). CT number was nearly identical between techniques (mean CT number difference: unenhanced 2 ± 2 HU; enhanced 4 ± 4 HU). AUC for malignancy was similar between multi-phase routine dose DE and lower dose PIR images [per patient: 0.950 vs. 0.916 (p = 0.356); per lesion: 0.931 vs. 0.884 (p = 0.304)]. Per patient sensitivity was also similar (78% routine dose vs. 82% lower dose [p ≥ 0.99]), as was specificity (91% routine dose vs. 93% lower dose PIR [p > 0.99]), with similar findings on a per lesion level. Subjective image quality was also similar (p = 0.34).
Prior iterative reconstruction is a new reconstruction method for multi-phase CT examinations that promises to facilitate radiation dose reduction by over 50% for multi-phase DE renal CT exams without compromising CT number or observer performance.
先前迭代重建（PIR）使用增强相的空间信息来降低其他相的图像噪声。我们旨在确定先前迭代重建是否可以在保留观察者性能和多期双能（DE）肾 CT 中的 CT 数的同时降低辐射剂量。
收集多期 DE 肾 CT 检查的 CT 投影数据。使用验证的噪声插入和先前迭代重建技术重建相应于 40%辐射剂量的图像。三位泌尿生殖放射科医生检查了常规和 40%剂量先前迭代重建图像。恶性肿瘤的可能性评估为 0 到 100，假设恶性肿瘤的概率≥75。在患者和病变水平上比较了观察者的性能。测量了 CT 数的准确性。
23 例患者中有 49 个肾脏病变（11 个实性肾肿瘤）。两种技术之间的 CT 数几乎相同（未增强时的平均 CT 数差异：2 ± 2 HU；增强时的平均 CT 数差异：4 ± 4 HU）。多期常规剂量 DE 和较低剂量先前迭代重建图像的恶性肿瘤 AUC 相似[每例患者：0.950 与 0.916（p=0.356）；每例病变：0.931 与 0.884（p=0.304）]。每例患者的敏感性也相似（常规剂量为 78%，较低剂量为 82%[p≥0.99]），特异性也相似（常规剂量为 91%，较低剂量先前迭代重建为 93%[p>0.99]），病变水平的结果也相似。主观图像质量也相似（p=0.34）。
先前迭代重建是一种新的多期 CT 检查重建方法，有望在不影响 CT 数或观察者性能的情况下，将多期 DE 肾 CT 检查的辐射剂量降低 50%以上。
