Abdominal CT with model-based iterative reconstruction (MBIR): initial results of a prospective trial comparing ultralow-dose with standard-dose imaging.
Abdominal CT with model-based iterative reconstruction (MBIR): initial results of a prospective trial comparing ultralow-dose with standard-dose imaging.
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DOI：
10.2214/ajr.12.9382
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发表时间：
2012-12
期刊：
影响因子：
--
通讯作者：
Chen GH
中科院分区：
文献类型：
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作者：
Pickhardt PJ;Lubner MG;Kim DH;Tang J;Ruma JA;del Rio AM;Chen GH
本研究的目的是报告正在进行的超低剂量腹部MDCT前瞻性试验的初步结果。对45名连续登记的成人（平均年龄57.9岁，平均体重指数28.5）进行了标准剂量对比增强（n = 21）和非增强（n = 24）临床腹部MDCT方案成像，随后立即进行超低剂量成像。采用滤波反投影（FBP）、自适应统计迭代重建（ASIR）和基于模型的迭代重建（MBIR）重建超低剂量图像。用FBP（参考标准）重建标准剂量系列。在多个预定义位点测量图像噪声。两名盲态腹部放射科医生随机解释了超低剂量图像的多层次主观图像质量（5分制）和基于器官的局灶性病变的描述。相对于标准系列的平均剂量减少为74%（中位数，78%;范围，57-88%;平均有效剂量，1.90 mSv）。低剂量MBIR的平均多器官图像噪声为14.7 ± 2.6 HU，显着低于标准剂量FBP（28.9 ± 9.9 HU）、低剂量FBP（59.2 ± 23.3 HU）和ASIR（45.6 ± 14.1 HU）（p < 0.001）。低剂量MBIR的平均主观图像质量评分（3.0 ± 0.5）显著高于低剂量FBP（1.6 ± 0.7）和ASIR（1.8 ± 0.7）（p < 0.001）。阅片者使用标准剂量的FBP识别出213处局灶性非钙化病变。低剂量MBIR（79.3% [169/213]）的合并病变检出率高于低剂量FBP（66.2% [141/213]）和ASIR（62.0% [132/213]）（p < 0.05）。MBIR显示了在常规腹部CT中大幅降低辐射剂量的巨大潜力。由于图像质量和诊断能力降低，FBP和ASIR在这方面都受到限制。需要进一步研究以确定维持足够诊断性能的MBIR的最佳剂量水平。一般来说，客观和主观图像质量测量不一定与超低剂量CT的诊断性能相关。
The purpose of this study was to report preliminary results of an ongoing prospective trial of ultralow-dose abdominal MDCT. Imaging with standard-dose contrast-enhanced (n = 21) and unenhanced (n = 24) clinical abdominal MDCT protocols was immediately followed by ultralow-dose imaging of a matched series of 45 consecutively registered adults (mean age, 57.9 years; mean body mass index, 28.5). The ultralow-dose images were reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR). Standard-dose series were reconstructed with FBP (reference standard). Image noise was measured at multiple predefined sites. Two blinded abdominal radiologists interpreted randomly presented ultralow-dose images for multilevel subjective image quality (5-point scale) and depiction of organ-based focal lesions. Mean dose reduction relative to the standard series was 74% (median, 78%; range, 57–88%; mean effective dose, 1.90 mSv). Mean multiorgan image noise for low-dose MBIR was 14.7 ± 2.6 HU, significantly lower than standard-dose FBP (28.9 ± 9.9 HU), low-dose FBP (59.2 ± 23.3 HU), and ASIR (45.6 ± 14.1 HU) (p < 0.001). The mean subjective image quality score for low-dose MBIR (3.0 ± 0.5) was significantly higher than for low-dose FBP (1.6 ± 0.7) and ASIR (1.8 ± 0.7) (p < 0.001). Readers identified 213 focal noncalcific lesions with standard-dose FBP. Pooled lesion detection was higher for low-dose MBIR (79.3% [169/213]) compared with low-dose FBP (66.2% [141/213]) and ASIR (62.0% [132/213]) (p < 0.05). MBIR shows great potential for substantially reducing radiation doses at routine abdominal CT. Both FBP and ASIR are limited in this regard owing to reduced image quality and diagnostic capability. Further investigation is needed to determine the optimal dose level for MBIR that maintains adequate diagnostic performance. In general, objective and subjective image quality measurements do not necessarily correlate with diagnostic performance at ultralow-dose CT.