Pauchard Bastien, Higashigaito Kai, Lamri-Senouci Aicha, Knebel Jean-Francois, Berthold Dominik, Verdun Francis Robert, Alkadhi Hatem, Schmidt Sabine
Department of Diagnostic and Interventional Radiology, University Hospital Lausanne, University of Lausanne, Rue du Bugnon, 1011 Lausanne, Switzerland.
Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Acad Radiol. 2017 Sep;24(9):1114-1124. doi: 10.1016/j.acra.2017.02.012. Epub 2017 Mar 29.
To compare adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) algorithms for reduced-dose computed tomography (CT).
Forty-four young oncology patients (mean age 30 ± 9 years) were included. After routine thoraco-abdominal CT (dose 100%, average CTDI 9.1 ± 2.4 mGy, range 4.4-16.9 mGy), follow-up CT was acquired at 50% (average CTDI 4.5 ± 1.2 mGy, range 2.2-8.4 mGy) in 29 patients additionally at 20% dose (average CTDI 1.9 ± 0.5 mGy, range 0.9-3.4 mGy). Each reduced-dose CT was reconstructed using both ASIR and MBIR. Four radiologists (two juniors and two seniors) blinded to dose and technique read each set of CT images regarding objective and subjective image qualities (high- or low-contrast structures), subjective noise or pixilated appearance, diagnostic confidence, and lesion detection.
At all dose levels, objective image noise was significantly lower with MBIR than with ASIR (P < 0.001). The subjective image quality for low-contrast structures was significantly higher with MBIR than with ASIR (P < 0.001). Reduced-dose abdominal CT images of patients with higher body mass index (BMI) were read with significantly higher diagnostic confidence than images of slimmer patients (P < 0.001) and had higher subjective image quality, regardless of technique. Although MBIR images appeared significantly more pixilated than ASIR images, they were read with higher diagnostic confidence, especially by juniors (P < 0.001).
Reduced-dose CT during the follow-up of young oncology patients should be reconstructed with MBIR to ensure diagnostic quality. Elevated body mass index does not hamper the quality of reduced-dose CT.
比较自适应统计迭代重建（ASIR）和基于模型的迭代重建（MBIR）算法在低剂量计算机断层扫描（CT）中的应用。
纳入44名年轻肿瘤患者（平均年龄30±9岁）。在进行常规胸腹CT扫描（剂量100%，平均CTDI 9.1±2.4 mGy，范围4.4 - 16.9 mGy）后，29名患者另外进行了50%剂量（平均CTDI 4.5±1.2 mGy，范围2.2 - 8.4 mGy）的随访CT扫描，还有部分患者进行了20%剂量（平均CTDI 1.9±0.5 mGy，范围0.9 - 3.4 mGy）的扫描。每组低剂量CT图像均使用ASIR和MBIR两种算法进行重建。四名放射科医生（两名初级和两名高级）在不知剂量和技术的情况下，对每组CT图像的客观和主观图像质量（高对比度或低对比度结构）、主观噪声或像素化外观、诊断信心以及病变检测进行阅读评估。
在所有剂量水平下，MBIR重建的图像客观噪声均显著低于ASIR（P < 0.001）。MBIR重建的低对比度结构主观图像质量显著高于ASIR（P < 0.001）。体重指数（BMI）较高患者的低剂量腹部CT图像的诊断信心显著高于体型较瘦患者的图像（P < 0.001），且无论采用何种技术，其主观图像质量均更高。尽管MBIR图像的像素化现象明显比ASIR图像更严重，但放射科医生对其诊断信心更高，尤其是初级医生（P < 0.001）。
年轻肿瘤患者随访期间的低剂量CT扫描应采用MBIR重建，以确保诊断质量。体重指数升高并不影响低剂量CT的质量。
