Racine Damien, Ott Julien G, Ba Alexandre, Ryckx Nick, Bochud François O, Verdun Francis R
Institute of Radiation Physics, CHUV, Lausanne, Switzerland
Institute of Radiation Physics, CHUV, Lausanne, Switzerland.
Radiat Prot Dosimetry. 2016 Jun;169(1-4):73-7. doi: 10.1093/rpd/ncw020. Epub 2016 Feb 27.
Evaluating image quality by using receiver operating characteristic studies is time consuming and difficult to implement. This work assesses a new iterative algorithm using a channelised Hotelling observer (CHO). For this purpose, an anthropomorphic abdomen phantom with spheres of various sizes and contrasts was scanned at 3 volume computed tomography dose index (CTDIvol) levels on a GE Revolution CT. Images were reconstructed using the iterative reconstruction method adaptive statistical iterative reconstruction-V (ASIR-V) at ASIR-V 0, 50 and 70 % and assessed by applying a CHO with dense difference of Gaussian and internal noise. Both CHO and human observers (HO) were compared based on a four-alternative forced-choice experiment, using the percentage correct as a figure of merit. The results showed accordance between CHO and HO. Moreover, an improvement in the low-contrast detection was observed when switching from ASIR-V 0 to 50 %. The results underpin the finding that ASIR-V allows dose reduction.
使用接受者操作特征研究来评估图像质量既耗时又难以实施。这项工作评估了一种使用通道化霍特林观察者（CHO）的新迭代算法。为此，在GE Revolution CT上，以3个容积计算机断层扫描剂量指数（CTDIvol）水平扫描了一个带有不同大小和对比度球体的拟人化腹部体模。使用迭代重建方法自适应统计迭代重建-V（ASIR-V）在ASIR-V 0%、50%和70%的情况下重建图像，并通过应用具有高斯密度差异和内部噪声的CHO进行评估。基于四选一强制选择实验，以正确百分比作为评价指标，对CHO和人类观察者（HO）进行了比较。结果显示CHO和HO之间具有一致性。此外，当从ASIR-V 0%切换到50%时，观察到低对比度检测有所改善。这些结果支持了ASIR-V能够降低剂量这一发现。
