A method for evaluating the performance of computeraided detection of pulmonary nodules in lung cancer CT screening: detection limit for nodule size and density

作者：Kobayashi Hajime; Ohkubo Masaki; Narita Akihiro; Marasinghe Janaka C; Murao Kohei; Matsumoto Toru; Sone Shusuke; Wada Shinichi^*

来源：British Journal of Radiology, 2017, 90(1070): 20160313.

DOI：10.1259/bjr.20160313

Objective: We propose the application of virtual nodules to evaluate the performance of computer-aided detection (CAD) of lung nodules in cancer screening using lowdose CT.
Methods: The virtual nodules were generated based on the spatial resolution measured for a CT system used in an institution providing cancer screening and were fused into clinical lung images obtained at that institution, allowing site specificity. First, we validated virtual nodules as an alternative to artificial nodules inserted into a phantom. In addition, we compared the results of CAD analysis between the real nodules (n=6) and the corresponding virtual nodules. Subsequently, virtual nodules of various sizes and contrasts between nodule density and background density (Delta CT) were inserted into clinical images (n=10) and submitted for CAD analysis.
Results: In the validation study, 46 of 48 virtual nodules had the same CAD results as artificial nodules (kappa coefficient = 0.913). Real nodules and the corresponding virtual nodules showed the same CAD results. The detection limits of the tested CAD system were determined in terms of size and density of peripheral lung nodules; we demonstrated that a nodule with a 5- mm diameter was detected when the nodule had a Delta CT> 220 HU.
Conclusion: Virtual nodules are effective in evaluating CAD performance using site-specific scan/reconstruction conditions.
Advances in knowledge: Virtual nodules can be an effectivemeans of evaluating site-specific CAD performance. The methodology for guiding the detection limit for nodule size/density might be a useful evaluation strategy.

• 出版日期2017