title: Application of CT-PSF-based computer-simulated lung nodules for evaluating the accuracy of computer-aided volumetry.
abstract: With the wide dissemination of computed tomography (CT) screening for lung cancer, measuring the nodule volume accurately with computer-aided volumetry software is increasingly important. Many studies for determining the accuracy of volumetry software have been performed using a phantom with artificial nodules. These phantom studies are limited, however, in their ability to reproduce the nodules both accurately and in the variety of sizes and densities required. Therefore, we propose a new approach of using computer-simulated nodules based on the point spread function measured in a CT system. The validity of the proposed method was confirmed by the excellent agreement obtained between computer-simulated nodules and phantom nodules regarding the volume measurements. A practical clinical evaluation of the accuracy of volumetry software was achieved by adding simulated nodules onto clinical lung images, including noise and artifacts. The tested volumetry software was revealed to be accurate within an error of 20 % for nodules >5 mm and with the difference between nodule density and background (lung) (CT value) being 400-600 HU. Such a detailed analysis can provide clinically useful information on the use of volumetry software in CT screening for lung cancer. We concluded that the proposed method is effective for evaluating the performance of computer-aided volumetry software.
authors.affiliation: Graduate School of Health Sciences, Niigata University, 2-746 Asahimachi-dori, Niigata 951-8518, Japan.
authors.forename: Ayumu
authors.initials: A
authors.lastname: Funaki
authors.forename: Masaki
authors.initials: M
authors.lastname: Ohkubo
authors.forename: Shinichi
authors.initials: S
authors.lastname: Wada
authors.forename: Kohei
authors.initials: K
authors.lastname: Murao
authors.forename: Toru
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Shinji
authors.initials: S
authors.lastname: Niizuma
mesh_terms: D003198:Computer Simulation; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D019047:Phantoms, Imaging; D012680:Sensitivity and Specificity; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods*; D047368:Tumor Burden