Quantitative volumetry of ground-glass nodules on high-spatial-resolution CT with 0.25-mm section thickness and 1024 matrix: Phantom and clinical studies

Yuriko Yoshida; Masahiro Yanagawa; Akinori Hata; Yukihisa Sato; Mitsuko Tsubamoto; Shuhei Doi; Kazuki Yamagata; Tomo Miyata; Noriko Kikuchi; Noriyuki Tomiyama

doi:10.1016/j.ejro.2021.100362

Quantitative volumetry of ground-glass nodules on high-spatial-resolution CT with 0.25-mm section thickness and 1024 matrix: Phantom and clinical studies

Eur J Radiol Open. 2021 Jun 1:8:100362. doi: 10.1016/j.ejro.2021.100362. eCollection 2021.

Authors

Affiliations

¹ Department of Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka Suita, Osaksa 565-0871, Japan.
² Department of Diagnostic Radiology, Suita Municipal Hospital, 5-7 Kishibeshinmachi Suita, Osaka 564-8567, Japan.
³ Department of Diagnositic Radiology, Nishinomiya Municipal Central Hospital, 8-24 Hayashidacho, Nishinomiya, Hyogo, 663-8014, Japan.
⁴ Department of Future Diagnostic Radiology, Osaka University Graduate School of Medicine 2-2 Yamadaoka Suita, Osaksa 565-0871, Japan.

Abstract

Objectives: To compare high-resolution (HR) and conventional (C) settings of high-spatial-resolution computed tomography (CT) for software volumetry of ground-glass nodules (GGNs) in phantoms and patients.

Methods: We placed -800 and -630 HU spherical GGN-mimic nodules in 28 different positions in phantoms and scanned them individually. Additionally, 60 GGNs in 45 patients were assessed retrospectively. Images were reconstructed using the HR-setting (matrix size, 1024; slice thickness, 0.25 mm) and C-setting (matrix size, 512; slice thickness, 0.5 mm). We measured the GGN volume and mass using software. In the phantom study, the absolute percentage error (APE) was calculated as the absolute difference between Vernier caliper measurement-based and software-based volumes. In patients, we measured the density (mean, maximum, and minimum) and classified GGNs into low- and high-attenuation GGNs.

Results: In images of the -800 HU, but not -630 HU, phantom nodules, the volumes and masses differed significantly between the two settings (both p < 0.01). The APE was significantly lower in the HR-setting than in the C-setting (p < 0.01). In patients, volumes did not differ significantly between settings (p = 0.59). Although the mean attenuation was not significantly different, the maximum and minimum values were significantly increased and decreased, respectively, in the HR-setting (both p < 0.01). The volumes of both low-attenuation and high-attenuation GGNs were not significantly different between settings (p = 0.78 and 0.39, respectively).

Conclusion: The HR-setting might yield a more accurate volume for phantom GGN of -800 HU and influence the detection of maximum and minimum CT attenuation.

Keywords: 3D, three-dimensional; APE, absolute percentage error; C-CT, conventional computed tomography; C-setting, conventional setting; CT, computed tomography; GGN, ground-glass nodule; HR-setting, high-resolution setting; HSR-CT, high-spatial-resolution computed tomography; Lung; Solitary pulmonary nodule; Spiral computed tomography; VDT, volume doubling time.