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Measurement of Focal Ground-glass Opacity Diameters on CT Images

2012; Elsevier BV; Volume: 19; Issue: 4 Linguagem: Inglês

10.1016/j.acra.2011.12.002

1878-4046

Ryutaro Kakinuma, Kazuto Ashizawa, Keiko Kuriyama, Aya Fukushima, Hiroyuki Ishikawa, Hisashi Kamiya, Naoya Koizumi, Yuichiro Maruyama, Kazunori Minami, Norihisa Nitta, Seitaro Oda, Yasuji Oshiro, Masahiko Kusumoto, Sadayuki Murayama, Kiyoshi Murata, Yukio Muramatsu, Noriyuki Moriyama,

Ultrasound in Clinical Applications

Purpose To evaluate interobserver agreement in regard to measurements of focal ground-glass opacities (GGO) diameters on computed tomography (CT) images to identify increases in the size of GGOs. Materials and Methods Approval by the institutional review board and informed consent by the patients were obtained. Ten GGOs (mean size, 10.4 mm; range, 6.5–15 mm), one each in 10 patients (mean age, 65.9 years; range, 58–78 years), were used to make the diameter measurements. Eleven radiologists independently measured the diameters of the GGOs on a total of 40 thin-section CT images (the first [n = 10], the second [n = 10], and the third [n = 10] follow-up CT examinations and remeasurement of the first [n = 10] follow-up CT examinations) without comparing time-lapse CT images. Interobserver agreement was assessed by means of Bland-Altman plots. Results The smallest range of the 95% limits of interobserver agreement between the members of the 55 pairs of the 11 radiologists in regard to maximal diameter was −1.14 to 1.72 mm, and the largest range was −7.7 to 1.7 mm. The mean value of the lower limit of the 95% limits of agreement was −3.1 ± 1.4 mm, and the mean value of their upper limit was 2.5 ± 1.1 mm. Conclusion When measurements are made by any two radiologists, an increase in the length of the maximal diameter of more than 1.72 mm would be necessary in order to be able to state that the maximal diameter of a particular GGO had actually increased. To evaluate interobserver agreement in regard to measurements of focal ground-glass opacities (GGO) diameters on computed tomography (CT) images to identify increases in the size of GGOs. Approval by the institutional review board and informed consent by the patients were obtained. Ten GGOs (mean size, 10.4 mm; range, 6.5–15 mm), one each in 10 patients (mean age, 65.9 years; range, 58–78 years), were used to make the diameter measurements. Eleven radiologists independently measured the diameters of the GGOs on a total of 40 thin-section CT images (the first [n = 10], the second [n = 10], and the third [n = 10] follow-up CT examinations and remeasurement of the first [n = 10] follow-up CT examinations) without comparing time-lapse CT images. Interobserver agreement was assessed by means of Bland-Altman plots. The smallest range of the 95% limits of interobserver agreement between the members of the 55 pairs of the 11 radiologists in regard to maximal diameter was −1.14 to 1.72 mm, and the largest range was −7.7 to 1.7 mm. The mean value of the lower limit of the 95% limits of agreement was −3.1 ± 1.4 mm, and the mean value of their upper limit was 2.5 ± 1.1 mm. When measurements are made by any two radiologists, an increase in the length of the maximal diameter of more than 1.72 mm would be necessary in order to be able to state that the maximal diameter of a particular GGO had actually increased.