Koji Sakai, Presenter: Nothing to Disclose

Ryo Sakamoto, Abstract Co-Author: Nothing to Disclose

Takeshi Kubo MD, Abstract Co-Author: Nothing to Disclose

Masahiro Yakami MD, Abstract Co-Author: Nothing to Disclose

Koji Fujimoto MD, PhD, Abstract Co-Author: Nothing to Disclose

Hiroyuki Sekiguchi, Abstract Co-Author: Nothing to Disclose

Yutaka Emoto MD, PhD, Abstract Co-Author: Nothing to Disclose

Naozo Sugimoto, Abstract Co-Author: Nothing to Disclose

Kaori Togashi MD, PhD, Abstract Co-Author: Nothing to Disclose

We stipulated an empirical definition of contour differentiation for solitary pulmonary nodules using a numerical scoring system and generated representative contour models. Pre-set score based on the stipulated definition showed a high agreement ratio with two expert radiologists. The stipulated definition of solitary pulmonary nodules will be expected to play important roles in intra-group sharing of information on nodules, in numerical understanding of the contour, and in the education of radiologists in training.

The contour of solitary pulmonary nodules obtained with computed tomography (CT) shows important information for differential diagnosis. Nevertheless, it is well known that there is frequent discrepancy in diagnosing nodules for the ambiguous definition of contour among radiologists. Therefore, we attempted to stipulate an empirical definition of contour differentiation based on numerical scores and generated models for sharing of nodule information. Furthermore, we investigated the relationships between the pre-set scores of the contour model and radiologists' scoring.

Solitary pulmonary nodules with a well-defined contour seen on CT were selected. The categorization and the scoring of nodules were stipulated by two highly experienced radiologists specializing in thoracic images. The features of the contour were grouped into 7 categories (smooth, ragged, corona radiata, coarse spiculation, notch, concave and convex). Each feature was scored on a 5-point scale. The 7 features were synthesized by the pixel operations of the polygon with custom-designed software using Matlab(R) (Mathworks, Natick, MA, USA). The 25 synthesized nodules embedded in a thoracic CT image were differentiated with the 5-point scoring system by two radiologists (A and B).

The agreement ratios between the pre-set scores and the radiologists' ratings was 65% (A: 67.8, B: 62.2). If a difference of ±1 is included in the agreement, the ratios was 86.7% (A: 87.8, B: 85.6). The agreement ratios within ±1.96 SD was 96.2% (A: 96.7, B: 95.6).

Sakai, K, Sakamoto, R, Kubo, T, Yakami, M, Fujimoto, K, Sekiguchi, H, Emoto, Y, Sugimoto, N, Togashi, K, A Method for Generating Solitary Pulmonary Nodule Contour Models Based on a Stipulated Empirical Definition for Detecting Contour Features.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12028142.html