Investigation of Human and Model Observer Performance of Mass Detection in a Prototype Digital Breast Tomosynthesis System

• Published in: Journal of the Korean Physical Society Vol. 76; no. 4; pp. 335 - 340
• Main Authors: Choi, Seungyeon, Lee, Donghoon, Kim, Hee-Joung, Choi, Young-Wook, Choi, Sunghoon
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Physical Society 01.02.2020; Springer Nature B.V; 한국물리학회
• Subjects: Digital imaging; Human performance; Image detection; Image quality; Matched filters; Mathematical and Computational Physics; Medical imaging; Observers; Particle and Nuclear Physics; Physics; Physics and Astronomy; Prewhitening; Prototypes; Quality assessment; Spatial resolution; Theoretical; 물리학; Fourier-based model observer; 4AFC; Mass detectability; Breast tomosynthesis
• ISSN: 0374-4884; 1976-8524
• DOI: 10.3938/jkps.76.335

Task-based assessment of image quality using a theoretical observer model has recently gained attention in medical imaging fields. Observer models whose performance can suitably match that of a human observer under various imaging conditions have been considered a key concept for virtual clinical studies. This work focused on experimental study in which a prototype digital breast tomosynthesis (DBT) system, developed by the Korea Electrotechnology Research Institute, was used to compare the task-based Fourier metrics of a detectability index with the performance of human observers. Different angular ranges of ±7°, ±10.5°, ±14°, ±17.5°, ±21°, and ±24.5° were used to detect four different sizes of spheroidal masses with the same 15-projection samplings. A total of 16 human observers participated in the study. Human observer performance was measured using four-alternative forced choice (4AFC) tests for different detection tasks, including detecting spheroidal masses. To determine the task-based detectability index ( d ′), the non-prewhitening matched filter observer was calculated by analyzing the task function, local spatial resolution, and local noise of spheroidal masses. The percentage of signals correctly detected ( P c ) with the 4AFC tests was then compared with the detectability index for tasks presented in 2D slices (d slice ′2 ). The average P c for 16 human observers was 0.87 (range = 0.56–1). Results showed that P c decreased as the angular range increased from ±7° to ±24.5° with different mass sizes. Our result also showed that the performance of the task-based theoretical model observer could reasonably estimate d ′ for all inserted lesions of different sizes and acquired under different conditions, while presenting a trend similar to those of the human observers. Consequently, our study is expected to contribute to quantitative imaging performance analysis under various DBT imaging acquisition parameters.