High-resolution μCT imaging for characterizing microcalcification detection performance in breast CT

• Published in: Journal of medical imaging (Bellingham, Wash.) Vol. 8; no. 5; p. 052107
• Main Authors: Hernandez, Andrew M, Becker, Amy E, Hyun Lyu, Su, Abbey, Craig K, Boone, John M
• Format: Journal Article
• Language: English
• Published: United States Society of Photo-Optical Instrumentation Engineers 01.09.2021
• Subjects: Special Section Celebrating X-Ray Computed Tomography at 50; breast cancer; micro-computed tomography; breast computed tomography; microcalcification; detectability
• ISSN: 2329-4302; 2329-4310
• DOI: 10.1117/1.JMI.8.5.052107

Purpose: To demonstrate the utility of high-resolution micro-computed tomography (μCT) for determining ground-truth size and shape properties of calcium grains for evaluation of detection performance in breast CT (bCT). Approach: Calcium carbonate grains (∼200  μm) were suspended in 1% agar solution to emulate microcalcifications (μCalcs) within a fibroglandular tissue background. Ground-truth imaging was performed on a commercial μCT scanner and was used for assessing calcium-grain size and shape, and for generating μCalc signal profiles. Calcium grains were placed within a realistic breast-shaped phantom and imaged on a prototype bCT system at 3- and 6-mGy mean glandular dose (MGD) levels, and the non-prewhitening detectability was assessed. Additionally, the μCT-derived signal profiles were used in conjunction with the bCT system characterization (MTF and NPS) to obtain predictions of bCT detectability. Results: Estimated detectability of the calcium grains on the bCT system ranged from 2.5 to 10.6 for 3 mGy and from 3.8 to 15.3 for 6 mGy with large fractions of the grains meeting the Rose criterion for visibility. Segmentation of μCT images based on morphological operations produced accurate results in terms of segmentation boundaries and segmented region size. A regression model linking bCT detectability to μCalc parameters indicated significant effects of μCalc size and vertical position within the breast phantom. Detectability using μCT-derived detection templates and bCT statistical properties (MTF and NPS) were in good correspondence with those measured directly from bCT (R2  >  0.88). Conclusions: Parameters derived from μCT ground-truth data were shown to produce useful characterizations of detectability when compared to estimates derived directly from bCT. Signal profiles derived from μCT imaging can be used in conjunction with measured or hypothesized statistical properties to evaluate the performance of a system, or system component, that may not currently be available.