Digital breast tomosynthesis: studies of the effects of acquisition geometry on contrast-to-noise ratio and observer preference of low-contrast objects in breast phantom images

Abstract

The effect of acquisition geometry in digital breast tomosynthesis (DBT) was evaluated with studies of contrast-to-noise ratios (CNRs) and observer preference. Contrast-detail (CD) test objects in 5 cm thick phantoms with breast-like backgrounds were imaged. Twelve different angular acquisitions (average glandular dose for each ~1.1 mGy) were performed ranging from narrow angle 16° with 17 projection views (16d17p) to wide angle 64d17p. Focal slices of SART-reconstructed images of the CD arrays were selected for CNR computations and the reader preference study. For the latter, pairs of images obtained with different acquisition geometries were randomized and scored by 7 trained readers. The total scores for all images and readings for each acquisition geometry were compared as were the CNRs. In general, readers preferred images acquired with wide angle as opposed to narrow angle geometries. The mean percent preferred was highly correlated with tomosynthesis angle (R=0.91). The highest scoring geometries were 60d21p (95%), 64d17p (80%), and 48d17p (72%); the lowest scoring were 16d17p (4%), 24d9p (17%) and 24d13p (33%). The measured CNRs for the various acquisitions showed much overlap but were overall highest for wide-angle acquisitions. Finally, the mean reader scores were well correlated with the mean CNRs (R=0.83).

Improving image quality for digital breast tomosynthesis: an automated detection and diffusion-based method for metal artifact reduction

“…The digital detector is stationary during image acquisition. The system uses a step-and-shoot design and can acquire DBT scan with variable combinations of number of projections and angular increments (Chan et al 2014, Goodsitt et al 2014). The DBT system uses an Rh-anode/Rh-filter x-ray source for all breasts.…”

Human observer performance on in-plane digital breast tomosynthesis images: Effects of reconstruction filters and data acquisition angles on signal detection

“…To optimize the performance of DBT system, image quality assessment plays an important role, and traditional metrics such as the contrast-to-noise ratio (CNR), signal power spectrum (SPS), and exponent β value of the anatomical noise power spectrum (NPS) have been used. In previous studies [7][8][9][10][11], CNR and SPS have been used to find the optimal data acquisition angle for the DBT system for various imaging tasks; they considered high CNR and SPS as indicators of better image quality. The β value was also used to compare signal detectability between breast imaging modalities [12][13][14], and they considered a small β value to be an indicator of high detection performance.…”

Characterization of photon‐counting multislit breast tomosynthesis

“…Specific parameters that have received much attention are angular range, number of projections, dose distribution, detector response, and reconstruction methods. Increasing the angular range has generally been found to increase depth resolution, which in a broad sense improves the in‐slice contrast‐to‐noise ratio . A larger angular range has, however, also shown a negative impact on resolving small microcalcifications with the proposed solution of variable dose distributions among projections .…”

“…Increasing the angular range has generally been found to increase depth resolution, which in a broad sense improves the in-slice contrast-to-noise ratio. 2,[14][15][16][17] A larger angular range has, however, also shown a negative impact on resolving small microcalcifications 18 with the proposed solution of variable dose distributions among projections. 19,20 Furthermore, increasing the angular sampling density has been found to increase detectability of small structures and to reduce anatomical noise.…”