UC Irvine

This study investigated the detectability of microcalcifications (MCs) using a low dose dedicated computed tomography (CT) system with a Cadmium Telluride (CdTe) photon-counting detector of 75 µm pixel pitch in a 12 cm diameter postmortem breast and an accredited mammography phantom. Calcium carbonate grains with size of 125–250 µm were inserted into the postmortem breast. Phantoms were imaged at 65 kVp with a mean glandular dose (MGD) of 1.7–21 mGy and reconstructed by Filtered back-projection (FBP) algorithm and analytical iterative reconstruction (AIR) at a voxel size of 50 µm3. Three and two blinded readers rated the visibility of MCs and the three groups of targets based on a 4-point scale and ACR phantom scoring scheme for the postmortem breast and ACR phantom, respectively. The MCs and targets detectability were evaluated by the averaged area under the receiver operating characteristic curves and the average score across readers, accordingly. The ACR phantom study showed an average score of 5.5 and 4.75 for fibers, 3.5 and 2.5 for speck groups, and 4.5 and 3.5 for masses at 3 mGy for AIR and FBP reconstruction, respectively. The postmortem breast study showed detectability of MCs larger than 125 μm with AUC greater than 0.912±0.038 at a MGD of 3 mGy and maintained an AUC greater than 0.843±0.038 at a mean glandular dose of 2 mGy.