No abstract

Objective Currently, dynamic contrast-enhanced breast MRI prioritizes spatial resolution over temporal resolution given the limitations of acquisition techniques. The purpose of our intra-patient study was to assess the ability of a novel high spatial and high temporal resolution DCE breast MRI method to maintain image quality compared to the clinical standard-of-care (SOC) MRI. Materials and Methods Thirty patients, each demonstrating a focal area of enhancement (29 benign, 1 cancer) on their SOC MRI consented to undergo a research DCE breast MRI on a second date. For the research DCE MRI, a method (DISCO) employing pseudo-random k-space sampling, view sharing reconstruction, two-point Dixon fat-water separation, and parallel imaging was used to produce images with an effective temporal resolution six times faster than the SOC MRI (27 seconds versus 168 seconds, respectively). Both the SOC and DISCO MR images were acquired with matching spatial resolutions of 0.8 × 0.8 × 1.6 mm3. Image quality (distortion/artifacts, resolution, fat suppression, lesion conspicuity, perceived SNR, and overall image quality) was scored by three radiologists in a blinded reader study. Results Differences in image quality scores between the DISCO and SOC images were all less than 0.8 on a 10-point scale, and both methods were assessed as providing diagnostic image quality in all cases. DISCO images with the same high spatial resolution, but six times the effective temporal resolution as the SOC MR images were produced, yielding 20 post-contrast time-points with DISCO compared with three for the SOC MRI, over the same total time interval. Conclusions DISCO provided comparable image quality compared to the SOC MRI, while also providing six-times faster effective temporal resolution and the same high spatial resolution.

Purpose This work investigates the impact of tissue‐equivalent attenuator choice on measured signal‐to‐noise ratio (SNR) for automatic exposure control (AEC) performance evaluation in digital mammography. It also investigates how the SNR changes for each material when used to evaluate AEC performance across different mammography systems. Methods AEC performance was evaluated for four mammography systems using seven attenuator sets at two thicknesses (4 and 8 cm). All systems were evaluated in 2D imaging mode, and one system was evaluated in digital breast tomosynthesis (DBT) mode. The methodology followed the 2018 ACR digital mammography quality control (DMQC) manual. Each system‐attenuator‐thickness combination was evaluated using For Processing images in ImageJ with standard ROI size and location. The closest annual physicist testing results were used to explore the impact of varying measured AEC performance on image quality. Results The measured SNR varied by 44%–54% within each system across all attenuators at 4 cm thickness in 2D mode. The variation appeared to be largely due to changes in measured noise, with variations of 46%–67% within each system across all attenuators at 4 cm thickness in 2D mode. Two systems had failing SNR levels for two of the materials using the minimum SNR criterion specified in the ACR DMQC manual. Similar trends were seen in DBT mode and at 8 cm thickness. Within each material, there was 115%–131% variation at 4 cm and 82%–114% variation at 8 cm in the measured SNR across the four imaging systems. Variation in SNR did not correlate with system operating level based on visual image quality and average glandular dose (AGD). Conclusion Choice of tissue‐equivalent attenuator for AEC performance evaluation affects measured SNR values. Depending on the material, the difference may be enough to result in failure following the longitudinal and absolute thresholds specified in the ACR DMQC manual.

No abstract

No abstract