Abstract Purpose: Ultrasound technology as a supplement to mammography for screening women with dense breasts increases cancer detection. However, automated whole breast ultrasound technologies have been shown to substantially increase radiologist reading time. We conducted a reading validation program to assess how quickly and accurately radiologists could interpret images from a new automated whole breast ultrasound prior to launching a prospective case collection registry. Methods: The study analyzed 500 reading times of bilateral screening breast ultrasounds obtained from SoftVue Automated Whole Breast Ultrasound (SV) (Delphinus Medical) in women with dense breasts. For this proctored reading validation program, 20 bilateral screening ultrasound cases were selected. Thecases included a mix of normal, cysts, benign masses, cancers, and implants. 25 MSQA-trained radiologists with varying experience from 9 institutions across the United States each read the 20 cases. The same hanging protocol was used, beginning with sequences of Wafer and Sound Speed to identify an area of interest, Reflection to determine if the area persists, and then Stiffness Fusion for further confirmation and characterization. The primary outcome was reading time per bilateral ultrasound. Reading times were compared using linear mixed effects models for findings in neither, one, or both breasts and for subgroups of cancer and benign findings. Mean reading time was 3.3± 1.76 minutes (n=498, median 2.9min) per case. Cases that were negative in both breasts tended to have faster read times (2.7min, sd=1.32) compared to those with findings in one breast (3.2min, sd=1.57) or findings in both breasts (3.8min, sd=2.14). Mean read times for cases with clinical findings were within a minute of the mean time for normal cases across all case types. Conclusion Breast image sequences of Wafer, Sound Speed, Reflection, and Stiffness Fusion from SV ultrasound tomography facilitate bilateral ultrasound mean reading times of less than 4 minutes per case. Clinical Significance: SV, used as an adjunct to mammography in screening women with dense breasts, offers the benefits of increased cancer detection with supplemental ultrasound with little increase in radiologist reading time. Table 1: Analysis of Bilateral SV Read Time Across Types of Case Clinical Findings Citation Format: Mary Yamashita, Taylor Mahoney, Patrick Walker, Linda Hovanessian Larsen. Analysis of whole breast ultrasound image sequence reading time with a new FDA approved automated whole breast ultrasound tomography system for supplemental screening in women with dense breasts [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-28-10.