Clinical Focus

  • Diagnostic Radiology

Academic Appointments

  • Clinical Professor, Radiology

Professional Education

  • Fellowship: UCSF Radiology Fellowships (1997) CA
  • Board Certification: American Board of Radiology, Diagnostic Radiology (1996)
  • Residency: UCLA Radiology Residency (1996) CA
  • Internship: California Pacific Medical Center Internal Medicine Residency (1992) CA
  • Medical Education: University of California at San Francisco School of Medicine (1991) CA


All Publications

  • Adaptations of Breast Imaging Centers to the COVID-19 Pandemic: A Survey of California and Texas JOURNAL OF BREAST IMAGING Chalfant, J. S., Cohen, E. O., Leung, J. T., Pittman, S. M., Kothari, P. D., Downey, J. R., Sohlich, R. E., Chong, A., Grimm, L. J., Hoyt, A. C., Ojeda-Fournier, H., Joe, B. N., Trinh, L., Rosen, E. L., Feig, S. A., Aminololama-Shakeri, S., Ikeda, D. M. 2021; 3 (3)
  • Impact of the COVID-19 Pandemic on Breast Imaging Education. Journal of breast imaging Chalfant, J. S., Pittman, S. M., Kothari, P. D., Chong, A., Grimm, L. J., Sohlich, R. E., Leung, J. W., Downey, J. R., Cohen, E. O., Ojeda-Fournier, H., Hoyt, A. C., Joe, B. N., Feig, S. A., Trinh, L., Rosen, E. L., Aminololama-Shakeri, S., Ikeda, D. M. 2021; 3 (3): 354-362


    Objective: To determine the impact of the COVID-19 pandemic on breast imaging education.Methods: A 22-item survey addressing four themes during the early pandemic (time on service, structured education, clinical training, future plans) was emailed to Society of Breast Imaging members and members-in-training in July 2020. Responses were compared using McNemar's and Mann-Whitney U tests; a general linear model was used for multivariate analysis.Results: Of 136 responses (136/2824, 4.8%), 96 U.S. responses from radiologists with trainees, residents, and fellows were included. Clinical exposure declined during the early pandemic, with almost no medical students on service (66/67, 99%) and fewer clinical days for residents (78/89, 88%) and fellows (48/68, 71%). Conferences shifted to remote live format (57/78, 73%), with some canceled (15/78, 19%). Compared to pre-pandemic, resident diagnostic (75/78, 96% vs 26/78, 33%) (P < 0.001) and procedural (73/78, 94% vs 21/78, 27%) (P < 0.001) participation fell, as did fellow diagnostic (60/61, 98% vs 47/61, 77%) (P = 0.001) and procedural (60/61, 98% vs 43/61, 70%) (P < 0.001) participation. Most thought that the pandemic negatively influenced resident and fellow screening (64/77, 83% and 43/60, 72%, respectively), diagnostic (66/77, 86% and 37/60, 62%), and procedural (71/77, 92% and 37/61, 61%) education. However, a majority thought that decreased time on service (36/67, 54%) and patient contact (46/79, 58%) would not change residents' pursuit of a breast imaging fellowship.Conclusion: The pandemic has had a largely negative impact on breast imaging education, with reduction in exposure to all aspects of breast imaging. However, this may not affect career decisions.

    View details for DOI 10.1093/jbi/wbab021

    View details for PubMedID 34056594

  • A behavioral training protocol using visual perceptual learning to improve a visual skill. STAR protocols Frank, S. M., Qi, A., Ravasio, D., Sasaki, Y., Rosen, E. L., Watanabe, T. 2021; 2 (1): 100240


    We describe a behavioral training protocol using visual perceptual learning (VPL) to improve visual detection skills in non-experts for subtle mammographic lesions indicative of breast cancer. This protocol can be adapted for the professional training of experts (radiologists) or to improve visual skills for other tasks, such as the detection of targets in photo or video surveillance. For complete details on the use and execution of this protocol, please refer to Frank etal. (2020a).

    View details for DOI 10.1016/j.xpro.2020.100240

    View details for PubMedID 33409503

  • Supervised Learning Occurs in Visual Perceptual Learning of Complex Natural Images. Current biology : CB Frank, S. M., Qi, A., Ravasio, D., Sasaki, Y., Rosen, E. L., Watanabe, T. 2020


    There have been long-standing debates regarding whether supervised or unsupervised learning mechanisms are involved in visual perceptual learning (VPL) [1-14]. However, these debates have been based on the effects of simple feedback only about response accuracy in detection or discrimination tasks of low-level visual features such as orientation [15-22]. Here, we examined whether the content of response feedback plays a critical role for the acquisition and long-term retention of VPL of complex natural images. We trained three groups of human subjects (n= 72 in total) to better detect "grouped microcalcifications" or "architectural distortion" lesions (referred to as calcification and distortion in the following) in mammograms either with no trial-by-trial feedback, partial trial-by-trial feedback (response correctness only), or detailed trial-by-trial feedback (response correctness and target location). Distortion lesions consist of more complex visual structures than calcification lesions [23-26]. We found that partial feedback is necessary for VPL of calcifications, whereas detailed feedback is required for VPL of distortions. Furthermore, detailed feedback during training is necessary for VPL of distortion and calcification lesions to be retained for 6months. These results show that although supervised learning is heavily involved in VPL of complex natural images, the extent of supervision for VPL varies across different types of complex natural images. Such differential requirements for VPL to improve the detectability of lesions in mammograms are potentially informative for the professional training of radiologists.

    View details for DOI 10.1016/j.cub.2020.05.050

    View details for PubMedID 32502415

  • Diffusion-weighted double-echo steady-state with a three-dimensional cones trajectory for non-contrast-enhanced breast MRI. Journal of magnetic resonance imaging : JMRI Moran, C. J., Cheng, J. Y., Sandino, C. M., Carl, M. n., Alley, M. T., Rosenberg, J. n., Daniel, B. L., Pittman, S. M., Rosen, E. L., Hargreaves, B. A. 2020


    The image quality limitations of echo-planar diffusion-weighted imaging (DWI) are an obstacle to its widespread adoption in the breast. Steady-state DWI is an alternative DWI method with more robust image quality but its contrast for imaging breast cancer is not well-understood. The aim of this study was to develop and evaluate diffusion-weighted double-echo steady-state imaging with a three-dimensional cones trajectory (DW-DESS-Cones) as an alternative to conventional DWI for non-contrast-enhanced MRI in the breast. This prospective study included 28 women undergoing clinically indicated breast MRI and six asymptomatic volunteers. In vivo studies were performed at 3ā€‰T and included DW-DESS-Cones, DW-DESS-Cartesian, DWI, and CE-MRI acquisitions. Phantom experiments (diffusion phantom, High Precision Devices) and simulations were performed to establish framework for contrast of DW-DESS-Cones in comparison to DWI in the breast. Motion artifacts of DW-DESS-Cones were measured with artifact-to-noise ratio in volunteers and patients. Lesion-to-fibroglandular tissue signal ratios were measured, lesions were categorized as hyperintense or hypointense, and an image quality observer study was performed in DW-DESS-Cones and DWI in patients. Effect of DW-DESS-Cones method on motion artifacts was tested by mixed-effects generalized linear model. Effect of DW-DESS-Cones on signal in phantom was tested by quadratic regression. Correlation was calculated between DW-DESS-Cones and DWI lesion-to-fibroglandular tissue signal ratios. Inter-observer agreement was assessed with Gwet's AC. Simulations predicted hyperintensity of lesions with DW-DESS-Cones but at a 3% to 67% lower degree than with DWI. Motion artifacts were reduced with DW-DESS-Cones versus DW-DESS-Cartesian (pā€‰<ā€‰0.05). Lesion-to-fibroglandular tissue signal ratios were not correlated between DW-DESS-Cones and DWI (r = 0.25, p = 0.38). Concordant hyperintensity/hypointensity was observed between DW-DESS-Cones and DWI in 11/14 lesions. DW-DESS-Cones improved sharpness, distortion, and overall image quality versus DWI. DW-DESS-Cones may be able to eliminate motion artifacts in the breast allowing for investigation of higher degrees of steady-state diffusion weighting. Malignant breast lesions in DW-DESS-Cones demonstrated hyperintensity with respect to surrounding tissue without an injection of contrast. LEVEL OF EVIDENCE: 2. TECHNICAL EFFICACY STAGE: 1.

    View details for DOI 10.1002/jmri.27492

    View details for PubMedID 33382171

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