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Songbai Ji headshot

Songbai Ji

Adjunct Associate Professor of Engineering

Adjunct Associate Professor of Surgery, Geisel School of Medicine
Adjunct Associate Professor of Orthopaedic Surgery, Geisel School of Medicine

Education

  • BSc, Materials Science, Shanghai Jiaotong University 1996
  • MS, Computer Science, Washington University in St. Louis 2003
  • DSc, Mechanical Engineering, Washington University in St. Louis 2003

Research Interests

Image-guided surgery; medical imaging; multi-modality imaging; image analysis; finite element; numerical methods; image registration; traumatic brain injury; computational modeling of the human head

Selected Publications

Surgical Image Guidance
  • S. Ji, X. Fan, K.D. Paulsen, D.W. Roberts, S.K. Mirza, S.S. Lollis. (2015). Patient Registration Using Intraoperative Stereovision in Image-guided Open Spinal Surgery. IEEE Transactions on Biomedical Engineering, (in press).
  • S. Ji, X. Fan, D.W. Roberts, K.D. Paulsen. Efficient Stereo Image Geometrical Reconstruction at Arbitrary Camera Settings from a Single Calibration. In: Barillot, C., Golland, P., Hornegger, J., Howe R. (eds.) MICCAI 2014, (Oral presentation; at a rate of ~4.00%, 36/~900)
  • S. Ji, X. Fan, D.W. Roberts, A. Hartov, Timothy J. Schaewe, David A. Simon, and K.D. Paulsen. (2014) "Brain Shift Compensation via Intraoperative Imaging and Data Assimilation," in CRC Handbook of Imaging in Biological Mechanics, (pp. 229–240) CRC Press and Taylor & Francis, Editors: Corey Neu and Guy Genin.
  • S. Ji, X. Fan, A. Hartov, D.W. Roberts, K.D. Paulsen. Cortical Surface Shift Estimation Using Optical Flow Motion Tracking and Stereovision via Projection Image Registration, Medical Image Analysis, 18:1169–1183, 2014. DOI: 10.1016/j.media.2014.07.001
  • S. Ji, D.W. Roberts, A. Hartov, and K.D. Paulsen. Intraoperative patient registration using volumetric true 3D ultrasound without fiducials, Medical Physics. 39(12), 7540–7552, (2012).
  • S. Ji, X. Fan, A. Hartov, D.W. Roberts, and K.D. Paulsen. "Estimation of intraoperative brain deformation", in Studies in Mechanobiology, Tissue Engineering and Biomaterials, Volume 11, 97–133, Y. Payan (Ed.), Springer-Verlag Berlin Heidelberg, 2012. DOI: 10.1007/8415_2012_129
  • S. Ji, X. Fan, D.W. Roberts, K.D. Paulsen, Cortical surface strain estimation using stereovision. In: Fichtinger, G., Martel, A., Peters, T. (eds.) MICCAI 2011, Part I. LNCS, vol. 6891, pp. 412–419. Springer, Berlin (2011) (Oral presentation; at a rate of 4.15%, 34/819)
Traumatic Brain Injury
  • S. Ji, W. Zhao, J.C. Ford, J.G. Beckwith, R.P. Bolander, R.M. Greenwald, L.A. Flashman, K.D. Paulsen, T.W. McAllister. (2015) Group-wise evaluation and comparison of white matter fiber strain and maximum principal strain in sports-related concussion. Journal of Neurotrauma. 32(7), 441-454. doi/abs/10.1089/neu.2013.3268 (front cover)
  • W. Zhao, J. Ruan, S. Ji. Brain pressure responses in translational head impact: a dimensional analysis and a further computational study. Biomechanics and Modeling in Mechanobiology. DOI: 10.1007/s10237-014-0634-0
  • S. Ji, W. Zhao. A pre-computed brain response atlas for instantaneous strain estimation in contact sports. Annals of Biomedical Engineering. DOI: 10.1007/s10439-014-1193-3
  • S. Ji, W. Zhao, Z. Li, T.W. McAllister. (2014) Head impact accelerations for brain strain-related responses in contact sports: a model-based investigation. Biomechanics and Modeling in Mechanobiology. DOI: 10.1007/s10237-014-0562-z
  • S. Ji, H. Ghadyani, R.P. Bolander, J.G. Beckwith, J.C. Ford, T.W. McAllister, L.A. Flashman, K.D. Paulsen, K. Ernstrom, S. Jain, R. Raman, L. Zhang and R.M. Greenwald. Parametric Comparisons of Intracranial Mechanical Responses from Three Validated Finite Element Models of the Human Head. Annals of Biomedical Engineering, 42(1): 11–24, 2014. doi:10.1007/s10439-013-0907-2

Patents

  • Method and apparatus for determining tumor shift during surgery using a stereo-optical three-dimensional surface-mapping system (9,336,592)

Other

Open Positions

1) Post-Doctoral Associate in Medical Imaging

A post-doctoral associate position is available at Thayer School. This position will support research in image-guidance in spinal surgeries, using stereovision, ultrasound, as well as intraoperative MRI and CT. The goal of the project is to translate techniques established in the context of brain shift compensation in neurosurgery into open spinal surgery, and develop advanced technologies for surgical image-guidance and navigation. We have a dedicated research-oriented Center for Surgical Innovation (CSI), Advanced Imaging Center (AIC) equipped with state-of-the-art imaging and intraoperative imaging capabilities at Dartmouth-Hitchcock Medical Center. We offer the possibility to work in a relaxed environment on this exciting research project with the flexibility to realize his/her own ideas. The successful applicant is expected to work closely with other biomechanical engineers and clinicians. Work in human operating room environment is required.

Applicants are expected to have an earned Ph.D. degree in biomedical engineering, medical imaging, or a closely related field. Four years minimum experience with medical image analysis, preferably in MATLAB, is required. The post-doc associate will be expected to prepare research articles, present research findings at conference meetings, and contribute to grants. Therefore, excellent writing and communication skills are important.

Dartmouth College is an Ivy League institution. Our lab works closely with researchers in the Advanced Imaging Center, Center for Surgical Innovation, Dartmouth-Hitchcock Medical Center, as well as with other faculty in the engineering school and Geisel School of Medicine.

Interested applicants please send a cover letter, CV, and a list of 3 professional references to Songbai.Ji@Dartmouth.edu. This position will remain open until filled.

Qualifications: A Ph.D. in biomedical engineering, medical imaging, or a closely related field, with strong experience (4 years minimum) with MATLAB and medical image analysis.

2) Post-Doctoral Associate in Diffusion Tensor Imaging/Brain Injury

A post-doctoral associate position funded by the NIH is available at Thayer School. This position will support research in studying the biomechanical mechanisms of traumatic brain injury (sports-related concussion in particular) using longitudinal diffusion tensor imaging and neurocognitive testing. We are interested in correlating brain tissue-level mechanical responses obtained from simulating external head impacts with longitudinal neuroimaging and/or neurocognitive alterations.

Applicants are expected to have an earned Ph.D. degree in biomedical engineering, computer science, or a closely related field. Prior working experience in diffusion tensor imaging analysis is required. Expertise with image analysis and MATLAB is essential. The successful post-doc candidate will work closely with other lab members who investigate tissue-level brain mechanical responses via biomechanical simulations using a sophisticated computational model of the human head.

This position will involve working with a team of world-class biomechanical researchers in the field of sports-related concussion. The post-doc associate will be expected to participate in preparing research articles, presenting research findings at conference meetings, and contributing to grants. Therefore, excellent writing and communication skills are important.

Dartmouth College is an Ivy League institution. Our lab works closely with researchers in the Advanced Imaging Center and Advanced Surgical Center, Dartmouth-Hitchcock Medical Center, as well as with other faculty in the engineering school and school of medicine.

Interested applicants please send a cover letter, CV, and a list of 3 professional references to Songbai.Ji@Dartmouth.edu. This position will remain open until filled.

Qualifications: A Ph.D. in biomedical engineering, computer science, or a closely related field, with significant experience with diffusion tensor imaging, image-analysis, and MATLAB.

Contact:
Songbai Ji
Thayer School of Engineering at Dartmouth
Hanover, NH 03755
Phone: (603) 646-9193

Research Projects

  • Image-guided neurosurgery

    Image-guided neurosurgery

    Image-guided neurosurgery gives the surgeon the ability to track instruments in reference to subsurface anatomical structures. Using clinical brain displacement data, a computational technique is being developed to model the brain deformation that typically occurs during neurosurgery. The resulting deformation predictions are then used to update the patient's preoperative magnetic resonance images seen by the surgeon during the procedure.

  • Traumatic brain injury in college athletes

    Traumatic brain injury in college athletes

    Traumatic brain injury in college athletes is being studied using finite element method to simulate brain mechanical response subject to the on-field head impact biomechanics of helmeted collegiate athletes. The predicted distributions of stress and strain are correlated with the degree of altered white matter integrity quantified using diffusion tensor imaging to investigate the mechanisms of concussion/mild traumatic brain injury.

  • Measuring material properties of the human brain in vivo

    Measuring material properties of the human brain in vivo

    Despite being critical to biomechanical models, material properties of the brain remain poorly understood and have been characterized variously in part because of limited access to the in vivo brain. We use a simple indentation technique feasible in the operating room coupled to a noninvasive stereovision system to induce and measure brain surface deformation in patients undergoing open cranial surgeries in order to estimate material properties of the human brain in vivo.