Multi-slot extended view imaging on the O-Arm: Image quality and application to intraoperative assessment of spinal morphology

X. Zhang, A. Uneri, P. Wu, M. D. Ketcha, S. A. Doerr, C. K. Jones, P. A. Helm, J. H. Siewerdsen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


Purpose. Surgical treatment of spinal deformity often seeks to achieve a given change in spinal curvature for the desired surgical outcome. However, it can be difficult to reliably evaluate changes in spinal curvature in the operating room based on qualitative evaluation or radiographs covering a limited field of view (FOV). We report a prototype beam filtration hardware configuration constructed on the O-arm imaging system and an image reconstruction algorithm for extended view (EV) imaging to enable such clear, long-length visualization of the spine and long surgical constructs. Methods. EV imaging on the O-arm involves a novel multi-slot collimator and longitudinal translation of the gantry. A weighted-backprojection algorithm was developed for EV image reconstruction. Image quality and geometric accuracy was evaluated in simulation and phantom studies to quantitatively characterize the depth resolution and potential sources of geometric distortion. A cadaver study was conducted to verify the quality of visualization in EV images and the potential for measurement of global spinal alignment (GSA) in the operating room. Results. EV imaging provided images spanning up to 65 cm length. Analogous to tomosynthesis, EV image reconstruction provides a modest degree of depth resolution and out-of-plane clutter rejection. The phantom study presenting highcontrast spheres in foam-core exhibited ∼11% reduction in signal magnitude at 60 cm from the specified focal plane. The geometric accuracy of EV image reconstructions was high for objects at the focal plane, and distortion outside the focal plane was accurately described by predictions based on the known system geometry and object location. In addition to extending the FOV length by more than a factor of 3, EV images demonstrated strong improvement in visual image quality compared to a plain radiograph, and provided clear visualization of structures necessary for evaluation of GSA- e.g., vertebral endplates at the cervical-thoracic, thoraco-lumbar, and lumbar-sacral junctions. Conclusions. The multi-slot EV imaging technique offers a promising means for intraoperative visualization and assessment of spinal deformity correction through improved visualization over a long FOV and accurate measurement of distance and angles for GSA analysis. Future work involves integration of EV imaging with automated vertebral labeling, GSA analysis, and registration of surgical instrumentation in long surgical constructs.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2020
Subtitle of host publicationImage-Guided Procedures, Robotic Interventions, and Modeling
EditorsBaowei Fei, Cristian A. Linte
ISBN (Electronic)9781510633971
StatePublished - 2020
EventMedical Imaging 2020: Image-Guided Procedures, Robotic Interventions, and Modeling - Houston, United States
Duration: Feb 16 2020Feb 19 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceMedical Imaging 2020: Image-Guided Procedures, Robotic Interventions, and Modeling
Country/TerritoryUnited States


  • Image-guided surgery
  • Intraoperative imaging
  • Long-length imaging
  • Spinal alignment
  • Spinal deformity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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