The quality of brain tumor resection surgery is dependent on the spatial agreement between preoperative image and
intraoperative anatomy. However, brain shift compromises the aforementioned alignment. Currently, the clinical standard
to monitor brain shift is intraoperative magnetic resonance (iMR). While iMR provides better understanding of brain shift,
its cost and encumbrance is a consideration for medical centers. Hence, we are developing a model-based method that can
be a complementary technology to address brain shift in standard resections, with resource-intensive cases as referrals for
iMR facilities. Our strategy constructs a deformation ‘atlas’ containing potential deformation solutions derived from a
biomechanical model that account for variables such as cerebrospinal fluid drainage and mannitol effects. Volumetric
deformation is estimated with an inverse approach that determines the optimal combinatory ‘atlas’ solution fit to best
match measured surface deformation. Accordingly, preoperative image is updated based on the computed deformation
field. This study is the latest development to validate our methodology with iMR. Briefly, preoperative and intraoperative
MR images of 2 patients were acquired. Homologous surface points were selected on preoperative and intraoperative scans
as measurement of surface deformation and used to drive the inverse problem. To assess the model accuracy, subsurface
shift of targets between preoperative and intraoperative states was measured and compared to model prediction.
Considering subsurface shift above 3 mm, the proposed strategy provides an average shift correction of 59% across 2
cases. While further improvements in both the model and ability to validate with iMR are desired, the results reported are
encouraging.
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