3D printing of an optic pathway model from 7T MRI for education.

Abstract

Background: The optic pathway is a complex neural structure responsible for transmitting visual information from the retina to the brain. Traditionally, the optic pathway has been depicted using two-dimensional (2D) illustrations, which, while useful for simplification, can obscure depth, orientation, and connectivity, limiting a full understanding of its three-dimensional (3D) nature which is important for surgical planning and neuroanatomy education. Due to a convergence of advancing technologies in MRI image acquisition, medical CAD and 3D illustration software, as well as 3D printing technologies, these 3D visualizations can now be physically manufactured to provide life size, patient specific, physical, color-coded 3D models. 3D models manufactured from advanced imaging can provide a more accurate, interactive, non-invasive, cost-effective alternative to medical illustration and animation than traditional dissected cadaveric anatomical specimens for both clinical and educational purposes.

Methods: The source data for this project came from both a 42 year old male patient and a 21 year old male volunteer after both had been scanned on the same seven tesla MRI including DTI for the patient and volumetric sequences for the volunteer. The model was created by segmenting the optic pathway using medical CAD software and 3D illustration software. The DTI tracts were coregistered to the anatomic brain. The model was optimized for printing and hypothetical "lesions" were added along the pathway with their corresponding visual deficits. The model was printed on an HP580 multijet fusion color printer and photorealistic eyes were printed using material jetting of photopolymer via a Stratasys J750 printer.

Results: Multiple challenges were overcome to successfully create a life size, physical, multicolor 3D printed representation of the optic pathway created from 7T MRI data.

Conclusion: This workflow resulted in a unique educational 3D representation of the human optic pathway that allows for direct manipulation, haptic feedback, and clear understanding of the anatomic relations both of this system normally and the correlations between lesion location and resultant expected visual field impairment. As opposed to the inconvenience, costs, and limited access accompanying the classical standard of advanced dissections of human specimens, this model is available to all learners in all environments.