Magnetic Resonance Imaging (MRI) is the gold-standard method for the detection and diagnosis of brain disease and surgical planning. Neurosurgery is closely guided by preoperative neuroimaging with MRI which can accurately localize and delineate lesions, map functionally critical brain regions, or probe tissue metabolism to guide clinical management. While the preoperative images are regularly consulted in the OR, the surgeon's ability to navigate with these maps is degraded by tissue deformation and brain shifts that occur during surgery. Dedicated intraoperative MRI suites have been constructed to address this but are relatively rare due to the cost of equipment and installation and the excessive time they add to the surgical procedure. The latter results from the need to either reposition the patient (with conventional scanners or even the latest generation of low-field portable brain scanners) or evacuate non-MR compatible equipment and then re- establish them with a track-driven high-field scanner such as the IMRIS system. To address this, we develop a portable, ultra-compact, low-field MRI scanner for intraoperative imaging. The scanner will be integrated with a commercially available low-profile stereotactic (Mayfield-like) frame that is necessary for most neurological surgeries. The size, weight, power, and cooling requirements of the scanner allow its integration into a standard operating room without special facility modifications. It is designed to rapidly engage and disengage from the patient to minimize time delays associated with imaging. The low-field and self-shielded nature of the "Halbach dome" magnet eliminate the need to evacuate ferromagnetic equipment from the vicinity further minimizing delays. Rapid intraoperative imaging with this system could directly guide the procedure by providing images to neuro-navigation software that identify tissue distortion (brain-shift) relative to high-resolution pre-operative images to allow more accurate and complete surgical resections with decreased repeat surgeries (call-backs). To efficiently mate with the stereotactic frame, we develop optimized RF coils that incorporate gaps and notches for the frame which has itself been made RF compatible. We also integrate an advanced electromagnetic interference (EMI) mitigation solution that obviates the need for an RF-shielded room (used in typical MRI suites) to allow for in situ operating room imaging. We will develop the critical acquisition sequences for neurosurgical guidance, e.g., T2, FLAIR, and DWI, and a user-friendly software solution for console control and ai-based image reconstruction. Finally, the new scanner will be validated with bench measurements and imaging tests in anthropomorphic phantoms and healthy subjects.
Public Health Relevance Statement: While MRI is essential for neurosurgical planning, the value of preoperative imaging is hindered by the structural brain shifts that occur during surgery. To address this, we propose a fast on-off, low-field, intraoperative MRI scanner that could map these deformations to the preoperative images and increase the accuracy of the surgical resection. The system is low-field (~150mT), compact, and integrated with a stereotactic frame, minimizing disturbances to the procedure, and preventing the time delays that occur in high-field intraoperative MRI scanners.
Project Terms: Air; air flow; airflow; Air Movements; Beds; Brain; Brain Nervous System; Encephalon; Brain Diseases; Brain Disorders; Encephalon Diseases; Intracranial CNS Disorders; Intracranial Central Nervous System Disorders; Charge; Dedications; Diagnosis; Diffusion; diffused; diffuses; diffusing; diffusions; Electromagnetics; Elements; Equipment; image reconstruction; image construction; image generation; Magnetic Resonance Imaging; MR Imaging; MR Tomography; MRI; MRIs; Medical Imaging, Magnetic Resonance / Nuclear Magnetic Resonance; NMR Imaging; NMR Tomography; Nuclear Magnetic Resonance Imaging; Zeugmatography; Maps; Metabolism; Intermediary Metabolism; Metabolic Processes; Methods; neurosurgery; Operating Rooms; Patients; Repeat Surgery; Reoperation; Robotics; San Francisco; Computer software; Software; Testing; Time; Tissues; Body Tissues; Twin Multiple Birth; Twins; Weight; weights; Roentgen Rays; X-Radiation; X-Ray Radiation; X-ray; Xray; fiberglass; glass fibers; polycarbonate; Generations; notch; notch receptors; notch protein; Artifacts; Morphologic artifacts; human subject; Procedures; brain surgery; Phase; Variation; Variant; Neurological; Neurologic; Lesion; Measurement; Earth; Planet Earth; Collaborations; light weight; lightweight; tool; Nature; Mechanics; mechanic; mechanical; Physiologic pulse; Pulse; Stream; In Situ; System; Neurosurgical Procedures; Neurological Surgery; Operative Surgical Procedures; Operative Procedures; Surgical; Surgical Interventions; Surgical Procedure; surgery; Services; Magnetism; magnetic; Surgeon; experience; monitoring device; user friendly software; user friendly computer software; Structure; simulation; neuroimaging; neural imaging; neuro-imaging; neurological imaging; novel; Partner in relationship; mate; Excision; Abscission; Extirpation; Removal; Surgical Removal; resection; Positioning Attribute; Position; design and construction; design and construct; Modeling; software development; develop software; developing computer software; portability; intra-operative imaging; intraoperative imaging; surgical imaging; Image-Guided Surgery; Boundary Elements; Frameless Stereotaxy; Neuronavigation; DWI (diffusion weighted imaging); DWI-MRI; Diffusion MRI; Diffusion Weighted MRI; Diffusion weighted imaging; Diffusion-weighted Magnetic Resonance Imaging; dMRI; diffusion tensor imaging; Diffusion Magnetic Resonance Imaging; Brain region; preventing; prevent; RF coil; Address; Interruption; Resolution; resolutions; Callback; Clinical Management; Tissue Differentiation; Update; Validation; validations; Conventional Surgery; transmission process; Transmission; Modification; Development; developmental; Image; imaging; cost; reconstruction; designing; design; flexible; flexibility; Secure; 3-D print; 3-D printer; 3D printer; 3D printing; three dimensional printing; 3D Print; diffusion weighted; image guidance; image guided; T2 imaging; T2 weighted image; T2 weighted imaging; Radiation exposure; phase I designs; phase 1 designs; detection procedure; detection technique; detection method; biomedical imaging; ultrasound; Diameter
