Intraoperative Magnetic Resonance Imaging for Neurologic Applications

Giving surgeons more timely access to imaging data during surgery could theoretically improve surgical outcomes. Because MRI is the preferred modality for imaging soft tissues of the brain, manufacturers developed iMRI technology to improve conventional image-guided neurosurgery techniques that rely on preoperative patient scans for guidance during the procedure.1-3

The majority of published research to date addresses the use of iMRI for resection of various tumors of the brain and skull base. More recently, investigators have evaluated the use of iMRI to implant electrodes for DBS therapy, with a majority of DBS reports focusing on Parkinson's disease (PD). Some researchers have suggested that iMRI might increase the accuracy of DBS electrode placement because it allows surgeons to implant electrodes in patients under general anesthesia.4 Traditionally, surgeons use electrophysiologic mapping to implant DBS electrodes in sedated but awake patients. However, some PD medications can affect placement accuracy by interfering with electrophysiologic mapping and masking the true source of abnormal brain signals.4

In neurosurgery for brain tumors, achieving good surgical margins while avoiding trauma to adjacent healthy tissue is critical.5 Common neurosurgical problems that iMRI systems were designed to address include the following:

Generally, iMRI scanners can be classified as having magnetic fields of either low strength (0.5 T or less) or high strength (1.5 T or greater).6 Low-field systems allow for real-time imaging and guidance during stereotactic neurosurgical procedures; however, low-field systems lack advanced MRI capabilities, such as angiography or diffusion-weighted imaging.6 High-field iMRI systems are based on conventional high-field MRI platforms; therefore, high-field MRI typically offers many...