Intraoperative, real‐time, functional MRI

Abstract

Functional MRI (fMRI) methods have been demonstrated to noninvasively identify motor-sensory, visual, and other areas of eloquent cortex for guiding surgical intervention. Typically, fMRI data are acquired preoperatively during a conventional surgical planning MRI examination. Unlike direct cortical stimulation at the time of surgery, however, preoperative fMRI methods do not account for the potential movement of tissues (relative to the time of functional imaging) that may occur in the surgical suite as a direct result of the intervention. Recently, an MRI device has been demonstrated for use in the surgical suite that has the potential to reduce the extent of cortical exposure required for the intervention. However, the invasive requirements of cortical mapping may supersede the invasive requirements of the surgical intervention itself. Consequently, we demonstrate here a modification to the intraoperative MRI device that facilitates a noninvasive, real-time, functional MR examination in the surgical suite.

TTC post-processing is beneficial for functional MRI at low magnetic field: a comparative study at 1 T and 3 T

“…Despite some successful demonstrations of feasibility of intraoperative fMRI [23][24][25], appropriate fMRI sequences (fluid-attenuated inversion recovery [26] or gradient echo) and mostly post-processing strategies at low magnetic field require more investigation to cope with inherently low signal-tonoise ratio.…”

Functional magnetic resonance imaging in real time (FIRE): Sliding-window correlation analysis and reference-vector optimization

“…, ជ s LϪ1 ) which contains the ជ s i as column vectors. 5 The reference vector is detrended in the same way as the measurement vector to account that not only apparent drifts, but also parts of the actual signal response are being removed. 6 The minimization leads to the equations (see Appendix A and (13))…”

“…[5], given by Eq. [2], corresponds to the component of the measurement vector ជ x orthogonal to the detrending vectors.…”

“…The minimum of the second quadratic term in Eq. [5] occurs when trying to "explain" the reference vector by a linear combination of detrending vectors. 6 If a measurement vector is synthesized by adding an arbitrary linear-combination of detrending vectors to any chosen reference vector, the correlation coefficient recovers to 1 (up to numerical accuracy) after detrending.…”

Intraoperative Guidance for Pediatric Brain Surgery based on Optical Techniques

“…Intraoperative MRI (iMRI) and intraoperative functional MRI (ifMRI) became a desirable technique to provide anatomical and functional mapping ever since its first implementation in a surgical imaging suite [15]. It has been reported that with iMRI/ifMRI, a maximum extent of resection, despite the lesion's proximity to eloquent brain cortex and fiber tracts, can be achieved, which leads to a favorable surgical outcome and acceptable neurological deficit rates [16].…”