Intraoperative perfusion magnetic resonance imaging: Cutting-edge improvement in neurosurgical procedures

Abstract

The goal in brain tumor surgery is to remove the maximum achievable amount of the tumor, preventing damage to "eloquent" brain regions as the amount of brain tumor resection is one of the prognostic factors for time to tumor progression and median survival. To achieve this goal, a variety of technical advances have been introduced, including an operating microscope in the late 1950s, computer-assisted devices for surgical navigation and more recently, intraoperative imaging to incorporate and correct for brain shift during the resection of the lesion. However, surgically induced contrast enhancement along the rim of the resection cavity hampers interpretation of these intraoperatively acquired magnetic resonance images. To overcome this uncertainty, perfusion techniques [dynamic contrast enhanced magnetic resonance imaging (DCE-MRI), dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI)] have been introduced that can differentiate residual tumor from surgically induced changes at the rim of the resection cavity and thus overcome this remaining uncertainty of intraoperative MRI in high grade brain tumor resection.

Keywords: Dynamic contrast enhanced magnetic resonance imaging; Dynamic susceptibility contrast magnetic resonance imaging; Intraoperative magnetic resonance imaging; Neurosurgery; Surgically induced contrast enhancement.

Figure 1

Surgically induced intraoperative contrast leakage. Reprinted from NeuroImage with permission[9]. A: T1-weighted magnetic resonance (MR) image of the initial resection control. Residual tumor was depicted (not shown), neuronavigation was updated and the residual tumor was removed; B: T1-weighted MR image in identical orientation as in (A) of the second intraoperative resection control. At the border of the resection cavity there is contrast enhancement of previously non-enhancing tissue (arrows), which is caused by the neurosurgical resection leading to a leakage phenomenon. Perfusion maps of rCBV (C) and rCBF (D) at the second resection control demonstrate no elevated values in areas of contrast enhancement but complete resection of the tumor. rCBV: Regional cerebral blood volume; rCBF: Regional cerebral blood flow.