iMRI During Transsphenoidal Surgery

Abstract

Surgeons routinely use adjunct imaging tools during transsphenoidal surgery (TSS). Intra-operative MRI (iMRI) was quickly adopted as a surgical adjunct for TSS. Currently, a variety of iMRI systems are in use during TSS. The variations in iMRI systems include field strengths (0.15 to 3 T), magnet configurations (open, retractable, double doughnut etc.) and room configurations. Most studies report that the primary utility of iMRI during TSS lies in detecting resectable tumor residuals following maximal resection with conventional technique. Additionally, stereotaxis, neuronavigation and complication avoidance/detection are enhanced by iMRI use during TSS. The use of iMRI during TSS can lead to increased extent of resection for large tumors. Additionally, improved remission rates from hormone secreting tumors have also been reported with iMRI use. Despite increased surgical duration with iMRI, the incidence of surgical or peri-operative complications are comparable with conventional TSS. In this chapter, the history, indications and future directions for iMRI during TSS are discussed.

Neurosurgical Tools to Improve Safety and Survival in Patients with Intracranial Tumors: Neuronavigation, MRI, and 5-ALA

“…A systematic review observed that complete radiological resection in patients whose procedure involved intraoperative ultrasound was 67.1% (range 63.5-77.8%) and endocrine remission was 88.4% (range 76-100%) [24]. Studies with ioMRI also evidences the benefits with intraoperative unexpected residuals in up to 42% (range 15-83%) of cases, of which re-exploration was attempted in 36% (range 9-83%) and further tumor resection occurred in 33% (range 9-83%) of the cases [25]. But this paper considered low-and high-field ioMRI.…”

“…Intraoperative image interpretation is even more difficult in transsphenoidal pituitary surgery than in glioma surgery, for example. This evaluation should only be done by an experienced neuroradiologist, because the literature shows relevant cases of false-positive leading to resection of normal tissue, in both ioMRI and ioUS [24,25]. The Congress of Neurological Surgeons (CNS) suggested in 2016 that intraoperative images in nonfunctioning adenomas may help to improve overall gross total resection but at the cost of removing normal tissue [26].…”

New intraoperative imaging technologies: Innovating the surgeon’s eye toward surgical precision

“…Inside the 5 G line, the surgical equipment has to be nonferromagnetic for MRI compatibility. Alternatively, larger ORs have been designed housing the magnetic resonance scanner and a surgical zone outside the 5 G line, for optimal use of standard surgical tools …”

“…A moveable operating table then allows to perform surgery with conventional instruments, while the patient can quickly be moved toward the scanner for intraoperative imaging. Twin ORs with a shared MRI improve the device efficiency …”

Advanced imaging to improve remission rates in patients undergoing transsphenoidal surgery for Cushing’s disease

“…Whether it helps to lateralise an otherwise undetectable adenoma is questionable, due to the often central location of the lesion and venous asymmetry 1 . Several other imaging modalities have been tried in an attempt to improve remission rates 3;4;5 . However, the sizes and the certainties of their effects on surgical remission rates for Cushing’s disease remains unclear.…”