Removal of Pituitary Tumors Aided by MRI

Neurosurgeons can determine how thoroughly they are excising pituitary tumors by using intraoperative magnetic resonance imaging (MRI).

Pituitary tumors can range in size from several millimeters to several centimeters, and they occupy a narrow channel along the midline of the base of the brain at the top of the nasal passages. After planning their approach with MRI, surgeons can insert an imaging pointer in a patient's nostril, capture images of the surrounding area, and make sure they are going in the right direction toward the tumor. They confirm the precise location of the tumor as they begin surgical resection and then document complete removal of the lesion at the end of the operation.

The intraoperative MRI unit is a vertical donut, with part of the magnet on the right side of the patient and part on the left side. The system has a 45 cm slot where the surgeon and an assistant stand to operate and obtain MRI images at any point during the procedure. A prospective study of the use of intraoperative MRI in all 12 patients who were treated for pituitary tumors since July 2002 at the Neurological Institute of Kentucky (Louisville, USA) showed that for all but two of the patients, MRI revealed that surgeons had completely removed the pituitary tumors. In the other two patients, MRI revealed that the tumors had invaded the cavernous sinus. The study was presented at the annual Clinical Congress of the American College of Surgeons (Chicago, IL, USA). Surgeons have also utilized the technique for plotting the trajectory of brain tumor procedures.

"If you are going to remove a brain tumor, you can use intraoperative MRI to localize the craniotomy and find the most direct pathway for navigating through the brain and avoiding critical structures as well as determining when all of the tumor has been resected,” said Todd Vitaz, M.D., director of neurosurgic oncology at the institute.




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Neurological Institute of KY