Ultrasound in pituitary tumor surgery.

Transsphenoidal microsurgery for pituitary tumors is practiced routinely by neurosurgeons with satisfactory results. However, in many cases the surgeon encounters difficulties in assessing the extent of resection achieved in large macroadenomas or in the intraoperative localization of microadenomas. Ultrasound has been routinely used for preoperative and intraoperative diagnostic purposes in a variety of surgical procedures, including in neurosurgery. However, until recently, its use as a diagnostic tool during pituitary surgery has not been evaluated. We review two new imaging modalities that use ultrasound during transsphenoidal surgery; transcranial doppler ultrasonography for resection of large pituitary macroadenomas, and transsphenoidal intraoperative ultrasound for the localization and targeted resection of pituitary microadenomas. These ultrasound-based techniques may assist the surgeon in determining the extent of tumor resection in large adenomas, in localizing small adenomas that may not be visualized on preoperative MRI scans, and perhaps, in enhancing the safety of transsphenoidal exploration of the pituitary.