Significance of MRI changes after surgery of the skull base

Abstract

Magnetic resonance (MR) imaging is commonly used in the followup of patients who have undergone surgical removal of tumors from the cranial base to assess the possibility of tumor recurrence, persistence, or surgical complications. Interpretations of this study must be cautious because postoperative enhanced signals are encountered frequently. Although technological improvements continue to enhance the usefulness of MR images for followup, problems remain in differentiating between fibrotic, reconstructive changes, and tumor recurrence. In this study, the hospital records and MR findings of 215 patients who had undergone skull base surgery were reviewed. The study was prompted by negative operative exploration in three patients in whom postoperative MR images strongly suggested tumor recurrence. One-year follow-up images were available in 174 patients. Of these, 94% showed signal enhancement on the 1-year follow-up study. Progressive changes were observed in 14% of patients. The correlation of preoperative MR findings and surgery, with regard to dural involvement, vascular involvement, cranial nerve infiltration, and extent of intracranial infiltration, was analyzed in 28 patients. Methods to facilitate the detection of tumor recurrence using MR images are reviewed.

Extracranial Lower Cranial Nerve Sheath Tumors

“…This can be accomplished in most patients without sacrifice of the external auditory canal or middle ear through either a preauricular or postauricular infratemporal fossa approach. Despite contemporary surgical techniques and intraoperative cranial nerve monitoring, lower cranial nerve deficits should be expected 12 . As in this series, most of the deficits are transient but may require temporary forms of nutritional support as well as airway protection.…”

Magnetic resonance navigation for head and neck lesions

“…Because these lesions tended to be near the skull base with the greatest propensity for bone‐related artifact, computed tomography would be of much less appeal and value. Nonpalpable lesions discovered on MRI require judicious consideration, especially when the patient is in the postoperative or postirradiation state 6 . Making a distinction between tumor recurrence and expected fibrosis may require specialized MRI techniques that include fat suppression and enhancement.…”

Endoscopic Transnasal Craniotomy and the Resection of Craniopharyngioma

“…A baseline MRI is performed at 3 months. This is important as postsurgical MRI signaling is often difficult to interpret 11 . Endocrine assessment is performed routinely in follow‐up; however, ophthalmologic evaluation is undertaken only if clinically indicated.…”

“…This is important as postsurgical MRI signaling is often difficult to interpret. 11 Endocrine assessment is performed routinely in follow-up; however, ophthalmologic evaluation is undertaken only if clinically indicated. The long-term follow-up is multidisciplinary, but the endocrinologist is the central team member who coordinates care.…”