Preoperative Evaluation of Adhesion with 3T-MRI-Balanced Fast Field Echo for Surgical Strategy in Petrous Meningiomas

Objective: Although the positional relationship between the surrounding tissue and the tumor has to be understood before surgery for petrous meningiomas, I believe that prediction of whether dissection of the brainstem and cranial nerve and major blood vessels is possible will be extremely useful for selecting the most suitable approach and type of surgery. I report that preoperative imaging using 3T-MRI-balanced fast field echo (b-FFE) was extremely useful in this regard.

Material and Methods: A total of 26 patients with petrous meningiomas who underwent b-FFE from February 2009 to November 2011 were included in this study. Operative findings of brainstem and surrounding tissue adhesion were compared.

Results: A peritumoral rim in the brainstem was observed on b-FFE in 16 patients (61.5%); detachment from the brainstem was easy in all of these patients. However, a strong adhesion was observed on the brainstem surface of 10 patients (38.5%) without the peritumoral rim, and subcapsular dissection was performed because of extremely convoluted blood vessels on the surface of the brain and cranial nerves. Of note, in patients with gross edema in the brain, stem adhesion was strong. These patients had a high chance of the subpial plane being dissected.

Conclusion: These findings suggest that a preoperative b-FFE scan for skull base meningioma surgery provides extremely useful information for performing surgery safely.