Surgical strategy of brain tumors adjacent to the optic radiation using diffusion tensor imaging-based tractography

Abstract

The present study evaluated the efficacy of diffusion tensor imaging (DTI)-based tractography in the surgery of brain tumors adjacent to the optic radiation. Of the 14 surgical cases included, 11 had metastatic brain tumors and 3 cerebral gliomas. Additionally, 4 of the 14 patients had pre-operative visual field defects, while the remaining 10 patients experienced no visual impairment. The optic radiations on the lesion side were evident in all 14 patients. On the basis of these tractographic findings, we employed optimal surgical approaches in each patient to avoid injury to the eloquent neural structures, including optic radiation, during surgery. Successful surgical resection was performed in all 14 patients. Of the 14 patients, 2 with visual field defects during the pre-operative period showed improvement in their visual field, and the remaining 12 patients experienced no visual deterioration. DTI-based tractography thus is a feasible modality for the surgical planning of brain lesions adjacent to the optic radiation.

Figure 1

Neuroimaging of an illustrative case. (a) Pre-operative T2 and gadolinium-enhancing MRI shows a heterogeneously enhanced mass of the visual cortex. (b) Pre-operative tractography shows a superolateral shifting of the optic radiation on the lesional side. (c) Postoperative MRI illustrates total extirpation of the tumor.

Figure 2

Intra-operative images of the illustrative case. (a) The arrow indicates the darkly discolored cortex, including perilesional hemorrhage. (b) Gross total resection was performed on the tumor using the inferior occipital approach.