Preoperative Diffusion Tensor Imaging : A landmark modality for predicting the outcome and characterization of supratentorial intra-axial brain tumours.

BACKGROUND AND AIM: In view of few large prospective studies available on the role of preoperative diffusion tensor imaging(DTI), and the potential of DTI in revealing tumour and white matter tracts relationship, we studied the role of 'preoperative DTI' in planning safe surgical corridor, predicting the neurological and surgical outcome and tumour characterization in supratentorial intra-axial brain tumours.

METHODOLOGY: We included 128 cases. Preoperative neurological status and tumour volume was assessed. MRI based surgical plan was decided and reviewed for changes after DTI ( site of corticotomy or limit of resection ) by senior faculty of neurosurgery and neuroradiologist. Tracts were divided as displaced, infiltrated and disrupted .Postoperative neurological and surgical outcome was assessed along with evaluation of association of DTI with tumour type.

RESULTS: DTI based change in surgical corridor was seen in 60 (47%) patients. 66 patients harbored Low grade gliomas( LGGs), 48 had High grade gliomas( HGGs) and 14 had metastastic lesions. Resectibility ( maximum safe resection )was found higher in patients with displaced fibers and lesser in those with disrupted/infiltrated fibers, which was statistically significant. Fewer patients had neurological deterioration in displaced category (7.1%) as compared to disrupted/infiltrated (13.9%). Although no significant association could be established between neurological outcome and fiber type. Displaced fibers were mainly associated with LGG( 71%) whereas disrupted/infiltrated fibers mainly with HGG(66%) and this correlation was significant.

CONCLUSION: Preoperative DTI is a landmark tool for planning safe surgical corridor and predicting the tumour type along with neurological and surgical outcome of patients.