PURPOSE

To evaluate the role of diffusion tensor imaging (DTI) in the differentiation of neoplastic and non-neoplastic brain lesions, on the basis of DTI parameters, fractional anisotropy (FA) and mean diffusivity (MD) from the lesion (L) and the perilesional edema (PE).

MATERIAL AND METHODS

Patients with newly diagnosed 25 neoplastic [10 high grade gliomas (HGG), 11 metastases, 4 low grade glioma (LGG)] and 25 non-neoplastic [13 tuberculomas and 12 neurocysticercosis (NCC)] brain lesions underwent an MRI, including the DTI sequences. Fractional anisotropy from the lesion (FAL) and mean diffusivity from the lesion (MDL), as well as fractional anisotropy from the perilesional edema (FAPE), and mean diffusivity from the perilesional edema (MDPE) were calculated and quantified using region of interest (ROI) based assessment on DTI derived FA and MD parametric maps. The mean values of FAL, FAPE, MDL and MDPE from the two groups were compared by the independent sample t-test.

RESULTS

In the non-neoplastic group, perilesional edema showed a significantly higher (P = 0.015) MD compared to the neoplastic group. Perilesional FA and lesional FA and MD showed no such statistically significant difference. On further subgroup analysis, MDPE was higher in metastases compared to HGG (P < 0.001), reflecting an increase in the vasogenic edema. Perilesional FA was higher in HGG compared to metastases and tuberculomas (P < 0.001) reflecting tumour infiltration in addition to vasogenic edema. FAL was higher in tuberculomas compared to metastases (P < 0.001), pointing to a more microstructural destruction in metastases.

CONCLUSION

Quantitative DTI parameters, FA and MD, from the lesion and from the area of perilesional edema are helpful in the evaluation and differentiation of brain lesions.