A 34-year-old right-handed female developed an episode of partial epilepsy with transient language disorder. She recovered completely after few minutes of a seizure episode. MRI showed the left insular lesion characteristic for low-grade glioma. Pre-operative DTI was done to demonstrate the relationship of a lesion to eloquent areas to allow maximum tumor resection and to avoid tumor recurrence and damage to vital areas, such as language and motor function. Axial whole brain tractography showed destruction and distortion of the left frontal fibers and the left IFO tract. Anterior part of arcuate fasciculus (AF) was seen in close relation to the anterior-superior part of the lesion. The left CST was intact, yet medially deviated (Figure ).
A 67-year-old man was admitted to our hospital with a history of weakened left limbs and muscle twitching. On physical examination the muscle strength of the left upper limb was grade 2 and grade 4 on the lower limb. T2-weighted MRI revealed the lesion involving the right centrum ovale and part of the precentral gyrus. The FA value of the affected white matter was slightly lower (0.28) compared with the contralateral side (0.40). DTI-based fiber-tracking displayed a right CST passing through the lesion without interruption (fig. ). The patient refused surgery, therefore no histopathological diagnosis was made. However, an increased choline concentration (maximum choline/creatine and choline/N-acetylaspartate ratios of 3.04 and 4.51, respectively) was detected in the lesion with MRS study, which was highly suggestive of tumor.