الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The aim of this work was to evaluate the role of diffusion tensor imaging (Fraction Anisotropy) in the differentiation between recurrent brain tumors and radiation necrosis.
The study included twenty patients with suspicious lesions of tumor recurrence or radiation necrosis on conventional MRI imaging studies.
All patients underwent conventional MR study, dynamic susceptibility contrast (DSC) perfusion MRI examination and Diffusion Tensor Imaging (FA map). Using an independent computer workstation, cerebral blood volume color map, Post Contrast T1 and FA map were compared and measuring the degree of anisotropy.
Thirteen cases showed to be tumor recurrence (65%), proved (four cases (20%) by biopsy and nine cases (45%) on serial follow up).
Nine cases out of thirteen showed to be tumor recurrence on top of radiation necrosis (45%), the remaining four cases (20%) were diagnosed as tumor recurrence.
On the other hand, seven lesions (35%) were considered as radiation necrosis based on the findings of prolonged follow-up MRI at 12 months follow up.
In the 20 patients, there were 29 lesions,13 lesions(44.8%) proved to be tumor recurrence and 16 lesions(55.2%) proved to be radiation necrosis.
We proposed a cutoff value for FA of 0.1 to discriminate between recurrent tumors and radiation necrosis.
In all the 13 lesions with tumor recurrence, FA>0.1(range from 0.11to 0.37).
In all the 16 lesions with radiation necrosis,FA<0.1(range from 0.04 to 0.09).
Our results showed Diffusion Tensor imaging (FA) would be of a great benefit in differentiating between brain tumor recurrence and radiation necrosis.