Astrocytomas
Astrocytomas are primary tumors originating from astrocyte cells and are neuroepithelial tissue tumors of the brain. Astrocytoma is the second most common primary brain tumor after meningioma (1). Central Brain Tumor Registry of the United State (CBTRUS) reports that astrocytic tumors including glioblastoma account for 75.8% of all glioma tumors with glioblastoma incidence reaching 3.21 per 100,000 population and an estimated 86,780 new cases per year. Astrocytoma has a high mortality, indicated by the life expectancy of sufferers of astrocytoma. In America the life expectancy of patients with high-grade astrocytomas is <10% for 2 years and 3.5% for 5 years (2).
Astrocytoma consists of three parts, the whole tumor, the solid part of the tumor and peritumoral edema. Peritumoral edema can reflect the characteristic characteristics of the degree of tumor astrocytoma (3). Peritumoral edema of high-grade astrocytomas consists of a combination of neoplasmic cell infiltration in which there is an increase in cell proliferation around the solid tumor, as well as an increase in neovascularization for tumor development and expansion (4).
Histopathological examination is still the gold standard for the diagnosis and classification of the degree of astrocytoma which will determine the subsequent management of the patient. Histopathological examination is done by invasive biopsy which can be accompanied by complications such as bleeding, neurological deficits and infection. The rate of post-biopsy bleeding after biopsy was reported to range from 1.2% to 59.8% (5). Multicarametric MRI imaging techniques such as Diffusion Weighted Imaging (DWI) and Apparent Diffusion Ceofficient (ADC) can improve the diagnostic accuracy of astrocytomas with a sensitivity reaching 93.75% and specificity to 92.68% in determining the tumor histopathology degree (6).