Brain imaging is necessary in clarifying intracranial pathology that produces clinical symptoms to the patients. The CT brain scan is a fast, simple and safe valuable neuroimaging tool that provides diagnosis. Brain tumors are a common disease that cause severe neurological symptoms and neurological deficits which require urgent treatment. Primary brain tumors such as the glioma group and meningioma as well as metastatic brain tumor are among the three most prevalent type of brain tumor encountered everywhere in the world, including Thailand. If a brain tumor has specific characteristic such as pathognomonic findings like meningioma, CT brain scans can give the right diagnosis and lead to treatment. However, glioma tumors, particularly glioblastoma multiforme (GBM), the most commonly encountered, have no pathognomonic characteristic along with solitary metastatic brain tumors. Both gliomas and metastatic tumors usually have hypodensity in the gray matter and heterogeneously enhancement surrounded by vasogenic edema. Both tumors have a significantly different prognosis and treatment method via surgery, radiation therapy and chemotherapy. Therefore, we quantitatively measured vasogenic edema on a CT scan to help differentiation between primary brain tumor and solitary brain metastasis.

Keywords: Peritumoral edema; Primary brain tumor; Metastatic brain tumor; CT brain scan