Measurement of the peritumoral edema and tumor volume ratio in differentiating malignant primary and metastatic brain tumor

Malignant primary and metastatic brain tumors are group of malignancies radiologically difficult to distinguish between one another. Meanwhile, the treatment regimens between the two entities are very different. The right regimen can maintain patient’s survival. MRI is the modality of choice for diagnosing brain tumors; although, malignant primary brain tumors and solitary metastases appear similar on conventional MRI. The difference in the pathophysiology of peritumoral edema in malignant primary and metastatic brain tumors has the potential for differentiation of the two entities. In malignant primary brain tumors, tumor cell infiltration occurs in the edema area, meaning that the peritumoral edema is narrower than that of the metastases. This study analyzed the ratio of peritumoral edema volume to tumor (EP/T volume ratio) in malignant primary and metastatic brain tumors by means of MRI examination with a cross-sectional design, using MRI data on FLAIR and T1WI sequences with contrast in malignant brain tumor of patients that have been pathologically proven. Then, volume contouring was performed on peritumoral edema (EP) and tumor (T), and comparation was done to obtain the EP/T volume ratio. The ratio of EP/T volume data in both groups was analyzed using the Mann–Whitney test with the SPSS 22 software. The results of statistical analysis revealed that the EP/T volume ratio of the malignant primary brain tumor group was smaller with a median value (max-min) of 1.1 (5.65-0.17) and in the metastatic group, 2.3 (64.03-0.09). There was a significant difference in the EP/T volume ratio between the two groups, which the brain metastatic tumor group have a double ratio of EP/T with a value of p=0.008 (p<0.05).