An analysis and detection of brain tumor is performed using MRI scanned images. Also a 3D visualization of the detected tumor part and its quantification is achieved through the proposed methodology. Initially, the noise is reduced by applying high pass filter and image enhancement is performed as a preprocessing step to enhance the input image quality. Morphological operations are applied to the enhanced image to detect the shape of the tumor in the enhanced image. The tumor part is mapped onto the original gray scale image with 255 intensity values to make the tumor visible more in the image. 3D Slicer is utilized to extract and visualize the 3D tumor data. The volume of the extracted 3D tumor portion is also calculated using 3D Slicer. The methodology has been tried out on a number of different input data sets and it is observed that it always gave the precise and desired result. © 2013 by CESER PUBLICATIONS.