Brain MRI images that are acquired from the scanner will be having the non-brain tissues like skull, cerebrospinal fluid, Dura as the integral part of the image. All such unwanted elements does considerable impact on the estimation of the volume of the damaged region from resultant segmented image, Hence all such unwanted components from the brain MR image are be eliminated for accurate results. In this paper we had proposed a computationally efficient approach called Structural Augmentation which uses distance measures and morphological operation over a threaded bitmap image to eliminate the undesired region from the brain tissues. On applying the above said procedure well before the segmentation of the MR image, the evaluation seems to be meticulous. The end results of the proposed approach are proven to be superior in term of the accuracy and precision over conventional approaches.