The brain is one of the largest and most complex organs in the human body. Some abnormal and uncontrolled growth of tissue taking place in human brain called “brain tumor”. The objective of biomedical image processing is that the image will be enhanced to support doctors more easily in diagnosing and treating. The detection of brain tumor can be performed by using various image processing techniques like brain Magnetic Resonance Imaging (MRI), Computer Tomography (CT), Positron Emission Tomography(PET), Electroencephalography (EEG) etc. Among these techniques the brain MRI is widely adopted in the world due to its significant features. Its correct detection and identification at an early stage is the only way to get cure. Brain tumor tissues may become malignant (cancerous) if not diagnosed. This paper deals with the various aspects of the brain tumor detection. The paper discusses the significant researches which are meant for the brain tumor detection through MRI quality enhancement.