Arterial-input-function(AIF) or vascular-input-function is a prerequisite for quantitative analysis of dynamic-contrast-enhanced(DCE)-MRI data. For DCE-MRI data of human brain used in the current study, previously reported automatic AIF estimation approach resulted in large variations from theoretically expected shape. In this study, DCE-MRI data of 25 treatment-naïve glioma patients were included. Proposed optimization enabled the removal of wrongly selected voxels having distorted concentration curve and hence provided an improved AIF. A substantial change in the shape of AIF was observed on optimization. Corrected AIF also resulted in significant improvement in quantitative perfusion parameters and glioma gradin