A method of determining a metric value of a predefined pixel of a diagnostic image is disclosed. The method includes receiving the diagnostic image and identifying a predefined pixel in the diagnostic image. The method further includes computing a plurality of first spatial statistical values of the diagnostic image and determining a homogenous region around the predefined pixel based on the plurality of first spatial statistical values of the diagnostic image. The method further includes computing a plurality of second spatial statistical values of the determined homogeneous region and determining a metric value for the predefined pixel based on the second spatial statistical values. The metric value is representative of a signal to noise ratio of the diagnostic image. FIG. 1
