Ultrasound images are difficult to segment because of their noisy and low contrast nature which makes them challenging to extract the important features. Typical intensity-gradient based approaches are not suitable for these low contrast images while it has been shown that local phase based technique provides far better results than intensity based methods for ultrasound images. In this study, we adopt local phase based feature asymmetry (FA) measure using monogenic signal for 3-D and 4-D feature extraction. This paper presents our work on: (1) comparison between intensity gradient based feature detectors and phase based feature detector, (2) formulating a 4-D version of FA measure and comparing its results with 3-D FA measure, and (3) comparing quadrature pair of filters in terms of feature detection performance.