In the liver many types of roundish lesions can appear, as well as near the liver. Finding the contour of such objects can improve both the segmentation of the liver from its environment, and the segmentation of the lesions within the liver. However, classical Hough transform, which is one of the main methods for finding objects described by a predefined parameterized formula, usually fails to identify these object as they possess not perfectly round or elliptic contours. A fuzzification of the Hough transform is described and suggested for using in image preprocessing for liver diagnosis based on CT images in this paper. Fuzzifying the Hough transform improves the detection of roundish contours.