Significant liver growths such as HCC lesions are detected during a contrast agent ultrasound exam by their early reception of contrast and brightening following a bolus injection, as compared with surrounding normal tissue and benign growths. A pixel classifier looks for and identifies pixel or voxel regions where this early wash-in of contrast occurs and denotes these pixel or voxel locations in a parametric image. The pixel classifier analyzes pixel or voxel values from a sequence of images and identifies suspicious regions in an image by uniquely coding the points in a parametric liver image where early wash-in occurs.