An ultrasonic diagnostic imaging system is described which quantifies regurgitant flow through a mitral valve, including the automatic indication of the location of a regurgitant orifice in an ultrasound image. A clinician images the regurgitant valve and indicates in the image the presumed location of the regurgitant orifice (130). A flow quantification processor is responsive to this initial location estimate by the clinician to calculate a refined estimation of the orifice location. The refined location is indicated on the ultrasound image by the imaging system, either by relocating an icon placed by the clinician, or displaying a second icon (132) on the image at the refined location.