A handheld touchscreen device (100) and method allowing ultrasound data to be manipulated to calculate the volume of a urinary bladder is disclosed. A first perimeter of the captured ultrasound image of the bladder is defined by the placement of a seed point on the touchscreen (104) by the user within a recognisable cross section of the bladder. The area defining a closed perimeter is then automatically calculated recognising similar echoic intensity within the image. The user is able to more precisely define the perimeter by dragging points of the perimeter to desired location via the touchscreen, the perimeter remains continuous. The volume of the bladder is calculated using the calculations of the first closed perimeter region and preselected data on the physical shape of the bladder. The process is repeated in an adjacent direction to further accurately define the volume of the bladder.
