The presence of calcium deposits on heart valve leaflets constitutes a clinically significant diagnostic indication. A novel method for imaging and detecting calcium deposits on tissue heart valves is presented. The method, called vibro-acoustography, uses the radiation force of ultrasound to vibrate the tissue at low (kHz) frequency and records the resulting acoustic response to produce images that are related to the hardness of the tissue. The method is tested on excised human heart valve tissues. Resulting images clearly show calcium deposits with high contrast and are in agreement with the corresponding radiographs of the specimens.