CT scan provide valuable medical image information and intravenous iodinated contrast medium injection can enhance the image contrast quality. Some patients, who may suffer palpitation, emesis, and other stress phenomena, even induce death after intravenous iodinated contrast medium injection. In this paper, we develop a real-time risk indicator based on patients? heart rate variation. The heart rate was extracted from Photoplethysmography by adaptive template matching and moving average algorithms. Preliminary data indicate that there is significant heart rate to be increased after iodinated contrast medium injection. Statistical differences between patients with different risk index were observed in linear and nonlinear HRV parameters. A new risk indicator based on cumulated heart rate deviation is also developed that is proven to be effective as early warning indicator less than short time after intravenous iodinated contrast medium injection.
