Cardiothoracic Ratio-X-ray" is a user-friendly app that allows you to calculate the cardio-thoracic ratio from X-ray images accurately. Just open the app and import your X-ray image or take a photo of the X-ray. Click on the appropriate reference points to define the heart and chest cavity boundaries. CardioRatio X-ray will then calculate the cardio-thoracic ratio and provide you with the result in seconds.