Quantification of echo contrast passage across a patent foramen ovale

A parent foramen ovale (PFO) is a potential cardiac source of embolus. Agitated saline is usually injected during transoesophogeal echocardiography (TOE) to detect PFOs by observing contrast passing from right to left atrium. The authors present a technique for quantifying the level of contrast passing through the septum into the left atrium by analysing captured TOE images. Images were analysed from ten patients with a recent history of stroke and in whom a PFO was found. The technique was sufficiently sensitive to detect a PFO in all cases despite sub-optimal opacification of the right atrium in four of the patients. This study has shown that it is practical to automate the detection and quantification of contrast using image analysis, which the authors believe is a first step towards a method of objectively quantifying contrast passage across a patent foramen ovale