Fusion of coronary angiography and stress echocardiography for myocardial viability evaluation

Identification of viable myocardial tissue is important for patients with a low left ventricular ejection fraction, since revascularization is effective only if the affected region is viable. After cineangiographic identification of occluded coronary vessels, the myocardial viability is usually determined using cardiac MRI or SPECT. Alternatively, myocardial deformation imaging by echocardiography has been introduced that allows detection of viable myocardium directly within the catheterization laboratory. Multimodality fusion of coronary angiograms and echocardiograms was developed to match viable regions with areas affected by occluded vessels. Identification of corresponding myocardial regions in both coronary angiograms and ultrasound scans was performed using multimodality image fusion. Geometrically correct superposition of these images was done to allow direct identification of the involved myocardial regions. An electromagnetic tracking system was used as a common base for co-registration of the images. The system was tested using a phantom test device in a cardiac catheterization laboratory. A 2D projection error of was achieved in trials using a cardiac phantom test object. Superimposition of the occluded coronary artery and the regional myocardial viability was achieved using automated multimodality fusion of coronary angiograms and stress echocardiograms with in vitro experiments. This system is promising for integrated single step angiography and angioplasty that may reduce procedure time, cost and length of hospitalization. Further testing in vivo is needed to verify and validate the system in a clinical setting.