Evaluation of Exposure Reduction Using Region-of-Interest Fluoroscopy (X-ray Fovea Imaging) in Cardiac Interventions

X-ray catheterization is used to guide minimally invasive procedures including percutaneous coronary interventions (PCIs), involving diffuse and multiple vessel disease and total chronic occlusion as well as electrophysiology (EP) procedures. While the medical benefit to patients outweighs the procedural risk, long fluoroscopy times associated with complex interventions have resulted in acute radiation injuries to patients. Radiation induced cancers have also become a concern in younger patient populations. With the increased number, diversity and complexity of the interventions performed, there has been a growing interest in reducing the long-term exposure risk to medical personnel (interventionists).

Conventional methods to reduce in radiation exposure, however, impact and often degrade diagnostic image quality. Catheterization procedures focus on a small portion of the anatomy forming the central region of the image with the periphery providing contextual information. Thus, decreasing the image quality in periphery can provide an overall exposure reduction to patients and interventionists without impacting on diagnosis. This can be achieved by introducing a pre-patient region-of-interest (ROI) attenuator that collimates the primary x-ray beam, reducing exposure to peripheral regions and decreasing integral radiation to the patient and scatter radiation to the interventionist.

The goal of this study is to investigate the exposure dose reduction provided by ROI imaging to patients and interventionists undergoing catheterization and to examine the feasibility of using the ROI attenuator in routine clinical practice for future integration into commercial x-ray imaging systems. The aim is to obtain exposure dose data and cardiac angiography images from subjects undergoing routine interventional procedures performed with and without ROI attenuation (experimental and control groups, respectively). For the experimental group, the interventionists performing the procedure will determine the appropriate application of the ROI attenuator and the duration of its use on specific patient lesions. An internal pilot study will be initially conducted on approximately 30 patients (15 per group) to obtain estimates on patient and operator dose reduction and variability. The on-going clinical trial will then be performed on an additional 40 patients (where the final protocol procedures and recruitment will be refined based on results from the pilot study).