Hybrid CT, angiography registration could help with CTO cases
A real-time hybrid CT and angiography image registration can be used to minimize foreshortening and vessel masking to determine stent size and location and provide a reference of vessel path and structure in cases of chronic total occlusion (CTO), according to a poster presentation at the American Heart Association conference held this week in Orlando, Fla.

Ariel Roguin and Subhi Abadi from the invasive cardiology and medical imaging department at the Rambam Medical Center in Haifa, Israel, were lead investigators for the study.

Currently, coronary angiography and percutaneous coronary interventions (PCI) are performed using contrast injections and fluoroscopic guidance, and only the lumen of the coronary vessel is imaged. The vessel wall composition—calcifications, soft plaque and lesion length usually cannot be accurately determined—which the researchers believed could be imaged using CT.

The researchers investigated the accuracy, feasibility and safety of real-time hybrid CT and angiography image registration. The purpose of the design is to integrate the two into a regular catheterization procedure and provide the cardiologist with data to assist in decision making and procedural intervention.

The study included 18 patients, who underwent cardiac CT followed by a cardiac catheterization, from which the phantoms were used to test the accuracy and potential of informational co-registration. Feasibility was performed off-line in the first 12 patients, and precision was tested using coronary marker wires and distance between bifurcations.

Preclinical validation showed that the registration is feasible, accurate and measurements are precise, which was precise also for custom-working angulations during coronary angiography. Real-time registration was successful in all cases and aided in decision-making as to what angulations work for least foreshortening, which length of balloons and stent to use and assist in deciding to attempt and cross chronic total occlusions.

The researchers concluded that the integration was easy and fast, and the system could be used also for peripheral interventions. The methods also reduce radiation dosages and contrast injections, as well as the overall duration of the procedure and enhance precision of interventions.