Cardiac polar mapping could speed diagnosis

Polar maps of the coronary arteries could speed diagnosis if clinicians learn to adjust to their imperfections, according to research presented at the European Congress of Radiology in March.

"The problem is that the near vessels are displayed bigger than the farther vessels, particularly around the pole areas and the sides," said Dr. Felix Schoth from Aachen University Hospital in Germany.

Schoth and colleagues used a 16-slice scanner to perform standard CT angiography in 10 subjects. An algorithm provided a maximum intensity projection of the myocardium and the coronary arteries in 3D polar coordinates. The images were then "unfolded" into two dimensions as planar projection polar maps.

The technique rendered arterial visibility that was good proximally, fair medially, and poor distally. It accurately displayed stents and coronary calcifications but showed poor contrast in the ventricles. A perfected technique should skirt time-consuming curved multiplanar reformatted or volume-rendered images of the coronaries, Schoth said.