Imaging description

Curved planar reformatted (CPR) images are a form of post-processing whereby the lumen of a vessel of interest is tracked automatically by dedicated 3D software and a centerline is created through the vessel. Reformatted images created orthogonal to the centerline then allow the entire vessel to be visualized on one imaging plane. This technique is very useful for providing a comprehensive view of the entire vessel of interest on a single image. However, occasionally these automated techniques can result in artifactual lesions in the coronaries due to difficulties with vessel tracking. This seems to occur most often when the vessel takes an acute turn and the software is unable to completely straighten the tortuous segment, resulting in truncation of portions of the vessels. The result is a discontinuity in the vessel at the location of incorrect vessel tracking that can mimic a stenosis (Figure 33.1).

Importance

Misdiagnosis of coronary artery stenosis due to inappropriate vessel tracking could result in additional diagnostic testing, such as invasive cardiac catheterization, and further risks and costs that are unnecessary.

Typical clinical scenario

CPR images are used routinely for evaluation of the coronary arteries by many centers. Vessel tracking errors are most frequent in tortuous vessels, which are more likely in older patients.

Differential diagnosis

Pseudostenosis from incorrect vessel tracking should be distinguished from true coronary artery stenoses caused by atherosclerotic disease. These entities can be differentiated by inspection of the unprocessed source images with manual multiplanar reformatting.

Teaching point

Incorrect vessel tracking on automated CPR images can result in a pseudostenosis of the coronary arteries. It is important to always confirm stenoses identified with auto- mated post-processing techniques on the source images.