Artifactual aortic coarctation: A processing error in aortic magnetic resonance angiography

Background: Aortic coarctation is the most commonly encountered congenital abnormality of the thoracic aorta. In recent years, magnetic resonance (MR) imaging has become the modality of choice for patients suspected of having coarctation. The preferred method for evaluating the aorta is 3-D contrast-enhanced MR angiography (CE-MRA), combined with maximum intensity projections (MIPs). Purpose: To contribute to the literature on CE-MRA and to alert readers to the possibility of a postprocessing artifact from an aortic MRA dataset. Results: MIP images from a 21-year-old woman showed an apparent stenosis of the upper descending thoracic aorta. The stenosis was believed to be artifactual because it was only visible on the MIP images where the thoracic aorta and left atrium overlay one another. Furthermore, the stenosis disappeared when the heart and pulmonary veins were electronically sculpted from the imaging volume. Conclusion: Sculpted removal of the heart and left pulmonary veins can improve the accuracy of the MIP generation process. Physicians should be alerted to the possibility of a postprocessing error when interpreting MRA datasets.