The Hammock Sign in Computed Tomography as a Detection Aid for Bicuspid Aortic Valves.

Abstract

Bicuspid aortic valve is difficult to detect on standard transverse images. We aimed to investigate the usefulness of the hammock sign for detection of bicuspid aortic valve. We retrospectively investigated the usefulness of a newly proposed 'hammock sign' in a population of 45 contrast enhanced computer tomographic studies to discern tricuspid (22) from anatomical bicuspid aortic (23) valves. The gold standard of aortic morphology was the definite diagnosis in the patient's medical file, established by computed tomography, magnetic resonance, or surgery. Computer tomographic (CT) studies of each aortic morphology were randomly evaluated for the presence of the hammock sign on coronal and sagittal images, by two readers blinded to the diagnosis. Sensitivity for detecting an anatomic bicuspid valve was 86%, and specificity was 100%. The hammock sign allows for a quick and easy diagnosis of an anatomical bicuspid aortic valve, merely by scrolling through the standard coronal reconstructions of any type of contrast-enhanced thoracic CT study, and regardless of any other findings associated with bicuspid aortic valve. Functional bicuspid aortic valves were not the scope of this study.