The Chalice Sign: Characteristic Morphology of the Cervical Carotid Bifurcation in Patients with Loeys-Dietz Syndrome

Background and Purpose: Loeys-Dietz syndrome (LDS) is a connective tissue disorder characterized by arterial aneurysms and dissections. This study sought to assess and describe the arterial changes of the cervical arterial vasculature of such patients, with an emphasis on the carotid bifurcation. Material and Methods: A retrospective review of patients with a known diagnosis of LDS was carried out. The maximum diameters of the external carotid artery (ECA) and internal carotid artery (ICA) origins, common carotid artery (CCA) terminus, maximum transverse and craniocaudal dimensions of the carotid bulb, and bifurcation angle were measured. The presence of a chalice sign was defined as a carotid bifurcation angle of ≥80°. A semi-quantified analysis of vertebral artery tortuosity was completed as well. All measurements were compared to a cohort of age-matched controls. Results: A total of 21 patients with LDS were included. Compared to normal controls, the presence of a chalice sign had 61.9% sensitivity and 100.0% specificity for LDS if present bilaterally; the sensitivity and specificity of a unilateral chalice sign were 66.7% and 82.3%, respectively. Patients with LDS also had significantly higher rates of a bilateral chalice sign compared to patients with vascular Ehlers-Danlos syndrome (vEDS) (61.9% versus 0%, P <0.0001) and patients with Marfan syndrome (61.9% versus 14.3%, P = 0.001). Conclusion: Patients with LDS have characteristic findings of the cervical arterial vasculature that enables them to be distinguished from normal controls as well as patients with connective tissue diseases, such as Marfan syndrome and vEDS; most notably including marked widening of the carotid bifurcation angle in what is proposed to be named the chalice sign.