Anatomical Targeting of the Superior Cervical Ganglion on Computed Tomography Imaging for Guidance of Endovascular Transmural Intervention.

Background: Endovascular transmural targeting of cervical and cranial perivascular structures is a novel approach for minimally invasive delivery of therapeutics. Components of the autonomic nervous system are in close anatomic proximity to major cervical vasculature and, therefore, represent potential targets for intervention. The superior cervical ganglion (SCG) is a discrete structure of interest for this approach, as sympathetic blockade may have therapeutic effects for various conditions. Variability of SCG location and its relationship to large cervical vessels, and the feasibility of endovascular transmural targeting has not been elucidated.

Methods: In this retrospective study, computed tomography angiography of head and neck from patients with subarachnoid hemorrhage or cerebral aneurysms were reviewed. SCG dimensions and spatial relationship to cervical vessels were measured. Measured anatomic parameters were used to determine endovascular transmural accessibility of the SCG from various cervical vessels.

Results: A total of 159 SCGs were identified and measured from 314 unilateral neck images of sufficient quality. SCGs had an average radio-opacity of 49.6 Hounsfield Units, length of 1.91 cm, and width of 0.71 cm. Internal carotid artery (ICA) has the longest contact length with the SCG (mean = 1.80 cm) compared to other major cervical vessels. A total of 95% of SCGs were accessible from ICA using an endovascular transmural approach, with the majority of SCGs located anteromedially to the ICA.

Conclusions: This is the first anatomical study to provide pertinent targeting information for endovascular transmural access to the SCG using computed tomography angiography. In most cases, endovascular transmural access to the SCG is anatomically feasible from the proximal cervical ICA.