Assessment of Optic Nerve Vascularity in Healthy Eyes Using Superb Microvascular Imaging: a Preliminary Study

Abstract

Background Changes in optic nerve vascularity are observed in many diseases. Superb microvascular imaging (SMI) has the potential to become the method of choice for detecting microvasculature in the optic nerves. Purpose To evaluate optic nerve vascularity in healthy individuals through power Doppler sonography (PDUS) and SMI. Material and Methods Twenty-seven healthy patients with 54 eyes were prospectively evaluated. The duration of the examination for optic nerve vascularity lasted until the posterior ciliary artery blood supply was observed in PDUS and SMI. The visibility of vascularity, as well as the ratio of the vascular structures to the optic nerves (vascular index [VI]), was evaluated. Results Fifty-four eyes were evaluated from a total of 27 patients (mean age = 49.0 +/- 19.42 years). The VI value for the right optic nerve was 29.58 +/- 4.00 while for the left optic nerve, it was 31.21 +/- 3.52. Vascularity was clearly observed in both eyes (n = 54) in all 27 cases in the evaluation performed with the SMI technique. However, with the power Doppler examination, vascular flow was not observed in 14 right eyes and in 10 left eyes within the specified timeframe. Conclusion The results indicate that imaging of vascular structures can be done faster and better with SMI than PDUS examination. The normal VI values may provide important information about the blood supply of the optic nerve, which is of relevance in orbital pathologies and many systemic conditions.