Optimizing magnetic resonance imaging for detection of greater occipital nerve pathology in migraine headache disorders.

Abstract

Migraine and occipital headache disorders are increasingly recognized as conditions that may rise from compression of extracranial peripheral nerves, particularly the greater occipital nerve (GON). Despite growing recognition of peripheral mechanisms contributing to headache pathophysiology, objective imaging tools to identify extracranial nerve pathology remain limited. Magnetic resonance neurography has been utilized to evaluate peripheral and extracranial nerves; however, key technical factors that substantially influence image quality - most notably radiofrequency coil selection - have not been systematically characterized. This limitation is especially relevant for small-caliber, superficial extracranial nerves, where diagnostic confidence depends heavily on adequate signal-to-noise ratio and spatial resolution to accurately delineate nerve-vascular relationships. We present a prospective, single-center imaging study evaluating the comparative image quality of MRI surface coils compared to volume coils in visualizing greater occipital nerve pathology in patients undergoing operative intervention for occipital headache disorders. All enrolled participants underwent a non-contrast MRI scan with both volume and surface coils. Images were taken at four anatomical regions of the greater occipital nerve (GON), and signal to noise ratio (SNR) was calculated for each coil with each sequence, at each anatomical landmark. Our imaging protocol was completed on three patients (n = 3). SNR measurements of the GON distal to crossing the occipital artery were significantly higher when using the surface coil compared to the volume coil (p = 0.003). On the log transformed scale, the surface coil had more than a two-fold increase in SNR when compared to the volume coil. In this pilot imaging study, we demonstrate that the surface coil provides superior image quality and higher SNR when compared to the volume coil for imaging of the extracranial portion of the greater occipital nerve. This serves as a foundational study for developing a specific Magnetic Resonance Neurography (MRN) protocol for diagnosing GON-related headache disorders, and justifies the need for similar studies with a larger cohort.