Fig. 1

Axial images through the SPG in one of the patients. Left: T1 weighted MRI. Right: CT scan. Both images show the same anatomical plane. The SPG (red dot) is first localized in the MRI scan and the closest point of the nasal mucosa through the SPF is localized in fusioned CT images. In this example, the distance was 8.1 mm (yellow line). Notice the typical crescent form of the SPG anterior to the opening of the Vidian canal