Radiological and functional evaluation
MR examinations were performed using a 3.0T MRI scanner (Discovery 750W;
GE Healthcare, Milwaukee, WI) equipped with a quadrature head coil. The
MR sialographic visualization of salivary ducts was performed on each
parotid gland before and after stimulation with a sialagogue. The MR
sialography findings including duct visualization, sialectasis, main
duct stenosis, and gland volume were reviewed using defined criteria.
The largest diameter of the megaduct portion was measured on pre- and
postoperative MR images, and the pre- and postoperative values were
compared. Pre- and postoperative salivary excretory flow was compared
between the two groups. The postoperative visualization of the distal
duct beyond the stenotic portion was considered as improved excretory
flow through the site of stricture. However, if the distal duct was not
visualized with a sialagogue after surgery, it was considered as no
improvement in saliva excretion.