Comparative Evaluation of Magnetic Field Strength and Fat Suppression for Magnetic Resonance Sialography in Healthy Dogs.

Abstract

This prospective study aimed to evaluate the feasibility of magnetic resonance (MR) sialography in dogs, compare image quality between 1.5 and 3 T scanners, and assess the effect of fat suppression (FS). Five healthy beagle dogs underwent MR imaging (MRI) at both field strengths using three-dimensional (3D) fast spin-echo (FSE) and 3D FSE-FS sequences. Qualitative (four-point scoring of visibility and delineation) and quantitative (signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]) assessments were performed for each salivary duct. Interobserver agreement was near-perfect (κ = 0.861; 95% confidence interval, 0.833-0.890). Qualitatively, the mandibular salivary duct was well visualized at both field strengths, whereas the sublingual salivary duct was reliably visualized only at 3 T (p = 0.031). The parotid salivary duct showed improved delineation at 3 T (p = 0.031), and the zygomatic salivary duct tended to improve visibility and delineation at 3 T. Quantitatively, the mandibular salivary duct showed increased SNR and significantly higher CNR at 3 T (p = 0.031). FS had no significant qualitative effect but increased CNR at 3 T for the mandibular, sublingual, and parotid ducts (p = 0.031). MR sialography is a feasible method for evaluating salivary ducts in dogs, with 3 T MRI providing superior visualization of small ducts such as the sublingual salivary duct. These findings indicate that MR sialography may be valuable for assessing the mandibular-sublingual salivary duct complex, a common site of salivary diseases in dogs, and may provide a normal reference for future studies on salivary gland diseases in dogs.