Magnetic resonance imaging anatomy of the feline salivary glands

摘要

Objective: The aim of the study was to define anatomical characteristics of feline salivary glands using magnetic resonance imaging (MRI) and to describe landmarks for their reliable identification. Material and methods: Heads of 37 adult cats without signs of diseased salivary glands on clinical examination or history were examined. In cats included in the prospective part of the study, the MRI study was completed within one hour after euthanasia (n = 16). In the retrospective part, previously performed MRI studies were evaluated (n = 21). The prospective part of the study included the following standardized sequences: T2-weighted (T2W) turbo spin echo (TSE), T2W fat-suppressed TSE and proton density weighted (PDW) TSE images in a transverse plane as well as T1-weighted (T1W) fast field echo (FFE) in the transverse, sagittal and dorsal planes. In the retrospective part, T2W TSE and T1W TSE transverse images pre- and post-contrast were analyzed. Initially, identification and delineation of the salivary glands from surrounding tissue was assessed. Anatomical structures of the head were then identified and defined as landmarks. The dimensions of the glands were measured on T2W TSE images and the signal intensity in relation to that of fat and muscle was described using all sequences. Results: In total, 95.9% of the parotid glands and 100% of the mandibular glands could be visualized on T1WTSE and FFE images and on T2W TSE images. Additionally, 93.3% of the zygomatic glands were identified on T2W TSE sequences and 82.5% on T1WTSE and FFE images. The ventral buccal glands could be demarcated in some sequences (T2W TSE: 51.4%, T1W TSE and FFE: 18.9%). Anatomical landmarks facilitated gland identification. Comparing the size of the salivary glands of both groups revealed differences of up to 2 mm. Conclusion: Both the large salivary glands (Glandula [GI.]. parotis and GI. mandibularis) and the small salivary glands (GI. zygomatica and GI. buccalis ventralis) of the cat can be reliably identified on MRI images.