Diagnostic Imaging in Veterinary Dental Practice.

Abstract

Diagnostic Imaging in Veterinary Dental Practice Figure 1—Intraoral photograph of the left parotid papilla of a 10-year-old 7-kg (15.4-lb) Chihuahua cross that was evaluated because of recurrent left-sided facial swelling and purulent discharge from the oral cavity. The papilla was slightly erythematous and more prominent than that on the right side. In cooperation with Figure 2—Ultrasonographic (A) and contrast-enhanced CT (B) images obtained from the same dog as in Figure 1. The ultrasonographic im- age (parasagittal view) was obtained over the region of facial swelling by use of a ven- tral approach with the animal in dorsal recumbency. The transverse CT image of the skull (slice thickness, 0.6 mm) was obtained at the level of the first maxillary molar teeth and viewed with bone (win- dow width, 2,500 Hounsfield units [HU]; window level, 480 HU) and soft tissue (window width, 750 HU; window level, 200 HU) window settings. L = Left. R = Right. History and Physical Examination Findings A 10-year-old 7-kg (15.4-lb) spayed female Chihuahua cross was referred to a veterinary teaching hospital because of recurrent left-sided facial swelling and purulent discharge from the oral cavity. The client had noticed an increase in lip smacking and licking approximately 6 months prior to the evaluation. Facial swelling and signs of pain on palpation had first been detected 10 weeks prior to the examination; the dog had been treated by the referring veterinarian for a suspected tooth root abscess or abscess secondary to a foreign body. An antimicrobial (amoxicillin trihydrate–clavulanate potassium; 18 mg/kg [8.2 mg/lb], PO, q 12 h for 14 days) and an NSAID (carprofen; 1.8 mg/kg [0.82 mg/lb], PO, q 12 h for 7 days) had been prescribed. Clinical signs had improved over the course of initial treatment but relapsed following cessation of the treatment. The referring veterinarian anesthetized the dog, obtained intraoral dental radiographs, and performed periodontal charting. Mild to moderate localized periodontitis was diagnosed with no evidence of a dentoal- veolar abscess or dental cause for the facial swelling. On examination at the referral visit, the dog was bright, alert, and responsive with no abnormalities found on general physical examination other than a fluctuating soft tissue swelling in the region over the left masseter muscle. Intraoral ex- amination revealed a prominent, erythematous left parotid papilla (Figure 1), concurrent sialorrhea upon digital manipu- lation of the ipsilateral parotid gland, hypodontia, and mild generalized plaque and calculus accumulation. Blood and urine samples were obtained for a CBC, serum biochemical analysis, and urinalysis. Laboratory test results were unremarkable. The dog was sedated with dexmedetomidine hydrochloride (3.0 mg/kg [1.36 µg/lb], IV) and butorphanol tartrate (0.1 mg/kg [0.045 mg/lb], IV), and ultrasonographic evaluation of the swollen facial region was performed; the follow- ing day, the dog was anesthetized, and contiguous transverse collimated CT images of the skull were obtained at a slice thickness of 0.6 mm before and after IV contrast medium administration (Figure 2). The images were viewed with bone (window width, 2,500 Hounsfield units [HU]; window level, 480 HU) and soft tissue (window width, 750 HU; window level, 200 HU) settings. Three-dimensional volume rendering was performed, and all digital images were reviewed on a medical-grade flat screen monitor, by use of commercially available software. a Determine whether additional studies are required, or make your diagnosis, then turn the page→ This report was submitted by Peter C. Strom, DVM; Daniel S. Bucy, DVM; and Boaz Arzi, DVM; from the Dentistry and Oral Surgery Service, William R. Pritchard Veterinary Medical Teaching Hospital (Strom, Bucy), and the Department of Surgical and Radiological Sciences (Arzi), School of Veterinary Medicine, University of California-Davis, Davis, CA 95616. Address correspondence to Dr. Arzi (barzi@ucdavis.edu). JAVMA • Vol 249 • No. 12 • December 15, 2016