Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Five The Skull 651
tooth, but lesions may also occur on the vertical surfaces due to involvement with accessory
canals. Radiographic changes may include widened periodontal spaces, focal
bone resorption in the periodontal space, periapical lucencies, pulp calcification, or internal
resorption of tooth structure (Fig. 5-50). Necrosis of the pulp cavity may produce a
dense, bony reaction adjacent to the apex of the tooth root. This has been referred to as
condensing osteitis. 4 Therefore it may be difficult to distinguish between endodontal and
periodontal diseases. All lesions reflect inflammation of the pulp. Endodontic lesions frequently
are associated with tooth fractures. 157
U LT R A S O N O G R A P H Y O F O C U L A R A B N O R M A L I T I E S
Ultrasonography is not needed in most animals with an ocular abnormality because the
lesion can be seen with an ophthalmoscope. However, when the cornea, lens, or anterior or
posterior chambers are opaque or when the disease is in the retrobulbar space, ultrasonography
can be used to examine the eye and adnexa. 31,32,35,158 Even when a mass can be seen
during an ocular examination, an ultrasonographic examination may still prove useful,
because it provides information about the structures behind the mass and will define more
completely the posterior extent of the mass (Fig. 5-51). 159
Foreign objects within the eye can be detected despite the presence of hemorrhage or
inflammation, which would interfere with a direct examination. These objects usually are
hyperechoic and have distant shadowing. Radiopaque foreign objects can be detected radiographically;
however, defining their exact position within the globe is difficult. The ultrasonographic
examination will locate the exact position of the foreign body and will
indicate whether it is in the globe or retrobulbar. Eye injury secondary to foreign body penetration
can be evaluated (Fig. 5-52).
Masses that arise from the iris or ciliary apparatus can be identified during an ultrasonographic
examination and their extent can be defined (Fig. 5-53). 160 Most masses are heteroechoic
and fixed in position. Iris and ciliary cysts are either attached to the iris or ciliary body
Fig. 5-50 A 5-year-old female German Shepherd dog with
excessive salivation. The open-mouth ventrodorsal view
revealed an enlarged pulp canal of the left canine tooth (black
arrow) when compared with the right canine tooth. The tooth
alveolus is also slightly enlarged (white arrow). The adhesive
tape that was used in positioning is also seen. Differential diagnoses
include infection and neoplasia. Diagnosis: Endodontic
resorption and periapical abscess. (Radiograph courtesy Dr. A.
Karmin, Bellerose Animal Hospital, Bellerose, NY.)