Page 646 - Atlas of Small Animal CT and MRI

6.2

Trauma

Fracture general anesthesia; however, sedated or fully conscious
imaging has also been reported to provide satisfactory
Fractures of small size or in complex anatomic regions image quality. 4
may not be appreciated on radiographs. CT and MR
imaging both have the spatial resolution to depict these
types of injuries in order to obtain a precise diagnosis Soft tissue trauma
and to aid in surgical planning. Muscle trauma can occur with or without accompanying
Fractures of long bones and joints are common trau- skeletal injury. The CT and MR anatomy of pelvic limb
matic injuries (Figure 6.2.1). Fractures may also occur in musculature has been described previously. Trauma to
7
sites predisposed to incomplete ossification, particularly musculature, such as iliopsoas injury, causes muscular
the humeral condyle of Spaniels and other breeds. A enlargement and heterogeneous contrast enhancement.
8
region of sclerosis is present on CT images in one or both Injury of the iliopsoas muscle may also result in tendi-
condyles, and a nondisplaced fissure or complete frac- nitis and avulsion fracture of the lesser trochanter of
1
ture of the condyle may occur (see also Figure 6.1.15). the femur. On STIR, T2, or contrast‐enhanced T1
9
MR imaging has detected a heterogeneous signal with images, tissue hyperintensity is visible in the region of
central hyperintensity in the condyle on STIR images injury (Figure 6.2.5). Myotendinous strains to the gas-
prior to fissure formation, and this may be an early sign trocnemius muscle have also been described in a group of
of condylar disease. 2 herding dogs with similar MR imaging characteristics.
10
The carpus and tarsus are anatomically complex, and Myositis can occur secondary to trauma or infectious or
small fractures, multiple fractures, and comminuted noninfectious inflammatory disease (Figure 6.2.6).
fractures may be difficult to assess on radiographs
(Figures 6.2.2, 6.2.3, 6.2.4). CT is most often used to Traumatic disorders of the shoulder
image these regions and provides good interobserver and stifle joints
3
agreement in complicated fractures. Tarsal bone trauma
is common in racing Greyhounds, and quantitative CT Because trauma to the shoulder and stifle are often eval-
measures of volumetry and density have been developed uated using cross‐sectional imaging, they are specifically
to predict changes in the central tarsal bone in response addressed in the following two sections.
to training. 4
The pelvis is a frequent site of multiple traumatic Shoulder disorders
fractures, which can be better appreciated on CT images Injuries of the shoulder joint or ligaments and tendons
in dogs and cats. The sites where CT is particularly adjacent to the joint are common in active dogs and can
valuable in accurate diagnosis include acetabular and be the result of either a single insult or repetitive trauma.
sacral fractures. Animals may be imaged under Stability of the joint relies on active and passive stabilizers.
5,6

Atlas of Small Animal CT and MRI, First Edition. Erik R. Wisner and Allison L. Zwingenberger.
© 2015 John Wiley & Sons, Inc. Published 2015 by John Wiley & Sons, Inc.
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