Chapter 20 Imaging in Canine Sports Medicine 509Adamiak, 2010). In addition to the cruciate liga-
ments, the collateral ligaments, long digital
extensor tendon, patellar tendons, and proximal
gastrocnemius and fabella can be evaluated with
ultrasound.
Tarsus
Evaluation of the tarsus and associated soft tissue
structures has been described (Kramer et al., 2001;
Nielsen & Pluhar, 2005; Liuti et al., 2007; Caine
et al., 2009; Cook, 2016). Ultrasound examination
of the components of the Achilles: common calca-
neal tendon, gastrocnemius tendon, and superfi-
cial digital flexor tendon, to characterize injury
and to follow healing post‐treatment or surgery
is a common clinical application.
Diagnostic ultrasonography can have signifi-
cant value in evaluating musculoskeletal
injuries, despite its limitations. Its image qual-
ity is not as good as that of MRI for soft tissue
evaluation, but it has some clear advantages:(1) It can be performed in the awake or lightly
sedated patient.
(2) The cost of equipment is significantly less
than for MRI or CT, making it more widely
accessible to the sports medicine specialist.
(3) Many injuries may be accurately identi-
fied using ultrasonography.Although diagnostic ultrasound is primarily
used to assess and identify musculoskeletal
injuries, it is also used to follow progression of
healing over time, especially when it was diag-
nosed by other means such as MRI. In these
cases, multiple MRI exams to follow healing are
impractical, but use of ultrasonography can be
quite reasonable for recheck examinations.Case Study 20.1 Hunting Retriever with waxing and waning thoracic limb lamenessSignalment: 5‐y.o. F/I Labrador Retriever. Competes
in Hunting Retriever tests. Presented for waxing and
waning left thoracic limb lameness.Physical exam: Sensitive to palpation of left shoul-
der in flexion and extension, and biceps stretch.
Painful on direct palpation of supraspinatus tendon at
insertion.Radiographs: No significant abnormalities (Figure 20.8).MRI: Reveals tear in the supraspinatus tendon at inser-
tion on greater tubercle and fatty replacement at
the myotendinous junction (Figure 20.9). Tendon
markedly enlarged, causing compression of the biceps
tendon. Following MRI, ultrasonographic exam under-
taken to evaluate and document the pathology noted
on MRI.Ultrasonographic findings: Marked enlargement of
the supraspinatus tendon with cross‐sectional area of
0.92 cm^2 apparently causing compression on the
biceps tendon in cross‐sectional and longitudinal
views. Significant disruption of normal tendon fiber
pattern and hypoechoic lesions were present, indi-
cating tear within the tendon (Figure 20.10, red
arrow). Multiple hyperechoic areas noted within ten-
don at dorsomedial aspect, indicating fibrosis or min-
eralization of tendon in that area (yellow arrow).Treatment: Patient started in intensive rehabilitation
and treatment program with changes in supraspinatustendon followed ultrasonographically. Initial improve-
ment observed in the first 8 weeks, with filling of the
hypoechoic defect with tendon fibers and a decrease
in cross‐sectional area of the tendon. By 12 weeks
the tendon fibers began to show a more normal and
homogenous fiber pattern.Figure 20.8 Lateral radiograph of the shoulder of
a dog diagnosed with a tear of the supraspinatus
tendon at the insertion. No significant abnormalities
were noted.
(Continued)