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Imaging in Cardiovascular Disease

Valérie Chetboul, DVM, PhD, DECVIM-CA (Cardiology)
National Veterinary School at Alfort, Maisons‐Alfort, France

The diagnosis of canine and feline heart diseases as well as caudal pulmonary vessels and of the hilar area than the
that of heart failure is predominantly based on thoracic ventrodorsal view, and therefore allow a better assess-
radiography associated with standard transthoracic echo- ment of cardiogenic pulmonary edema, particularly in
cardiography, also called conventional echocardiography. the canine species. Additionally, dorsoventral views
In the late 1980s, the miniaturization of tran sesophageal are often better tolerated than ventrodorsal views in
probes led to the use of transesophageal echocardiography the case of dyspnea. Ventrodorsal views, which are
especially for analyzing specific abnormalities or for moni- most often associated with a more central position of
toring surgical and interventional techniques. During the the heart within the thorax, may sometimes be used to
last decade, newer imaging modalities such as tissue complement the dorsoventral view to detect small vol-
Doppler imaging, strain and strain rate imaging, and umes of pleural effusion and to better assess specific
speckle tracking echocardiography have been introduced lung lesions.
in veterinary cardiology, allowing an accurate assessment In both canine and feline species, the heart shape is
of myocardial performance, deformation, and synchrony. most often relatively ovoid with a pointed ventral apex.
The following chapter provides an overview of these imag- Nevertheless, several noncardiac factors (Table 16.1) can
ing techniques and their application in clinical settings, influence heart size and shape, including respiratory
with particular emphasis on the two most commonly phase, pericardial fat accumulation (Figure 16.1), age and,
used in practice: thoracic radiography and conventional most of all, breed (see details below and Figure 16.2). All
echocardiography. these are important to take into consideration, as they
may be a source of misinterpretation of cardiomegaly.
Cardiac Radiography
Lateral Views
Either right or left lateral views may be performed.
Although most radiographic findings are not specific and Nevertheless, as some variations may exist according to
therefore do not lead to an accurate definitive diagnosis positioning of the patient, the same lateral projection
of a given heart disease, thoracic radiography remains a should be used to ensure a reliable comparison of radio-
key complementary examination to detect heart enlarge- graphic findings over time in sequential radiographs.
ment, assess the presence or absence of congestive heart On lateral views, the heart, which is located between
failure, and distinguish between respiratory and cardio- the third and sixth intercostal spaces, tends to “lie”
vascular diseases. more on the sternum in cats than in dogs, and in older
cats (>7 years old) more than in younger cats (Figure
Normal Thoracic Radiography
16.3). The maximum heart width (or maximum cra-
Heart and thoracic vessels should be systematically nial–caudal diameter) is usually around two intercostal
evaluated on at least two good‐quality views taken spaces in the cat and between 2.5 and 3.5 intercostal
during inspiration – the dorsoventral view and a lateral spaces in the dog, with breed variations (Figures 16.2
view. Ventrodorsal views may also be used, but dors- and 16.3). For example, the heart in “barrel‐chested”
oventral views usually provide a better definition of dogs tends to be more globular, with a greater sternal

Clinical Small Animal Internal Medicine Volume I, First Edition. Edited by David S. Bruyette.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.
Companion website: www.wiley.com/go/bruyette/clinical