Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Three The Abd omen 261
Fig. 3-13 Transverse sonogram of
the duodenum and pancreas of a 12-
year-old spayed female dog with a
history of icterus, hepatomegaly, and
splenomegaly. The pancreas is normal.
The oval hypoechoic area is the
pancreaticoduodenal vein. The pancreas
is triangular in shape and similar
to slightly hypoechoic in echo
intensity to the surrounding normal
fat. Diagnosis: Normal pancreas,
lymphoma.
Spleen. Radiographically, the spleen usually is clearly visible as a homogeneous tissue density.
Its normal size varies. On the lateral view, the canine spleen usually is seen as a triangular
density just caudal and slightly ventral to the stomach or liver. This is a
cross-sectional view of the body and/or tail of the spleen. If the spleen is adjacent to and
touches the liver, the lack of contrasting density between them will make exact identification
difficult. If the spleen is positioned along the length of the left body wall, the spleen
may not be apparent in the lateral radiograph. In some cases the head of the spleen, which
appears as a triangular density just caudal to the stomach, may be seen in the dorsal part of
the abdomen, superimposed on or dorsal to the shadow of the right kidney. On the ventrodorsal
view, the body of the spleen usually is seen as a triangular tissue density on the
left side, just caudal and slightly lateral to the stomach, and cranial and slightly lateral to
the left kidney. If the spleen is positioned so that it crosses the midline, it will be difficult
to visualize its full length. If it is positioned along the left body wall, the entire length of the
spleen may be visible. The variable locations of the spleen are caused by its relatively lax
attachment to the stomach by the gastrosplenic ligament (Fig. 3-14). The spleen of the cat
differs from that of the dog in that it is usually smaller and somewhat less variable in both
size and position. The body and tail of the spleen may not be identified on the lateral view,
and its head may be seen as a small triangular tissue density just caudal and dorsal to the
stomach. Frequently, the entire extent of the spleen may be seen on the ventrodorsal view
in the cat.
The spleen is identified easily during an ultrasonographic examination. It is located on
the left side, caudal or lateral to the stomach. It is moveable and often extends into the caudal
abdomen and across the midline to the right side. It may be adjacent to the liver, lateral
to the stomach, may extend into the caudal abdomen along the left lateral abdominal wall,
or may cross the midline caudal to the stomach or cranial to the urinary bladder. The size