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ABDOMINAL ULTRASOUND
C
Figure 6.6 cont’d
the spleen.
(C) Multiple granulomata throughout
Calcification is also associated with posttraumatic
injury and may be seen around the wall
of an old, resolving post-traumatic haematoma.
Conditions which predispose to the deposition
of calcium in tissues, such as renal failure requiring
dialysis, are also a source of splenic calcification.
Haemolytic anaemia
Increased red blood cell destruction, or haemolysis,
occurs under two circumstances: when there is an
abnormality of the red cells, as in sickle cell
anaemia, thalassaemia or hereditary spherocytosis,
or when a destructive process is at work, such as
infection or autoimmune conditions. Fragile red
cells are destroyed by the spleen, which becomes
enlarged (Fig. 6.7).
Sickle-cell anaemia is most prevalent in the black
American and African populations. Progression of
the disease leads to repeated infarcts in various
organs, including the spleen, which may eventually
become shrunken and fibrosed. Patients have
(non-obstructive) jaundice because the increased
destruction of red blood cells (RBCs) releases
excessive amounts of bilirubin into the blood.
Vascular abnormalities of the spleen
Splenic infarct
Splenic infarction is most commonly associated
with endocarditis, sickle cell disease and myeloproliferative
disorders 11 and also with lymphoma and
Figure 6.7
Splenomegaly in hereditary spherocytosis.
cancers. It usually results from thrombosis of one
or more of the splenic artery branches. Because the
spleen is supplied by both the splenic and gastric
arteries, infarction tends to be segmental rather
than global. Patients may present with LUQ pain,
but not invariably.
Initially the area of infarction is hypoechoic and
usually wedge-shaped, solitary and extending to
the periphery of the spleen (Fig. 6.8 A and B). The
lesion may decrease in time, and gradually fibrose,
becoming hyperechoic.
It demonstrates a lack of Doppler perfusion
compared with the normal splenic tissue. In rare
cases of total splenic infarction (Fig. 6.8C), due to
occlusion of the proximal main splenic artery, greyscale
sonographic appearances may be normal in
the early stages. Although the lack of colour
Doppler flow may assist in the diagnosis, CT is the
method of choice.
Occasionally infarcts may become infected or
may haemorrhage. Sonography can successfully
document such complications and is used to
monitor their resolution serially. In patients with
multiple infarcts, such as those with sickle-cell disease,
the spleen may become scarred, giving rise to
a patchy, heterogeneous texture.
Splenic vein thrombosis
This is frequently accompanied by portal vein
thrombosis and results from the same disorders.