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ABDOMINAL ULTRASOUND
E
Figure 10.1 cont’d (E) CT demonstrating pancreatic
fracture (arrow) in the tail of the pancreas following a
road traffic accident. Ultrasound was not able to
demonstrate the fracture but did demonstrate free fluid
following the accident and also diagnosed
devascularization of the left kidney (no Doppler flow
within the kidney) following a severed left renal artery.
This is also confirmed on CT.
linear probe, many useful indicators can be found
with the basic curvilinear or sector abdominal scan.
The presence of fluid-filled bowel segments, which
may also show ‘overactive’ peristalsis, should alert
the operator to the possibility of acute intestinal
obstruction. Such segments frequently lie proximal
to the obstructing lesion, and so the point at which
they appear to end should be the subject of
detailed examination. Ultrasound is highly accurate
in demonstrating obstruction. However, it is
less successful in finding its cause and contrast CT
or other bowel studies are usually undertaken
when obstruction is diagnosed. With both intestinal
obstruction and focal pain it may be necessary
to examine the hernial orifices. A small but symptomatic
epigastric hernia often goes unnoticed
unless a detailed scan of the abdominal wall is
performed.
Fluid collections such as abscesses may also
point to the diseased segment, for example in
Crohn’s disease or acute diverticulitis. Such inflammatory
bowel conditions may well present with an
established history which helps the operator to
focus the ultrasound examination accordingly.
Perforation of an abdominal viscus can produce
small amounts of ascites. This is usually ‘mucky’,
i.e. containing particulate or gas bubble echoes,
and may be localized close to the perforation site,
around the duodenum or within the lesser sac.
Although gas is usually regarded as an obstacle to
ultrasound diagnosis, recent studies have shown
that specific patterns of gas echoes can make ultrasound
more sensitive than plain radiography in the
diagnosis of pneumoperitoneum. 10
Figure 10.2
Appendicitis abscess.
has a high sensitivity for acute appendicitis, particularly
in children.
Although the detailed assessment of the primary
gastrointestinal pathology usually requires evaluation
by an experienced operator with a high-frequency
HEPATOBILIARY EMERGENCIES
Ultrasound scanning is invariably the first-line
investigation for suspected biliary tract emergencies.
These include inflammatory conditions causing
right upper quadrant and epigastric pain,
mostly acute cholecystitis or gallstone pancreatitis,
and the various causes of obstructive jaundice
(Fig. 10.3). If possible, interventional treatment
should be delayed until a detailed imaging assessment
of the cause of biliary obstruction has been
made, since the presence of a biliary stent can
compromise subsequent imaging by CT, MRI or
endoscopic ultrasound. Similarly, biliary stents