9%20ECOGRAFIA%20ABDOMINAL%20COMO%20CUANDO%20DONDE

THE RETROPERITONEUM AND GASTROINTESTINAL TRACT 207
A
B
Figure 8.9 (A) Normal oesophagus between the aorta and the left lobe of the liver—thin, hypoechoic walls with a
hyperechoic lumen due to the presence of air. (B) Thickened walls of the oesophagus in a carcinoma involving the
lower oesophagus.
patients who undergo laparotomy turn out to have
normal appendices.
The use of ultrasound in the investigation of
acute abdominal pain is well established and can
increase the reliability of the diagnosis of acute
appendicitis when performed by an experienced
operator. 15
The normal appendix is difficult to locate. A
high-frequency (7 MHz or more) linear or curved
array probe is useful. Gentle, graduated compression
may move overlying bowel. Raising the
patient’s left side may encourage bowel gas to
move away from the area of interest. The normal
appendix is compressible by gentle transducer
pressure, which is usually well tolerated by the
patient.
The ultrasound features of acute appendicitis
include an enlarged, usually hypoechoic appendix
greater than 6 mm in diameter. The inflamed
appendix is non-compressible. Attempted compression
of the acutely inflamed appendix obviously
requires great care from the operator.
Compression must be very slow and the release of
compression must be equally as gentle. These features
have a high sensitivity and specificity for acute
appendicitis (74% and 94% respectively). 15 Acute
appendicitis often demonstrates hypervascularity
on power Doppler.
Other causes for right iliac fassa masses in
patients presenting with pain include inflamed
diverticula in patients with diverticulitis. 16
Perforation of the appendix may result in a
demonstrable periappendiceal fluid collection, or
free fluid plus or minus dilated loops of non-peristaltic
small bowel. The presence of an ill-defined
fluid mass in the right iliac fossa of a symptomatic
patient is highly suggestive of acute appendicitis
with perforation (Fig. 8.11). This may become
infected, leading to peritonitis.
Occasionally, a hyper-reflective appendicolith
may be seen in the blind end of the inflamed
appendix, casting an acoustic shadow.
Mesenteric ischaemia
Mesenteric ischaemia is a potentially lethal condition,
associated with atherosclerosis of the mesenteric
vessels, which can cause bowel necrosis and
death if left untreated. It is a difficult diagnosis to
make on clinical grounds because the symptoms
are varied and non-specific, including acute
abdominal pain following meals, diarrhoea and