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ABDOMINAL ULTRASOUND
pancreatitis) rather than diseased liver. The
appearance of cavernous transformation of the
PV is quite striking (Fig. 4.22A) and colour
Doppler is particularly useful in its
diagnosis. 22
Make sure, before diagnosing PV thrombosis, that
the vein axis is less than 60˚ to the transducer and
that the Doppler sensitivity is set to pick up lowvelocity
flow. Ultrasound is known to have a falsepositive
rate for PV thrombosis but this is often due
to inadequate technique or insensitive equipment.
False-negative results, indicating that flow is present
in a vein which is actually thrombosed, are due to
the detection of flow within a collateral vessel at the
porta, which can be mistaken for the main PV.
A
B
C
D
Figure 4.22 Portal hypertension—further signs. (A) Cavernous transformation of the PV. (Note also the small cyst at
the porta, which does not demonstrate flow.) (B) The tortuous vessels of a spleno-renal shunt are demonstrated along
the inferior border of the spleen. (C) Colour Doppler demonstrates the tortuous vascular channel of a spleno-renal
shunt. (D) Large patent para-umbilical channel running along the ligamentum teres to the anterior abdominal wall in a
patient with end-stage chronic liver disease and portal hypertension.
(Continued)