Ultrasound techniques pancreas
Because the pancreas lies posterior to the stomach and duodenum, a variety of techniques must usually be employed to examine it fully. Although ultrasound
may still be considered the first line of investigation, CT, MRI and/or endoscopic retrograde cholangiopancreatography (ERCP) are frequently required to augment and refine the diagnosis.
The operator must make the best use of available acoustic windows and different patient positions and techniques to investigate the pancreas fully.
The most useful technique is to start by scanning the epigastrium in transverse plane, using the left lobe of the liver as an acoustic window. Using
the splenic vein as an anatomical marker, the body of the pancreas can be identified anterior to this.
The tail of pancreas is slightly cephalic to the head, so the transducer should be obliqued accordingly to display the whole organ (Fig. 5.1). Different transducer angulations display different sections of the pancreas to best effect:
● Identify the echo-free splenic vein and the superior mesenteric artery posterior to it. The latter is surrounded by an easily visible, hyperechoic fibrous sheath. The pancreas is ‘draped’ over the splenic vein (Fig. 5.1).
● Where possible, use the left lobe of the liver as an acoustic window to the pancreas, angling slightly caudally.
● The tail, which is often quite bulky, may require the transducer to be angled toward the patient’s left.
The spleen also makes a good window to the tail in coronal section. If you can’t see the pancreatic head properly, turn the patient left side raised, which moves the duodenal gas up towards the tail of the pancreas. Right side raised may demonstrate the tail better. If these manoeuvres still fail to demonstrate
the organ fully, try:
—asking the patient to perform the Valsalva manoeuvre with abdominal protrusion
—scanning the patient erect
—filling the stomach with a water load to create an acoustic window through which the pancreas can be seen.
ultrasound images Transverse section (TS) showing the normal pancreas
Ultrasound images Longitudinal section (LS) oblique to the
right of midline, demonstrating the head of pancreas, P, with the common bile duct (CBD) running through it.
ultrasound images LS at the midline, demonstrating the body of pancreas.
ultrasound images LS angled through the left lobe of the liver towards the tail of
pancreas (p).
Ultrasound images Water in the stomach, ST, provides a window through which to view the pancreas
Ultrasound images The main pancreatic duct (arrow) is normally up to 2 mm in diameter (arrow = CBD).
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