Ultrasound Intestines

Intestines Ultrasound 

The (small) intestines can never be imaged in their entirety by ultrasound.  However, ultrasound may be very helpful in common intestinal pathologies.
The intestinal wall appearance changes markedly from the small intestine (Kerkring folds) to the colon (haustrations). Intestinal gas is a limiting factor in reliable evaluation of the intestinal wall (fig. 19).

In some cases, intestinal compression may improve imaging. When compression does not help, evaluation of the intestinal anterior wall will have to suffice.
Figures 20/21 show a number of ultrasound images of normal intestinal loops.

For the purpose of evaluating the duodenum or pylorus, it may be very helpful to have the patient drink a few cups of water prior to or during the examination.  A fluid-filled lumen creates the ideal acoustic window for evaluation of the entire intestinal wall.

We are frequently asked to assess patients with abdominal pain for appendicitis. The appendix is in the right lower quadrant. The appendix is compressible and normally has a diameter of under 7 mm (fig. 22/23).

Checklist

Each radiologist will have his or her personal preferences for imaging abdominal organs.  A common sequence of a full abdominal ultrasound examination is aorta - pancreas - liver/gallbladder - kidneys - bladder region - intestines.

As a general rule, each organ and abnormality is imaged in two directions; in most cases the transversal and sagittal directions. 

Tips for viewing stored ultrasound images: 

• Top is always the skin side 
• Use the marker on the screen to see in which region and which direction (sagittal or transversal) the structures have been imaged. 
• Fluid does not reflect sound waves, making it anechogenic (=black). If you therefore see an anechogenic structure, this could be a fluid-filled organ or fluid-filled abnormality (e.g. gallbladder, bladder, vessels, cysts, ascites).  
• Calcified structures (such as bile stones and kidney stones) may cause acoustic shadowing.  
• Compare the echo reflection pattern of the liver parenchyma with the cortex of the right kidney in order to evaluate for the presence of liver steatosis (see Pathology section).  
• Comparison with normal anatomy is useful and can help improve the identification of pathology. Examples: do the kidneys appear symmetrical or is there (mild) hydronephrosis? Intestinal wall thickening versus normal intestinal wall (see Pathology section).