Ultrasound Aorta

Aorta

Ultrasound is an effective and convenient way to confirm or exclude an abdominal aortic aneurysm (fig. 45).
Dimensions of the abdominal aorta: 

• Normal < 2.5 cm
• Dilatation > 2.5 cm 
• Aneurysm > 3 cm 

In the event of abdominal aortic aneurysm, a CTA examination may be performed for additional evaluation.

Renal pathology

Renal pathology

Hydronephrosis

Urinary outflow obstruction will cause the pyelocaliceal system to dilate: this is termed hydronephrosis (fig. 36).

Gallbladder/bile duct pathology

Gallbladder/bile duct pathology

Bile stones

When the gallbladder contains bile stones, they can be imaged effectively using ultrasound. Bile stones are echogenic and opaque, causing “acoustic shadowing” immediately behind the stone (fig. 30).

Pathology

Pathology

• Liver pathology (steatosis, liver lesions)
• Gallbladder/bile ducts (bile stones, cholecystitis, dilated bile ducts)
• Renal pathology (hydronephrosis, kidney stones, kidney lesions)
• Bladder pathology (clot, bladder tumor)
• Spleen (splenomegaly)
• Pancreas (pancreatic tumor)
• Aorta (aneurysm)
• Intestines (appendicitis, diverticulitis, intestinal wall thickening)
• Trauma

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).

Ultrasound Bladder

Bladder Ultrasound 

The bladder must be filled for adequate evaluation.  A filled bladder has thin walls with hypoechogenic content (fig. 13). A filled bladder creates a perfect acoustic window for evaluation of the distal ureteral orifices in the bladder posterior wall.

Ultrasound abdomen general

Indication/Technique

This course provides general information about ultrasound examination of the abdomen, with details on how it can and cannot be used.

Primary indications: 

• Abdominal pain (including appendicitis, bile stones, kidney stones), herniation, umbilical hernia, inguinal hernia. 
• Ascites
• Abdominal aneurysm 
• Abnormal blood test results (liver and renal impairment)
• Unexplained fever
• Trauma (internal bleeding screening)
• Oncology (liver metastases screening)

Reflection/deflection/absorption/scatter

Reflection/deflection/absorption/scatter

When sound waves move on the boundary surface between two media with different densities, part of the beam is reflected to the transducer. This phenomenon is called reflection. The remainder of the beam continues on into the tissue, but under a different angle. This is called deflection. As sound waves penetrate the tissue, part of the energy is converted into heat. This energy loss is called absorption. Finally, part of the sound waves are lost in scatter. This takes place when sound waves move through inhomogeneous tissue or in a 'hard’ boundary surface (= large density difference between two media). Part of the sound waves are reflected in random directions, a small part of which towards the transducer. For a summary see figure 10.

Ultrasound

Ultrasound Technique

• General

• Technique
  - Transducers
  - Frequency
  - Different planes
  - Reflection/deflection/absorption/scatter
  - Color Doppler
  - Duplex Doppler

• Artifacts