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Vascular/Cardiac » Aortoiliac
Abdominal Aorta Aneurysm
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Author(s) :
Leandro Fernandez, MD
 
Presentation 61 year old asymptomatic male patient. Smoker of 2 packages of cigarettes/day for many years. A screening abdominal sonogram was performed.
 
 
 
Caption: Transverse view of epigastric region
Description: The sonogram shows a round anechoic space defined by thick hyperechoic walls. The internal wall surface is irregular. No anatomical relation with pancreas was observed.
 
 
 
Caption: 3D Volumetric Image of lesion
Description: The lesion is anechoic with well defined thick and hyperechoic walls. The internal wall surfaces are irregular, especially the posterior wall. The rendered 3D view shows an oblique perspective from distal to proximal through this abdominal aortic aneurysm. The internal surfaces are well depicted and some irregularities are seen in the posterior wall. In this case the fusiform shape of the aneurysm and the partial volume effect causes the 3D rendering to falsely convey the impression of thrombus within the vessel. The orthogonal 2D planes provide the information needed to avoid this misinterpretation.
 
 
 
Caption: Sagittal 3D rendering
Description: The sagital 3D rendering of the aneurysm provides greater detail on the configuration of the aneurysm. The irregularity of the internal wall surface is also well appreciated in this image. The perspective shows a right longitudinal point of view with digital subtraction of the right half of the vessel. The interior wall is irregular due to calcification and probably detritus. The proximal portion of the vessel is located on the left of the screen and distal portion is on the right
 
Differential Diagnosis 1.    Pancreatic Cyst
2.    Abdominal Aorta Aneurysm
3.    Giant Mesenteric Artery Aneurysm
 
Final Diagnosis Abdominal Aorta Aneurysm
 
Discussion An abdominal aortic aneurysm (AAA) can develop in anyone, but it is most frequently seen in males over 60 with one or more risk factors. The larger the aneurysm, the more likely it is to rupture. Aneurysms develop slowly over many years and often have no symptoms unless it expands rapidly and then, dissection or rupture can occur.
Ultrasonography (US) can screen for AAA safely, cheaply, and accurately. Once detected, an AAA can be monitored and repaired before it is likely to rupture. The United States Preventive Services Task Force recently recommended a one-time screening for AAA by US for men age 65 to 75 years who have ever smoked. AAA is defined as any measured diameter greater than 3 cm and surgery is recommended for lesions more than 5 cm in transversal or anterior-posterior diameter. According some authors, US has 100% sensitivity, 98% specificity, 93% positive predictive value, and 100% negative predictive value, for the diagnostic of AAA in symptomatic patients.
The use of Three-Dimensional (3D) US offers a more comprehensive image by rendering the whole lesion, allows to see details of the surface of internal walls and save volumetric data in order to be compared with posterior 3DUS examination.

 
Case References
  1. Fernandez L. 3DUS in Abdomen. Ultrasound Med Biol (England) May 2006 32, (5S) p4
  2. Latif AA et al. Should we screen for abdominal aortic aneurysms? Cleve Clin J Med.  2006; 73(1):9-10, 13, 16-7  
  3. Tayal VS et al. Prospective study of accuracy and outcome of emergency ultrasound for abdominal aortic aneurysm over two years. Acad Emerg Med.  2003; 10(8):867-71

 
Technical Details Philips iU22 ultrasound system with a C6-2 (6 to 2 MHz) curved volumetric transducer.
 
Follow Up No further studies were done for the abdominal aorta. Control 3D Ultrasound has been performed each 6 months the first year without changes on measurements.
Severe Internal Carotid Artery stenosis was found and a stent was successfully placed.

 
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