Foundational Image Analyses for Ultrasonographic Screening of Abdominal Aortic Aneurysm

Fig. 1 Approach routes and ultrasonographic images of the ABA. (A) CT shows the route of posterior approaches. The ABA and IVC are scanned from the dorsal side of the colon via the retroperitoneal tissue. The order of ABA and IVC depends on the approach side. The IVC to ABA from the right side (B), and vice versa from the left side (C). (D) The color signal is clearly depicted with acceptable image quality within 20 cm. ABA: abdominal aorta; IVC: inferior vena cava; CT: computed tomography

Fig. 2 Measurements in the computed tomograms. (A) Level values in the slices of the proximal and distal ends of the infrarenal area, navel, and inferior poles of the kidney were recorded. (B) While no acoustic window is available from the anterior approach, the window is available via both posterior approaches. (C) Good acoustic window and a narrow window. (D): Anterior approach to the aneurysm. (E) Posterior approaches to the aneurysm.

Fig. 3 Unavailable acoustic window in the right posterior approach. Visualization of the ABA is disturbed by the protrusion of the vertebra (A) or the vertebral body (B) due to the dorsal location of the ascending colon. ABA: abdominal aorta

Fig. 4 Underestimation of aorta size in a limited acoustic window. Despite some underestimation, aneurysmal change (>3 cm) was correctly estimated.

Fig. 5 Influence of obesity on the depth of the aorta in three approaches. (A, B) Influence of BW and BMI in the anterior approach. (C, D) Influence of BW and BMI in the posterior approaches. BW: body weight; BMI: body mass index

Fig. 6 Proposed algorithm for ultrasonographic screening of AAA. The screening begins with a transverse scan of the AAA area using the anterior approach. If an aorta-like image is seen at a depth of 5–10 cm, pulsatile movement or flow signal is checked to confirm it as the aorta. If the aorta is not identified, the left or right posterior approach is utilized, targeting a depth of 10–20 cm. The aorta is then assessed to determine if its diameter exceeds 30 mm. AAA: abdominal aortic aneurysm