Abdominal pain: Gallstones or something else?

This week's image of the week comes from Toxicology Fellow, Dr. Adam Pomerleau. While evaluating a patient with abdominal pain, he obtained the following images. 

This is a RUQ view capturing the gallbladder.  Note the shadowing from a gallbladder full of stones. Is this the primary cause of pain?  Note the secondary finding more toward the midline, what is that hypoechoic structure?

In the image above, the probe has been moved to the midline from the RUQ. Note the cross-sectional view of the aorta. Do you see the mural thrombus? This is a classic US image for a mural thrombus in the setting of a AAA. 

In the image above, note the saccular aneurysm in addition to the mural thrombus.  This is a less common type of aneurysm compared to the more common fusiform aneurysm. 

As a reminder, to correctly image the aorta, 5 images should be obtained:

1. Proximal Aorta – cross section with measurement of diameter
2. Mid Aorta – cross section with measurement of diameter
3. Distal Aorta – cross section showing bifurcation
4. Iliacs – cross section showing individual diameter measurements
5. Longitudinal view – capturing celiac trunk and SMA

The aorta is imaged in cross-section with the curvilinear probe, indicator to the right, and the diameter is measured from the outer wall to outer wall. The single longitudinal image rotates the probe 90 degrees with the indicator to the head of the patient.