Figure 1c:

US images show pulse wave propagation as the wave enters (left column), crosses (middle column), and exits (right column) the field of view in the abdominal aortas of (a) a normal mouse with no AAA disease, (b) a mouse with a stable aneurysm, and (c) a mouse with an unstable aneurysm that ruptured between 18 and 20 days after the start of angiotensin II infusion. The normal mouse was imaged the day before angiotensin II infusion started, while the mice with AAA were imaged after 15 days of angiotensin II infusion (and before it was known whether the aneurysm would rupture or not). The color overlay on the B-mode images represents the axial wall displacement induced by the pulse wave, while the arrow indicates the lateral position of the wave (ie, along the longitudinal axis of the aorta). The time stamp in each frame indicates the time elapsed since the start of the cardiac cycle (ie, the R wave of the ECG signal). The lateral position axes of all three fields of view are aligned such that the superior mesenteric artery appears at approximately 8 mm.