Figure 6c. (a, b) On color Doppler US images obtained in a 55-year-old man with bilateral popliteal aneurysms that were diagnosed with US, the right-sided aneurysm is patent (arrow in a) and the left-sided aneurysm is occluded (arrowheads in b). (c) Angiogram of the left lower extremity shows typically tortuous vasculature with atherosclerotic changes.