Introduction Abdominal vascular sonography focuses on the assessment of the arterial and venous circulation of the abdomen using gray-scale imaging, color Doppler, and spectral Doppler. This section includes evaluation of the abdominal aorta, its major branches, the inferior vena cava (IVC), and the portal venous system. Many of these conditions are life-threatening if not detected early, making this section highly tested on the ARDMS Abdomen exam. Key Terminology • Abdominal Aortic Aneurysm (AAA): Abdominal aorta diameter > 3 cm • Aneurysm: Focal or diffuse dilation of a vessel • True Aneurysm: Involves all three vessel wall layers • False Aneurysm (Pseudoaneurysm): Contained rupture of a vessel wall • Atherosclerosis: Plaque accumulation in arterial walls • Budd–Chiari Syndrome: Occlusion of hepatic veins ± IVC • Embolism: Obstruction caused by traveling material • Thrombus: Blood clot formed in situ • Fusiform Aneurysm: Spindle-shaped dilation • Saccular Aneurysm: Sac-like focal dilation • Intimal Flap: Sonographic sign of aortic dissection • True Lumen / False Lumen: Original vs residual vessel channel • Hepatopetal Flow: Blood flow toward the liver • Low-Resistance Flow: Persistent forward diastolic flow • High-Resistance Flow: Reduced or reversed diastolic flow