Pseudoaneurysm (PSA) refers to a tear or puncture in the arterial wall from which blood flows out of the breach and becomes encapsulated in the tissue adjacent to the aorta and forms a hematoma, mostly due to trauma. There is a local mass with distending pulsations, systolic tremor can be palpated, and a systolic murmur can be heard. Compression of the proximal side of the artery may cause the mass to shrink, tension to decrease, pulsation to stop, and tremor and murmur to disappear. Huge aneurysms may have adjacent nerve compression damage and distal tissue ischemia symptoms. If there is wall thrombosis within the aneurysm, there is a risk of thrombus migration causing embolism of the distal artery and corresponding symptoms, or rupture and bleeding due to trauma or increased intrinsic pressure. The diagnosis is generally not difficult and selective arteriography is essential in addition to the medical history and physical examination. The angiogram can reveal the location, size, number of pseudoaneurysms, arteries carrying the aneurysm, and the presence of intra-aneurysmal thrombus, and often the image of the aneurysm cavity shown on the angiogram is smaller than the actual size of the aneurysm, which provides a basis for diagnosis and differential diagnosis, and provides a reference for the selection of treatment. In addition, CT and MRI examinations also have a greater reference value for diagnosis, especially MRI can determine whether there is wall thrombus in the aneurysm when examining giant aneurysms. Giant aneurysms often show mixed signals of various components, such as no signal for blood flow and vortex due to flow-space effect, no signal for calcification, high signal for thrombus, low signal for iron-containing hemoglobin, and concentric circles of layered mixed signals in the aneurysm, with the thrombus on the inner surface of the aneurysm wall, which may be concentric.