④Thrombus can usually be seen in arterial cavity.
⑤CDFI shows swirling blood flow pattand sagittal images show a fusiform aneurysm with a large amount of thrombus in the arterial walls
Both longitudinal and transverse images show the tearing of intima in an external carotid artery
B-mode image of a dissecting aortic aneurysm. the true and false lumens are seen. Color flow imaging demonstrates flow in the false lumen.
②Most aneurysms are fusiform in shape
③The three layers of arterial wall can be seen.
The abdominal aorta is dilated locally. It measures 51mm in the anteroposterior dimension. The distal normal artery measures 20mm in diameter.
False Aneurysm
➢ It is often caused by trauma, angiography or surgery after artery puncture.
➢ Blood continues to flow backward and forward through the puncture site into a false flow cavity outside the artery.
➢ If there is a full dissection, a false flow lumen is created.
Ultrasound findings
①The tearing of intima can be seen;
②The true and false lumens can be seen; but the entry is difficult to be detected
③Thrombus can be seen in false lumen;
④Blood flows may appear in false lumen. But it is less brighter and low velocity compared with that in true lumen.
Peripheral Vascular Ultrasound
PART Ⅰ Aneurysm （动脉瘤）
Aneurysm（动脉瘤）
Aneurysms develop as the structural integrity of the arterial wall weakens.
➢ True Aneurysm ➢ False Aneurysm ➢ Dissective Aneurysm
F and G: dissecting; I: False aneurysm .
True Aneurysm
➢ It is abnormal dilations of arteries having at least a 50% increase in diameter compared to the normal diameter.
Aneurysms are very variable in shapes
Aneurysms develop as the structural integrity of the arterial wall weakens.
A: fusiform;
B: tortuous elongated;
C: saccular; D: infrarenal; E: suprarenal;
➢ It is often caused by arteriosclerosis.
➢ It is the common type in aneurysms.
Ultrasound findings--1
①The artery is dilated locally. The width of dilated segment is 1.5 times wider than that of normal segment.
Dissective Aneurysm
➢ Dissecting ananeurysm can occur due to a tear in the intima and blood can enter the subintimal space.
➢ If the aorta partially dissects, large amounts of thrombus may be seen in the subintimal space.
②Sometimes a narrow route from artery to the mass can be imaged;
③Thrombus can be seen within the mass;
④ CDFI: the blood flow within the mass is eddied flow.
➢ The wall of aneurysm is made up of hematoma and surrounding compressed tissue.
Ultrasound findings
①A mixed or cystic mass can be seen by the side of artery;