1、Peripheral VascularUltrasoundPART Aneurysm（动脉瘤动脉瘤）Aneurysm（动脉瘤）（动脉瘤）True Aneurysm False Aneurysm Dissective AneurysmAneurysms develop as the structural integrity of the arterial wall weakens.A:fusiform;B:tortuous elongated;C:saccular;D:infrarenal;E:suprarenal;F and G:dissecting;I:False aneurysm.Aneu
2、rysms develop as the structural integrity of the arterial wall weakens.Aneurysms are very variable in shapesTrue Aneurysm It is abnormal dilations of arteries having at least a 50%increase in diameter compared to the normal diameter.It is often caused by arteriosclerosis.It is the common type in ane
3、urysms.Ultrasound findings-1The artery is dilated locally.The width of dilated segment is 1.5 times wider than that of normal segment.Most aneurysms are fusiform in shapeThe three layers of arterial wall can be seen.The abdominal aorta is dilated locally.It measures 51mm in the anteroposterior dimen
4、sion.The distal normal artery measures 20mm in diameter.Thrombus can usually be seen in arterial cavity.CDFI shows swirling blood flow pattern.Both transverse and sagittal images show a fusiform aneurysm with a large amount of thrombus in the arterial wallsDissective Aneurysm Dissecting ananeurysm c
5、an 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.If there is a full dissection,a false flow lumen is created.Ultrasound findingsThe tearing of intima can be seen;The true and fa
6、lse lumens can be seen;but the entry is difficult to be detectedThrombus can be seen in false lumen;Blood flows may appear in false lumen.But it is less brighter and low velocity compared with that in true lumen.Both longitudinal and transverse images show the tearing of intima in an external caroti
7、d arteryB-mode image of a dissecting aortic aneurysm.the true and false lumens are seen.Color flow imaging demonstrates flow in the false lumen.False Aneurysm It is often caused by trauma,angiography or surgery after artery puncture.Blood continues to flow backward and forward through the puncture s
8、ite into a false flow cavity outside the artery.The wall of aneurysm is made up of hematoma and surrounding compressed tissue.Ultrasound findingsA mixed or cystic mass can be seen by the side of artery;Sometimes a narrow route from artery to the mass can be imaged;Thrombus can be seen within the mas
9、s;CDFI:the blood flow within the mass is eddied flow.Systolic and diastolic images of false aneurysm:A:swirling motion of blood;B:a small channel.C:the classic to-and-fro waveformclassic to-and-fro waveform Aneurysm（动脉瘤）（动脉瘤）Aneurysm（动脉瘤）（动脉瘤）PART Arteriosclerotic Occlusive Disease（动脉硬化（动脉硬化性闭塞性性闭塞性
10、疾病）疾病）(ASO)It is due to arteriosclerosis.It often occurs at large-medium sized arteries in the elderly.Several risk factors are associated with ASO:increasing age hypertension diabetes elevated cholesterol tobacco smoking a family history of atherosclerosisInjury to the vascular endothelium progress
11、ive deposition of lipids,proliferation of smooth muscle cells,and migration of fibrocytes plaque forming and growing vascular stenosis(狭窄)or occlusionPlaque CharacterizationPlaque is usually described by surface feature,density,and texture.Surface features are smooth,irregular,and ulcerated.Hypoecho
12、ic,isoechoic,and hyperechoic are the terms used to describe plaque density.Plaque texture is either homogeneous or heterogeneous.Anechoic plaqueHypoechoic plaqueCalcified plaqueHyperechoic plaquea crater suggesting an ulcerheterogeneous-intraplaque hemorrhageblood flows into ulcerated plaques(hypere
13、choic and hypoechoic heterogeneous)CDFI:narrow bloodstream means arterial stenosis PW:high speed wave and wide frequency band 2D:the plaque makes the artery stenosis CDFI:the narrow multicoloured jet blood flow signals through stenosis PW:high speed flow with wide frequency bandPART Deep Vein Thromb
14、osis深静脉血栓深静脉血栓(DVT)DVT is a common disorder that can lead to fatal pulmonary embolism.DVT usually affects the lower limb veins,especially due to trauma,surgery,pregnancy or malignancy.Epidemiology and Pathology Typical symptoms include pain,tenderness,heat and swelling.But these signs are nonspecifi
15、c and can be caused by several local or systemic conditions.The superficial veins may be dilated.If the DVT involves the proximal veins,there may be significant swelling of the thigh.Signs and Symptoms1.Acute thrombus(within 2 weeks)2.Sub-acute thrombus(more than two weeks)3.Chronic thrombus(several
16、 months to years)Ultrasound FindingsThe distinction between acute and chronic DVT is difficult on all imaging modalities The vein is enlarged obviously;compressing action can not make the cavity shrunken;The internal echoes of cavity are echo-free or hypoechoic;No blood flows with complete thrombosi
17、s.1.Acute Thrombus The deep veins of the lower extremity are filled and distended by acute hypoechoic thrombusThe acute hypoechoic thrombus filling and distending deep vein does not compress The size of cavity may become normal;The internal echoes of DVT increase;The re-opening may occur and CDFI ca
18、n show blood flow in different shapes in the cavity.2.Sub-acute thrombus A-a thrombus around jugular vein catheter.B-CDFI shows an color void or defect.They appear more echogenic than acute clots;The wall is thickened,irregular,echogenic,the vein is incompletely compressible;CDFI show blood flows in
19、 cavity when complete or partial re-opening occurs.3.Chronic thrombus A-an acute thrombus distending the vein.B-partial recanalization with chronic DVT remaining after 2 months.PW shows straight wave of lower limb veins with no response to Valsalva or respiration.It indicates a more proximal obstruc
20、tion.Venous Insufficiency Veins contain valves to prevent the reflux of blood to the extremities.Venous insufficiency occurs when the lower extremity venous valves are destroyed or become incompetent.Chronic venous insufficiency is caused by valvular damage following DVT in about 40%of individuals.H
21、owever,the other 60%of patients with venous insufficiency have incompetent valves,unrelated to DVT.Pathophysiology Clinically,venous insufficiency leads to leg swelling,chronic skin changes such as eczema,pigmentation,woody induration and nonhealing venous stasis ulcers finally.Signs and Symptoms Su
22、perficial venous insufficiency leads to distended subcutaneous varicosities.1.Subcutaneous varicosities.2.CDFI:retrograde flow during a Valsalva action or following distal squeeze release.3.PW:reflux wave(reflux duration1 s).4.The degree of reflux is assessed by reflux duration and the velocity of r
23、eflux.Ultrasound FindingsA-Subcutaneous varicosities of right leg.B-The B-mode image showed tortuous dilated varicose veins.Subcutaneous VaricositiesA：flow in the SSV and POV is antegrade during distal squeeze(blue).B：significant retrograde flow(red)due to saphenopopliteal junction incompetence foll
24、owing squeeze release A-Retrograde blue flow indicates partial venous insufficiency.B-PW showed low-velocity reflux following squeeze release.450ms2sA-Augmentation following calf compression.There is a short duration of normal retrograde flow as the venous valves close.B-Severe venous reflux during a whole Valsalva action(ruflux duration 2s.11/15/2022
