医学影像诊断学课件：周围血管疾病超声诊断-英文

1、Peripheral VascularUltrasoundPART Aneurysm（动脉瘤）Aneurysm（动脉瘤）True AneurysmFalse AneurysmDissective 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 .

2、 Aneurysms develop as the structural integrity of the arterial wall weakens.Aneurysms are very variable in shapesTrue AneurysmIt 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

3、in aneurysms.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 anteroposteri

4、or dimension. The distal normal artery measures 20mm in diameter.ABCThrombus 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 AneurysmDissecting

5、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. If there is a full dissection, a false flow lumen is created.Ultrasound findingsThe tearingofintima can be seen; T

6、he true and false 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 tearingofintima in an

7、external carotid 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 AneurysmIt is often caused by trauma, angiography or surgery after artery puncture. Blood continues to flow backward and forward thro

8、ugh the puncture site 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

9、 seen within the mass; 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 waveformABCclassic to-and-fro waveform Aneurysm（动脉瘤）Aneurysm（动脉瘤）PART Arteriosclerotic Occlusive Disea

10、se（动脉硬化性闭塞性疾病） (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 agehypertensiondiabeteselevated cholesteroltobacco smokinga family history of atherosclerosisInjury to the vascular endothelium pr

11、ogressive 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 ulcer

12、ated.Hypoechoic, isoechoic, and hyperechoic are the terms used to describe plaque density. Plaque texture is either homogeneous or heterogeneous. Anechoic plaqueHypoechoic plaqueCalcified plaqueHyperechoic plaqueA: a crater suggesting an ulcerB: heterogeneous - intraplaque hemorrhageABblood flows in

13、to ulcerated plaques ( hyperechoic and hypoechoic heterogeneous )CDFI: narrow bloodstream means arterial stenosis PW:highspeed wave andwide frequencyband2D: the plaque makes the artery stenosisCDFI: the narrow multicoloured jet blood flowsignals through stenosisPW: high speed flow with wide frequenc

14、ybandPART Deep Vein Thrombosis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 PathologyTypical symptoms include pain, tenderness, heat and swelling. Bu

15、t these signs are nonspecific 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 SymptomsAcute thrombus (within 2 weeks )Sub-acute thrombus ( more than two we

16、eks )Chronic thrombus ( several months to years )Ultrasound FindingsThe distinction between acute and chronic DVT is difficult on all imaging modalitiesThe vein is enlarged obviously; compressing action can not make the cavity shrunken;The internal echoes of cavity are echo-free orhypoechoic;No bloo

17、d flows with complete thrombosis. 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 compressThe size of cavity may become normal; The internal echoes of DVT increase; Th

18、e re-opening may occur and CDFI can 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. BAThey appear more echogenic than acute clots; The wall is thickened, irregular, echogenic, the vein is incomp

19、letely compressible; CDFI show blood flows in 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 . ABPW shows straight wave of lower limb veins with no response to Valsalv

20、a or respiration. It indicates a more proximal obstruction.Venous InsufficiencyVeins 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 val

21、vular damage following DVT in about 40% of individuals.However, the other 60% of patients with venous insufficiency have incompetent valves, unrelated to DVT.PathophysiologyClinically, venous insufficiency leads to leg swelling, chronic skin changes such as eczema, pigmentation, woody induration and

22、 nonhealing venous stasis ulcers finally.Signs and SymptomsSuperficial venous insufficiency leads to distended subcutaneous varicosities. Subcutaneous varicosities. CDFI: retrograde flow during a Valsalva action or following distal squeeze release.PW: reflux wave (reflux duration1 s). The degree of r