Skip to main content

Peripheral Arterial Studies: Non-Atherosclerotic Pathologies

Duplex sonography can be used to detect stenoses: the accuracy of the technique is estimated at 90%. The loss in specificity can be explained by turbulent flow patterns set up within venous access fistulas. The diagnostic accuracy is improved in straight segment grafts to the efferent veins, where the accuracy increases to 95%.

Peak-systolic velocities in well functioning dialysis access grafts are typically above 100 to 200 cm/sec (figure 11), tending to be higher in the first 6 months after graft placement or shunt creation. Superimposed stenosis can therefore be difficult to detect given the high baseline velocities. The length of the graft or fistula must be examined with color Doppler imaging in order to insure detection of any significant stenoses. An area of increased blood flow velocity of 100% (velocity ratio of 2 or more) is considered to be consistent with a high grade stenoses. Color flow and gray scale images are also useful for confirming the presence of an anatomic lesion. Stenotic lesions tend to develop on the venous side of the access fistula in more than 80% of cases. Occasionally, the stenosis can be at the level of the subclavian vein, specifically in individuals who have had temporary hemodialysis access with indwelling large diameter catheters. Low flow states of 50 cm/sec or less are indicative of the presence of high-grade stenoses.

 

Figure 11: A typical dialysis access graft has blood flow velocities above 100 to 200 cm/sec. The double echogenic lines (white arrows) identifies this dialysis access channel as a PTFE graft.

To view an enlargement, click on the image.

Lymph nodes and other masses

Although the patient that presents with a palpable mass might give a history of acute onset of the abnormality, the source is often a sub-acute and sometimes chronic abnormality. The differential diagnosis of palpable masses in close proximity to arteries is a wide one.

The possible etiologies include lymph nodes, lipomas, ganglia and rarely neoplasms.

Lymph nodes will have a typical kidney bean appearance with inflow artery and outflow vein arising from the center. Malignancy in a lymph node will normally distort the anatomy of the node, making the contour less regular often with loss of the well defined echogenic central portion of the node. Inflammatory or hyperplastic nodes can sometimes reach quite large sizes but tend to keep the normal nodal architecture. Lymph nodes show a cluster of color Doppler signals at the level of the hilum where the artery and vein exit and enter the node (figure 13). An echogenic central portion is typically seen. The contour of the node if regular and without irregular lobulations suggests a benign nature. An hyperplastic lymph node can contain strong arterial and venous signals (figure 14). The nodes can sometimes be mistaken for a pseudoaneurysm. The Doppler waveform from hyperplastic nodes will not show the typical to-and-fro waveform of the pseudoaneurysm and should be easily distinguished when

Lipomas are hypovascular and tend to be small in size. Their echogenic texture tends to be even and typically echodense and they are avascular. Ganglion cysts are also avascular and will normally be seen in close proximity to a joint (figure 15). They can present as a pulsatile mass since the arterial pulsations are transmitted from an artery that lies in close proximity.

 

Figure 12a: The typical blood flow velocity in a dialysis access is in the 200 cm/sec range. This dialysis access fistula shows a decreased blood flow velocity (less than 100cm/sec). The waveform has a typical appearance, showing evidence of turbulence as witnessed by the shaggy contour of the waveform. Turbulence is manifest by a random fluctuation of the peaks seen in the spectral tracing from millisecond to millisecond. This accounts for the rough and shaggy contour of the Doppler spectral envelope.

To view an enlargement, click on the image.

     

 

Figure 12b: The reason for the decreased blood flow velocities in this fistula is the presence of a stenosis. This is associated with a bruit and a perceived "thrill" on physical examination. This is different from the expected "thrill" normally felt near to the arterial anastomosis within the vein. The thrill associated with the stenosis is felt higher up in the arm, in the outflow portion of the vein.

To view an enlargement, click on the image.

 

Figure 13: This enlarged lymph node shows a cluster of color Doppler signals at the level of its hilum. The echogenic central portion is not clearly delineated on this transverse projection. The contour of the node is regular and without irregular lobulations that are seen with malignancies. This hyperplastic node can, on occasion, be mistaken for a pseudoaneurysm.

To view an enlargement, click on the image.

     

 

Figure 14: The Doppler tracing obtained from the base of the node shows a typical low resistance waveform typical of an hyperplastic node. This patient had chronic cellulitis of the lower leg, accounting for the development of the enlarged draining node. Such a tracing confirms that this is not a pseudoaneurysm.

Lipomas are hypovascular and tend to be small in size. The echogenic texture tends to be even and typically echodense and are avascular. Ganglion cysts are also avascular and will normally be seen in close proximity to a joint. They can present as a pulsatile mass since the arterial pulsations are transmitted from an artery that lies in close proximity.

To view an enlargement, click on the image.

     

 

Figure 15: This echolucent mass (arrows) displaces the radial artery superiorly. The patient presented with a pulsatile mass. This echolucent mass seen at the wrist is a ganglion cyst that displaces the radial artery superiorly. Ganglion cysts are a rare cause of a pulsatile mass at the wrist. A more common cause is that of a pseudoaneurysm developing following radial artery catheterization.

To view an enlargement, click on the image.

Baker's cysts are typically located behind the knee and are hypoechoic. They are hypovascular although pannus formation in Rheumatoid Arthritis can also show areas of increased blood flow on color Doppler imaging. Various soft tissue neoplasms such as sarcomas, are rarely detected on ultrasound imaging. Color Doppler imaging of malignant lymph nodes and vascular tumors will often show central areas of arterial flow (figure 16). Abscess formation is typically accompanied by more peripherally located areas of increased vascularity. Neovascularity is typically seen at the level of the capsule that forms around the infected collection. Sub-acute hematomas may also be associated with a capsule that has evidence of increased arterial blood flow signals.

 

Figure 16: This hypoechoic mass lies behind the knee in a location that is typical of that of a Baker's (synovial) cyst. However, the mass contains areas of neovascularity and has well defined arterial branches. This excludes a Baker's cyst from the diagnosis. Although pannus formation can have areas of increased blood flow similar to what is seen her, the knee joint is devoid of any such changes. This mass is a relatively vascular sarcoma that has developed behind the patients' knee. An abscess is also unlikely since the areas of vascularity are in the center of the mass and not at the periphery.

To view an enlargement, click on the image.

Summary

Doppler sonography is a versatile imaging approach for evaluating a wide range of pathologies associated with the arterial system. This diagnostic use extends beyond the traditional evaluation of peripheral arterial disease due to atherosclerosis. The use of this non-invasive technique extends beyond the simple diagnosis of suspected arterial stenoses and occlusions.

Reference List

Abu-Yousef MM, Wiese JA, Shamma AR. The "to-and-fro" sign: duplex Doppler evidence of femoral artery pseudoaneurysm. AJR 1988; 150:632-634.

Altin RS, Flicker S, Naidech HJ. Pseudoaneurysm and arteriovenous fistula after femoral artery catheterization: association with low femoral punctures. AJR 1989; 152:629-631.

Bjork L, Leven H. Intra-arterial DSA and duplex-Doppler ultrasonography in detection of vascularized inguinal lymph node. Acta Radiol 1990; 31:106-107.

Dangas G, Mehran R, Kokolis S, et al. Vascular complications after percutaneous coronary interventions following hemostasis with manual compression versus arteriotomy closure devices. Journal of the American College of Cardiology. 2001; 38:638-41.

Dean S, Olin J, Piedmonte M, Grubb M, Young J. Ultrasound-guided compression closure of postcatheterization pseudoaneurysms during concurrent anticoagulation: a review of seventy-seven patients. J Vasc Surg 1996; 23:28 -35.

Dousset V, Grenier N, Douws C, et al. Hemodialysis grafts: color Doppler flow imaging corelated with digital subtraction angiograhy and functional status. Radiology 1991; 181:89-94.

Fellmeth BD, Roberts AC, Bookstein JJ, et al. Postangiographic femoral artery injuries: nonsurgical repair with US-guided compression. Radiology 1991; 178:671-675.

Kanterman RY, Vesely TM, Pilgram TK, Guy BW, Windus DW, Picus D. Dialysis access grafts: anatomic location of venous stenosis and results of angioplasty. Radiology 1995; 195:135-139.

Katzenschlager R, Ugurluoglu A, Ahmadi A, al. e. The incidence of pseudoaneurysm after diagnostic and therapeutic angiography. Radiology 1995; 195:463-466.

Kirchhof C, Schickel S, Schmidt-Lucke C, Schmidt-Lucke JA. Local vascular complications after use of the hemostatic puncture closure device Angio-Seal. Vasa. 2002; 31:101-6.

Koksoy C, Kuzu A, Erden I, Turkcapar AG, Duzgun I, Anadol E. Predictive value of colour Doppler sonography in detecting failure of vascular access grafts. Br J Surg 1995; 82:50-52.

Kotval PS, Khoury A, Shah PM, Babu SC. Doppler sonographic demonstration of the progressive spontaneous thrombosis of pseudoaneurysms. J Ultrasound Med 1990; 9:185-190.

Kresowik TF, Khoury MD, Miller BV, et al. A prospective study of the incidence and natural history of femoral vascular complications after percutaneous transluminal coronary angioplasty. J Vasc Surg 1991; 13:328-335.

Mihmanli I, Besirli K, Kurugoglu S, et al. Cephalic vein and hemodialysis fistula: surgeon's observation versus color Doppler ultrasonographic findings. Journal of Ultrasound in Medicine. 2001; 20:217-22

Middleton WD, Picus DD, Marx MV, Melson GL. Color Doppler sonography of hemodialysis vascular access: comparison with angiography. AJR 1989; 152:633-639.

Morton MJ, Charbonneau JW, Banks PM. Inguinal lymphadenopathy simulating a false aneurysm on color-flow Doppler sonography. AJR 1988; 151:115-116.

Mohler ER, 3rd, Mitchell ME, Carpenter JP, et al. Therapeutic thrombin injection of pseudoaneurysms: a multicenter experience. Vascular Medicine. 2001; 6:241-4.

Paulson EK, Sheafor DH, Kliewer MA, et al. Treatment of iatrogenic femoral arterial pseudoaneurysms: comparison of US-guided thrombin injection with compression repair. Radiology. 2000; 215:403-8.

Polak JF, Donaldson MC, Whittemore AD, Mannick JA, O'Leary DH. Pulsatile masses surrounding vascular prostheses: real-time US color flow imaging. Radiology 1989; 170:363-366.

Reeder SB, Widlus DM, Lazinger M. Low-dose thrombin injection to treat iatrogenic femoral artery pseudoaneurysms. AJR. American Journal of Roentgenology. 2001; 177:595-8.

Roubidoux MA, Hertzberg BS, Carroll BA, Hedgepeth CA. Color flow and image-directed Doppler ultrasound evaluation of iatrogenic arteriovenous fistulas in the groin. JCU 1990; 18:463-469.

Schwab SJ, Quarles LD, Middleton JP, Cohan RH, Saeed M, Dennis VW. Haemodialysis-associated subclavian vein stenosis. Kidney Int 1988; 33:1156-1159.

Tordoir JH, de Bruin HG, Hoeneveld H, Eikelboom BC, Kitslaar PJ. Duplex ultrasound scanning in the assessment of arteriovenous fistulas created for hemodialysis access: comparison with digital subtraction angiography. J Vasc Surg 1989; 10:122-128.

Villemarette P, Hower J. Evaluation of functional longevity of dialysis access grafts using color flow Doppler imaging. J Vasc Tech 1992; 16:183-188.

Enjoy The Savings

IAME's Unlimited CME Plan is now the internet's best value for online CME in ultrasound. Just $75!

Your CME credits are available at any time in your Online CME Control Panel. They are automatically transferred to the ARDMS/APCA CME Bank and RSNA's CME Gateway (when you include your credentials).

"Thank you so very much for providing a top rate service."

Eric T. Dickinson BS RDMS, London, United Kingdom