Diagnostic ultrasound ( PDFDrive )

CHAPTER 27 Peripheral Vessels 973
A
B
C
D
FIG. 27.13 Common Femoral Artery Pseudoaneurysm. (A) Common femoral artery pseudoaneurysm with “yin-yang” color low pattern in
the pseudoaneurysm (arrows). (B) Spectral Doppler of the pseudoaneurysm neck shows a high-velocity “to-and-fro” pattern. (C) Measurement of
the length of the neck from the common femoral artery to the pseudoaneurysm (calipers). (D) Measurement of the diameter of the neck (calipers)
off of the common femoral artery indicates size of hole in artery; a “rent” in the artery is less amenable to thrombin injection. It is preferable to
measure the diameter in gray-scale because color may overestimate the diameter, but sometimes the neck cannot be seen without color (as in
this case). See also Video 27.4.
injection into the pseudoaneurysm to thrombose is commonly
performed, with a success rate of 94% to 97% without surgical
intervention. 35-37 Treatment with sonographically guided direct
compression has been used in the past but is less successful (up
to 85% pseudoaneurysm thrombosis). 38
Arteriovenous Fistula
he term “istula” describes an abnormal communication between
the arterial and venous circulations. here is disruption through
all layers of the arterial wall as well as a focal disruption of a
nearby venous structure, allowing communication from high–
arterial pressure to low-pressure veins. his communication
bypasses the capillary bed. It can be congenital, acquired, or
rarely spontaneous in nature. Fistulas may be seen ater autologous
vein bypass grating 39 and do not appear to afect patency of the
grat. 40 In the absence of bypass grat, most are acquired and
usually associated with a history of trauma. 41 A traumatic
arteriovenous istula may course from normal artery to normal
vein in the setting of trauma, but congenital arteriovenous
malformations (AVMs) may occur with associated abnormal
vascular structures. Many are asymptomatic. However, symptomatic
AVFs do not typically spontaneously resolve and oten
require surgery. 42
Gray-scale imaging may show very little arterial abnormality
in a traumatic istula, but the cluster of dilated structures of an
AVM can be identiied. In either abnormality, there may be venous