Diagnostic ultrasound ( PDFDrive )

1002 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
A
B
C
D
E
FIG. 27.58 Normal Mature Forearm Arteriovenous Fistula (AVF)
Ultrasound Evaluation (Radial Artery at the Wrist to Cephalic
Vein). (A) Normal feeding artery internal diameter (cursors). (B) Color
and spectral Doppler 2 cm upstream to the anastomosis measures
2.62 m/sec. (C) peak systolic velocity (PSV) measures 3.97 m/sec
for a PSV ratio at anastomosis of less than 3 : 1, normal. Visual
assessment of anastomosis is also normal, without stenosis. (D)
Normal cephalic vein cranial to the anastomosis (cursors show internal
diameter measurement). (E) Mid AVF draining vein volume low rate
measurement (in midforearm) is 1000 mL/min.
in an area with parallel vessel walls, minimal vessel tortuosity,
and no stenosis (Fig. 27.60).
Graft
Sonographic evaluation of the forearm or thigh grat is similar
to that of the AVF. A normal grat is seen as two echogenic lines
that represent strong specular relection from polytetraluoroethylene
material. A low-resistance low (arterialized low) should
be seen within a grat. Duplex Doppler evaluation of the feeding
artery (including luminal diameter), arterial-grat anastomosis,
grat (arterial side and venous side if loop grat), and venous
anastomosis is performed, as well as draining vein and central
vein evaluation. Flow volume is assessed within the midgrat
(Fig. 27.61), and both arterial and venous limbs if a loop grat.
Any points of visible narrowing are further assessed with spectral
and color Doppler.
Palpable Focal Masses Near Arteriovenous Fistula
and Graft
Hematoma. Avascular, hypoechoic lesions adjacent to the
AVF or grat oten represent postaccess or postprocedure
hematomas (Fig. 27.62, Video 27.26). hese collections should