Diagnostic ultrasound ( PDFDrive )

1000 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
FIG. 27.55 Thick-Walled Cephalic Vein With Chronic Thrombus.
This vein may not dilate normally after arteriovenous istula (AVF) placement
and should not be chosen for a potential AVF draining vein. See
accompanying Video 27.25.
FIG. 27.56 Cephalic vein is quite deep from the skin surface (0.9 cm;
X cursor), and may need to be supericialized after arteriovenous istula
creation.
Ultrasound Examination and Imaging Protocol
Upper Extremity. Ater assessment of the brachial and radial
arteries, the inner luminal diameter of the brachial artery 2 cm
proximal to the antecubital fossa, and the radial artery at the
wrist are measured, along with the axillary artery diameter. Using
sequential tourniquet placement and ater wrist percussion of
the cephalic vein region, the cephalic vein inner diameter is
measured at the wrist, midforearm, and proximal forearm
(approximately 4 cm from the antecubital fossa). he proximal
forearm measurement is used to evaluate the length of vein
available to surgically move the vein from the forearm to the
brachial artery in upper arm AVF creation.
he cephalic and basilic vein diameters are measured at
the antecubital fossa and mid and cranial upper arm. Distance
of the anterior wall of the cephalic vein to the skin surface is
measured. he axillary vein diameter is measured. he subclavian
vein and IJV are assessed in the longitudinal plane with
color and spectral Doppler assessment, and IJV compression
is performed to assess for thrombus, stenosis, and occlusion.
Subclavian and internal jugular spectral Doppler waveforms
are assessed for respiratory phasicity and transmitted cardiac
pulsatility.
Thigh. Once options to place AVF and grats in the upper
extremity are exhausted, the thigh grat becomes a viable option.
high grats are similar to upper extremity grats in length of
time to permanent failure, with a trend toward increased loss
because of infection. 147 high grats are superior to dialysis via
a catheter. 148 If heavy arterial common femoral or supericial
femoral arterial calciication is found at ultrasound, pelvic CT
may be useful to determine the degree of atherosclerotic disease
present. Careful sonographic assessment of atherosclerotic
calciication and stenosis may limit immediate grat failure at
surgical placement. 128 high grat creation has typically been at
the common femoral artery and vein (Fig. 27.57). An alternate
place to anastomose the venous end of the grat is the GSV, to
preserve the CFV when grat revision is necessary. However, to
preserve proximal vasculature for grat revision, and potentially
because of fewer infectious complications, midthigh grats are
now being increasingly placed in the mid SFA and supericial
femoral vein. 149
Technical considerations for mapping the arteries and veins
of the thigh for hemodialysis grat placement are similar to
mapping the upper extremity as described earlier, although a
lower-frequency linear transducer may be necessary because of
greater thigh size. Evaluation of the degree of arterial calciication
and the presence of thrombus is carefully performed in the thigh.
More central stenosis or obstruction is assessed by spectral
Doppler evaluation of the CFV and common femoral artery.
Distance of the vein to the skin is not measured, because typically
only thigh grats are surgically created. A tourniquet is not used
in sonographic thigh grat mapping.
he common femoral artery and vein inner luminal diameters
are measured, and evaluated for the degree of atherosclerotic
calciication. Spectral and color Doppler evaluation of the common
femoral artery and vein are performed to evaluate for more
proximal stenosis or occlusion. SFA waveforms are also assessed
for normalcy. he length of the GSV, which is at least 0.4 cm
inner diameter, is measured from its insertion into the CFV
extending distally. Inner diameter measurements of the proximal
and mid supericial femoral artery and FV are obtained. Compressibility
of the veins assessing for thrombus and wall thickening
is performed. 128
Arteriovenous Fistula and Graft
A surgically created hemodialysis access can have a variety of
complications, and most of these can be successfully evaluated
by ultrasound. Operative notes and pertinent patient history
should be reviewed before sonographic evaluation of hemodialysis
access. An overall ultrasound scan is performed initially to obtain
an overview of the access anatomy and anastomoses. When the
general layout is known, sonographic assessment is performed
with duplex Doppler sonography, typically in a seated patient
with his or her arm resting comfortably on a table. he caudal
third of the feeding artery is assessed for stenosis, and the
intraluminal diameter is measured in the transverse plane using
gray-scale techniques. he feeding artery is further assessed with