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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5780_Библиотеки_им_академика_М_И_Перельмана.pdf
8.1 Examination
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
a
b
Fig. 301a, b Vertebral artery. a Portions of the vertebral artery can be identified in
the intervertebral foramina. b Waveform sampled from the vertebral artery resembles that of the ICA
Scanning Protocol
..............................................................................................................
n
The patient is examined in the supine position with the head turned slightly to the
opposite side (Fig.
302).
8
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8
Cervical Vessels
Cervical Vessels
Cervical Vessels
Fig. 302 Transducer
positioned on the right
side of the neck in a
supine patient
n
The cervical vessels are scanned in transverse and longitudinal sections over their
entire accessible length.
n
Generally the examination covers all of the carotid arteries (common, internal and
external), the vertebral arteries, and the right and left internal jugular veins.
n
Transducer: longitudinal array, generally with an operating frequency of 5 MHz
n
Locating the vessels in longitudinal scans:
x
First identify the ICA in longitudinal section.
x
ECA: Angle the probe slightly anteromedially from its position over the ICA.
x
VA: From the ICA position, angle the probe slightly posterolaterally to scan
between the intervertebral foramina.
n
Locating the vessels in transverse scans:
x
First locate the CCA, then the ICA.
219
8.1 Examination
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
8
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x
The ICA usually has a larger caliber than the ECA (Fig. 303).
x
The VA is posterolateral to the ICA, and the ECA is anterior.
x
The internal jugular vein lies anterior to the carotid artery and can be compressed by applying gentle transducer pressure.
Cervical Vessels
Cervical Vessels
Cervical Vessels
ab
Fig. 303a, b Transverse scans of the external carotid artery (ECA) and internal
carotid artery (ICA). a The internal carotid artery has a larger diameter than the
external carotid artery (right side of the neck). b CDS appearance of the carotid
arteries (left side of the neck)
n
Intracranial Doppler sonography (Fig. 304): Some intracranial vascular segments
can be examined by transcranial ultrasound scanning : ICA, middle cerebral artery
(MCA), posterior cerebral artery (PCA), and anterior cerebral artery (ACA).
x
Prerequisites:
– Proper ultrasound equipment
– Use of a low transducer frequency (here, 2 MHz). Delineation can be
enhanced by the use of ultrasound contrast agents.
– Previous interventions (stent implantations) or preceding stroke
Table 39.Criteria for interpreting sonographic findings
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Criterion Possible findings
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Morphology of the vessel wall
Flow characteristics (flow direction,
flow velocity, flow disturbances)
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Hard and soft plaques
Abnormal intima-media thickness
Turbulence
Waveform changes
Flow direction, flow reversal, absent flow
Stenosis
220
8.2 Abnormal Findings
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
Table 40.Abnormal findings in the cervical vessels
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Atherosclerotic plaques Stenosis, occlusion Thrombosis, dissection
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Soft plaque (p. 221)
Hard plaque (p. 222) ECA stenosis (p. 225)
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Carotid stenosis, previous
stent implantation (p. 223)
ICA stenosis (p. 225)
ICA occlusion (p. 226)
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Jugular vein thrombosis (p. 229)
Fig. 304 Transtemporal
scan of the MCA and PCA
on the left side
n
Indirect signs of carotid artery stenosis (spectral analysis):
x
Prestenotic: increased pulsatility, decreased systolic amplitude
x
Intrastenotic: decreased pulsatility, increased amplitude
x
Poststenotic: delayed systolic peak, decreased pulsatility
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Cervical Vessels
Cervical Vessels
Cervical Vessels
8.2 Abnormal Findings
Atherosclerotic Plaques
..............................................................................................................
n
Soft plaques (Fig. 305): luminal narrowing without an acoustic shadow
Fig. 305 Small, soft plaque (arrow) in
the CCA: faint, smoothly curved area of
luminal narrowing without an acoustic
shadow
221
8.2 Abnormal Findings
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
8
8
8
n
Hard plaques (Figs. 306, 307):
x
Irregular surface
x
Calcifications, sometimes with acoustic shadows (Fig. 307)
x
Luminal narrowing
Cervical Vessels
Cervical Vessels
Cervical Vessels
ab
Fig. 306a, b Luminal narrowing by hard plaques. a Calcified plaque in the carotid
bulb. Luminal narrowing by plaque with an irregular surface is associated with a
higher risk of thromboembolism. b Luminal narrowing by hard plaque with zones of
turbulent flow
ab
cd
Fig. 307a–d Hard plaques with and without acoustic shadowing. a Rough, calcified plaques with acoustic shadowing in the CCA. b Small, hard, echogenic plaque
without an acoustic shadow. c Small, flat, shadowing plaque in the CCA. d Acoustic
shadow behind a calcified plaque mimics reverse flow
222
8.2 Abnormal Findings
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
Stenosis, Occlusion
..............................................................................................................
n
Carotid stenosis following stent implantation : See Figs. 308–311.
ab
c
Fig. 308a–c Carotid stent in the CCA.
a Longitudinal scan. The stent (arrow)
appears as an interrupted echogenic
band. b Transverse scan. The stent
appears as an echogenic ring.
c Longitudinal CDS scan. The segments
without color flow signals are caused by
acoustic shadows from the stent
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8
8
Cervical Vessels
Cervical Vessels
Cervical Vessels
a
Fig. 309a a Carotid
stent near the origin of
the ECA: flow acceleration
in the ECA with turbulent
flow (mixed color pattern)
223
8.2 Abnormal Findings
Schmidt, Ultrasound © 2007 Thieme
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b
Cervical Vessels
Cervical Vessels
Cervical Vessels
c
Fig. 309b, c b Carotid
stent near the origin of
the ICA: turbulence without flow acceleration in
the CCA. c Doppler trace
from the ICA with a stent
in the CCA
Fig. 310 This patient previously had
a stent implanted for carotid stenosis,
presented now with a proximal
stenosis of the ECA. Measurement of
the maximum flow velocity (V
indicates a 60–70 % stenosis
224
max
Fig. 311 Transverse scan of a stented
ECA. The color flow signals confirm
patency of the stent
)
n
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
ECA stenosis : See Fig. 312.
8.2 Abnormal Findings
8
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8
a
b
Fig. 312a, b Flow in the
ICA associated with a 50 %
stenosis of the ECA.
a No alteration of ICA flow.
b Alteration of ICA flow in
the presence of a 50 %
ECA stenosis
n
ICA stenosis: See Figs. 313 and 314.
ab
Cervical Vessels
Cervical Vessels
Cervical Vessels
Fig. 313a, b ICA stenosis. a Conspicuous echogenic plaques in the ICA with
luminal narrowing. b CDS: turbulence (green/blue/yellow pixels) and acoustic
shadowing in the stenosis (the “shadow” from the plaque obscures color flow)
225
8.2 Abnormal Findings
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
8
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a
Cervical Vessels
Cervical Vessels
Cervical Vessels
b
c
Fig. 314a–c
ICA stenosis.
a Decreased flow velocity
with an intact frequency
spectrum upstream of
the stenosis.
b Markedly decreased
flow velocity just proximal
to the stenosis.
c Increased flow velocity
in the stenosis, with V
up to 140 cm/s
max
n
ICA occlusion:
x
Ipsilateral ICA: spectral waveform cannot be recorded (Figs. 315c and 316f)
x
Ipsilateral ECA: turbulence and increased flow velocity (Fig. 315)
x
Ipsilateral CCA: spectral waveform resembles that of the ECA (with ICA occlusion, the CCA becomes a pure resistance vessel, Fig.
316)
226
8.2 Abnormal Findings
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
a
b
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Cervical Vessels
Cervical Vessels
Cervical Vessels
c
Fig. 315a–d Typical
findings in the cervical
vessels associated with
occlusion of the ICA.
a CDS appearance of the
ECA in the presence of an
ICA occlusion. Turbulent
flow (mixed color pattern)
in the ECA. b Spectrum
from the ECA: V
c A spectrum cannot be
recorded from the ICA.
d Spectrum from the CCA
in the presence of an ICA
occlusion. The spectral
waveform resembles
that of the ECA (the CCA
becomes a pure
resistance vessel in
cases where the ICA is
occluded)
max
i 2 m/s.
d
227
8.2 Abnormal Findings
Schmidt, Ultrasound © 2007 Thieme
All rights reserved. Usage subject to terms and conditions of license.
8
8
8
Cervical Vessels
Cervical Vessels
Cervical Vessels
a
b
c
d
228
Fig. 316a–d Typical
findings in the cervical
vessels associated with
occlusion of the ICA.
a Abnormal spectrum
from the CCA shows an
end-diastolic dip with a
relatively low diastolic
flow velocity. The waveform resembles that of
the ECA. b i 50 % luminal
narrowing of the ICA.
Turbulent signals are not
detected in this case.
c ECA stenosis. The spectrum from the ECA indicates flow acceleration.
d Doppler interrogation
of the ECA stenosis. The
maximum measurable
flow velocity in the ECA,
at 2.45 cm/s, indicates
an approximately 70 %
stenosis of the ECA