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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5780_Библиотеки_им_академика_М_И_Перельмана.pdf
7.3 Vena Cava and Peripheral Veins
Schmidt, Ultrasound © 2007 Thieme
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b
a
Fig. 284a, b Aortic, mitral, and tricuspid insufficiency. a B-mode image :
hepatic vein dilated to 14.6 mm (cursors). b CDS : pulsatile reflux (encoded in red)
in the hepatic veins. Spectral analysis indicates systolic reflux (positive waveform
component)
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Arteries and Veins
Arteries and Veins
Arteries and Veins
ab
Fig. 285a, b Chronic venous insufficiency resulting from saphenous incompetence. a An incompetent venous valve (arrow) b is detected at the termination
of the dilated long saphenous vein (LSV). CFV = common femoral vein,
SFV = superficial femoral vein
n
Vascular collapse due to dehydration: The peripheral veins of the lower leg, for
example, cannot be visualized with ultrasound.
n
Note: This is an important guide for treatment.
n
Differentiation from thrombosis: Thrombosis is marked by an increase in luminal
diameter; the nonvisualization of veins is not characteristic of thrombosis
n
Chronic venous insufficiency, saphenous incompetence (Fig. 285): saphenofe-
moral, saphenopopliteal and perforator incompetence are easily diagnosed by
detecting flow reversal when the patient performs a Valsalva maneuver.
209
7.3 Vena Cava and Peripheral Veins
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Intraluminal Changes
..............................................................................................................
n
Thrombosis (Figs. 286 and 287; see also Fig. 663, p. 441; Table 35, p. 213):
x
Incompressibility (most important sign)
x
Luminal diameter increased by a factor of i 1.5
x
Intraluminal echogenicity
x
CDS: absence of color flow signals even at a low PRF setting. A correspondingly
low initial flow-velocity setting should be used (e.g., 0.10–0.24 m/s).
n
Arteries and Veins
Arteries and Veins
Arteries and Veins
Tumor invasion (Fig. 288; see also Fig. 677, p. 449) :
x
Flow voids caused by scalloped, echogenic tumor thrombi (indistinguishable
from blood clots in the B-mode image)
x
Vascular dilatation
x
The primary tumor can usually be visualized (often renal cell carcinoma).
ab
Fig. 286a, b Signs of thrombus: luminal expansion, intraluminal echoes, and
absence of flow by CDS. a Thrombosis of the femoral vein (FV). FA = femoral artery.
b Thrombosis of the popliteal vein (PV). V = short saphenous vein, PA = popliteal
artery. Posterior scan in the prone position
ab
Fig. 287a, b Thrombosis (TH, cursors) of the femoral vein (FV): high-level intraluminal echoes with residual peripheral perfusion (small cursors). a Longitudinal
scan, b transverse scan. Note the increased femoral vein diameter compared with
the femoral artery (FA)
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7.3 Vena Cava and Peripheral Veins
Schmidt, Ultrasound © 2007 Thieme
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a
Fig. 288a, b a Spontaneous partial
thrombosis of the vena cava (VC). Upper
abdominal transverse scan: high-level intraluminal echoes. Only CDS can detect
residual flow. AO = aorta. b Tumor (T) infiltrating the vena cava (VC). L = liver,
PV = portal vein
Associated Effects
..............................................................................................................
n
Compression (Fig. 289; see also Fig. 677, p. 449; Fig. 269, p. 200):
x
Occurrence: organ enlargement or displacement due to benign or malignant
tumors
x
Sonographic criteria:
– Vascular displacement
– Extrinsic narrowing
n
Infiltration (Fig. 290): always signifies a malignant tumor (see also Fig. 677,
p. 449)
Fig. 289 Compression of the vena
cava (VC) by a large lymph node (LN).
Infiltration of the liver (L) by chronic
lymphatic leukemia. L = liver
b
Fig. 290 Infiltration of the vena cava
(inferior vena cava syndrome) by a pancreatic carcinoma that has undergone
regional and hepatogenic metastasis.
CDS: marked caliber changes (arrows) in
the vena cava (VC) with zones of color
reversal indicating flow acceleration and
turbulence
Arteries and Veins
Arteries and Veins
Arteries and Veins
Anomalies
..............................................................................................................
n
Duplication of the vena cava (Fig. 291a): rare
n
Duplication of the popliteal vein (Fig. 291b): common
!
Caution: Thrombosis involving only one vessel may give a false-negative result.
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7.3 Vena Cava and Peripheral Veins
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a
Arteries and Veins
Arteries and Veins
Arteries and Veins
Fig. 291a, b Duplication of veins.
a Duplication of the inferior vena cava
(VC). CDS shows duplicate venae cavae
on the right and left sides of the aorta
(AO). Upper abdominal transverse scan
at the level of the left renal vein (LRV).
This anomaly is clinically significant only
when thrombosed or at operation.
b Duplication of the popliteal vein (PV),
b
scanned from the posterior side.
PA = popliteal artery
Interpretation and Further Testing
..............................................................................................................
n
Sonography:
x
Congestion of the vena cava and hepatic veins permits a diagnosis of right-sided
heart failure.
x
Origin of lower-extremity edema: High-resolution vascular ultrasound has
become the method of choice in the diagnosis of varicose veins, saphenous
incompetence, and perforator incompetence when practiced by an experienced
examiner.
x
Deep lower-extremity venous thrombosis (see also Table 35, p. 213): In patients
with unilateral or bilateral leg edema, venous compression ultrasound (even
without CDS) can quickly confirm or exclude deep venous thrombosis with
almost 100 % confidence, eliminating the need for invasive tests. (Accuracy is
limited in the distal femoral vein, certain lower leg veins, and pelvic veins.)
x
Follow-up of thrombolytic therapy: Sonography is the method of choice for daily
follow-ups.
x
Vena cava thrombosis and tumor compression (inferior vena cava syndrome due
to metastasis in the caudate lobe of the liver)
x
Invasion by renal carcinoma: Ultrasound is not such a well-recognized indication in these cases but still has an important role in diagnostic evaluation.
n
Venography: Conventional venography (phlebography) is a standardized tech-
nique that defines all groups of lower extremity veins, largely independent of
the examiner, and is therefore the standard by which ultrasound must be evaluated (except in the pelvic veins and vena cava). Table
for conventional venography in patients with suspected thrombosis.
n
CT: This is largely examiner-independent and may be rewarding even under unfa-
vorable conditions, although it can delineate only relatively large veins. It provides
excellent views of the iliac veins when they have been opacified by injecting contrast medium through a dorsal pedal vein.
35 shows the indications
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7.3 Vena Cava and Peripheral Veins
Schmidt, Ultrasound © 2007 Thieme
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Table 35.Indication for venography based on clinical and sonographic
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Deep venous thrombosis of the lower extremity
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy yyyyyyyyyyy
Clinical
Sonographic evidence of thrombosis Yes/no No No
Indication for venography No May be done after
findings
yyyyyyyyyyyyyyy
Unlikely
yyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Possible
preliminary ultrasound
yyyyyyyyyyyyyyyy
Very likely
Yes
Arteries and Veins
Arteries and Veins
Arteries and Veins
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8.1 Examination
Schmidt, Ultrasound © 2007 Thieme
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8 Cervical Vessels
8.1 Examination
Duplex Sonography of the Cervical Vessels
..............................................................................................................
Cervical Vessels
Cervical Vessels
Cervical Vessels
n
Indications:
x
Physical findings: e.g., audible bruits, neck swelling
x
History: e.g., headache, vertigo, syncopal episodes
x
Previous interventions (e.g., stent implantation) or previous stroke
n
Overview of duplex methods: see Table 36.
Table 36.Duplex examination of the cervical vessels
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Method Yields information on :
yyyyyyyyyyyyyyyyyyyyyyyy
B-mode image
CDS Flow characteristics, vascularity
Pulsed Doppler Time course of blood flow, flow velocities (displayed in a spectral
n
Note: Angle correction is essential in determining flow velocities.
n
B-mode imaging : for morphological evaluation of the vessel wall
x
Detection of hard or soft plaques
x
Determination of the intima-media thickness (IMT) of the common carotid
artery 1 cm proximal to the carotid bulb (Fig.
The IMT is determined in the vessel’s far wall (the blood providing a “fluid offset”) by measuring from the high-amplitude entry echo of the intima to the
high- amplitude exit echo of the adventitia
– Normal values (age-dependent): see Table
– An increased IMT is associated with an increased risk of cardiovascular
events.
n
CDS: for evaluating flow characteristics
x
Determination of the flow direction
x
Detection of turbulence
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Morphological changes
waveform; the spectrum reflects frequency distribution)
292; see also Fig. 282, p. 206).
37.
Fig. 292 Common carotid artery,
measurement of the intima-media
thickness. The IMT is slightly increased,
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measuring 0.82 mm
8.1 Examination
Schmidt, Ultrasound © 2007 Thieme
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Table 37.Normal IMT values for age
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
Age (years) Thickness (mm)
yyyyyyyyyyyyyyyyyyyyyyyy
20–40
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
0.5
40–60 0.6–0.8
i 60 0.8–1.0
– Anomalous position or course (Fig. 293): Possible variants or anomalies in the
course of the vessels must be taken into account to correctly interpret flow
directions and presumed zones of turbulent flow.
Fig. 293 Looping of the
internal carotid artery
n
Pulsed Doppler: Each of the arteries has a characteristic spectral waveform by
which it can be identified. When the waveforms are analyzed, they should always
be compared between the sides in order to detect abnormalities.
x
Positioning the transducer: The transducer should be positioned so that the
beam angle relative to the long axis of the vessel is less than 60h. If manual
transducer orientation is not sufficient for this purpose, the insonation angle
can also be set electronically on the ultrasound unit (most scanners have this
feature).
x
Determination of peak systolic velocity (PSV) (Table 38): The measuring system
of the ultrasound scanner is used to measure the PSV.
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Cervical Vessels
Cervical Vessels
Cervical Vessels
Table 38.Reference values for internal carotid artery stenosis
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
V
(cm/s) Degree of stenosis ( %)
max
yyyyyyyyyyyyyyyyyyyyyyyy
I 120
yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
I 50
120 approx. 60
200 approx. 70
300 approx. 80
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8.1 Examination
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x
Doppler indices (see also p. 193): The indices that can be determined by spectral
analysis are considered indirect signs of stenosis. They are difficult to interpret,
however, because of marked variations in the stiffness of the vessel walls (e.g.,
leading to pulsatility changes with ageing). Normal values:
– Resistance index (RI): I 0.75
– Pulsatility index (PI): I 1
Cervical Vessels
Cervical Vessels
Cervical Vessels
Sonographic Anatomy and Normal Findings
..............................................................................................................
n
Topography of the cervical vessels: see Fig. 294).
Fig. 294 Vascular topography of the neck. 1 = Ascending thoracic artery,
2 = descending thoracic artery, 3 = brachiocephalic trunk, 4 = left common carotid
artery, 5 = left subclavian artery, 6 = right common carotid artery, 7 = right internal
carotid artery, 8 = right external carotid artery, 9 = right vertebral artery,
10 = basilar artery, 11 = circle of Willis
n
Common carotid artery (CCA, Figs. 295–297):
x
The CCA arises from the aortic arch on the left side and from the brachiocephalic trunk on the right side. It bifurcates into the internal carotid artery (ICA) and
external carotid artery (ECA).
x
Spectral waveform: The diastolic flow velocity of the CCA is intermediate
216
between the diastolic velocities of the ICA and ECA.
8.1 Examination
Schmidt, Ultrasound © 2007 Thieme
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Fig. 295 Common carotid artery with a typical
spectral waveform. The
clear spectral window
below the waveform
indicates an absence of
turbulent flow
ab
Fig. 296a, b Common carotid artery. a CCA with the carotid bulb and jugular vein:
relatively hyperechoic vessel wall. The CCA dilates normally toward the bulb, with a
change in the audible flow signal. b CCA with the jugular vein. The jugular vein is
closer to the transducer and encoded in blue; the CCA is encoded in red
Cervical Vessels
Cervical Vessels
Cervical Vessels
Fig. 297 Carotid bifurcation with zones
of apparent turbulence in the ICA
(mixed color pattern). Cause: flow in the
overlying jugular vein
n
Internal carotid artery (ICA, Fig. 298):
x
The ICA gives off no extracranial branches
x
Spectral waveform: As a parenchymal artery (supplying the brain), the ICA has a
monophasic spectral waveform with a higher diastolic velocity than the CCA.
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8.1 Examination
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Cervical Vessels
Cervical Vessels
Cervical Vessels
n
External carotid artery (ECA, Fig. 299):
x
The ECA gives off numerous extracranial branches.
x
Spectral waveform: As a resistance vessel, the ECA has a triphasic waveform
with a low diastolic velocity.
x
Scanning tip: The ECA is easily distinguished from the ICA by repeatedly compressing a terminal branch of the ECA and watching for retrograde pulsation in
the waveform sampled from the ECA.
n
Vertebral artery (VA, Figs. 300 and 301):
x
The VA arises from the subclavian artery on each side, at a more lateral site than
the CCA.
x
Spectral waveform: resembles that of the ICA
Fig. 298 Internal carotid
artery with a typical
spectral waveform. The
diastolic flow velocity is
higher than in the CCA
Fig. 299 External carotid
artery with a typical
spectral waveform. The
ECA (encoded in red) is
easily identified by the
vessels arising from it.
The diastolic flow velocity
is lower than in the ICA,
and a small negative dip
appears at end-diastole
(typical of resistance
vessels)
Fig. 300 Vertebral artery
with a typical spectral
waveform. The vertebral
artery exhibits a higher
diastolic flow velocity
218
than the ICA