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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5782_Библиотеки_им_академика_М_И_Перельмана.pdf
CHAPTER 4 Abdominal Aorta Scanning Protocol 69
13. Which of the following is not a direct branch of the abdominal
aorta?
a) celiac trunk.
b) renal artery.
c) mesenteric artery.
d) external iliac artery.
14. What is the most common location of an abdominal aortic
aneurysm?
a) suprarenal.
b) aortic arch.
c) infrarenal.
d) thoracic.
15. The biggest risk factor for rupture of an abdominal aortic
aneurysm is
a) location.
b) size.
c) velocity of flow through the vessel.
d) age of the patient.
Superior mesenteric artery
Superior vena cava
Right common iliac vein
Hepatic veins
Diaphragm
Left hepatic artery
Middle hepatic artery
Right hepatic artery
Proper hepatic artery
Common hepatic artery
Gastroduodenal artery
Right renal vein
A
o
r
t
a
Heart
Left gastric artery
Splenic artery
Left renal artery
Left renal vein
Right renal artery
Right internal iliac vein
Right external iliac vein
Inferior mesenteric artery
Left common iliac vein
Left internal iliac vein
Left external iliac vein
Inferior Vena Cava Anatomy
Inferior Vena Cava Scanning
Protocol
Betty Bates Tempkin
Key Words
Adventitia
Common iliac veins
Distal IVC
Hepatic veins
Iliac veins
Inferior phrenic vein
Inferior vena cava (IVC)
Intima
Lumbar veins
Media
Medial sacral vein
Mid IVC
Proximal IVC
Renal veins
Retroperitoneum
Right adrenal vein
Right ovarian or testicular vein
Tortuous
Valsalva maneuver
CHAPTER 5
Objectives
At the end of this chapter, you will be able to:
• Define the key words.
• Distinguish the sonographic appearance of the inferior vena cava
(IVC), its tributaries, and the terms used to describe them.
• Describe the transducer options for scanning the IVC.
• List the various suggested breathing techniques for patients when
scanning the IVC.
• List the suggested patient position (and options) when scanning
the IVC.
• Describe the patient prep for an IVC study.
• Name the survey steps and explain how to evaluate the entire
length, width, and depth of the IVC and its tributaries.
• Explain the order and exact locations to take representative
images of the IVC.
• Answer the review questions at the end of the chapter.
Overview
Location
• The inferior vena cava (IVC) originates at the junction of the two
common iliac veins anterior to the body of the fifth lumbar vertebra. The IVC is vertically oriented in the body; it ascends through
the retroperitoneum (portion of abdominopelvic cavity posterior
to the peritoneal sac) anterior and just to the right of the spine and
71
72 PART III Abdominal Scanning Protocols
then passes through the diaphragm to enter the right atrium of the
heart.
• As the IVC ascends through the retroperitoneum on its way to the
heart it passes through a deep fossa on the posterior surface of the
liver between the caudate lobe and bare area.
Anatomy
• The inferior portion of the body’s largest vein.
• Consists of 3 muscle layers:
1. Intima (innermost)
2. Media (middle layer)
3. Adventitia (outer)
• Tributaries:
1. 3 hepatic veins
2. 2 renal veins
3. 2 common iliac veins
4. Right adrenal vein
5. Right ovarian vein or testicular vein
6. Inferior phrenic vein
7. 4 lumbar veins
8. Medial sacral vein
• Size is variable and normal up to 4 cm
• Can be very tortuous (marked by twists, turns, or bends)
Physiology
• The IVC returns deoxygenated blood from the tissues to the heart
for oxygenation and recirculation.
Sonographic Appearance
• Anechoic lumen surrounded by bright, echogenic walls.
• During real-time examination it is not uncommon to visual-
ize multiple, small, moving echoes within the lumen of the IVC,
which are thought to be related to the flow of blood.
• During real-time evaluation the IVC demonstrates significant vari-
ation in diameter relative to arterial vessels. The IVC is seen to
increase in size with deep inspiration or the Valsalva maneuver
(exhaling with airways closed–mouth shut, nose pinched shut)
and decrease in size during expiration. Note that a momentary collapse of the IVC can be observed by having a patient “sniff.”
• Since the IVC is vertically orientated in the body, longitudinal and
long axis views are seen in coronal scanning planes and sagittal scanning planes as demonstrated in the following image. The IVC appears
like a large long tube, anechoic with thin, bright walls, immediately
anterior to the spine and right renal artery and immediately posterior
to the head of the pancreas, portion of the distal common bile duct,
CHAPTER 5 Inferior Vena Cava Scanning Protocol 73
Common
rior
Inferior
ow
in
ft
Posterior
portion of the portal vein, and the right lobe of the liver. Note that the
space between the IVC and the spine affords passage of the right renal
artery, seen here in an axial section, on its way to the right kidney.
Liver
Portal
vein
Superior
Inferior
vena cava
Diaphragm
Anterior
Posterior
(Courtesy University of Virginia Health Systems Imaging Center.)
• Short axis (or axial) sections of the IVC are seen in transverse scan-
ning planes. The following transverse scanning plane image shows
how easy it is to recognize the short axis section of the mid portion of the IVC in the posterior portion of the image, immediately
anterior to the right renal artery and anterior and just to the right
of the spine, and immediately posterior to the head of the pancreas
and the gallbladder. It appears large, round, anechoic with bright,
thin walls, and at this level the right and left renal vein tributaries
are easily identified. Notice how the space between the IVC and
the spine affords passage of the right renal artery, seen here in a
longitudinal section, on its way to the right kidney.
bile duct
Pancreas
head
Right
renal
artery
Infe
Spine
vena cava
Anterior
Gallbladder
Liver
Right
Right
renal vein
Diaphragm
Right
kidney
(Courtesy University of Virginia Health Systems Imaging Center.)
Vertebra
Pancreas
head
Bowel
Shad
Le
Left
renal ve
Right renal
artery
74 PART III Abdominal Scanning Protocols
• The proximal (closest to origin) portion of the IVC is described as
the area seen extending from its origin at the common iliac veins to
the area just inferior to the renal vein tributaries.
• The mid portion of the IVC is seen at the level of the renal vein tribu-
taries, posterior to the head of the pancreas.
• The distal (farthest from origin) portion of the IVC is seen extend-
ing from the area just superior to the renal vein tributaries to the right
atrium of the heart; it includes the hepatic vein tributaries located
just inferior to the diaphragm.
• The 3 hepatic veins, 2 renal veins, and 2 common iliac veins are
the IVC tributaries that are routinely visualized with ultrasound.
The remaining tributaries are usually too small to distinguish.
Normal Variants
• Duplication.
• Total or partial absence.
• May be particularly short.
• Visceral transposition lying to the left of the aorta.
• Crosses to lie to the left of the aorta.
• Joins with the azygos vein; enters the superior vena cava.
Preparation
Patient Prep
• The patient should fast for at least 6 to 8 hours before the ultra-
sound examination.
• If the patient has eaten, still attempt the examination.
Transducer
• 3.0 MHz or 3.5 MHz.
• 5.0 MHz for thin patients.
Breathing Technique
• Normal respiration or deep, held respiration.
NOTE: Different breathing techniques should be used whenever the
suggested breathing technique does not produce the desired results.
The diameter of the IVC will vary depending on the level of respiration.
Normal veins increase with held respiration or the Valsalva maneuver.
Patient Position
• Supine.
• Left lateral decubitus, right lateral decubitus, left posterior oblique,
right posterior oblique, or sitting semierect to erect as needed.
CHAPTER 5 Inferior Vena Cava Scanning Protocol 75
T)
Pat
NOTE: Different patient positions should be used whenever the
suggested position does not produce the desired results.
Inferior Vena Cava Survey Steps
Inferior Vena Cava • Longitudinal Survey
Sagittal Plane • Transabdominal Anterior Approach
NOTE: While you are scanning, experiment using different amounts of
transducer pressure (keeping patient comfort in mind) to improve imaging.
1. Begin scanning with the transducer perpendicular, at the midline
of the body, just inferior to the xiphoid process of the sternum.
Transducer
Patient’s left (L
ient’s right (RT)
2. Slightly move or angle the transducer to the patient’s left and identify the longitudinal, anechoic, section of the proximal aorta just
posterior to the liver.
RT
LT
NOTE: Use held respiration or locate the diaphragm to differentiate
the IVC from the abdominal aorta. As mentioned, varying respiration
changes the size of the IVC. The IVC passes through the highly reflective
diaphragm that can be visualized in the superior portion of the image;
the aorta lies posterior to the diaphragm.
76 PART III Abdominal Scanning Protocols
3. Return to the midline and slightly move or angle the transducer to
the patient’s right; identify the longitudinal, anechoic, section of
the distal IVC just posterior to the liver.
4. While viewing the distal IVC, it may be necessary to slightly twist/
rotate the transducer, first one way, then the other, to resolve the
longest sections and long axis of the IVC. When the long axis is
located, barely twisting/rotating the transducer can help resolve
the hepatic vein tributaries, which are seen within the liver, emptying into the IVC anteriorly (Figure 5-1, A). Now, very slightly
rock or move the transducer from right to left, scanning completely through each side of the IVC. Continue this and slowly
slide the transducer inferiorly following along the length of the
IVC. Keep your eyes on the screen; use the image as a guide, evaluating the appearance of the mid and proximal IVC until you reach
the right and left common iliac veins (usually at or just beyond
the level of the umbilicus).
LT
RT
RT
LT
LT
RT
CHAPTER 5 Inferior Vena Cava Scanning Protocol 77
Anterior
Area of
attenuation
Superior
A
Left hepatic vein
Right
Middle
hepatic
vein
B
Posterior
Anterior
Inferior
vena cava
Posterior
Liver
Inferior
Inferior
vena cava
Liver
Left
Left
hepatic
vein
Figure 5-1 Hepatic Vein Tributaries. A, Sagittal scanning plane image showing a longitudinal section of the left hepatic vein
emptying into the long section of the inferior vena cava (IVC). B, Axial section of the IVC from a transverse scanning plane, showing sections of the middle and left hepatic veins emptying into the anterior portion of the IVC.
5. In some cases, the convergence of the common iliac veins can be
better visualized with the transducer angled from a lateral position.
At the level of the most proximal portion of the IVC, move the
transducer slightly toward the patient’s right then angle the transducer at varying degrees aiming the sound beam back toward the
IVC until you relocate the proximal portion. Keeping this angle,
very slowly slide the transducer inferiorly until the convergence
site and right and left common iliac veins come into view.
RT
LT
78 PART III Abdominal Scanning Protocols
RT
NOTE: The longitudinal sections of the convergence of the right and
left common iliac veins into the proximal IVC can be difficult to resolve
from a sagittal plane. In most cases, visualization is easier from a coronal
plane, right lateral approach as described below. While distal and middle
portions of the IVC tend to be better visualized from a transabdominal
sagittal plane, alternatively, they may also be evaluated from the coronal
plane, right lateral approach.
Proximal IVC and Common Iliac Veins • Coronal Plane •
Right Lateral Approach
Patient Position: Left Lateral Decubitus (or Supine, Sitting
Semierect to Erect)
1. Begin with the transducer perpendicular, midcoronal plane,
just super to the iliac crest.
2. Use the inferior pole of the right kidney as a landmark; it is usually easy to visualize at this level or by sliding the transducer
slightly superiorly.
3. When the inferior pole is located, the proximal IVC, convergence site, and common iliac veins should be seen in the
medial and inferior portions of the image. It may be necessary to slightly twist/rotate the transducer at varying degrees
to oblique the coronal plane and resolve the long axis of the
proximal IVC, convergence site, and right and left common
iliac veins.
4. To evaluate the middle and distal portions of the IVC, move
the transducer superiorly from the level of the convergence site
or scan intercostally, looking for the IVC medially.
5. To avoid moving the patient, the survey of the proximal IVC,
convergence site, and common iliac veins in the decubitus
position can be done following the axial survey of the IVC.
LT