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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5782_Библиотеки_им_академика_М_И_Перельмана.pdf
PART III
ABDOMINAL SCANNING
PROTOCOLS
49
Left common carotid artery
thoracic aorta
Brachiocephalic trunk
(innominate artery)
Right brachiocephalic vein
(RT innominate vein)
Superior vena cava
Ascending aorta
Left subclavian artery
Left brachiocephalic vein
(LT innominate vein)
C
H
R
A
Hepatic veins
Diaphragm
Left hepatic artery
Middle hepatic artery
Right hepatic artery
Proper hepatic artery
Common hepatic artery
Gastroduodenal artery
Right renal vein
Right renal artery
Inferior vena cava
Right common iliac artery
Right internal iliac artery
Right external iliac artery
HEART
Aorta Anatomy
Left gastric artery
Celiac trunk
Splenic artery
Left renal artery
Left renal vein
Superior mesenteric artery
Inferior mesenteric artery
Left common iliac artery
Left internal iliac artery
Left external iliac artery
Descending
Abdominal
aorta
CHAPTER 4
Abdominal Aorta Scanning
Protocol
Betty Bates Tempkin
Key Words
Abdominal aorta
Adventitia
Celiac artery (CA)
Common hepatic artery
Common iliac arteries
Gastric artery
Inferior mesenteric artery (IMA)
Intima
Left renal artery (LRA)
Objectives
At the end of this chapter, you will be able to:
• Define the key words.
• Identify the sonographic appearance of the aorta, its branches,
and the terms used to describe them.
• List the transducer options for scanning the aorta.
• Name the various suggested breathing techniques for patients
when scanning the aorta.
• Identify suggested patient position (and options) when scanning
the aorta.
• Describe patient prep for an abdominal aorta study.
• Describe the survey steps and how to evaluate the entire length,
width, and depth of the aorta and its branches.
• Identify the order and exact locations to take representative
images of the aorta.
• Describe normal variations of the abdominal aorta.
• Answer the review questions at the end of the chapter.
Media
Proximal
Retroperitoneum
Right renal artery (RRA)
Splenic artery
Superior mesenteric artery (SMA)
Thoracic aorta
Tortuous
Overview
Location
• The aorta originates at the left ventricle of the heart then ascends
posterior to the pulmonary artery; it arches to the left then descends
(thoracic aorta) posterior to the diaphragm into the retroperitoneum
(portion of abdominopelvic cavity posterior to the peritoneal sac)
of the abdominal cavity (abdominal aorta).
51
52 PART III Abdominal Scanning Protocols
• The abdominal aorta is vertically orientated in the body. It descends,
anterior to the spine, just to the left of the midline then bifurcates
into the common iliac arteries anterior to the body of the fourth
lumbar vertebra.
Anatomy
• The largest artery in the body
• Consists of three muscle layers:
1. Intima (innermost)
2. Media (middle)
3. Adventitia (outer)
• 3 anterior branches:
1. Celiac artery (CA) trunk: also known as “celiac axis,” branches
into the left gastric artery, common hepatic artery, and
splenic artery
2. Superior mesenteric artery (SMA): just inferior to the CA,
divides into several small arteries that supply the ascending portion of the colon and largest portion of the small intestine
3. Inferior mesenteric artery (IMA): inferior to the SMA and
renal arteries, divides into several small arteries that supply
the transverse and descending portions of the colon and the
rectum
• 2 lateral branches:
1. Right renal artery (RRA): located a few centimeters within the
origin of the SMA, it courses anterior to the spine and posterior
to the inferior vena cava in route to the right kidney
2. Left renal artery (LRA): located a few centimeters within the
origin of the SMA, it courses left lateral to the spine and posterior to the tail of the pancreas in route to the left kidney
• Size is normal up to 3 cm in diameter, gradually tapering toward
the bifurcation
• Can be very tortuous (marked by twists, turns, or bends)
Physiology
• Supplies the organs, bones, and connective structures of the body
with oxygen and nutrient-rich blood.
Sonographic Appearance
• Anechoic lumen surrounded by bright, echogenic walls.
• Because the aorta 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
aorta appears like a large long tube, anechoic with bright walls,
immediately anterior to the spine, and immediately posterior to
CHAPTER 4 Abdominal Aorta Scanning Protocol 53
Splenic artery
process
Confluence of splenic
Stomach
c
the esophageal gastric junction, crus of the diaphragm, SMA, and
splenic artery.
Liver
AO
L
Pleural
space
Esophageal-
gastric
junction
Crus of the
diaphragm
Pancreas
body
Stomach
Aorta
Splenic vein
• Short axis (or axial) sections of the aorta are seen in transverse
scanning planes. The following transverse scanning plane image
shows how easy it is to recognize the short axis section of the aorta
in the posterior portion of the image, immediately anterior and
just to the left of the spine. It appears large, round, and anechoic
with bright walls.
vein and superior
mesenteric vein
Pancrease
neck
Liver
Pancreas
head
Right
Inferior
vena cava
uncinate
VertebraPancreas
(Courtesy Geoffrey E. Hayden, MD, Charleston, S.C.)
mesenteric
Anterior
Posterior
Superior
artery
Note the axial section of the SMA branch. It appears “separate”
from the aorta because following the rise of its trunk from the aorta’s anterior wall, it runs in front of, or anterior to, and parallel to
the aorta. The space left between the aorta and SMA affords passage
Superior
mesenteric artery
Pancreas
body
Aorta
Pancreas
Left
renal vein
Spleni
vein
Left
tail
54 PART III Abdominal Scanning Protocols
of the left renal vein (LRV) seen here in longitudinal section, on its
way to the inferior vena cava (IVC).
• The proximal (closest to origin) portion of the abdominal aorta is
described as the area seen inferior to the diaphragm and superior to the
CA trunk; it lies anterior to the spine and posterior to the esophageal gastric junction and liver.
• The mid portion of the abdominal aorta is seen from the CA trunk
running along the length of the SMA; it lies anterior to the spine and
posterior to the CA, SMA, splenic artery, splenic vein, body of the
pancreas, a portion of the stomach, and the liver.
• The distal (farthest from origin) portion of the abdominal aorta is
described as inferior to the SMA and superior to the bifurcation; it lies
anterior to the spine and posterior to the bowel.
Normal Variants
• Normal variations of the abdominal aorta are rare but include:
• Markedly tortuous
• May lie on the right side of the inferior vena cava
• May include an anterior pulmonary branch close to the CA
trunk
Preparation
Patient Prep
• The patient should fast for at least 6 to 8 hours before the ultra-
sound study.
• 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.
• Deep, held respiration.
NOTE: Different breathing techniques should be used whenever the
suggested technique does not give the desired results.
Patient Position
• Supine.
• Right lateral decubitus, left lateral decubitus, left posterior oblique,
right posterior oblique, or sitting semierect to erect as needed.
CHAPTER 4 Abdominal Aorta Scanning Protocol 55
Patient’s left (LT)
Patient’s right (RT)
NOTE: Different patient positions should be used whenever the
suggested position does not give the desired results.
Abdominal Aorta Survey Steps
Abdominal Aorta • Longitudinal Survey
NOTE: While you are scanning, experiment using different amounts of
transducer pressure (keeping patient comfort in mind) to improve imaging.
Sagittal Plane • Transabdominal Anterior Approach
1. Begin scanning with the transducer perpendicular, at the midline
of the body, just inferior to the xiphoid process of the sternum.
Transducer
2. Slightly move or angle the transducer to the patient’s right and
identify the longitudinal, anechoic section of the distal inferior
vena cava (IVC), just posterior to the liver.
LT
RT
NOTE: Use the diaphragm to differentiate the IVC from the aorta. 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.
56 PART III Abdominal Scanning Protocols
3. Return to the midline and 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
4. While viewing the proximal aorta, 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 aorta. Additional slight
twists can help reveal the proximal aorta’s anterior branches, the
CA, and the SMA, if they are not already visualized. Now, very
slightly rock or move the transducer from right to left, scanning
completely through each side of the aorta. Continue this as you
slowly slide the transducer inferiorly following along the length of
the aorta. Keep your eyes on the screen; use the image as a guide,
evaluating the appearance of the aorta until you scan completely
through the middle and distal portions to the bifurcation (usually
seen at the level of the umbilicus) and right and left common iliac
arteries.
LT
LT
RT
LT
RT
5. In some cases, the bifurcation site and common iliac arteries can
be better visualized with the transducer angled from a lateral position. At the level of the most distal portion of the aorta, move the
transducer slightly toward the patient’s left, then angle the transducer at varying degrees aiming the sound beam back toward the
aorta until you relocate the distal portion. Keeping this angle, very
slowly slide the transducer inferiorly until the bifurcation site and
common iliac arteries come into view.
CHAPTER 4 Abdominal Aorta Scanning Protocol 57
LT
RT
NOTE: The longitudinal sections of the distal aorta and bifurcation (into
the right and left common iliac arteries) can be difficult to resolve from a
sagittal plane. In most cases, visualization is easier from a coronal plane,
left lateral approach as described below. While middle and proximal
portions of the aorta tend to be better visualized from a transabdominal
sagittal plane, alternatively, they may also be evaluated from the coronal
plane, left lateral approach.
Distal Aorta and Bifurcation • Coronal Plane • Left Lateral
Approach
Patient Position: Right Lateral Decubitus (or Supine,
Sitting Semierect to Erect)
1. Begin with the transducer perpendicular, midcoronal plane,
just superior to the iliac crest.
2. Use the inferior pole of the left 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 distal aorta, bifurcation
site, and common iliac arteries 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 distal aorta,
bifurcation site, and common iliac arteries.
4. To evaluate the middle and proximal aorta, move the transducer superiorly from the level of the bifurcation or scan intercostally, looking for the aorta medially.
5. To avoid moving the patient, the survey of the bifurcation in
the decubitus position can be done following the axial survey
of the aorta.
LT
RT
58 PART III Abdominal Scanning Protocols
Abdominal Aorta • Axial Survey
Transverse Plane • Transabdominal Anterior Approach
1. Begin scanning with the transducer perpendicular, at the midline of the body, just inferior to the xiphoid process of the
sternum.
2. Angle the transducer superiorly until the heart is identified by its
pulsations. Keeping your eyes on the screen, very slowly return the
transducer to a perpendicular position while looking for the round,
anechoic axial section of the aorta to come into sight just to the
left of midline, anterior to the spine.
LT
RT
LT
RT
NOTE: An alternative method for locating the axial section of the proximal aorta begins by viewing a longitudinal section of the proximal aorta
from a sagittal plane. From that position, slowly rotate the transducer
90 degrees into the transverse plane. The axial view of the aorta should
come directly into sight.
3. With the proximal aorta in sight, very slightly rock or move the
transducer from right to left, scanning completely through the
aorta. Continue this as you slowly slide the transducer inferiorly. Keep your eyes on the screen; use the image as a guide to
avoid losing sight of the aorta. Note and evaluate the aorta’s
anterior branches. Slightly twisting/rotating the transducer can