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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3850_Библиотеки_им_академика_М_И_Перельмана
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Jos C. van den Berg Chapter 1 Radio-Anatomy of the Thoracic Aorta. 3D Imaging of the Aorta (CT, MRI and 3D Rotational Angiography)
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Fig. 1.1 e, f
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1.3.2 Supra-aortic Vessels
The first and largest branch is the innominate or brachio-cephalic artery, which arises from the commencement of the aortic arch. It divides into the right subclavian and common carotid artery (Figs. 1.3, 1.4.). The
innominate artery is bordered by the right innominate
vein and pleura on the right side, and is crossed in
front by the left brachiocephalic vein. Initially the
course of the innominate artery is in front of the trachea, and then to the right of it. The second branch is
the left common carotid artery that arises slightly to
the left of the innominate artery. It extends upward, at
first in front and then to the left of the trachea. Finally
the left subclavian artery arises from the aortic arch,
behind the left common carotid artery, and ascends lateral to the trachea.
ab
Fig. 1.2. a
rowhead) and left (arrow) coronary arteries; the ostium of the
right coronary artery is located in the anterior Valsalva sinus.
Axial CT; aortic root with heavily calcified right (ar-
b Axial CT; slightly higher plane, demonstrating the ostium of
the left coronary artery (arrowhead), originating in the left
posterior Valsalva sinus.
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c
Fig. 1.2 c Curved reformatted MPR demonstrating the main
stem of the left coronary artery, and its bifurcation into the left
anterior or descending artery (arrowhead) and the left circumflex artery (arrow)
1.3.4 Anterior Spinal Artery
The most important arterial feeding vessel of the thoracolumbar part of the spinal cord is the most dominant
of the anterior radiculomedullary arteries (also known
as the great anterior radiculomedullary artery or artery
of Adamkiewicz). This artery arises from the radiculomedullary artery, which is a division of the posterior
branches of intercostal and lumbar arteries. The distal
portion of the great anterior radiculomedullary artery
forms a characteristic ªhairpinº turn. The artery originates in 68±73% of cases from left intercostal or lumbar
arteries, with the level of origin ranging from the level
of the ninth intercostals to the second lumbar artery (in
62±75% of cases at the ninth to twelfth intercostal artery) [30, 31]. With use of meticulous technique the artery of Adamkiewicz can be visualized in 66.7±69% of
cases using MRA, and in 68±90% of cases using CTA
[30±33].
1.3.5 Bronchial Arteries
1.3.3 Intercostal Arteries
In most patients there are nine pairs of intercostal arteries that originate from the posterior aortic wall along
the lower nine intercostals spaces [29]. In general, the
orifices of the left and right intercostal arteries are located in close proximity to each other (Fig. 1.5).
Almost all bronchial arteries originate from the thoracic
aorta between the level of Th4 and Th7 [29]. There are
usually two bronchial arteries supplying the right side.
The first commonly arises from the descending aorta as
a common intercostobronchial trunk with the third
right posterior intercostal artery, and has a posterolaterally lying orifice. The second important artery is the
common right and left bronchial artery, which arises
from the anterior surface and supplies both lungs. On
the left side a separate left bronchial artery is usually
present, and arises from the anterolateral surface of the
aorta. Many variations occur, including origins from
the internal thoracic artery, left subclavian artery and
inferior thyroid artery (Figs. 1.6, 1.7).
a
Fig. 1.3. a 3D rotational angiography (3D-RA); cinefluoroscopic
image of selective injection into the innominate artery.
RA; reconstructive zoom with measurements (yellow arrows)of
the innominate artery distally from stenosis at its origin (white
bc
b 3D-
arrow); green, red, and blue arrows indicate orientations of x-,
y-, and z-axes. c 3D-RA; cut plane (red) indicating the plane of
cross-section used for the measurements
Jos C. van den Berg Chapter 1 Radio-Anatomy of the Thoracic Aorta. 3D Imaging of the Aorta (CT, MRI and 3D Rotational Angiography)
https://t.me/med1917
ab
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cd
Fig. 1.4. a Axial CT of a patient after deceleration trauma dem-
onstrating extravasation of the contrast medium at the level of
the aortic arch (arrow).
aortic rupture at the inner curve of the aortic arch, at the level
b Sagittal oblique MPR demonstrating
of the isthmus (arrowhead).
eral from slice shown in b showing extension of the rupture
(arrowhead).
sion of the rupture to advantage (arrowhead).
d VRT image demonstrating semicircular exten-
c Sagittal oblique MPR slightly lat-
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e
Fig. 1.4. e VRT image with the cut plane running through the
aortic arch (same level as the MPR in Fig. 1.9 b) demonstrating
contrast extravasation (arrowhead); the relationship to supraaortic vessels can be clearly seen (asterisk left subclavian
f
artery). f VRT image with the cut plane perpendicular to the
aortic arch; semicircular extension of contrast extravasation
(arrowhead)
1.4 Congenital Variants and Abnormalities
1.4.1 Coronary Arteries
The commonest congenital anomalies are a left circumflex artery arising from the right coronary artery or
right sinus and separate origins of the left circumflex
and left anterior or descending artery from the left coronary sinus. Right coronary aneurysms (either congenital or acquired) can be clearly depicted using 3D techniques, thus aiding surgeons in preoperative planning
[26, 34]. The aortic sinus itself can also demonstrate
aneurysmal degeneration, which can be depicted using
3D imaging techniques [18]. Finally 3D techniques can
be used to demonstrate aorto-coronary bypass grafts.
Fig. 1.5.
Magnetic resonance angiography (MRA); maximum-intensity projection (MIP) reconstruction demonstrating lower
intercostal arteries (arrowheads)
1.4.2 Supra-aortic Vessels and Aortic Arch
The normal aortic arch configuration with the innominate artery, the left common carotid artery and the left
subclavian artery is seen in about 70% of patients
(Fig. 1.8). The most frequent variant is a common origin of the brachiocephalic and the left common carotid
arteries (a so-called bovine trunk).The second most frequent variation is a left vertebral artery, directly arising
from the aorta; other but less common (less than 1%)
variants are a common origin of both common carotid
arteries, the presence of two brachiocephalic arteries
Jos C. van den Berg Chapter 1 Radio-Anatomy of the Thoracic Aorta. 3D Imaging of the Aorta (CT, MRI and 3D Rotational Angiography)
https://t.me/med1917
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a
c
b
d
e
Fig. 1.6. a Axial CT; origin of the left hypertrophied left bronchial artery (arrow) in a patient
with aortic coarctation. b Axial CT; slice at a level below that in a demonstrating the subsequent course of the left bronchial artery. c Sagittal MPR; the course of the left bronchial artery (arrow), and the origin of an intercostal artery (arrowhead) can be clearly seen. d Sagittal oblique MPR demonstrating coarctation (arrowhead) at a typical location at the level of
the aortic isthmus.
cates the level of the origin of the left bronchial artery. (Courtesy of Richard G. McWilliams,
Liverpool, UK)
e Shaded surface display of the descending thoracic aorta; the arrow indi-
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c
and finally a separate origin of all four great vessels
[29].
The commonest malformation of the aortic arch is a
left aortic arch with an aberrant origin of the right subclavian artery (arteria lusoria) (Fig. 1.9). In this type of
malformation the right subclavian artery arises distally
from the left subclavian artery and the right and left
common carotid arteries. Another common anomaly is
the presence of a right aortic arch, in which the ascending thoracic aorta arches posteriorly to the right side of
trachea and esophagus (Fig. 1.10).
Vascular rings are characterized by encirclement of
the trachea and esophagus by the aortic arch and associated structures. Vascular rings are the result of an abnormal embryologic development of the paired fourth
Fig. 1.7. a Coronal MPR; aortic arch with main supra-aortic ar-
teries: innominate artery (curved arrow), left common carotid
artery (arrow) and left subclavian artery (arrowhead).
tal MPR; descending thoracic aorta (asterisk) with several intercostal arteries (arrowheads).
gin of the common intercostobronchial trunk (arrow) and bifurcation into the right bronchial artery and the intercostal artery (arrowhead)
c Curved reformatted MPR; ori-
b Sagit-
aortic arches, in which primitive aortic arches fail to
fuse or regress normally. Typically, each embryonic arch
gives rise to their respective common carotid artery
and subclavian artery. Normally the embryonic right
arch regresses, while the left aortic arch persists, resulting in a left-sided aortic arch and great vessels. When
the left embryonic arch regresses, the result is a right
aortic arch, while failure of either arch to regress results
in a double aortic arch. The commonest (symptomatic)
vascular rings are associated with a complete double
aortic arch, an incomplete double aortic arch with an
atretic portion, a left aortic arch with an aberrant right
subclavian artery (arteria lusoria, see before) and a
right aortic arch with an aberrant left subclavian artery
[11] (Fig. 1.11).
Jos C. van den Berg Chapter 1 Radio-Anatomy of the Thoracic Aorta. 3D Imaging of the Aorta (CT, MRI and 3D Rotational Angiography)
https://t.me/med1917
ab
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c
Fig. 1.8. a Axial CT in a patient with type A dissection; the inti-
mal flap is clearly seen (arrowhead).
patient at the level of the origin of the supra-aortic vessels
demonstrating the common origin of the innominate artery
and the left common carotid artery (bovine trunk; asterisk).
3D reconstructions of CT and MRI images can obviate the need for diagnostic angiography [13, 35]. Imaging studies should be evaluated for aortic position,
coarctation, vascular compression of airways, collateral
vessel formation and aortopulmonary shunts [6].
b Axial CT of the same
d
c Coronal MPR demonstrating the extent of the intimal flap
(arrow) with calcification; the flap is limited to the ascending
thoracic aorta.
(asterisk).
d Coronal MPR; bovine trunk clearly depicted
1.4.3 Aortic Coarctation
Aortic coarctation is one of the commonest congenital
cardiovascular lesions, defined as a congenital narrowing of the aorta characterized by stenosis of the juxtaductal aorta (i.e., at the ductus arteriosus just distal to
the origin of the left subclavian artery) [36]. 3D gadolinium-enhanced imaging is helpful in determining
coarctation severity by demonstrating collateral vessels
(e.g., intercostal and bronchial arteries), which are indi-
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ef
Fig. 1.8. e Sagittal oblique MPR demonstrating dilation of the
ascending thoracic aorta, the origin of the supra-aortic vessels
and aneurysmal changes in the descending thoracic aorta.
a
Fig. 1.9. a
tient with aneurysm of an aberrant right subclavian artery (asterisk). b 3D reconstruction; posterior view demonstrating the
extent of an aneurysm to advantage (arrowhead); origin of the
right subclavian artery on the posterior aspect of the aortic
arch (arrow). (Courtesy of Reinhard S. Pamler, Ulm, Germany)
Axial CT at the level of the aortic arch (arrow); pa-
f VRT image; depiction of the intimal flap (arrow) in the as-
cending thoracic aorta
b
Jos C. van den Berg Chapter 1 Radio-Anatomy of the Thoracic Aorta. 3D Imaging of the Aorta (CT, MRI and 3D Rotational Angiography)
https://t.me/med1917
ab
Fig. 1.10. a Axial CT; right-sided aortic arch (arrow); note the presence of the double superior caval vein (arrowheads). b Axial CT
at a lower level demonstrating the course of the descending thoracic aorta to the right side of the vertebral column (arrow)
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abc
Fig. 1.11. a 3D-RA; default reconstruction in a patient with a
double aortic arch; smaller ventral arch (arrowhead) and larger
posterior arch (arrow).
clearly depicting the separate origin of the left and right sub-
b 3D-RA; reconstructive zoom, more
cative of the hemodyamic significance of the lesion
[11], while black blood images can demonstrate location and length of the aortic narrowing [10].
clavian arteries and both common carotid arteries (absence of
innominate artery). c 3D-RA; true cranio-caudad view depicting the double arch to advantage
true lumen has a higher density/signal intensity than
the false lumen, owing to faster flow [11]. Delayed
phase imaging can be used to depict the false lumen
better [10]. The precise extent of an intimal flap and its
relationship to the arch vessels can be clearly defined
with customized reconstructions following the aortic
1.5 Acquired Aortic Disease
course and angioscopic views [1].
1.5.1 Dissection
1.5.2 Aneurysms
MRI and CTA are established techniques in the assessment of aortic dissection, and are able to classify dissection according to the De Bakey or Stanford classification [9] (Figs. 1.13, 1.14). Detection of the intimal flap
is best done using contrast-enhanced MRA or CTA [5].
High signal intensity/density within the false and
true lumina is a finding consistent with patency, and allows for visualization of the intimal flap; in general, the
Thoracic aortic aneurysms occur in up to 10% of elderly patients, and are most commonly atherosclerotic
in etiology (Figs. 1.15, 1.16). In the evaluation of aneurysms accurate depiction of aortic caliber, morphology,
relationship to aortic arch vessels and the presence of
thrombus or ulceration are of importance in deciding
whether and how to intervene.
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Fig. 1.12. a MRA; MIP reconstruction in a patient with a false aneurysm (asterisk) at the level of aortic coarctation (treated with
percutaneous balloon angioplasty in the past (arrow)). b MRA; MPR showing the distal extent of a false aeurysm (asterisk)
a
Fig. 1.13. a Axial CT at the level of the carina (asterisk) in a pa-
tient with widening of the descending thoracic aorta and an
intimal flap (arrowhead); type B dissection.
the same patient depicting a larger-diameter false lumen (aster-
isk) and a small-diameter true lumen (arrow); note the difference in the enhancement with higher density in the, high-flow,
true lumen
b Coronal MPR in
b
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