Radiological description of the Abdominal aorta and its branches

1. Radiological anatomy of the
abdominal aorta and its major
branches.
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2. outline
Introduction
Radiological anatomy
Imaging modalities
Conclusion
References
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3. Introduction
 Continuation of thoracic
aorta at diaphragmatic
hiatus(12th thoracic
vertebra)
 It is 12cm long,2-3cm wide
 It lies anterior to T12/l1 to l4
vertebrae
 Accompanied by the
thoracic duct, azygous and
hemi-azygous vein, the
sympathetic trunk and
splanchnic nerve.
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4. Relations
 the diaphragmatic crura
enveloped the anteriolateral
surface of the abdominal
aorta at the hiatus.
Posteriorly
 it lies along the anterior
aspect of the lumbar
vertebrae slightly to the left
and closed to the left psoas
muscle
 The left lumbar veins passes
posterior to abdominal aorta
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5. Relations
• IVC lies right to it
Anteriorly
• splenic vein and
body of pancreas,
left renal vein,3rd
part of the
duodenum.
Posterior
• left psoas, left
lumbar vein
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6. Branches of the abdominal aorta seen on
angiogram
as follows:
• Three unpaired anterior branches:
Coeliac trunk at T12/L1
Superior mesenteric artery at L1
Inferior mesenteric artery at L3
• Three lateral paired visceral arteries:
Adrenal arteries at L1
Renal arteries at L1/L2
Gonadal arteries at L3
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7. Cont’d
• Five lateral paired parietal branches:
Inferior phrenic arteries at T12
Four pairs of lumbar arteries
• Terminal arteries:
The common iliac arteries
Median sacral artery.
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9. Radiological anatomy of abdominal aorta
and its major branches
 The following imaging modalities are used for demonstrating
the abdominal aorta and it major branches:
 Ultrasonography
 Angiography
 Computed tomography(CT) and CT angiography
 Magnetic resonance imaging(MRI)
 MRI angiography
 Radionuclide imaging(RN)/ RN angiography
 Plain radiograph
Others not routinely used includes:
Intravascular ultrasonography
ANGIOSCOPY
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10. Ultrasonography
It is a non-invasive imaging modality
Cheap and readily available
Does not use ionizing radiation
Abdominal aorta is visualized posterior to
the pancreas, where coeliac and superior
mesenteric arteries are easily seen
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11. Pulsatile hypo echoic tubular structure with
brightly echogenic wall anterior to the
spine on longitudinal scan.
On transverse scan it is seen as a
rounded hypo echoic structure with
echogenic wall.
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12. Abdominal Aorta
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13. Long. Scan demonstrating the abd. Aorta
and it branch
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14. Transverse scan
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15. Doppler ultrasound of the Aorta
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• Sharp increase
antegrade flow velocity
followed
• Rapid decrease that
bottoms out in early
diastole with a brief
period of reversed flow.
• Low velocity
antegrade flow then
resumes and continue
for the rremainder of
diastole.

16. coeliac trunk and branches on ultrasound
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17. 17

18. coeliac trunk
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19. splenic artery
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22. Intravenous Ultrasonography
• Uses IVUS catheters with silicon PEC of
20-40mhz.
• Reflected sound wavs visualizes the
arterial wall in 2D, tomographic format,
• analogous to the histologic cross section
• Can be Diagnostic or Interventional
procedures
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24. Angiography
Contrast investigation of the aorta and it
branches
It is an invasive procedure
It uses ionizing radiation
The aorta and its branches are seen as
tubular branching structures with reduction in
caliber from above downward.
All major branches of the aorta are
demonstrable on angiograpic films
The branches are:
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25. Computed tomography and CT angiography
 Both axial and coronal images can demonstrate the
abdominal aorta either on plain or post contrast study
 With CT angiography tiny branches of the abdominal aorta
can be demonstrated
 Axial CT demonstrate the axial relations of the abdominal
aorta, it branches to other abdominal structures
 On pre-contrast slices it is seen as a well circumscribed
hypodense structure anterior to the lumber vertebrae and to
the left of midline .
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26.  The aorta is seen posterior to the pancreas
 The major branches of the aorta are seen supplying the
accompany structures
e.g. renal arteries are traced to the kidneys, spleenic
artery is traced to the spleen
CT angiography, digital subtraction angiography can
demonstrate the abdominal aorta and it major branches.
They are seen as hyperdense tubular branching
structures.
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27. CT at supra renal level demonstrating abd.
Aorta and it branches
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28. Sketch of ct at supra renal level
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29. coeliac trunk
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30. Renal Artery
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31. SMA
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32. Inferior Mesenteric Artery
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33. CT at level of kidneys
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34. Magnetic resonance imaging and MRI
angiography
It is non invasive method of demonstrating
abd. Aorta and its branches
Has the advantage of demonstrating the
vessel without the use of contrast
Non ionizing technique
It is expensive and not readily available in
this environment
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35. On T1WI and T2WI flowing blood
produces a signal void thus, appear black
But by using time-of-flight and phase
contrast fast gradient echo sequence they
produce high signal thus appears white.
And the aorta and it major branches are
demonstrated
Anterior branches are demonstrated on on
sagittal views while, the lateral branches
best seen on a plane parallel to their
course.
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37. Radionuclide imaging
Though no longer perform but can be use
to demonstrate abdominal aorta and it
major branches.
It is expensive and uses ionizing radiation
 Done by injection of radiopharmaceuticals
into the artery and activity measured by
gamma camera.
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38. Plain films
 Uses ionizing radiation
though cheap and
readily available
 The abd. Aorta and its
major branches are not
demonstrable on plain
radiograph except if
calcified
 if calcified, It is then
seen as linear
calcification vertically in
the midline and to the
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39. Tortuosity of the aorta in the elderly may
cause considerable variation in the site of
this calcification.
Proximity of the vertebral bodies may lead
to bony erosion by aneurysms of the aorta,
which may be detectable on radiographs.
Bony erosions of the anterior vertebral
bodies are seen in aneurysms of the
abdominal aorta causing Scalloping
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40. others
• Not routinely used includes:
Angioscopy
Elastography
Optical Coherence Tomography
Intravascular Nuclear Imaging
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41. References
• Weirs imaging anatomy Atlas
• Anatomy of Diagnostic Imaging by Ryan.
• Online sources; Slideshare, Radiopedia.
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42. .
• Thank you for your attention and time
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