1. ACQUIRED AORTIC ABNORMALITIES
Hidayatullah Hamidi
Fourth Year Radiology Resident
FMIC, Kabul, May 2016

2. کسی که خوب فکر می کند لازم نیست زیاد فکر کند

3. Pre Presentation Self Assessment
What is Acute aortic syndrome?
Which site of aorta is more prone to laceration in traumatic injury
What is the aim of performing CT in a sonographically detected AAA
How to DDx true Vs False lumen in aortic dissection?
What is Mid aortic syndrome

4. Traumatic aortic injury (TAI)1
Traumatic aortic injury (TAI)
Site
Blunt or penetrating injury
80–90%: Complete rupture →immediate death.
Half of %: Adventitia is intact (False aneurysm)
Severity: Intimal haemorrhage/Laceration, Medial laceration Complete laceration, False aneurysm, Peri-aortic haemorrhage.
Image:

5. Imaging: Radiographic findings
Based on presence of mediastinal hematoma
Widening of mediastinum: 92.7%
Mediastinal width (at level of aortic arch): >8 cm
M/C ratio (at level of aortic arch): >¼
M/C ratio: >1/4
Widening of right paratracheal stripe

6. Imaging: Thoracic aortography
Intimal flap
Dissection: linear filling defect
Pseudoaneurysm: Discontinuity/irregularity of aortic contour
Luminal filling defect: Thrombus formation
Pseudoaneurysm at aortic concavity just distal to arch
Linear lucency traversing the aortic lumen

7. Imaging: CT Angiography
Depicts direct and indirect signs
Intimal flap
Pseudoaneurysm
Mediastinal haemorrhage

8. Acute Aortic Syndrome (AAS)
Three closely related emergency entities
Aortic Dissection (AD)
Intramural Hematoma (IMH)
Penetrating Atherosclerotic Ulcer (PAU)
Clinically indistinguishable but CT
initial diagnosis
Differentiation
Disease staging

10. 2 Aortic dissection Non-traumatic acute aortic emergency
Unknown etiology but related to advancing age and hypertension.
Classic dissection: Intimal tear →Blood splitting the medial layer.
False lumen separated from true by an intimomedial flap.
Less elasticity of false lumen wall → aneurysmal dilatation.

11. Classification
To decide for surgical Vs medical treatment

12. Imaging purpose:
Establish diagnosis, define extent, identify true and false lumens, assess for presence of complications
Type A Intimal flap in arch Type B: Entry point distal to left SCA

13. Abdominal Aortic dissection
Collapse of true lumen.
The coeliac axis, SMA and RRA arise from the true lumen.
LRA arises from the false lumen
Acute type B dissection in patient with mesenteric ischemia

14. True Vs False lumen True False
Surrounded by calcifications (if present)
Smaller than false lumen
Usually origin of celiac trunk, SMA and RRA
Flow or occluded by thrombus (chronic).
Delayed enhancement
Wedges around true lumen (beak-sign)
Larger than true lumen
Circular configuration
Outer curve of the arch
Usually origin of LRA

15. 3 Intramural Hematoma What the clinician needs to know Type A or B
Predictors of mortality:  - Ascending Aorta > 5 cm - IMH thickness > 2 cm - Pericardial effusion
IMH may persist or evolve into aneurysm or PAU
Associated PAU - worse prognostic outcome

16. Penetrating Atherosclerotic Ulcer4
Penetrating Atherosclerotic Ulcer
Ulceration of an atheromatous plaque that has eroded the inner elastic layer of the aortic wall. It has reached the media and produced a hematoma within the media.
What the clinician needs to know
Type A or Type B
Single or multiple
Associated IMH

17. Imaging features
Extensive atherosclerosis + intima calcifications/atherosclerotic plaques
Focally displaced and separated intima calcifications
Contrast extravasation
Focal IMH,

18. AD & PAU
Contrast tracking into aortic wall outside the confines of the normal lumen.
Penetrating atherosclerotic ulcer.
Aortic wall thickening due to intramural haematoma.

19. Inflammatory diseases and mid aortic syndrome5
Inflammatory diseases and mid aortic syndrome
Granulomatous vasculitis (Takayasu's disease): Chronic inflammatory disease of aorta, branch & PAs.
Mid aortic syndrome: Segmental narrowing of proximal abdominal aorta and ostial stenosis of major branches
Narrowing of Celiac trunk and abdominal aorta
20Y, F: Thickening of all layers of descending aortic. Elevated ESR, Dx: Takayasu's disease

20. 6
Aortic aneurysms
Characterized by degeneration and remodelling of aortic wall.
Commonly atherosclerotic, but also result from trauma, infection, syndromes
Commonly affects the aortic root, ascending aorta and arch.

21. Atherosclerotic aortic aneurysms7
Atherosclerotic aortic aneurysms
95% affect the abdominal rather than the thoracic aorta.
Natural history: Progressive remodelling, expansion and eventual rupture.

22. Aim of CT evaluation AP and transverse size of AAA.
Diameter of aorta at levels of and just below visceral arteries
Length of aneurysm neck from lowest RA
Shape of neck; conical
Angulation of the neck in AP and lateral planes
Presence of excessive atheroma in the neck
Any accessory RAs
Distance from lowest RA to aortic bifurcation.
Tortuosity and degree of calcification of iliac arteries.
Diameter of the common iliac arties

23. References

24. Post Presentation EvaluationDx
Type
True Vs False
Clues

25. Collageneous media-remnants (cobwebs sign)

26. Dx
Type
True Vs False
Clues

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