Multimodality Imaging of

Diseases of Thoracic Aorta

Steven Goldstein MD, FACCDirector Noninvasive CardiologyMedStar Heart InstituteWashington Hospital CenterSunday, October 9, 2016

DISCLOSURE

I have N O relevant financial relationships

J Am Soc Echocardiogr 2015;28:119-82

GUIDELINES AND STANDARDS

asecho.org Guidelineswww.

Multimodality Imaging of the AortaSpecial Features (“unique”)

1. Uniform protocol for measuring aorta

2. Variability of measurements (what

3. Firstline, secondary tests for each entity

represents real change: 2, 3, 4, 5 mm ?)

Leading edge to leading edgeInner-to-innerOuter-to-outer

continued . . .

Measuring The Aorta

Measure perpendicular to the long-axis of the aorta

Imaging Modalities

Imaging Techniques• Chest X-ray• Echo (TTE, TEE, 3D-echo, epiaortic)• Intravascular echo (IVUS)• Intracardiac echo (ICE)• CT/MDCT• Magnetic resonance imaging• Aortography

Imaging Techniques• Chest X-ray

• Echo (TTE, TEE, 3D-echo, epiaortic)• Intravascular echo (IVUS)• Intracardiac echo (ICE)

• CT/MDCT• Magnetic resonance imaging• Aortography

Diseases of

Thoracic Aorta

Diseases of the Thoracic Aorta• Acute aortic syndromes

• Thoracic aortic aneurysms

continued . . .

- Aortic dissection- Intramural hematoma- Penetrating aortic ulcer- Ruptured aortic aneurysm

- Bicuspid aortic valve-related aortopathy- Marfan syndrome- Other genetic diseases

(Ehlers-Danlos; Loeys-Dietz, Turner syndrome,etc)

Diseases of the Thoracic Aorta

• Traumatic injury of thoracic aorta

• Aortic coarctation

• Atherosclerosis

• Aortitis- Noninfectious- Infectious

Acute AorticSyndromes

Acute Aortic Syndromes

• Aortic dissection

• Intramural hematoma

• Penetrating aortic ulcer

• Ruptured aortic aneurysm

Acute Aortic Syndromes

• Delay in recognition and treatment isassociated with unacceptable increase in mortality

• Signs and symptoms may be subtle/atypical

• Diagnosis requires high index of suspicion

AorticDissection

Tear

Aortic Dissection

AdventitiaMediaIntima

Tear

BloodTrue Lumen

False Lumen

Aortic Dissection - ImagingPrimary Objectives

• Identify entry site• Determine type A vs B• Involvement of coronary arteries ?• Identify complications:

• Presence, severity, mechanism of AR• Pericardial or pleural effusion• Rupture ?• Branch ischemia

aortic dissection

Imaging Modalities for Aortic Dissection

• Initial test in >70% of patients (IRAD)

• Widely available, quickest diagnostic times

• Very high diagnostic accuracy

• Relatively operator independent

• Allows evaluation of entire aorta

CT-Scan

(including arch vessels, mesenteric vessels, and renal arteries)

CT-Scan for Aortic Dissection

• Ionizing radiation exposure

• Requires iodinated contrast material

• Pulsation artifact in ascending aorta

Disadvantages

(can be improved with ECG gating)

Imaging Modalities for Aortic Dissection

• Very high diagnostic accuracy• Widely available, portable, convenient, fast• Excellent for:

• Can detect involvement of coronary arteries• Safely performed on critically ill patients• Optimal procedure for guidance in OR

TEE

- Pericardial effusion- Presence, degree, mechanism of AR- L V function

Author Year n WithDiss'n

ErbelHashimotoAdachiBallalSimonNienaber

198919891991199219921993

16422456132

110

822245342844

Sens Spec

99%100%98%97%

100%98%

98%N/AN/A

100%100%77%

Totals 99% 94%655 376Kang 1998 200 100 100% 91%

Detection of Aortic DissectionAccuracy of TEE

TEE for Aortic Dissection

• Depends on skill of operator

• “Blind spot” upper ascending aorta

• Not reliable for cerebral vessels,

• Semi-invasive

• Reverberation artifacts (rarely a problem)

Disadvantages

mesenteric vessels, renal arteries

Imaging Modalities for Aortic Dissection

• Very high diagnostic accuracy

• 3D multiplanar and high resolution

• Does not require ionizing radiation or

• Appropriate for serial imaging over many years

MRI

iodinated contrast material

MRI for Aortic Dissection

• Less widely available• Difficult monitoring critically ill patients• Longer examination time• Not feasible in emergent of unstable

• Caution with use of gadolinium in

Disadvantages

clinical situations

renal failure

Spiral CT

MRI

TEE

Sensitivity Specificity Time

100% 100%

100%

100%

94%

94%

28 min

27 min

45 min

Diagnosis of Aortic DissectionComparative Study of Spiral CT, MRI, TEE

49 suspected aortic dissection25 had dissection (18 type A; 7 type B)

Sommer Radiology 199:347(1996)

Aortic Dissection2D-Echo Findings

• .

• Double-channel aorta (TL and FL)

• Dilated aorta (usual)

• Re-entry sites (ostia of intercostals)

• “Cobwebs” (false lumen)

• Aortic insufficiency

• Pericardial and/or pleural effusion

Hallmark: dissection flap

LA

TL

FL

TEE CT-scan

Descending Thoracic Aorta

CT-scan TEE

Aortic Arch

Aortic RegurgitationMechanisms of Aortic Regurgitation

• Dilatation of aortic root leading to

• Cusp prolapse• Disruption of aortic annular support

• Invagination of dissection flap through

• Pre-existing aortic valve disease (eg,Bic AoV)

incomplete aortic leaflet copatation

resulting in flail leaflet

the aortic valve in diastole

Mechanisms of Aortic RegurgitationA B

C

Case 1

Case 2

Intramural Hematoma

“Atypical" Aortic Dissection

TL

FL

Typical"Atypical"

= Dissection flap and false lumen= No dissection flap; Medial hematoma

(Intramural Hematoma)

"Atypical" Aortic Dissection(Intramural Hematoma)

• Prevalence 10-20% in CT/MRI/TEE studies

• Type III more common

• Normal size lumen

• False negative aortograms

Totals 17%289/1,687

Note: Often missed by aortogram which is a luminogram

Intramural HematomaImaging Features

• Focal aortic wall thickening• Preserved luminal shape with a smooth

• Absence of dissection flap and false lumen• Echolucent regions may be present in the

luminal border

aortic wall

Intramural Hematoma

Intramural HematomaCT-scan

MRI

Intramural Hematoma

Case 3

Case 4RM - 46 year old manKnown bicuspid aortic valveS/P coarct repair (remote)Sudden onset of severe chest painSyncope

Summary

• Advances in imaging techniques have

• Indications for specific modality depends on:

• TTE used most often for aortic root assessment

greatly increased our understanding of thoracic aortic diseases

- Accuracy for specific diseases- Availability- Cost/benefit ratio

continued . . .

Summary

• CT-scan high resolution of entire aorta

• MRI greatest morphologic and dynamic

• TEE optimal procedure for guidance in OR

information without radiation, but lesswidely available

including arch, mesenteric, and renal vessels

safely performed on critically ill patients, even those on ventilators