Drs. Angela Pikus, Alex Blackwell, Mark Baumgarten, Rosa Malloy-Post are Emergency Medicine Residents and interested in medical education. With the guidance of Dr. Michael Gibbs, a notable Professor of Emergency Medicine, they aim to help augment our understanding of emergent imaging. Follow along with the EMGuideWire.com team as they post these educational, self-guided radiology slides. This set will cover: • Abnormalities of the Thoracic Aorta o Traumatic aortic disruption o Thoracic aortic aneurysm with acute dissection

1. Adult Chest X-Rays Of The Month
Angela Pikus, MD, Mark Baumgarten, MD,
Alex Blackwell, MD, Rosa Malloy-Post, MD
Department of Emergency Medicine
Carolinas Medical Center & Levine Children’s Hospital
Michael Gibbs, MD - Faculty Editor
CMC Imaging Mastery Project
Presentation #46

2. Disclosures
 This ongoing imaging interpretation series is proudly sponsored by the
Emergency Medicine Residency Program at Carolinas Medical Center.
 The goal is to promote diagnostic imaging interpretation mastery.
 There is no personal health information [PHI] within, and all ages have
been changed to protect patient confidentiality.

3. Visit Our Website
www.EMGuidewire.com
For A Complete Archive Of Imaging Presentations And Much More!

4. Airway
Bones
Cardiac
Diaphragm
Effusion
Foreign body
Gastric
Hilum

5. It’s All About The Anatomy!

6. This Presentation Will Focus On Abnormalities Of The
Thoracic Aorta
Leonardo Da Vinci (1452-1591)

7. Chest X-Ray Imaging Of The Mediastinum
The common causes of an anterosuperior mediastinal masses can be
remembered by using the mnemonic “5 Ts.”
T: thymus
T: thyroid
T: thoracic aorta
T: terrible lymphoma
T: teratoma and germ cell tumors

8. Chest X-Ray Imaging Of The Mediastinum
1Marsh DG, Strum JT. Traumatic aortic rupture roentgenographic indications for angiography. Annals of Thoracic Surgery 1976; 21:337-340.
2Strum JT, Marsh DG, Kenton CB. Ruptured thoracic aorta: evolving radiological concepts. Surgery 1979; 85:363-367.
• The evaluation of mediastinal width and contour is important when
assessing the thoracic aorta.
• Studies done in the 1970’s suggested an upper limit of mediastinal
width of 8 cm – 8.8 cm.1,2
• The position of the patient and the X-ray projection may influence the
radiographic width and contour of the thoracic aorta.

9. Mediastinal Width
X-Ray
Source
Patient
Position
Apparent
Size
Detector
Magnification:
• Structures within the patient that are
closer to the X-ray source appear
enlarged (magnified) compared to
structures that are further away from the
source.
• Magnification is further exaggerated
when the X-ray source is close to the
patient, as with portable antero-posterior
(AP) chest X-rays.
Result:
Depending on patient position and the X-ray
projection, mediastinal structures may
appear enlarged.

10. Mediastinal Width
patient, often required when acquiring an AP image. This leads
to a more divergent beam to cover the same anatomical field.
As a rule of thumb, you should never consider the heart size to
be enlarged if the projection used is AP. If however the heart
size is normal on an AP view, then you can say it is not
enlarged.
Click image to align with top of page
AP v PA projection
The upper diagram shows an AP projection. Heart size
is exaggerated because the heart is relatively farther
from the detector, and also because the X-ray beam is
more divergent as the source is nearer the patient.
The lower diagram shows a conventional PA
projection. The apparent heart size is nearer to the
real size, as the heart is relatively nearer the detector.
Magnification of the heart is also minimised by use of a
narrower beam, produced by the increased distance
between the source and the patient.
AP v PA projection
Radiographers will often label a chest X-ray as either PA or AP.
If the image is not labelled, it is usually fair to assume it is a
AP v PA - Scapular edges

11. Rotation Effects
Is Rotation Present?
• Relative position of one
sternoclavicular joint compared
with the other
• Alignment of the transverse
processes relative to clavicles.
Transverse processes should be
equidistance from the clavicles
in an un-rotated patient
Possible Effects Of Rotation
• Apparent mediastinal widening
• Tracheal deviation
• Apparent increased thickness of
the paratracheal stripes
• Asymmetric lung densities

12. From: Gibbs MA. EM Critical Care 2011.

13. From: Gibbs MA. EM Critical Care 2011.

14. From: Gibbs MA. EM Critical Care 2011.

15. From: Gibbs MA. EM Critical Care 2011.

16. Case #1
68-Year-Old In A
High-Speed Car
Crash Complains Of
Chest And Upper
Abdominal Pain.
Initial ED Chest X-Ray

17. Case #1
68-Year-Old In A
High-Speed Car
Crash Complains Of
Chest And Upper
Abdominal Pain.
Initial ED Chest X-Ray
Even After Accounting For
Magnification And
Possible Rotation There Is
Mediastinal Widening

18. Case #1
68-Year-Old In A
High-Speed Car
Crash Complains Of
Chest And Upper
Abdominal Pain.
Diagnosis:
Blunt Aortic Injury
Initial Chest CT

19. 68-Year-Old In A High-Speed Car Crash Complains Of Chest And Upper Abdominal Pain.
Diagnosis: Blunt Aortic Injury
Aortic Transection & Contrast Extravasation (→) And Mediastinal Hematoma (*)
*
*

20. Aortic Injury Chest X-Ray Findings
1. Wide mediastinum (<8 cm)
2. Abnormal aortic contour
3. Loss of the aortopulmonary window
4. Tracheal deviation
5. Depressed left mainstem bronchus
6. Apical cap
7. Deviated nasogastric tube

21. Aortic Injury Chest X-Ray Findings
1. Wide mediastinum (<8 cm)
2. Abnormal aortic contour
3. Loss of the aortopulmonary window
4. Tracheal deviation
5. Depressed left mainstem bronchus
6. Apical cap
7. Deviated nasogastric tube

22. Aortic Injury Chest X-Ray Findings
1. Wide mediastinum (<8 cm)
2. Abnormal aortic contour
3. Loss of the aortopulmonary window
4. Tracheal deviation
5. Depressed left mainstem bronchus
6. Apical cap
7. Deviated nasogastric tube

23. Aortic Injury Chest X-Ray Findings
1. Wide mediastinum (<8 cm)
2. Abnormal aortic contour
3. Loss of the aortopulmonary window
4. Tracheal deviation
5. Depressed left mainstem bronchus
6. Apical cap
7. Deviated nasogastric tube

24. Aortic Injury Chest X-Ray Findings
1. Wide mediastinum (<8 cm)
2. Abnormal aortic contour
3. Loss of the aortopulmonary window
4. Tracheal deviation
5. Depressed left mainstem bronchus
6. Apical cap
7. Deviated nasogastric tube

25. Aortic Injury Chest X-Ray Findings
1. Wide mediastinum (<8 cm)
2. Abnormal aortic contour
3. Loss of the aortopulmonary window
4. Tracheal deviation
5. Depressed left mainstem bronchus
6. Apical cap
7. Deviated nasogastric tube

26. Aortic Injury Chest X-Ray Findings
1. Wide mediastinum (<8 cm)
2. Abnormal aortic contour
3. Loss of the aortopulmonary window
4. Tracheal deviation
5. Depressed left mainstem bronchus
6. Apical cap
7. Deviated nasogastric tube

27. Aortic Injury Chest X-Ray Findings
1. Wide mediastinum (<8 cm)
2. Abnormal aortic contour
3. Loss of the aortopulmonary window
4. Tracheal deviation
5. Depressed left mainstem bronchus
6. Apical cap
7. Deviated nasogastric tube

28. Blunt Aortic Injury
Cases From Carolinas Medical Center

29. 32-Year-Old Male Involved In A High-Speed Car Crash

30. 32-Year-Old Male Involved In A High-Speed Car Crash
Tracheal
Deviation
Wide
Mediastinum
Loss Of The
Aortopulmonary
Window

31. 32-Year-Old Male Involved In A High-Speed Car Crash
Aortic
Disruption

32. 32-Year-Old Male Involved In A High-Speed Car Crash
Aortic
Endograph

33. 22-Year-Old Male Involved In A Head-On Car Crash

34. 22-Year-Old Male Involved In A Head-On Car Crash
Tracheal
Deviation
Wide
Mediastinum

35. 22-Year-Old Male Involved In A Head-On Car Crash
Aortic
Disruption

36. 22-Year-Old Male Involved In A Head-On Car Crash
Aortic
Endograph

37. 21-Year-Old On A Motorcycle Collided Head-On With A Car
www.EMGuirewire.com

38. 21-Year-Old On A Motorcycle Collided Head-On With A Car
www.EMGuirewire.com
Traumatic Aortic Disruption

39. Aortic Endograph (→)
21-Year-Old On A Motorcycle Collided Head-On With A Car
www.EMGuirewire.com

40. Proposed
Mechanisms
Of Blunt
Aortic Injury

41. www.mdcalc.com

42. Patients Enrolled 9905
Thoracic Injury 1478 (14%)
Thoracic Injuries
• Pneumothorax
• Hemothorax
• Aortic or great vessel injury
• 2 or more rib fractures
• Ruptured diaphragm
• Sternal fracture
• Pulmonary contusion
When all 7 criteria were absent
the negative predictive value for
thoracic was 99.9%.

43. Methods
• Review of the NEXUS Chest dataset from 10 Trauma Centers to describe: (1) the incidence of aortic injury, (2) the
screening value of traditional risk factors/markers (e.g.: high-risk mechanism and wide mediastinum on CXR)
compared with the NEXUS Chest Decision Instrument.
• Subjects: (1) >14 years-old, (2) within 6 hours of blunt trauma, (3) CXR and/or CT at provider discretion.
Academic Emergency Medicine 2020; 27(4):291-296.

44. Results
• Of 24,010 enrolled subjects, 42 (0.17%, 95% [CI] = 0.13% - 0.24%) had aortic injury
• 79% of patients had associated thoracic injuries: rib fractures, pneumothorax/hemothorax,
pulmonary contusions
Academic Emergency Medicine 2020; 27(4):291-296.
Sensitivity
High-Energy Mechanism1 76% (95% CI: 62% to 87%)
Wide Mediastinum On Chest X-Ray 33% (95% CI: 21% to 49%)
NEXUS Decision Instrument 100% (95% CI: 92% to 100%)
1Fall >20 feet, motor vehicle crash > 40 mph, pedestrian stuck by a motorized vehicle.

45. Case #2
57-Year-Old With
Sudden Chest And
Back Pain While
Working
Construction.
ED Vitals:
HR 87 BP,
156/110,
Afebrile, Sa02
95%
Initial ED Chest X-Ray

46. Enlargement & Tortuosity Of The Descending Thoracic Aorta (→)

47. 57-Year-Old With Sudden Chest And Back Pain While Working Construction.
Dissection Flaps (→) And Mediastinal Hematoma (*)
*
*
*
*

48. Descending Thoracic Aneurysm With Dissection Flaps (→) And Prior Aortic Stenting (☐)

49. A Thoracic Aneurysm And
Acute Aortic Dissection
Extends Distally To Just
Above A Previously Placed
Endovascular Abdominal
Aortic Stent.
The Patient Was Taken To
The Operating Room For
Immediate Endovascular
Repair.

50. Case #2
57-Year-Old With
Sudden Chest And
Back Pain While
Working
Construction.
Diagnosis:
Thoraco-
abdominal Aortic
Aneurysm With
Dissection.
Post-Op Chest X-Ray
Aortic
Endograph

51. Case #2
57-Year-Old With
Sudden Chest And
Back Pain While
Working
Construction.
Diagnosis:
Thoraco-
abdominal Aortic
Aneurysm With
Dissection.
Post-Op Day #7
Left Pleural
Effusion

52. Case #2
57-Year-Old With
Sudden Chest And
Back Pain While
Working
Construction.
Diagnosis:
Thoraco-
abdominal Aortic
Aneurysm With
Dissection.
Post-Op Day #8
Pigtail
Chest Drain

53. Case #2
57-Year-Old With
Sudden Chest And
Back Pain While
Working
Construction.
Diagnosis:
Thoraco-
abdominal Aortic
Aneurysm With
Dissection.
Post-Op Day #14
Patent Celiac + SMA (→) Patent Right Renal (→)

54. Thoracic Aneurysm
Cases From Carolinas Medical Center

55. 65-Year-Old With No Prior Healthcare Assess Presents With Chest & Back Pain

56. Thoracic Aortic Aneurysm
Clotted
Aneurysmal
Sac

57. Proximal Aortic Arch Endovascular Stent

58. Healthy 26-Year-Old
Male Presents To
The Emergency
Department With
Two Days Of Chest
Pain.
www.EMGuidewire.com
November 2021 Emergency Department Chest X-Ray

59. An ECHO Reveals A Dilated Aortic Root And A Chest CT Is Then Ordered.
Maximal Diameter Of 93.7 mm
www.EMGuidewire.com
November 2021

60. Reconstructed CT Images
www.EMGuidewire.com
November 2021

61. Let’s Take Another Look At The ED Chest X-Ray
www.EMGuidewire.com
November 2021

62. Fullness Along The Right Mediastinal Boarder
www.EMGuidewire.com
November 2021

63. Aneurysm In Situ Aneurysm Resection Graft Placement
Images Courtesy Of: Marriane Dannemiller, PA
www.EMGuidewire.com
November 2021

64. Narrowing Of Mediastinal Width After Surgery
ED Chest X-Ray Post-Op Chest X-Ray
www.EMGuidewire.com
November 2021

67. Once A Thoracic
Aneurysm Reaches A
Diameter Of 6 cm The
Risk Of Complications
Increases Dramatically!

70. Acute Aortic Dissection
Cases From Carolinas Medical Center

71. 36-Year-Old With Acute Chest And Back Pain With Leg Numbness
ED CXR Prior CXR

72. 36-Year-Old With Acute Chest And Back Pain With Leg Numbness
ED CXR Prior CXR

73. Type A Aortic Dissection Extending Into The Abdomen
36-Year-Old With Acute Chest And Back Pain With Leg Numbness

74. Endovascular Stent Graft Repair
36-Year-Old With Acute Chest And Back Pain With Leg Numbness

75. ED CXR Prior CXR
44-Year-Old With Hypertension With Chest And Abdominal Pain

76. ED CXR Prior CXR
44-Year-Old With Hypertension With Chest And Abdominal Pain

77. Type A Aortic Dissection
44-Year-Old With Hypertension With Chest And Abdominal Pain

78. Type A Aortic Dissection – Evidence Of Hemopericardium (*)
*
*
*
*
44-Year-Old With Hypertension With Chest And Abdominal Pain

79. 69-year-Old With 5 Days Of Vague Chest And Abdominal Pain

80. 69-year-Old With 5 Days Of Vague Chest And Abdominal Pain
Eggshell
Sign
The Eggshell Sign
Represents Intimal
Calcium “Pushed Away”
From The Aortic Wall By
An Aortic Dissection.

81. Type B Aortic Dissection
44-Year-Old With Hypertension With Chest And Abdominal Pain

82. Stanford Type B
Does Not Involve The
Ascending Aorta
Stanford Type A
Involves The
Ascending Aorta

84. Demographics
Type A 67%
Type B 33%
Risk Factors
Hypertension 77%
Atherosclerosis 27%
Known aneurysm 16%
Cardiac surgery 16%
Marfan syndrome 5%
Iatrogenic 4%
Cocaine use 2%
66% of patients were male
The mean age was 63 years

85. Pain1 reported in 93.7%:
A B
Chest pain 79% 63%
Back pain 43% 64%
HPTN on presentation 36% 70%
Pulse deficit 30% 20%
Syncope2 19%
1,2Painless AAD and patients presenting with syncope had
a higher risk of death.
A = Type A Dissection
B = Type B Dissection
Clinical Manifestations

86. Comprehensive English language MEDLINE literature review from 1966 to 2000.
Thirteen studies permitted the analysis of 1337 chest X-rays.
 90% of patient with aortic dissection had at least one CXR abnormal finding
 The absence of a wide mediastinum had a [-] LR of 0.3 (95% CI: 0.2 – 0.4)

87. Evidence-based review of nine studies between 1986 and 2013 [n=2,400]
The absence of a wide mediastinum on CXR had a negative likelihood ratio
ranging from 0.14 to 0.60, making this a finding that decreases the risk of
aortic dissection
Annals of Emergency Medicine 2018; 73(4):400-402.
What Signs Increase the Likelihood of Acute Aortic Dissection?

88. Our Final Case Reminds Us That While Abnormal Chest X-Rays Provide
Important Clues, A “Normal” Chest X- Ray” Should Not Be Used Alone
To Rule Out Acute Aortic Dissection In High-Risk Patients.

89. A Recent Case
A 36-Year-Old In
Good Health
Presents With
Acute, Constant,
Non-Migratory,
Central Chest Pain.
BP 168/52, HR 75
“Uncomfortable”
“Diaphoretic”
Heart exam normal
Lung exam normal
Pulses normal

90. A Healthy 36-Year-Old With Acute Onset And Constant Retrosternal Chest Pain.
Radiology Report
“No acute findings. The cardio-mediastinal silhouette is within normal limits.”

91. Laboratory Data
• Normal CBC
• Normal electrolytes
• Normal renal function
• HS Troponin <6 ng/L x2
Radiology Report
“No acute findings. The cardio-mediastinal
silhouette is within normal limits.”
ED Cardiac POCUS
No pericardial effusion, no LV dysfunction,
RV not dilated.
Because Of The Nature Of The Patient’s Pain And The Fact That It Persisted Despite
Nitroglycerin And Morphine, A Chest CT Was Ordered.

92. Using The Aortic Dissection Risk Score, The Presence of
“Any High Risk Pain Feature” Would Yield A Score of +1 And
Suggest That A Work-Up For Aortic Dissection Is Indicated.

93. Type A Dissection Extending To Both Iliac Arteries
Ascending Aorta Aortic Arch Iliac Bifurcation
A Healthy 36-Year-Old With Acute Onset And Constant Retrosternal Chest Pain.

94. A Healthy 36-Year-Old With Acute Onset And Constant Retrosternal Chest Pain.

95. Diagnoses This Month
• Traumatic aortic disruption
• Thoracic aortic aneurysm with acute dissection

96. Visit Our Website
www.EMGuidewire.com
For A Complete Archive Of Imaging Presentations

97. See You Next Month!