The Normal Alveolus with an
Intra-alveolar Macrophage to Police the Alveolus
The diagram shows the lining of the normal alveolus composed of type 1 pneumocyte squamous in nature and the cuboidal cell (type pneumocyte) which rest on a lamina propria, and basement membrane (not shown) shared with the inner endothelial layer of the capillary. Intra-alveolar macrophage lies within the alveolar lumen
Ashley Davidoff
TheCommonVein.net
Lung Injury
Infection Inflammation or Toxic Injury
Diagram shows inflammation (red ) in the walls of the alveoli. The increased density in the interalveolar septa results in a ground glass opacity on T scan
Ashley Davidoff TheCommonVein.net
lungs-0736b
Diagram shows inflammation (red ) in the walls of the alveoli. The increased density in the interalveolar septa results in a ground glass opacity on T scan
Ashley Davidoff TheCommonVein.net
lungs-0736
Within the Alveolus
Basic Cellular Response
Neutrophil Mediated Inflammation
Neutrophils predominate in the first 6 to 24 hours
Monocytes predominate in 24-48 hours
Exudative (acute) phase: 1 – 7 days
Ashley Davidoff MD TheCommonVein.net lungs-0698d
Acute Inflammatory Activity in the Alveolus
Cellular Response,
Hyperemia, Edema and Exudation
The initial injury results in an acute severe inflammatory response consisting hyperemia , edema with migration initially of neutrophils in the first 6-24 hours followed by monocytes (24-48 hours). The intra -alveolar macrophages are activated.
Ashley Davidoff TheCommonVein.net
Types of Fluid Accumulations in
Acute Inflammatory or Infectious Diseases
The acute inflammatory process results in fluid exudation into the alveoli which can take the form of a serous transudate, and exudate or in the form of mucus, and when severe (eg ARDS) can result in tissue and vessel destruction and could be be blood tinged. Infected fluid could be mucoid or purulent. The extent of filling the alveoli results either in a ground glass appearance when partially filled or a consolidation when filled.
Ashley DAvidoff MD TheCommonVein.net
lungs-0701d- lo res
Radiology of Fluid in the Alveoli
An air filled alveolus appears as black, a fluid filled alveolus appears as white and a a half filled alveolus appears as gray
Ashley Davidoff MD TheCommonvein.net lungs-00688b
Presenting as Ground Glass Infiltrates
The Alveolus is
Half Filled
Inflammatory fluids half fill the alveolus and will therefore result in ground Glass Infiltrates
Ashley Davidoff MD TheCommonVein.net
lungs-0703d
Imaging Features
The CT scan confirms the presence of confluent extensive ground glass change in the superior segment of the right lower lobe and bilateral, nodular, and peripheral ground glass and opacification in the lower lobes. These findings are consistent with but not diagnostic with the diagnosis of COVID 19. Differential diagnosis however includes other viral pneumonias, allergic alveolitis and other multifocal and organizing pneumonias.
8months later
53F ARDS
Diffuse Ground Glass Pattern
Ashley Davidoff
TheCommonVein.net
134262
Types of Fluid Accumulations Presenting Consolidative Infiltrates
The Alveolus is Totally Filled
Ashley Davidoff MD TheCommonVein.net
lungs-0705d- lo res
CXR
diffuse coarse reticular opacities
does not imply irreversible fibrosis,
opacities may resolve
Diffuse Ground Glass Pattern
Ashley Davidoff
TheCommonVein.net
Diffuse Ground Glass Pattern
Bibasilar Infiltrates
Ashley Davidoff
TheCommonVein.net 134245
8months later
53F ARDS
Diffuse Ground Glass Pattern Ashley Davidoff TheCommonVein.net
134262
Post MVA 58M
Acute Exudative Phase
Diffuse Ground Glass Pattern
Post MVA
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TheCommonVein.net 134269
58M Diffuse Ground Glass Pattern Peribronchovascular Infiltrates
Focal Consolidation and Effusion Post MVA
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58M Post MVA 3rd Spacing in the Subcutaneous Tissue
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Post MVA 12 Days Later
12 Days later Still Intubated
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12 Days later Improved Diffuse Ground Glass Pattern
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12 Days later Improved Diffuse Improved subcutaneous 3rd spacing of fluids
Organized collection in the LUQ
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ARDS – Dominant Central Distribution with Relative Lower Lobe Subpleural Sparing
2 Weeks Earlier
79M 2 weeks earlier Cardiomegaly CHF with interstitial edema and complex left effusion
Ashley Davidoff TheCommonVein.net 134304a
2 Weeks Later
79M Patchy Diffuse Ground Glass Pattern Dominant – Central Location
Relative Lower Lobes and Subpleural Sparing
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79M Patchy Diffuse Ground Glass Pattern Dominant – Central Location
Relative Lower Lobes and Subpleural Sparing
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79M
Patchy Diffuse Ground Glass Pattern
Dominant – Central Location
Relative Lower Lobes and Subpleural Sparing
Ashley Davidoff
TheCommonVein.net
134300
79M
Patchy Diffuse Ground Glass Pattern
Dominant – Central Location
Relative Lower Lobes and Subpleural Sparing
Ashley Davidoff
TheCommonVein.net
134301
Ground Glass Pattern with Patchy Infiltrates
54 year old female with acute respiratory distress syndrome
ARDS-54-f001
54 year old female with acute respiratory distress syndrome
Ashley Davidoff MD thecommonvein.net ARDS 54 f002
54 year old female with acute respiratory distress syndrome
Ashley Davidoff MD thecommonvein.net ARDS 54 f003
AIP ARDS Immunotherapy Toxicity
Pneumonitis in a 65-year-old man with diffuse large B-cell lymphoma after three cycles of rituximab with cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone (R-CHOP) therapy who presented with new shortness of breath. Axial CT image shows bilateral diffuse GGOs and areas of consolidation in both lungs, with traction bronchiectasis and loss of lung volumes. The findings reflect an AIP/ARDS pattern of pneumonitis related to rituximab. Bilateral pleural effusions were also present. The patient?s condition significantly deteriorated, and he died 1 month after presentation. Autopsy results showed diffuse alveolar damage in the lungs.
Nishino, M et al Thoracic Complications of Precision Cancer Therapies: A Practical Guide for Radiologists in the New Era of Cancer Care RadioGraphicsVol. 37, No. 5
Diffuse Ground Glass ARDS vs Atypical Pneumonia
43F Diffuse Ground Glass Pattern
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43F Diffuse Ground Glass Pattern Mosaic Attenuation
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43F Diffuse Ground Glass Pattern Mosaic Attenuation
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43F Diffuse Ground Glass Pattern Mosaic Attenuation Ashley Davidoff TheCommonVein.net 117672
43F Diffuse Ground Glass Pattern
Ashley Davidoff TheCommonVein.net 117687
54 year old male alcoholic with seizures presents with diffuse alveolar disease consistent with pulmonary edema (a). CT scan (b) shows bibasilar infiltrates consistent with aspiration.
Follow up CXR 6 months later (c) shows resolution
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70F Aspiration and Pneumonia with Crazy Paving
Ashley Davidoff MD TheCommonVein.net crazy paving ICU 001
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Ashley Davidoff MD TheCommonVein.net crazy paving ICU 002
Ashley Davidoff MD TheCommonVein.net crazy paving ICU 003
62F-ARDS-post-abdominal-surgery-and-abdominal -abscess-shock
post-abdominal-surgery-and-abdominal -abscess-shock
Ashley Davidoff MD TheCommonVein.net abscess-shock-001
post-abdominal-surgery-and-abdominal -abscess-shock
Ashley Davidoff MD TheCommonVein.net abscess-shock-002
References and Links
Radiopaedia
- Akira Yoshikawa, M.D., Andrey Bychkov, M.D., Ph.D. Pathology Outlines ARDS / DAD
- Sheard S et al Imaging of Acute Respiratory Distress Syndrome