VG Med IF lungs pulmonary arteries LPA RPA Fleischner sign large Possible Westermark sign LLL Pulmonary emboli CXR 78M bladder cancer acute dyspnea

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Ashley Davidoff MD

78M bladder cancer
Acute dyspnea
Question PE

1 Major Finding
1 Possible Finding
Hardware

2. Findings


Fleischner Sign
Possible Westermark Sign
Tunneled Port Right IJ

Pulmonary Embolism with Right-Sided Fleischner Sign and Possible Westermark Sign
The frontal chest radiograph of a 78-year-old man with dyspnea, chest pain, and a history of bladder cancer and Merkel cell carcinoma demonstrates asymmetric pulmonary vascularity. There is a prominent right pulmonary artery (Fleischner sign) and relative paucity of vessels in the left lower lobe, raising concern for regional oligemia. These findings, together with the clinical presentation, suggest the possibility of bilateral pulmonary emboli, with the left-sided oligemia potentially representing a Westermark sign.
The constellation of imaging and symptoms—acute dyspnea, chest discomfort, and radiographic signs of regional vascular abnormalities—supports a high suspicion for acute thromboembolic disease. Given the patient’s underlying malignancies, his risk for venous thromboembolism is substantially elevated, making these radiographic clues particularly important. Further evaluation with CT pulmonary angiography is warranted to confirm the diagnosis and guide urgent management.
Ashley Davidoff MD
TheCommonVein.com 062H(140634)

Finding Definition
Fleischner Sign RPA Definition

  • Prominent or enlarged central pulmonary artery, specifically the Right Pulmonary Artery (RPA).
  • Can be caused by the distension of the vessel from a large pulmonary embolus or by pulmonary hypertension.
  • Often seen in massive pulmonary embolism, defined as involving 50% or more of the major pulmonary artery branches.
  • May present as enlargement of the right interlobar artery.

Comment

  • This sign points to enlargement of the proximal pulmonary arteries secondary to pulmonary embolism.
  • Felix Fleischner first associated a prominent right hilar shadow on a chest x-ray with a large embolus in the right pulmonary artery.

Citation

  • Fleischner FG, Clin Radiol, 1962.
Possible Westermark sign LLL Definition

  • A focal area of oligemia (reduced blood flow) in the lung, in this case, the Left Lower Lobe (LLL).
  • Appears as a region of increased lucency or transparency on a chest radiograph, distal to an occluded pulmonary artery.

Comment

  • The sign is a result of mechanical obstruction by the embolus or reflex vasoconstriction in the hypoxic lung.
  • It has a high specificity (around 92%) but low sensitivity (10-14%) for diagnosing pulmonary embolism.

Citation

  • Westermark N, Acta Radiologica, 1938.

Other Images from this Case

Large Right Pulmonary Artery Embolus Consistent With Fleischner Sign and Subtotal Occlusion of the Left Lower Lobe Pulmonary Artery
Coronal CT demonstrates a dominant, markedly enlarged right pulmonary artery containing a large acute pulmonary embolus, producing a Fleischner sign—a classic CXR manifestation of central pulmonary arterial enlargement in the setting of PE. A subtotal occlusion of the left lower lobe pulmonary artery is also present, contributing to bilateral perfusion deficiency in this symptomatic 78-year-old man with chest pain and dyspnea.
Ashley Davidoff MD TheCommonVein.com (062H 140643b)

Bilateral Large Emboli (062H 140636)
Massive Bilateral Pulmonary Emboli
CTA shows massive thromboembolic burden involving both the right and left pulmonary arteries, with large central emboli nearly obstructing flow. The bilateral extent, combined with the patient’s clinical presentation of dyspnea and malignancy-related risk factors, is consistent with high-risk acute pulmonary embolism requiring immediate therapeutic intervention.
Ashley Davidoff MD
TheCommonVein.com (062H 140636)

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3. Diagnosis


 

Large Pulmonary Emboli

Topic Details
Definition
  • A large proximal pulmonary embolus refers to a significant blockage within the main pulmonary artery or its lobar branches, typically originating from a deep vein thrombosis in the lower extremities or pelvis.
  • These emboli can occlude a substantial portion of the pulmonary vasculature, potentially up to 50% of pulmonary blood flow, and are associated with increased mortality.
Causes
  • The vast majority of pulmonary emboli, including large proximal ones, arise from thrombi within the deep venous system of the lower extremities or pelvis.
  • Other less common sources include thrombi originating in the pelvic, renal, or upper extremity veins, as well as within the right heart chambers.
  • Risk factors contributing to deep vein thrombosis and subsequent pulmonary embolism include immobility, surgery, malignancy, trauma, inherited thrombophilias, estrogen-based medications, pregnancy, and obesity.
Pathophysiology
  • Upon dislodging, venous thrombi travel through the venous system and the right side of the heart before lodging in the pulmonary arteries.
  • Large proximal emboli can obstruct major pulmonary arteries, leading to an acute increase in pulmonary vascular resistance and right ventricular pressure overload.
  • This elevated afterload can precipitate acute right ventricular strain and failure, which is the primary cause of death in massive pulmonary embolism.
  • Additionally, the obstruction leads to ventilation-perfusion (V/Q) mismatch and impaired gas exchange, contributing to hypoxemia.
  • Pulmonary infarction can occur if lung tissue is not adequately perfused.
Structural Result
  • Large proximal pulmonary emboli result in the mechanical obstruction of flow within the central pulmonary arteries.
  • This obstruction leads to acute dilation and strain of the right ventricle due to increased pulmonary artery pressure and afterload.
  • In severe cases, this can progress to right ventricular failure.
  • Indirect signs on imaging can include RV dilation, flattening of the interventricular septum, and reflux of contrast into the inferior vena cava.
Functional Impact
  • The primary functional impact of large proximal pulmonary emboli is profound hemodynamic compromise.
  • The significant obstruction to pulmonary blood flow leads to increased pulmonary artery pressures, reduced cardiac output, and systemic hypotension.
  • This can manifest as obstructive shock, leading to end-organ hypoperfusion.
  • Furthermore, the V/Q mismatch results in hypoxemia and respiratory distress.
  • Acute right ventricular failure is a critical functional consequence that can rapidly lead to cardiovascular collapse and death.
Imaging
  • Computed tomography pulmonary angiography (CTPA) is the gold standard for diagnosing pulmonary embolism and can effectively visualize large proximal emboli.
Large Right Pulmonary Artery Embolus Consistent With Fleischner Sign and Subtotal Occlusion of the Left Lower Lobe Pulmonary Artery
Ashley Davidoff MD TheCommonVein.com (062H 140643b)
  • Other imaging modalities include ventilation-perfusion (V/Q) scanning, which can show mismatched areas of ventilation and perfusion, and is often used when CTPA is contraindicated.

 

 

 

 

 

 

 

    • Echocardiography, particularly transesophageal echocardiography, may identify central pulmonary emboli and is crucial for assessing right ventricular strain.
    • Pulmonary angiography, while historically the gold standard, is now typically reserved for interventional management rather than primary diagnosis.
    •  

    Catheter Positioning for Bilateral Pulmonary Thrombolysis
  •  
Labs
  • Laboratory tests may include D-dimer, which can be elevated in patients with PE, though it is not specific.
  • Arterial blood gases (ABGs) can reveal hypoxemia and a respiratory alkalosis due to hyperventilation, though findings are not pathognomonic.
  • Elevated serum troponin levels and brain natriuretic peptide (BNP) can indicate right ventricular strain and are associated with increased mortality.
Treatment
  • The mainstay of treatment for large proximal pulmonary emboli involves anticoagulation to prevent further clot formation and propagation.
  • For hemodynamically unstable patients with massive PE, systemic thrombolysis with agents like alteplase (tPA) is the preferred initial therapy to rapidly dissolve the clot.
  • Catheter-directed thrombolysis or surgical embolectomy are alternative options for clot removal, particularly in cases where thrombolysis is contraindicated or ineffective.
  • In select cases, inferior vena cava filters may be considered.
Prognosis
  • The prognosis for patients with large proximal pulmonary emboli is variable and depends significantly on the extent of clot burden, hemodynamic stability, and the presence of comorbidities.
  • Massive PE carries a high mortality rate, with up to 20% or more dying in the acute phase, often due to right ventricular failure and shock.
  • However, with prompt diagnosis and appropriate treatment, including anticoagulation and potentially thrombolysis or embolectomy, mortality can be reduced to less than 5%.
  • Patients who survive the acute event may experience long-term sequelae, such as chronic thromboembolic pulmonary hypertension (CTEPH) or post-PE syndrome, characterized by persistent dyspnea and reduced exercise capacity.

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4. Medical History and Culture


Fleischner Sign on the right and possible Westermark in the right lower lobe
Ashley Davidoff MD TheCommonVein.com 140634.MAD.lungs pulmonary artery emboli

🎵 “The Ballad of the Fleischner Sign”

(Verse 1)
ISeventy-eight-year-old male
With acute dyspnea and chest pain
A history of bladder cancer
A high-risk, of pulmonary embolism
We check the frontal X-ray
What shadows do we find?
Some very subtle story in the radiograph
He may be in a serious bind.

(Verse 2)
The right pulmonary artery
Looks prominent, distended
Could it be a warning of a dreaded proximal clot
From where the blood flow should have extended.
This swelling, may be a signal
A dangerous design
It’s the subtle, classic finding
We call the Fleischner sign.

(Chorus)
Oh, the Fleischner sign, the Fleischner sign
A clot that we suspect
The X-ray is suggestive
But we have to double-check.
A proximal em-ba-liss (embolus)
Is what this might imply
We have to move here quickly
We have to know the “why.”

(Verse 3)
And look! The left lower lobe
Are there a  “paucity of vessels” seen
A subtle, focal oligemia
If you know just what I mean.
That may be a Westermark the  companion sign
Is the  blood sparse and low?
Two potential clues together 
Telling us where to go.

(Bridge)
But these Chest X-Ray signs are subtle
They’re “inconclusive” still
We need a confirmation
To treat this patient’s ill.
Is the right heart straining?
Is the RV under stress?
The X-ray cannot tell us
We’re only left to guess.

(Chorus)
Oh, the Fleischner sign, the Fleischner sign
A clot that we suspect
The X-ray is suggestive
But we have to double-check.
A proximal em-ba-liss (embolus)
Is what this might imply
We have to move here quickly
We have to know the “why.”

(Outro)
Get the CTPA!
It’s essential, make the call.
To confirm the diagnosis
Before the patient falls.
The Fleischner and the Westermark
Are the classic, subtle X-ray clues
For a pulmonary embolism
That’s the high-risk, heavy news.

Part 1b: Literal Medicine

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Part 2: Poetry

Title: “The Swollen Snake and the Barren Field”

A shadow on the X-ray film,
A vessel, wide and bright.
A clot that’s come to do its harm,
A sudden, dreadful fright.

The right PA, a swollen sign,
(That’s Fleischner’s, you should know).
While Westermark’s, a barren field,
Where vessels fail to show.

Oligemia, a pale-white lung,
A prominent, full “snake,”
These classic clues, though subtle,
A life is now at stake.

The dyspnea, the sudden pain,
The risk is high, it’s clear.
“Get the CT,” the doctor calls,
To conquer all the fear.

Part 3: History, Etymology & Descriptors

 

Title Comments
History

• Felix Fleischner (1893-1969): An Austrian-American radiologist who fled the Nazis and became a prominent figure at Harvard Medical School.


• He described this sign: a prominent central pulmonary artery, often caused by a large, proximal embolus distending the vessel.



• Nils Westermark (1892-1980): A Swedish radiologist who described the “Westermark sign.”


• This is the opposite finding: a focal area of oligemia (lack of blood vessels) downstream from the blockage, making that part of the lung look blacker (more radiolucent).



• Rudolf Virchow (1821-1902): The “father” of modern pathology.


• While he didn’t name these signs, his “Virchow’s Triad” (stasis, hypercoagulability, endothelial injury) from 1856 remains the foundational concept for why emboli form in the first place.
Etymology

• Fleischner Sign: An eponym, named after Dr. Felix Fleischner.



• Westermark Sign: An eponym, named after Dr. Nils Westermark.



• Embolism: From Greek embolos, meaning “plug” or “stopper,” which itself comes from en- (“in”) + ballein (“to throw”). An embolus is a “plug thrown into” a vessel.



• Oligemia: From Greek oligo- (“few” or “scant”) + haima (“blood”). “Scant blood.”
Key Descriptors

• Fleischner Sign: The radiologic finding of a distended, prominent proximal pulmonary artery (PA). It suggests a large, central clot is “plugging” the artery and making it swell.



• Westermark Sign: The radiologic finding of focal oligemia (a “black-out” lack of vessel markings) in the lung periphery. This is the consequence of the upstream clot blocking blood flow to that region.



• CTPA (CT Pulmonary Angiography): The gold standard diagnostic test. The X-ray signs (Fleischner, Westermark) are “subtle and inconclusive” and exist to raise suspicion for this definitive test.



• RV Heart Strain: The critical complication. A massive PE blocks outflow from the right ventricle (RV), causing acute strain, which can lead to cardiovascular collapse. This is what the CTPA also evaluates.

 

🏛️ Part 4: Cultural Context

 

Title Comments
Engineering (The Dam Metaphor)

• The Right Ventricle is the pump, the Pulmonary Artery is the main outflow pipe, and the Lungs are the fields to be irrigated.


• The Embolus is a massive log that jams in the main pipe.


• The Fleischner Sign is the pipe (PA) itself bulging at the blockage, unable to push the log through.


• The Westermark Sign is the dry, empty riverbed (the oligemic lung) downstream that is no longer receiving any flow.
Transportation (The Highway Metaphor)

• A Pulmonary Embolism is a catastrophic, multi-car pileup that shuts down all lanes of a major highway (the PA).


• The Fleischner Sign is the massive traffic jam (distension) of cars (blood) before the crash, seen from a helicopter.


• The Westermark Sign is the eerily empty highway (oligemia) after the crash, where no cars can get through.
Public Health (“The Great Masquerader”)

• PE is famously known as “The Great Masquerader” or a “Silent Killer” because its symptoms (shortness of breath, chest pain) are dangerously non-specific and can mimic a Heart Attack, Pneumonia, or even an Anxiety Attack.


• The “subtle and inconclusive” nature of the X-ray signs reinforces this treacherous reputation.
Modern Life (Stasis)

• The most common cultural context for PE risk is Deep Vein Thrombosis (DVT), or “Economy Class Syndrome.”


• This is the clot that forms in the leg from stasis (a key part of Virchow’s Triad) during a long-haul flight, a long car ride, or post-operative bed rest.


• This DVT then breaks off and travels to the lungs to become the PE.

 

👥 Part 5: Notable People

 

Category Names & Comments
The Observers (Doctors)

• Dr. Felix Fleischner (1893-1969): The Austrian-American radiologist at Harvard who gave his name to the sign of the distended proximal artery. He was a key figure in establishing chest radiology as a specialty.



• Dr. Nils Westermark (1892-1980): The Swedish radiologist who identified the lack of blood flow (oligemia) downstream from the clot. His sign is the “ghost” where blood should be.



• Dr. Rudolf Virchow (1821-1902): A giant of medicine. He is the one who first coined the terms “embolism” and “thrombosis.”


• His Virchow’s Triad (stasis, vessel injury, hypercoagulability) is the fundamental memory tool for recalling the three main risk factors for PE.
The Patients (Famous Examples)

• Serena Williams (b. 1981): One of the most famous public examples. She suffered a life-threatening PE after giving birth (a major risk period due to C-section, hormonal changes, and bed rest).


• Her story highlights the acute danger and the importance of self-advocacy in a high-risk setting.



• Dick Cheney (b. 1941): The former US Vice President has a long, public history of cardiovascular disease, including DVTs (the source of most PEs) in his legs, requiring anticoagulants.



• Hillary Clinton (b. 1947): In 2012, she was treated for a transverse sinus thrombosis (a clot in the brain) after a fall, but she has also experienced a DVT in the past (1998), placing her in a high-risk category.



• David Bloom (1963-2003): A tragic and high-profile example. The NBC journalist died from a PE while embedded with troops in Iraq.


• It was attributed to a DVT formed from spending long, cramped hours inside an armored vehicle (profound stasis).

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6. MCQs


 

Part A: Questions and Answers

Question Options
Which of the following is the most common origin of pulmonary emboli? Superior vena cava
Deep veins of the lower extremities
Right atrium
Pulmonary veins
In a patient with massive pulmonary embolism, which of the following is the most common cause of death? Myocardial infarction
Cerebrovascular accident
Right ventricular failure
Respiratory failure
What is the primary pathophysiological consequence of a large proximal pulmonary embolism? Pulmonary hypertension and reduced pulmonary vascular resistance
Increased right ventricular afterload leading to potential failure
Bronchoconstriction and airway inflammation
Decreased pulmonary dead space and improved gas exchange
Which of the following clinical findings is MOST suggestive of a massive proximal pulmonary embolism? Pleuritic chest pain
Hemoptysis
Hypotension and syncope
Fever
What is the preferred imaging modality for the diagnosis of pulmonary embolism? Ventilation-perfusion (V/Q) scan
Chest X-ray
CT pulmonary angiography (CTPA)
Lower extremity compression ultrasound
On CT pulmonary angiography (CTPA), which finding is indicative of right ventricular strain in the setting of acute pulmonary embolism? Enlarged left ventricle and thin interventricular septum
Normal right ventricle-to-left ventricle ratio
Flattening or bowing of the interventricular septum towards the left ventricle
Increased pulmonary artery caliber without ventricular changes
Which of the following findings on a chest CT scan, in the context of suspected pulmonary embolism, can be an indirect sign of severity? Atelectasis in the lung periphery
Small pleural effusion
Enlarged right ventricle relative to the left ventricle
Focal consolidations

Part B: Answers and Explanations

Q1. Which of the following is the most common origin of pulmonary emboli?
Option Status Explanation & Citation
a) Superior vena cava ✗ Incorrect
  • The vast majority of pulmonary emboli originate from deep vein thrombosis (DVT) in the lower extremities.
b) Deep veins of the lower extremities ✓ Correct
  • The vast majority of pulmonary emboli originate from deep vein thrombosis (DVT) in the lower extremities. These thrombi can dislodge and travel through the venous system to the pulmonary arteries. Other origins, such as the superior vena cava, right atrium, or pulmonary veins, are significantly less common.
  • Stein PD, Henry JW. Multicenter study of the utility of D-dimer testing in the diagnosis of venous thromboembolism. Am J Med. 1998;105(2):137-142.
c) Right atrium ✗ Incorrect
  • The vast majority of pulmonary emboli originate from deep vein thrombosis (DVT) in the lower extremities.
d) Pulmonary veins ✗ Incorrect
  • The vast majority of pulmonary emboli originate from deep vein thrombosis (DVT) in the lower extremities.
Q2. In a patient with massive pulmonary embolism, which of the following is the most common cause of death?
Option Status Explanation & Citation
a) Myocardial infarction ✗ Incorrect
  • In cases of massive pulmonary embolism, the sudden increase in pulmonary vascular resistance and pressure overload on the right ventricle is the most common cause of hemodynamic instability and death.
b) Cerebrovascular accident ✗ Incorrect
  • In cases of massive pulmonary embolism, the sudden increase in pulmonary vascular resistance and pressure overload on the right ventricle is the most common cause of hemodynamic instability and death.
c) Right ventricular failure ✓ Correct
  • In cases of massive pulmonary embolism, the sudden increase in pulmonary vascular resistance and pressure overload on the right ventricle is the most common cause of hemodynamic instability and death. While respiratory failure can occur, RV failure is the direct consequence of the embolic burden.
  • Becattini C, Agnelli G, for the Italian Cooperative Study on Acute Pulmonary Embolism. The acute hemodynamic effects of pulmonary embolism. Circulation. 1997;96(8):2460-2464.
d) Respiratory failure ✗ Incorrect
  • In cases of massive pulmonary embolism, the sudden increase in pulmonary vascular resistance and pressure overload on the right ventricle is the most common cause of hemodynamic instability and death.
Q3. What is the primary pathophysiological consequence of a large proximal pulmonary embolism?
Option Status Explanation & Citation
a) Pulmonary hypertension and reduced pulmonary vascular resistance ✗ Incorrect
  • Large proximal pulmonary emboli obstruct major pulmonary arteries, significantly increasing pulmonary vascular resistance and thus the afterload on the right ventricle.
b) Increased right ventricular afterload leading to potential failure ✓ Correct
  • Large proximal pulmonary emboli obstruct major pulmonary arteries, significantly increasing pulmonary vascular resistance and thus the afterload on the right ventricle. This acute pressure overload can lead to right ventricular dilation, dysfunction, and eventually failure. Pulmonary hypertension is a consequence, but the immediate effect is on RV afterload. Bronchoconstriction is not a primary mechanism, and gas exchange is worsened due to ventilation-perfusion mismatch.
  • Fedullo PF, Wells PS, Anderson DR, et al. A comprehensive strategy for the diagnosis of pulmonary embolism. Ann Intern Med. 2003;139(7):565-574.
c) Bronchoconstriction and airway inflammation ✗ Incorrect
  • Large proximal pulmonary emboli obstruct major pulmonary arteries, significantly increasing pulmonary vascular resistance and thus the afterload on the right ventricle.
d) Decreased pulmonary dead space and improved gas exchange ✗ Incorrect
  • Large proximal pulmonary emboli obstruct major pulmonary arteries, significantly increasing pulmonary vascular resistance and thus the afterload on the right ventricle.
Q4. Which of the following clinical findings is MOST suggestive of a massive proximal pulmonary embolism?
Option Status Explanation & Citation
a) Pleuritic chest pain ✗ Incorrect
  • While pleuritic chest pain, hemoptysis, and fever can be associated with pulmonary embolism, hypotension and syncope are hallmark signs of a massive embolus causing significant hemodynamic compromise due to obstruction of pulmonary blood flow and reduced cardiac output. Pleuritic pain is more often associated with smaller, peripheral emboli causing infarction.
b) Hemoptysis ✗ Incorrect
  • While pleuritic chest pain, hemoptysis, and fever can be associated with pulmonary embolism, hypotension and syncope are hallmark signs of a massive embolus causing significant hemodynamic compromise due to obstruction of pulmonary blood flow and reduced cardiac output. Pleuritic pain is more often associated with smaller, peripheral emboli causing infarction.
c) Hypotension and syncope ✓ Correct
  • While pleuritic chest pain, hemoptysis, and fever can be associated with pulmonary embolism, hypotension and syncope are hallmark signs of a massive embolus causing significant hemodynamic compromise due to obstruction of pulmonary blood flow and reduced cardiac output. Pleuritic pain is more often associated with smaller, peripheral emboli causing infarction.
  • Wood KE, Durr E, He Z, et al. Massive pulmonary embolism: diagnosis and management. Chest. 2018;153(4):976-990.
d) Fever ✗ Incorrect
  • While pleuritic chest pain, hemoptysis, and fever can be associated with pulmonary embolism, hypotension and syncope are hallmark signs of a massive embolus causing significant hemodynamic compromise due to obstruction of pulmonary blood flow and reduced cardiac output. Pleuritic pain is more often associated with smaller, peripheral emboli causing infarction.
Q5. What is the preferred imaging modality for the diagnosis of pulmonary embolism?
Option Status Explanation & Citation
a) Ventilation-perfusion (V/Q) scan ✗ Incorrect
  • CT pulmonary angiography (CTPA) is the gold standard and first-line imaging modality for the diagnosis of pulmonary embolism due to its high sensitivity and specificity for detecting emboli in the pulmonary arteries.
b) Chest X-ray ✗ Incorrect
  • CT pulmonary angiography (CTPA) is the gold standard and first-line imaging modality for the diagnosis of pulmonary embolism due to its high sensitivity and specificity for detecting emboli in the pulmonary arteries.
c) CT pulmonary angiography (CTPA) ✓ Correct
  • CT pulmonary angiography (CTPA) is the gold standard and first-line imaging modality for the diagnosis of pulmonary embolism due to its high sensitivity and specificity for detecting emboli in the pulmonary arteries. While V/Q scans can be used when CTPA is contraindicated, and lower extremity ultrasound can identify the source of a potential embolus, CTPA directly visualizes the pulmonary vasculature for filling defects.
  • Tapson VF, for the ACEP Clinical Policies Committee. American College of Chest Physicians guidelines for the diagnosis and management of patients with pulmonary embolism and deep vein thrombosis: evidence-based clinical practice guidelines. Chest. 2012;141(2 Suppl):e307S-e352S.
d) Lower extremity compression ultrasound ✗ Incorrect
  • CT pulmonary angiography (CTPA) is the gold standard and first-line imaging modality for the diagnosis of pulmonary embolism due to its high sensitivity and specificity for detecting emboli in the pulmonary arteries.
Q6. On CT pulmonary angiography (CTPA), which finding is indicative of right ventricular strain in the setting of acute pulmonary embolism?
Option Status Explanation & Citation
a) Enlarged left ventricle and thin interventricular septum ✗ Incorrect
  • Right ventricular strain due to increased afterload from pulmonary embolism causes RV dilation. This dilation leads to displacement of the interventricular septum, causing it to flatten or bow into the left ventricle, a key imaging sign of RV dysfunction on cross-sectional imaging. An enlarged left ventricle is not a direct sign of PE-induced RV strain.
b) Normal right ventricle-to-left ventricle ratio ✗ Incorrect
  • Right ventricular strain due to increased afterload from pulmonary embolism causes RV dilation. This dilation leads to displacement of the interventricular septum, causing it to flatten or bow into the left ventricle, a key imaging sign of RV dysfunction on cross-sectional imaging. An enlarged left ventricle is not a direct sign of PE-induced RV strain.
c) Flattening or bowing of the interventricular septum towards the left ventricle ✓ Correct
  • Right ventricular strain due to increased afterload from pulmonary embolism causes RV dilation. This dilation leads to displacement of the interventricular septum, causing it to flatten or bow into the left ventricle, a key imaging sign of RV dysfunction on cross-sectional imaging. An enlarged left ventricle is not a direct sign of PE-induced RV strain.
  • Gozzo, L., et al. (2018). CT signs of right ventricular dysfunction in acute pulmonary embolism: a review. Insights into Imaging, 9(4), 525-536.
d) Increased pulmonary artery caliber without ventricular changes ✗ Incorrect
  • Right ventricular strain due to increased afterload from pulmonary embolism causes RV dilation. This dilation leads to displacement of the interventricular septum, causing it to flatten or bow into the left ventricle, a key imaging sign of RV dysfunction on cross-sectional imaging. An enlarged left ventricle is not a direct sign of PE-induced RV strain.
Q7. Which of the following findings on a chest CT scan, in the context of suspected pulmonary embolism, can be an indirect sign of severity?
Option Status Explanation & Citation
a) Atelectasis in the lung periphery ✗ Incorrect
  • An enlarged right ventricle (RV dilation), often visualized as an increased RV-to-left ventricle (LV) ratio on CTPA, is a crucial indirect sign indicating right ventricular strain and increased afterload caused by significant pulmonary emboli. While other findings like atelectasis or pleural effusions can occur with PE, RV dilation is a direct marker of hemodynamic compromise related to the embolic burden.
b) Small pleural effusion ✗ Incorrect
  • An enlarged right ventricle (RV dilation), often visualized as an increased RV-to-left ventricle (LV) ratio on CTPA, is a crucial indirect sign indicating right ventricular strain and increased afterload caused by significant pulmonary emboli. While other findings like atelectasis or pleural effusions can occur with PE, RV dilation is a direct marker of hemodynamic compromise related to the embolic burden.
c) Enlarged right ventricle relative to the left ventricle ✓ Correct
  • An enlarged right ventricle (RV dilation), often visualized as an increased RV-to-left ventricle (LV) ratio on CTPA, is a crucial indirect sign indicating right ventricular strain and increased afterload caused by significant pulmonary emboli. While other findings like atelectasis or pleural effusions can occur with PE, RV dilation is a direct marker of hemodynamic compromise related to the embolic burden.
  • Sista AK, Spencer TR, Queeney K, et al. CT Angiography Predictors of Hemodynamic Compromise in Acute Pulmonary Embolism. J Thorac Imaging. 2019;34(5):294-300.
d) Focal consolidations ✗ Incorrect
  • An enlarged right ventricle (RV dilation), often visualized as an increased RV-to-left ventricle (LV) ratio on CTPA, is a crucial indirect sign indicating right ventricular strain and increased afterload caused by significant pulmonary emboli. While other findings like atelectasis or pleural effusions can occur with PE, RV dilation is a direct marker of hemodynamic compromise related to the embolic burden.

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1. Challenge

2. Findings

3. Diagnosis

4. Medical History and Culture

6. MCQs