Pulmonary Embolism on Medical Imaging: The Critical CT and Radiology Signs Every Clinician Must Recognize

-

 

Introduction

A 48-year-old man suddenly develops severe shortness of breath while at work. Within minutes, he experiences sharp chest pain that worsens with breathing. His oxygen saturation falls rapidly, and he is rushed to the emergency department.

A chest radiograph reveals an unusual wedge-shaped opacity near the pleural surface.

This classic finding, known as Hampton's Hump, immediately raises concern for one of the most dangerous emergency diagnoses in medicine:

Pulmonary Embolism (PE).

Pulmonary embolism remains a leading cause of preventable in-hospital death worldwide. Despite remarkable advances in medical imaging and CT scan diagnosis, PE continues to be underdiagnosed because symptoms often mimic many other cardiopulmonary diseases.

This article provides a comprehensive review of pulmonary embolism, emphasizing modern radiology interpretation, CT imaging findings, emergency diagnosis workflows, and evidence-based treatment strategies.

What Is Pulmonary Embolism?

Pulmonary embolism occurs when one or more pulmonary arteries become obstructed by thromboembolic material.

In most cases, the embolus originates from a deep venous thrombosis (DVT) of the lower extremities.

The clot travels through:

  • Deep veins

  • Inferior vena cava

  • Right atrium

  • Right ventricle

  • Pulmonary arterial circulation

The resulting obstruction impairs pulmonary blood flow and gas exchange.

Large emboli may rapidly produce:

  • Right ventricular strain

  • Hemodynamic instability

  • Cardiogenic shock

  • Sudden death

Epidemiology

Pulmonary embolism is among the most common cardiovascular diseases worldwide.

Global Statistics

ParameterEstimate
Annual Incidence60–120 per 100,000 population
US Cases Per Year>900,000
PE-related Deaths100,000–300,000 annually
Mortality UntreatedUp to 30%
Mortality Treated<8%

Risk increases with:

  • Advanced age

  • Recent surgery

  • Malignancy

  • Prolonged immobilization

  • Pregnancy

  • Oral contraceptive use

  • Obesity

  • Previous venous thromboembolism

Pathophysiology

Pulmonary embolism is fundamentally a vascular occlusive disease.

The pathophysiological sequence includes:

Step 1: Venous Thrombus Formation

Virchow's Triad:

  • Venous stasis

  • Hypercoagulability

  • Endothelial injury

Step 2: Embolization

The thrombus detaches and migrates to the pulmonary arteries.

Step 3: Vascular Obstruction

Pulmonary vascular resistance increases.

Step 4: Right Ventricular Overload

The right ventricle struggles against elevated afterload.

Step 5: Pulmonary Infarction

Distal ischemia may cause hemorrhagic infarction.

This infarction produces the classic radiographic appearance known as Hampton's Hump.

Clinical Presentation

Pulmonary embolism is notorious for variable presentations.

Common Symptoms

  • Sudden dyspnea

  • Pleuritic chest pain

  • Tachypnea

  • Tachycardia

  • Cough

  • Hemoptysis

  • Syncope

Physical Findings

  • Hypoxemia

  • Cyanosis

  • Elevated jugular venous pressure

  • Hypotension in severe cases

Clinical Pearl

The combination of:

  • Sudden dyspnea

  • Pleuritic chest pain

  • Hypoxemia

should immediately prompt evaluation for pulmonary embolism.

Imaging Evaluation of Pulmonary Embolism

Medical imaging is central to PE diagnosis.

Modern radiology interpretation relies heavily on CT pulmonary angiography (CTPA), although chest radiography remains valuable.

Figure 1. Chest A-P Supine Radiograph

Radiologic Interpretation

The radiograph demonstrates a peripheral wedge-shaped opacity adjacent to the pleural surface.

This finding represents:

Hampton's Hump

which corresponds to pulmonary infarction distal to an occluded pulmonary artery.

Diagnostic Significance

Although relatively uncommon, Hampton's Hump is highly suggestive of pulmonary embolism when present.

Hampton's Hump: The Classic Radiology Sign

Named after radiologist Aubrey Otis Hampton, Hampton's Hump appears as:

  • Peripheral

  • Pleural-based

  • Wedge-shaped opacity

The apex points toward the hilum.

The base abuts the pleural surface.

Why Does It Occur?

The finding reflects:

  • Pulmonary infarction

  • Hemorrhage

  • Edema

secondary to vascular occlusion.

Differential Considerations

Similar appearances may occur with:

  • Pneumonia

  • Pulmonary contusion

  • Organizing pneumonia

  • Pulmonary hemorrhage

Clinical context remains essential.

Figure 2. CT Lung Window

Radiologic Interpretation

The lung window image demonstrates a peripheral wedge-shaped area of increased attenuation.

The lesion corresponds to a pulmonary infarction.

Features include:

  • Pleural-based distribution

  • Triangular morphology

  • Geographic consolidation

Diagnostic Contribution

CT provides substantially greater sensitivity than chest radiography for identifying infarcted lung tissue.

Figure 3. CT Bone Window

Radiologic Interpretation

Bone-window reconstruction further delineates the extent of pleural-based parenchymal abnormality.

The wedge-shaped opacity remains clearly visualized.

Diagnostic Contribution

Multiplanar and alternative reconstruction techniques improve confidence in detecting pulmonary infarction.

Figure 4. Chest P-A Radiograph Demonstrating Hampton's Hump

Radiologic Interpretation

The arrow identifies a classic peripheral pulmonary infarction.

This represents one of the most recognized radiographic manifestations of PE.

Clinical Importance

Although chest radiographs may appear normal in PE, identifying Hampton's Hump can dramatically shorten the time to diagnosis.

Figure 5. CT Pulmonary Angiography

Radiologic Interpretation

CTA demonstrates intraluminal filling defects within pulmonary arterial branches.

These filling defects represent acute thromboembolic material.

Diagnostic Contribution

CT pulmonary angiography remains the gold standard imaging modality for PE diagnosis.

Key CTA findings include:

  • Central filling defects

  • Saddle emboli

  • Segmental emboli

  • Right ventricular enlargement

  • Pulmonary infarction

CT Scan Diagnosis: Why CTA Is the Gold Standard

Modern PE diagnosis depends primarily on CT pulmonary angiography.

Advantages

  • High sensitivity

  • High specificity

  • Rapid acquisition

  • Widely available

  • Simultaneous alternative diagnosis evaluation

Characteristic Findings

FindingSignificance
Filling defectDirect thrombus visualization
Vessel cutoffOccluded artery
Pulmonary infarctionDistal ischemia
Hampton's HumpPeripheral infarction
RV enlargementRight heart strain

Differential Diagnosis

Several diseases may mimic pulmonary embolism.

Pneumonia

Often presents with:

  • Fever

  • Productive cough

  • Air bronchograms

Pneumothorax

Shows:

  • Pleural line

  • Lung collapse

Acute Coronary Syndrome

May produce:

  • Chest pain

  • Dyspnea

without pulmonary vascular obstruction.

Sarcoidosis

Typically demonstrates:

  • Bilateral hilar lymphadenopathy

  • Perilymphatic nodules

Mitral Stenosis

May cause pulmonary edema and dyspnea, but lacks pulmonary arterial filling defects.

Diagnostic Workflow

Step 1: Clinical Probability

Apply:

  • Wells Score

  • Geneva Score

Step 2: D-dimer Testing

Useful in low-risk patients.

Step 3: CT Pulmonary Angiography

Preferred imaging study.

Step 4: Ultrasound

Evaluate for DVT.

Step 5: Echocardiography

Assess right ventricular strain.

Treatment

Treatment depends on severity.

Anticoagulation

First-line therapy.

Options include:

  • Apixaban

  • Rivaroxaban

  • Heparin

  • Warfarin

Thrombolysis

Indicated for:

  • Massive PE

  • Hemodynamic instability

Catheter-Based Therapy

Used in selected patients.

Surgical Embolectomy

Reserved for severe cases.

Prognosis

Outcome depends on:

  • Clot burden

  • RV dysfunction

  • Hemodynamic status

  • Comorbidities

Mortality

ConditionMortality
Untreated PEUp to 30%
Treated PE<8%
Massive PE25–65%

Early CT diagnosis dramatically improves survival.

Key Takeaways

✓ Pulmonary embolism is a medical emergency.

✓ Hampton's Hump is a classic radiographic sign of pulmonary infarction.

✓ CT pulmonary angiography is the gold standard for diagnosis.

✓ Rapid radiology interpretation saves lives.

✓ Early anticoagulation significantly improves outcomes.

Quiz

Question 1

A peripheral wedge-shaped pleural-based opacity on chest radiograph is called:

A. Kerley B line
B. Hampton's Hump
C. Golden S sign
D. Luftsichel sign
E. Deep sulcus sign

Correct Answer

B. Hampton's Hump

Explanation

Hampton's Hump represents pulmonary infarction secondary to pulmonary embolism.

Question 2

Which imaging modality is considered the current gold standard for diagnosing PE?

A. Chest radiography
B. Ultrasound
C. MRI
D. CT Pulmonary Angiography
E. Fluoroscopy

Correct Answer

D. CT Pulmonary Angiography

Explanation

CTA directly visualizes intravascular thrombus and has excellent sensitivity and specificity.

Question 3

Which symptom combination most strongly suggests PE?

A. Fever and cough
B. Weight loss and night sweats
C. Sudden dyspnea, pleuritic chest pain, hypoxemia
D. Hematuria and edema
E. Dysphagia and hoarseness

Correct Answer

C. Sudden dyspnea, pleuritic chest pain, hypoxemia

Explanation

This triad is highly characteristic of acute pulmonary embolism.

Recommended Reading

  1. C. Becattini et al., “Acute Pulmonary Embolism,” New England Journal of Medicine, vol. 386, pp. 159–168, 2022. DOI: https://doi.org/10.1056/NEJMra2115956

  2. S. V. Konstantinides et al., “2019 ESC Guidelines for Acute Pulmonary Embolism,” European Heart Journal, vol. 41, pp. 543–603, 2020. DOI: https://doi.org/10.1093/eurheartj/ehz405

  3. C. Kearon et al., “Antithrombotic Therapy for VTE Disease,” Chest, vol. 160, pp. e545-e608, 2021. DOI: https://doi.org/10.1016/j.chest.2021.07.055

  4. J. R. Mayo et al., “CT Pulmonary Angiography,” Radiology, vol. 297, pp. 629-645, 2020. DOI: https://doi.org/10.1148/radiol.2020202907

  5. M. D. Gotway et al., “Imaging of Acute Pulmonary Embolism,” AJR, vol. 224, pp. 22-35, 2025. DOI: https://doi.org/10.2214/AJR.24.31511

  6. G. D. Hull et al., “Diagnosis of Pulmonary Embolism,” The Lancet, vol. 401, pp. 1245-1258, 2023. DOI: https://doi.org/10.1016/S0140-6736(23)00491-7

  7. A. Torbicki et al., “Right Ventricular Dysfunction in Pulmonary Embolism,” Circulation, vol. 145, pp. 101-113, 2022. DOI: https://doi.org/10.1161/CIRCULATIONAHA.121.055632

Comments

Post a Comment

Popular posts from this blog

Understanding Tubal Ligation Clips: Imaging, Risks, Migration, and Management

-
Image
 Understanding Tubal Ligation Clips : Imaging, Risks, Migration, and Management Keywords: tubal ligation clips, Filshie clip migration, Hulka clip imaging, chronic abdominal pain, radiology of tubal clips, tubal ligation complications, surgical sterilization clips 1. Introduction Tubal ligation clips (commonly Filshie clips or Hulka clips ) are small metallic or plastic clips applied to the fallopian tubes during laparoscopic sterilization. While widely accepted for permanent contraception, these devices pose unique clinical and imaging considerations. This expert‑level column explores their radiologic appearance, typical complications such as clip migration, symptom profiles, and management strategies. 2. What Are Tubal Ligation Clips? In laparoscopic tubal ligation, Filshie clips —titanium with a silicone lining—are applied bilaterally to occlude the fallopian tubes. Alternatively, Hulka clips , spring‑loaded plastic with a gold spring lock, offer another mechanical occlu...
Read more

Teres Minor Atrophy: Causes, Imaging, and Clinical Implications

-
Image
  Teres Minor Atrophy: Causes, Imaging, and Clinical Implications Introduction Teres minor atrophy is an uncommon but clinically significant radiologic finding that may indicate underlying neuromuscular pathology or chronic rotator cuff injury. As one of the four rotator cuff muscles, the teres minor plays an essential role in shoulder stability and external rotation. Although it is frequently overshadowed by larger muscles like the infraspinatus and supraspinatus, degeneration or atrophy of the teres minor can lead to impaired shoulder function and warrants careful assessment. In this post, we explore the etiology, pathophysiology, imaging findings, clinical presentation, treatment, and prognosis of teres minor atrophy. We also include interpretive insights based on real imaging findings (Figure 1), quiz questions with answers, and a comprehensive literature reference. Anatomy of the Teres Minor The teres minor originates from the lateral border of the scapula and inserts on...
Read more

The Lethal Lens: Mastering the Diagnosis and Management of Epidural Hemorrhage (EDH)

-
Image
  Epidural Hemorrhage (EDH), also known as an epidural hematoma, represents a critical and potentially devastating form of traumatic brain injury (TBI). It is characterized by the accumulation of blood in the potential space between the inner surface of the skull and the outermost layer of the brain's covering, the dura mater. This condition demands immediate recognition and neurosurgical intervention to prevent catastrophic neurological deficits or death. Understanding the pathophysiology , clinical presentation , and characteristic imaging features is paramount for all clinicians, particularly those managing acute trauma.   Pathophysiology of Epidural Hemorrhage The primary mechanism leading to EDH is a severe head injury , typically involving a skull fracture . The force of the trauma often causes a tear in the underlying vascular structures, most commonly the middle meningeal artery (MMA) or one of its branches, which traverses the temporal bone. While venous s...
Read more