Radiology · Year 4 · from Radiology

Case 2: Pulmonary Embolism - CT Pulmonary Angiography

Patient Demographics

  • Age: 45 years
  • Sex: Female

Chief Complaint

Sudden onset shortness of breath and pleuritic chest pain

Presenting Symptoms

The patient presents with acute onset of dyspnea and right-sided pleuritic chest pain that began 6 hours ago. She reports a 12-hour flight from Australia 5 days ago and has been relatively sedentary since returning due to jet lag. She has a history of obesity and takes oral contraceptive pills. She describes the dyspnea as sudden and severe, with mild hemoptysis.

Physical Exam Findings

  • Vital Signs: BP 108/72 mmHg, HR 118 bpm, RR 26/min, SpO2 88% on room air, Temp 37.4C
  • General: Anxious, tachypneic female in moderate respiratory distress
  • Pulmonary: Clear to auscultation bilaterally, no wheezing or crackles
  • Cardiovascular: Tachycardic, loud P2, JVP elevated at 12 cm
  • Extremities: Right calf swelling and tenderness, positive Homans sign

Imaging Findings and Interpretation

CT Pulmonary Angiography:

  • Pulmonary Arteries: Large filling defect straddling the main pulmonary artery bifurcation (saddle embolus)
  • Additional bilateral segmental and subsegmental emboli in both lower lobes
  • "Polo mint sign" visible on axial images where emboli are surrounded by contrast
  • Right Heart: RV/LV ratio 1.4 (elevated, normal <1.0), indicating right ventricular strain
  • Reflux of contrast into the hepatic veins and IVC indicating elevated right heart pressures
  • Lung Parenchyma: Peripheral wedge-shaped opacity in right lower lobe (Hampton hump - pulmonary infarct)
  • No pleural effusion
  • Incidental: No evidence of aortic dissection

Wells Score (Pre-test Probability):

  • Clinical signs of DVT: 3 points
  • PE most likely diagnosis: 3 points
  • Heart rate >100: 1.5 points
  • Immobilization/surgery: 1.5 points
  • Total: 9 points (high probability)

Diagnosis

Massive/submassive pulmonary embolism (saddle embolus) with right ventricular strain and pulmonary infarction, associated lower extremity DVT

Management

  1. Immediate anticoagulation with IV heparin bolus and infusion
  2. ICU admission for hemodynamic monitoring given RV strain
  3. Echocardiography to confirm RV dysfunction
  4. Consider systemic thrombolysis or catheter-directed therapy given RV strain (submassive PE)
  5. Lower extremity duplex ultrasound to confirm DVT
  6. Troponin and BNP for prognostication
  7. Transition to DOAC (rivaroxaban or apixaban) after stabilization
  8. Hypercoagulability workup after acute treatment (consider Factor V Leiden, antiphospholipid syndrome)
  9. Minimum 3 months anticoagulation; consider extended duration given unprovoked nature

Radiological Image

Image Description: CT pulmonary angiography demonstrating a large pulmonary embolism with filling defects visible within the pulmonary arteries. The "polo mint sign" shows central thrombus surrounded by contrast when viewed in cross-section.

Source: Radiopaedia - Educational image demonstrating pulmonary embolism findings URL: https://radiopaedia.org/articles/pulmonary-embolism License: Educational use per Radiopaedia terms (Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported)

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