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Difficulty: EasyInterpreting Imaging Results

A 62-year-old man comes to the emergency department due to sudden-onset, severe chest pain that radiates to his back. He describes the pain as "tearing" in nature. His medical history is significant for long-standing, poorly controlled hypertension. His temperature is 37.0°C (98.6°F), heart rate is 105/min, and blood pressure is 185/110 mmHg in the right arm and 145/90 mmHg in the left arm. A chest radiograph demonstrates a widened mediastinum. A subsequent contrast-enhanced computed tomography (CT) scan of the chest reveals an intimal flap separating a true and false lumen. The intimal flap originates just distal to the left subclavian artery and extends down the descending thoracic aorta. There is absolutely no involvement of the ascending aorta or the aortic arch. Based on the interpretation of these imaging findings, which of the following is the most accurate diagnosis?

  1. A
    Stanford type A aortic dissection
  2. B
    Pulmonary embolism
  3. C
    Thoracic aortic aneurysm
  4. Stanford type B aortic dissectionAnswer
  5. E
    Esophageal perforation

Answer

Stanford type B aortic dissection
The patient's CT scan demonstrates an intimal flap that originates distal to the left subclavian artery and is confined to the descending aorta, with no involvement of the ascending aorta. Under the Stanford classification, this specific anatomic finding defines a type B aortic dissection.

Step-by-Step Solution

1
Identify the patient's acute clinical presentation and preliminary findings.
The patient has severe tearing chest pain, unequal blood pressures, and a widened mediastinum.
These are hallmark features of an acute aortic syndrome, indicating the need for definitive imaging to determine the exact pathology.
2
Interpret the specific findings on the contrast-enhanced CT scan.
The CT shows an intimal flap originating distal to the left subclavian artery, entirely sparing the ascending aorta.
Accurate interpretation of the dissection's anatomical location is essential for classification and subsequent management.
3
Apply the appropriate classification system based on the imaging interpretation.
The dissection is classified as Stanford type B.
The Stanford classification defines type A as involving the ascending aorta and type B as involving only the descending aorta (typically originating distal to the left subclavian artery).

Key Concept

Stanford type B aortic dissection is diagnosed on imaging when an intimal flap is identified in the descending aorta, distal to the left subclavian artery, without ascending aorta involvement.
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Interpreting Imaging Results

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