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Question

Difficulty: MediumOrdering Imaging Studies

Match each patient's clinical presentation with the single most appropriate initial or next imaging study to establish the diagnosis.

  • A 28-year-old pregnant woman at 16 weeks gestation presents with acute dyspnea and pleuritic chest pain. Her chest radiograph is normal, and bilateral lower extremity venous ultrasound shows no deep vein thrombosis.Ventilation-perfusion (V/Q) scan
  • A 70-year-old man with a non-conditional permanent pacemaker presents with rapidly progressive bilateral lower extremity weakness, sensory loss below the umbilicus, and acute urinary retention.CT myelography
  • A 55-year-old man presents with sudden-onset, severe, tearing chest pain radiating to the back. Examination shows asymmetric radial pulses. Laboratory testing reveals a serum creatinine of 3.8 mg/dL.Transesophageal echocardiography (TEE)
  • A 9-year-old girl presents with a 1-day history of periumbilical pain that has migrated to the right lower quadrant, accompanied by fever, nausea, and localized rebound tenderness.Graded compression ultrasonography

Answer

The pregnant patient with suspected pulmonary embolism matches with Ventilation-perfusion (V/Q) scan. The patient with suspected spinal cord compression and a pacemaker matches with CT myelography. The patient with suspected aortic dissection and acute kidney injury matches with Transesophageal echocardiography (TEE). The pediatric patient with suspected appendicitis matches with Graded compression ultrasonography.
Each correct match directly applies evidence-based guidelines for imaging selection while navigating a major patient-specific contraindication (e.g., pregnancy, severe kidney injury, non-compatible medical devices, and young age).

Step-by-Step Solution

1
Analyze the pregnant patient's presentation (acute dyspnea, pleuritic pain, normal chest radiograph, and negative lower extremity ultrasound).
Identify that the next best step is pulmonary imaging that strictly minimizes radiation exposure.
V/Q scan is preferred over CT pulmonary angiography in pregnancy when the initial chest radiograph is completely normal.
2
Evaluate the patient with acute spinal cord compression symptoms and a non-conditional pacemaker.
Determine that Magnetic Resonance Imaging (MRI) is absolutely contraindicated.
CT myelography provides the necessary visualization of the spinal canal and cord when an MRI cannot be safely performed.
3
Assess the patient with signs of acute aortic dissection and severe acute kidney injury.
Recognize that iodine-based contrast for CT angiography is contraindicated.
Transesophageal echocardiography (TEE) accurately diagnoses aortic dissection without the need for nephrotoxic contrast agents.
4
Consider the pediatric patient with classic symptoms of acute appendicitis.
Select an imaging modality that entirely avoids ionizing radiation.
Graded compression ultrasonography is the first-line imaging choice in children to adhere to radiation safety principles.

Key Concept

When ordering diagnostic imaging, the choice of modality must be strictly tailored to patient-specific contraindications, such as avoiding ionizing radiation in children and pregnant women, avoiding iodinated contrast in severe acute kidney injury, and avoiding MRI in patients with non-conditional metallic implants.
Estimated Time:1m 30s
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Ordering Imaging Studies

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