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Difficulty: Very hardOrdering Imaging Studies

Evaluate the following complex clinical presentations and match each patient with the most appropriate next imaging or diagnostic study, taking into consideration their specific comorbidities and absolute or relative contraindications.

  • A 67-year-old male presenting with acute, tearing interscapular pain and diaphoresis. His blood pressure is 85/50 mmHg and heart rate is 120/min. His estimated glomerular filtration rate is 18 mL/min/1.73m².Transesophageal echocardiography
  • A 54-year-old female with progressive bilateral lower extremity weakness, a distinct sensory level at T10, and urinary retention. She has a history of severe Parkinson disease treated with a non-MRI-compatible deep brain stimulator.CT myelography
  • A 28-year-old female at 8 weeks gestation with sudden-onset pleuritic chest pain and dyspnea. Her chest radiograph is normal, and bilateral lower extremity compression ultrasonography reveals no deep vein thrombosis.Ventilation-perfusion (V/Q) scan
  • A 45-year-old male with recurrent right upper quadrant pain and normal liver biochemistries. A prior abdominal ultrasound was inconclusive due to body habitus. He has a documented history of severe anaphylaxis to iodinated contrast media.Magnetic resonance cholangiopancreatography

Answer

The correct pairings are: the hemodynamically unstable patient with suspected aortic dissection requires transesophageal echocardiography; the patient with a deep brain stimulator requires CT myelography; the pregnant patient with a normal chest X-ray requires a V/Q scan; and the patient with an iodine allergy requires magnetic resonance cholangiopancreatography.
Each correct match pairs the patient's specific clinical presentation with an imaging modality that circumvents their unique contraindications, such as hemodynamic instability, implanted metal devices, pregnancy, or severe contrast allergies.

Step-by-Step Solution

1
Evaluate the hemodynamically unstable patient with suspected aortic dissection.
Identify that the patient requires bedside diagnostic imaging.
The patient is too unstable for transport to the CT scanner, and his severe renal impairment makes iodinated contrast highly risky. TEE is the safest and most effective choice.
2
Evaluate the patient with suspected spinal cord compression.
Identify the absolute contraindication to magnetic resonance imaging.
The presence of a non-MRI-compatible deep brain stimulator precludes MRI, necessitating CT myelography as the definitive alternative study to visualize the spinal canal.
3
Determine the optimal pulmonary embolism imaging for the pregnant patient.
Select V/Q scan over CT pulmonary angiography.
In pregnant patients with a normal chest radiograph, a V/Q scan delivers significantly less radiation to the maternal breast tissue while maintaining high diagnostic accuracy for pulmonary embolism.
4
Select imaging for suspected complicated biliary colic with a severe contrast allergy.
Choose magnetic resonance cholangiopancreatography (MRCP).
With an inconclusive initial ultrasound, further cross-sectional imaging is needed. The iodinated contrast allergy precludes CT, making MRCP the best non-invasive modality to evaluate the biliary tree.

Key Concept

Selecting appropriate imaging modalities by integrating clinical stability, diagnostic capabilities, and absolute or relative contraindications (e.g., pregnancy, incompatible implants, contrast allergies).
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Ordering Imaging Studies

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