Perfusion-only imaging in pregnant women: A comparative reader study with implications for practice patterns.

Area of Science:

• Radiology and Imaging
• Nuclear Medicine
• Cardiopulmonary Diagnostics

Background:

• Pulmonary embolism (PE) diagnosis in pregnant patients requires careful consideration of imaging risks.
• Ventilation-perfusion (VQ) scans are commonly used but involve radiation exposure.
• Evaluating the necessity of the ventilation component in VQ scans for pregnant patients is crucial.

Purpose of the Study:

• To assess the diagnostic value of ventilation imaging in pregnant patients with suspected PE.
• To compare ventilation-perfusion (VQ) scans with perfusion-only (Q) scans in this population.
• To determine if excluding ventilation imaging impacts the rate of positive PE diagnoses.

Main Methods:

• Retrospective, blinded, comparative reader study of 203 VQ and Q scans from pregnant patients (2012-2017).
• Eight readers (fellows and faculty) independently reviewed VQ scans and perfusion-only (Q) scans.
• Scans were classified as PE, no PE, or non-diagnostic using logistic mixed-effects models.

Main Results:

• Perfusion-only (Q) scans showed a slightly higher rate of positive PE classifications (7.6%) compared to VQ scans (6.7%).
• The difference in positive classifications between Q and VQ scans was minimal (<1%).
• No significant association was found between scan type and positive/indeterminate or negative/indeterminate classifications.

Conclusions:

• Excluding ventilation imaging in VQ scans for pregnant patients suspected of PE is associated with a small increase in positive interpretations.
• Given the high percentage of normal perfusion-only exams (>90%) and the benefits of omitting ventilation imaging, perfusion-only imaging is a viable option.
• Perfusion-only imaging should be considered a reasonable alternative for diagnosing PE in pregnant patients, potentially reducing radiation exposure.