Ventilation-perfusion scan for diagnosing pulmonary embolism: do chest x-rays matter?

Area of Science:

• Radiology
• Diagnostic Imaging
• Pulmonary Medicine

Background:

• Ventilation-perfusion (V/Q) scans with SPECT are standard for pulmonary embolism (PE) diagnosis.
• An abnormal chest x-ray (CXR) is often considered a contraindication for V/Q scan interpretation.

Purpose of the Study:

• To evaluate the impact of abnormal CXR findings on V/Q scan interpretation.
• To assess the influence of CXR results on the management of suspected acute PE.

Main Methods:

• Retrospective analysis of 340 patients undergoing V/Q scans for suspected PE (March 2016-2022).
• CXR reports were classified as normal or abnormal.
• Data on V/Q scan results and subsequent management (anticoagulation, further investigations) were collected.

Main Results:

• No significant difference in anticoagulation initiation or further investigations between normal and abnormal CXR groups for both positive and negative V/Q scans.
• Anticoagulation rates were high (98.3% vs. 100%) for positive V/Q scans regardless of CXR status.
• Indeterminate V/Q scan results were rare (9 cases) with similar management across CXR groups.

Conclusions:

• Abnormal CXR does not compromise the reliability of V/Q scan interpretation for PE diagnosis when combined with SPECT.
• Clinical guidelines recommending a normal CXR prior to V/Q scans should be reconsidered unless clinically indicated.