Is Scintigraphy the Same as a VQ Scan?
A VQ (ventilation-perfusion) scan is a specific type of scintigraphy—scintigraphy is the broader nuclear medicine imaging technique, while VQ scanning is its application to lung ventilation and perfusion assessment. 1
Understanding the Terminology
Scintigraphy is the general term for nuclear medicine imaging that uses radioactive tracers to visualize organ function and blood flow. 2
VQ scanning (also called ventilation-perfusion scintigraphy or lung scintigraphy) is a specific scintigraphic technique that:
- Uses intravenous injection of Tc-99m-labeled macroaggregated albumin particles to assess lung perfusion 1
- Combines this with ventilation studies using tracers such as xenon-133 gas, Tc-99m-labeled aerosols, or Tc-99m-labeled carbon microparticles (Technegas) 1
- Provides functional imaging of both ventilation and perfusion in the lungs 2, 3
Key Clinical Context
The terms are often used interchangeably in clinical practice when referring to lung imaging, but technically:
- "Scintigraphy" encompasses all nuclear medicine functional imaging across various organs 2
- "VQ scan" specifically refers to lung ventilation-perfusion scintigraphy 1
When clinicians order a "VQ scan," they are requesting a specific type of scintigraphic study focused on detecting pulmonary embolism, chronic thromboembolic pulmonary hypertension (CTEPH), or other pulmonary vascular abnormalities. 1, 4
Modern Technical Variations
VQ scanning has evolved to include:
- Planar VQ scanning (traditional 2D imaging) 1
- VQ SPECT (single-photon emission CT) with improved sensitivity and specificity, achieving 94% accuracy 1, 5
- VQ SPECT/CT combining functional and anatomical imaging 1, 5
All of these remain forms of scintigraphy but represent technological advances in the VQ scanning technique. 5, 6