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Updated: May 8, 2026
Quantitative Mapping of Specific Ventilation in the Human Lung using Proton Magnetic Resonance Imaging and Oxygen as a Contrast Agent
Published on: June 5, 2019
Regional lung ventilation in humans during hypergravity studied with quantitative SPECT.
M Ax1, L L Karlsson, A Sanchez-Crespo
1Department of Anesthesiology and Intensive Care, Karolinska University Hospital Solna, 171 76 Stockholm, Sweden; Department of Physiology and Pharmacology, Section of Anesthesiology and Intensive Care Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden.
Hypergravity causes arterial desaturation by shifting regional lung ventilation to non-dependent areas. This study provides the first high-resolution measurements of human ventilation under hypergravity conditions.
Area of Science:
- Physiology
- Aerospace Medicine
- Respiratory System
Background:
- Arterial desaturation during hypergravity was previously attributed to blood flow redistribution to dependent lung regions.
- Recent findings challenged this view, suggesting paradoxical blood flow redistribution to non-dependent lung regions.
Purpose of the Study:
- To quantify regional lung ventilation in healthy volunteers under normal (1G) and hypergravity (3G) conditions.
- To investigate the role of regional ventilation changes in arterial desaturation during hypergravity.
Main Methods:
- 10 healthy supine volunteers participated.
- Regional ventilation was measured using Technegas ((99m)Tc) and quantitative single photon emission computed tomography (SPECT).
- Measurements were taken at 1G and 3G.
Main Results:
- Hypergravity (3G) induced significant arterial desaturation (mean decrease of 8%).
- A significant shift in regional ventilation from dependent to non-dependent lung regions was observed under 3G (ratio increased from 0.81±0.12 at 1G to 1.63±0.35 at 3G).
- This ventilation redistribution was quantitatively different from blood flow redistribution patterns.
Conclusions:
- Arterial desaturation during hypergravity is likely caused by quantitatively different redistributions of blood flow and ventilation.
- This study presents the first high-resolution measurements of regional ventilation in humans under normal breathing during hypergravity.
