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Updated: Jun 7, 2026
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3D Cine Magnetic Resonance Imaging of Respiratory Motion in Mechanically Ventilated Mice and Rats
Published on: September 19, 2025
Highly constrained backprojection for improving dynamic 3He MR ventilation imaging in rats.
Katarzyna Cieślar1, Achraf Al Faraj, Vasile Stupar
1Université Lyon 1, Creatis-LRMN, UMR CNRS, Lyon, France.
Contrast Media & Molecular Imaging
|October 26, 2010
Summary
The highly constrained backprojection (HYPR) algorithm accelerates MRI, enabling faster hyperpolarized helium-3 (³He) lung ventilation imaging in rats. This technique improves temporal resolution for small animal respiratory studies.
Area of Science:
- Magnetic Resonance Imaging (MRI)
- Medical Imaging Physics
- Pulmonary Function Testing
Background:
- Accelerated acquisition techniques are crucial for dynamic imaging, especially in small animal models with rapid physiological processes.
- Hyperpolarized gas MRI offers unique insights into lung ventilation, but temporal resolution has been a limitation.
- The highly constrained backprojection (HYPR) algorithm has shown promise for speeding up various MRI applications.
Purpose of the Study:
- To evaluate the feasibility and performance of the 2D HYPR and iterative HYPR (I-HYPR) techniques for hyperpolarized helium-3 (³He) ventilation imaging in rats.
- To assess the impact of HYPR on temporal resolution for both single and multiple inspiration ventilation protocols.
- To compare image quality and signal kinetics between HYPR and I-HYPR variants.
Main Methods:
- Application of 2D HYPR and I-HYPR algorithms to hyperpolarized ³He ventilation imaging in rats.
- Utilized two distinct imaging protocols: single inspiration (gas inflow followed by apnea) and multiple inspiration (spontaneous breathing).
- Acquired series of HYPR frames to increase temporal resolution and reconstructed T(2)(*) maps for the multiple inspiration protocol.
Main Results:
- Achieved a four-fold increase in temporal resolution for the single inspiration protocol using HYPR.
- Successfully reconstructed T(2)(*) maps representing inspiration and expiration phases in the multiple inspiration protocol.
- Demonstrated the feasibility of 2D HYPR for diverse ³He ventilation imaging protocols in small animals.
Conclusions:
- The 2D HYPR technique is a viable method for accelerating hyperpolarized ³He ventilation imaging in small animals.
- HYPR significantly enhances temporal resolution, crucial for capturing rapid respiratory dynamics.
- Both HYPR and I-HYPR show potential for improved small animal lung imaging, with comparable image quality and kinetics representation.
