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Updated: Jun 11, 2026
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Pulmonary Structural MRI using Free-Breathing, Self-Gated Ultra-short Echo Time Imaging
Published on: September 6, 2024
A fully automatic and highly efficient navigator gating technique for high-resolution free-breathing acquisitions:
P Jhooti1, J Keegan, D N Firmin
1Radiological Physics, University Hospital Basel, Basel, Switzerland. permi.jhooti@gmail.com
Magnetic Resonance in Medicine
|July 2, 2010
Summary
A new free-breathing imaging technique, continuously adaptive windowing strategy (CLAWS), significantly improves scan efficiency. CLAWS minimizes scan time by dynamically adjusting to breathing patterns, outperforming standard methods.
Area of Science:
- Medical Imaging
- Radiology
- Cardiovascular Imaging
Background:
- Respiratory motion significantly impacts medical imaging quality and scan efficiency.
- Current navigator-gated techniques often require manual adjustments and can be inefficient due to respiratory variations.
Purpose of the Study:
- To introduce and evaluate a novel, fully automatic free-breathing navigator-gated technique called continuously adaptive windowing strategy (CLAWS).
- To compare the efficiency and ease of use of CLAWS against standard accept/reject algorithm (ARA) and end-expiratory following ARA (EE-ARA) methods.
Main Methods:
- CLAWS employs a dynamic acquisition strategy to maximize image acquisition efficiency irrespective of respiratory pattern changes.
- The technique eliminates the need for manual acceptance window settings and navigator trace monitoring.
- CLAWS was tested in 20 healthy subjects and 10 patients, comparing scan times against retrospectively determined optimal efficiencies.
Main Results:
- CLAWS demonstrated superior efficiency, with scan times only 0.6% longer than the best possible, compared to 14.4% for ARA and 32.6% for EE-ARA.
- When applied to ARA and EE-ARA traces, CLAWS further reduced scan time differences to 0.2% and 0.5%, respectively.
- All techniques yielded comparable image quality, including respiratory gating, motion artifacts, navigator performance, and coronary artery imaging.
Conclusions:
- CLAWS offers a highly efficient, automatic, and user-friendly solution for free-breathing navigator-gated imaging.
- The adaptive strategy significantly reduces scan duration and operator dependence compared to conventional methods.
- CLAWS represents a substantial advancement in optimizing respiratory-gated imaging protocols.
