Background: Quantitative susceptibility mapping (QSM) depicts biodistributions of tissue
magnetic susceptibility sources, including endogenous iron and calcifications, as well as exogenous
paramagnetic contrast agents and probes. When comparing QSM with simple susceptibility
weighted MRI, QSM eliminates blooming artifacts and shows reproducible tissue susceptibility
maps independent of field strength and scanner manufacturer over a broad range of image acquisition
parameters. For patient care, QSM promises to inform diagnosis, guide surgery, gauge medication,
and monitor drug delivery. The Bayesian framework using MRI phase data and structural prior
knowledge has made QSM sufficiently robust and accurate for routine clinical practice.
Objective: To address the lack of a summary of US patents that is valuable for QSM product development
and dissemination into the MRI community.
Method: We searched the USPTO Full-Text and Image Database for patents relevant to QSM technology
innovation. We analyzed the claims of each patent to characterize the main invented method
and we investigated data on clinical utility.
Results: We identified 17 QSM patents; 13 were implemented clinically, covering various aspects
of QSM technology, including the Bayesian framework, background field removal, numerical optimization
solver, zero filling, and zero-TE phase.
Conclusion: Our patent search identified patents that enable QSM technology for imaging the brain
and other tissues. QSM can be applied to study a wide range of diseases including neurological diseases,
liver iron disorders, tissue ischemia, and osteoporosis. MRI manufacturers can develop QSM
products for more seamless integration into existing MRI scanners to improve medical care.