Initial version

# [TECH] MRI (Magnetic Resonance Imaging)
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**MRI** applies NMR physics with spatial magnetic field gradients to create detailed images of soft tissue in living patients, revolutionising medical diagnosis.
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## Overview
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Paul Lauterbur (1973) proposed using magnetic field gradients to spatially encode NMR signals. Peter Mansfield developed echo-planar imaging (1977), enabling fast whole-body imaging. The first clinical MRI system (Fonar, 1980) was installed in hospitals. Functional MRI (fMRI) maps brain activity (1990s). Modern 7-Tesla systems image sub-millimetre anatomy. MRI requires large superconducting magnets (from BCS theory) and sophisticated signal processing — a direct product of the semiconductor and computing revolutions.
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## Key Actors
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- **Companies**: GE Healthcare, Siemens Healthineers, Philips Healthcare, Fonar (first MRI system), Bruker
- **Inventors**: Paul Lauterbur (1929–2007), Peter Mansfield (1933–2017)
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## Key Patents
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- Lauterbur, P. US Patent 3,974,402 (1976) — MRI imaging
- Damadian, R. US Patent 3,789,832 (1974) — NMR tissue characterisation
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## Economic Value
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Global MRI market: **$8 billion/year** (2023, Grand View Research). Broader diagnostic imaging market: $40B/year. Healthcare decisions based on MRI prevent unnecessary surgery and improve outcomes worth $200B+/year globally.
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## Notes
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Grand View Research *MRI Market* 2023. **Nobel Prize 2003** awarded to Lauterbur and Mansfield. The value of early cancer detection enabled by MRI is included in the broader diagnostic imaging estimate.
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# Parents
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* [SCI] Nuclear Magnetic Resonance (NMR)⏎