Science · 1998 · 244 citations · 16 references
MedicineBiophysicsRadiologyBiomedical ImagingDiagnostic ImagingDiagnostic RadiologyBrain ImagingMagnetic Resonance Contrast MechanismsMagnetic Resonance ImagingMagnetic Resonance Imaging PhysicsMagnetic Resonance Signal FormationMedical ImagingContrast EnhancementFunctional MriImage Contrast MechanismsMagnetic ResonanceMagnetic Resonance PhysicsMagnetic Resonance Relaxation TimesRelaxation TimesSusceptibility Effects
A new method for magnetic resonance imaging (MRI) based on the detection of relatively strong signal from intermolecular zero-quantum coherences (iZQCs) is reported. Such a signal would not be observable in the conventional framework of magnetic resonance; it originates in long-range dipolar couplings (10 micrometers to 1 millimeter) that are traditionally ignored. Unlike conventional MRI, where image contrast is based on variations in spin density and relaxation times (often with injected contrast agents), contrast with iZQC images comes from variations in the susceptibility over a distance dictated by gradient strength. Phantom and in vivo (rat brain) data confirm that iZQC images give contrast enhancement. This contrast might be useful in the detection of small tumors, in that susceptibility correlates with oxygen concentration and in functional MRI.
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Generation of Impossible Cross-Peaks Between Bulk Water and Biomolecules in Solution NMR
Warren S. Warren, W. Richter, Amy H. Andreotti et al. · Science · 1993 · 353 citations