Magnetic susceptibility effects in MRI

Magnetic susceptibility describes how much a material becomes magnetized when exposed to an external magnetic field. In MRI, differences in susceptibility between tissues or between tissues and foreign objects (e.g., metal implants, blood breakdown products, contrast agents) lead to local magnetic field inhomogeneities, which can cause signal loss, image distortion, and "susceptibility artifacts". Biological tissues are generally weakly diamagnetic, but certain metal-containing compounds (like ferritin, hemosiderin, or exogenous MRI contrast agents) introduce paramagnetic or superparamagnetic properties, intensifying susceptibility effects. These effects are not targets of drug action, but are exploited diagnostically in "susceptibility-weighted imaging" (SWI) to highlight abnormal tissue components or microbleeds. Magnetic susceptibility effects are not classified as a therapeutic target, protein, enzyme, transporter, or receptor—they are a core concept in MRI physics, reflecting how magnetic materials interact with fields and influence image formation.

Other names

Magnetic susceptibilitySusceptibility artifactSusceptibility effects in MRI

Drugs (contrast agents) alter tissue magnetic susceptibility to enhance imaging contrast, typically by exploiting paramagnetic properties