Highly branched macromolecules, e.g. poly(amidoamine) dendrimers (known as PAMAM dendrimers, or 'starburst polymers') or Gadomer 17, a contrast agent designed for angiography and tumor differentiation.

Device that measures optical density.

(PDWI) In density weighted imaging, the contrast is dependent on the density of protons in the tissue. Proton density weighted images are generated by choosing TR greater than T1 (typically ≥ 2 000 ms) and TE less than T2 (typically ≤ 30 ms), the two exponential terms are both close to one and therefore M is relatively independent of T1 and T2, thereby emphasizing Mxy0, which is proportional to the proton density. Also called (Rho) ρ-weighted.

See also Proton Density Weighted Image.

Metal dental work can cause, depending of the material, an associated artifact distant from the source. There is no risk for the patient but for good MRI quality should every removable dental work be removed.

The spins (protons) go out of phase in the transverse plane when the Rf pulse is switched of. This dephasing is due to static magnetic field inhomogeneities intrinsic (i.e. susceptibility changes at tissue interfaces) and extrinsic (i.e. field inhomogeneities of the main magnetic field) to the examined object.

See also T2*.