Human knee:: In vivo T1p-weighted MR imaging at 1.5 T -: Preliminary experience

A fast spin-echo sequence weighted with a time constant that defines the magnetic relaxation of spins under the influence of a radio-frequency field (T1(rho)) was used in six subjects to measure magnetic resonance (MR) relaxation times in the knee joint with a 1.5-T MR imager. A quantitative comparison of T2- and T1(rho)-weighted MR images was also performed. Substantial T1(rho) dispersion was demonstrated in human articular cartilage, but muscle did not demonstrate much dispersion. Tl-rho-weighted images depicted a chondral lesion with 25% better signal-difference-to-noise ratios than comparable T2-weighted images. This technique may depict cartilage and muscular abnormalities.