title: In vivo sodium multiple quantum spectroscopy of human articular cartilage.
abstract: The authors report, for the first time, sodium properties of human articular cartilage in vivo using sodium multiple-quantum-filtered methods with a surface coil. A flip angle-independent, phase-cycled pulse sequence was used to obtain triple-quantum-filtered spectra as a function of preparation time. Biexponential relaxation rates were calculated by fitting the triple-quantum-filtered spectral amplitudes to a theoretical expression. Theoretical analysis of the flip angle dependence of even rank two-quantum coherence (T2[2]), odd rank two-quantum coherence (T2[3]), and triple-quantum coherence are presented and verified against experimental results on a cartilage specimen. Sodium multiple-quantum-filtered spectral lineshapes obtained in vivo correlate well with those observed on in vitro specimens. Relaxation rates obtained from asymptomatic volunteers were found to be: T(2rise) = 1.0 + 0.12 ms, T(2decay) = 12.0 +/- 0.75 ms (mean +/- SD). The diagnostic potential of this method in detecting early changes in articular cartilage is described.
authors.affiliation: School of Medicine, Department of Radiology, University of Pennsylvania, Philadelphia 19104-6100, USA.
authors.forename: R
authors.initials: R
authors.lastname: Reddy
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: E A
authors.initials: EA
authors.lastname: Noyszewski
authors.forename: J B
authors.initials: JB
authors.lastname: Kneeland
authors.forename: J S
authors.initials: JS
authors.lastname: Leigh
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000737:chemistry*; D002417:Cattle; D006801:Humans; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012964:Sodium / Q000032:analysis*
chemical_list: D012964:Sodium