Multicomponent T2* mapping of knee cartilage: Technical feasibility ex vivo

✍ Scribed by Yongxian Qian; Ashley A. Williams; Constance R. Chu; Fernando E. Boada

• Book ID: 102954420
• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 890 KB
• Volume: 64
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.22450

✦ Synopsis

Abstract

Disorganization of collagen fibers is a sign of early‐stage cartilage degeneration in osteoarthritic knees. Water molecules trapped within well‐organized collagen fibrils would be sensitive to collagen alterations. Multicomponent effective transverse relaxation (T~2~*) mapping with ultrashort echo time acquisitions is here proposed to probe short T~2~ relaxations in those trapped water molecules. Six human tibial plateau explants were scanned on a 3T MRI scanner using a home‐developed ultrashort echo time sequence with echo times optimized via Monte Carlo simulations. Time constants and component intensities of T~2~* decays were calculated at individual pixels, using the nonnegative least squares algorithm. Four T~2~*‐decay types were found: 99% of cartilage pixels having mono‐, bi‐, or nonexponential decay, and 1% showing triexponential decay. Short T~2~* was mainly in 1‐6 ms, while long T~2~* was ∼22 ms. A map of decay types presented spatial distribution of these T~2~* decays. These results showed the technical feasibility of multicomponent T~2~* mapping on human knee cartilage explants. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.