Timothy John Mosher MD, Presenter: Nothing to Disclose

Yi Liu, Abstract Co-Author: Nothing to Disclose

Scott A. Lynch MD, Abstract Co-Author: Nothing to Disclose

Kevin P. Black MD, Abstract Co-Author: Nothing to Disclose

Bernard Joseph Dardzinski PhD, Abstract Co-Author: Nothing to Disclose

Michael Bruce Smith PhD, Abstract Co-Author: Nothing to Disclose

To determine prevalence of isolated focal MRI T2 elevation of patellar cartilage in symptomatic and asymptomatic subjects, and to correlate site of elevated T2 with arthroscopic findings.

A double blind prospective evaluation of patellar cartilage was performed in 27 patients scheduled for arthroscopic knee surgery and an age-matched population of 24 asymptomatic volunteers. Quantitative MRI T2 maps of the patellofemoral joint were obtained using a Bruker 3.0T MR scanner with a TR/TE: 1500/8-88 ms, 3 mm section thickness and in-plane pixel resolution of 0.55 mm. For analysis, the patella was divided into 3 sections: medial facet, median ridge, and lateral facet. Color T2 maps were analyzed to identify sites of focal T2 elevation that involved less than full cartilage thickness, and were stratified as to whether or not T2 elevation involved the articular surface. For arthroscopy subjects, T2 results were correlated with arthroscopic scoring using the Beguin and Locker grade.

Focal T2 elevation involving the articular surface was identified in 14 of 81 sites of subjects undergoing arthroscopy (17%), and 8 of 72 sites in asymptomatic subjects (11%). At arthroscopy, the 14 sites with elevated T2 were scored normal in 4 sites, chondromalacia in 2 sites, superficial fissures in 4 sites, deep fissures in 3 sites, and fissure extending to bone in 1 site. Focal T2 elevation limited to cartilage beneath the articular surface was observed at 4 sites in arthroscopy subjects (5%), and 2 sites in asymptomatic subjects (3%). For arthroscopy subjects, this cartilage was scored as normal in 2 of 4 sites, and as having chondromalacia (B&L grade I) in 2 sites.

Focal elevation of cartilage T2 at the articular surface is frequently associated with structural cartilage damage observed at arthroscopy. Focal T2 elevation limited to the subsurface of cartilage appears normal or as areas of cartilage softening without surface irregularity at arthroscopy, and can be observed in asymptomatic subjects. Based on literature that indicates T2 is sensitive to degeneration of the type II collagen matrix, this may represent early cartilage injury related to cystic degeneration.

Mosher, T, Liu, Y, Lynch, S, Black, K, Dardzinski, B, Smith, M, Prevalence of Isolated Focal T2 Elevation of Patellar Cartilage and Association with Arthroscopic Findings.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4406030.html