Cluster analysis of quantitative MRI T2 and T1? relaxation times of cartilage identifies differences between healthy and ACL-injured individuals at 3T. Osteoarthritis and cartilage Monu, U. D., JORDAN, C. D., Samuelson, B. L., Hargreaves, B. A., Gold, G. E., McWalter, E. J. 2016


To identify focal lesions of elevated MRI T2 and T1? relaxation times in articular cartilage of an ACL-injured group using a novel cluster analysis technique.Eighteen ACL-injured patients underwent 3T MRI T2 and T1? relaxometry at baseline, 6 months and 1 year and six healthy volunteers at baseline, 1 day and 1 year. Clusters of contiguous pixels above or below T2 and T1? intensity and area thresholds were identified on a projection map of the 3D femoral cartilage surface. The total area of femoral cartilage plate covered by clusters (%CA) was split into areas above (%CA+) and below (%CA-) the thresholds and the differences in %CA(+ or -) over time in the ACL-injured group were determined using the Wilcoxon signed rank test.%CA+ was greater in the ACL-injured patients than the healthy volunteers at 6 months and 1 year with average %CA+ of 5.2 ± 4.0% (p = 0.0054) and 6.6 ± 3.7% (p = 0.0041) for T2 and 6.2 ± 7.1% (p = 0.063) and 8.2 ± 6.9% (p = 0.042) for T1?, respectively. %CA- at 6 months and 1 year was 3.0 ± 1.8% (p > 0.1) and 5.9 ± 5.0% (p > 0.1) for T2 and 4.4 ± 4.9% (p > 0.1) and 4.5 ± 4.6% (p > 0.1) for T1?, respectively.With the proposed cluster analysis technique, we have quantified cartilage lesion coverage and demonstrated that the ACL-injured group had greater areas of elevated T2 and T1? relaxation times as compared to healthy volunteers.

View details for DOI 10.1016/j.joca.2016.09.015

View details for PubMedID 27720806