An in vitro comparative study of T2 and T2* mappings of human articular cartilage at 3-Tesla MRI using histology as the standard of reference.

Abstract

OBJECTIVE: The aim of this study was to evaluate the correlations between T2

value, T2* value, and histological grades of degenerated human articular

cartilage. MATERIALS AND METHODS: T2 mapping and T2* mapping of nine tibial

osteochondral specimens were obtained using a 3-T MRI after total knee

arthroplasty. A total of 94 ROIs were analyzed. Histological grades were assessed

using the David-Vaudey scale. Spearman's rho correlation analysis and Pearson's

correlation analysis were performed. RESULTS: The mean relaxation values in T2

map with different histological grades (0, 1, 2) of the cartilage were 51.9 +/-

9.2 ms, 55.8 +/- 12.8 ms, and 59.6 +/- 10.2 ms, respectively. The mean relaxation

values in T2* map with different histological grades (0, 1, 2) of the cartilage

were 20.3 +/- 10.3 ms, 21.1 +/- 12.4 ms, and 15.4 +/- 8.5 ms, respectively.

Spearman's rho correlation analysis confirmed a positive correlation between T2

value and histological grade (rho = 0.313, p < 0.05). Pearson's correlation

analysis revealed a significant negative correlation between T2 and T2* (r =

-0.322, p < 0.05). Although T2* values showed a decreasing trend with an increase

in cartilage degeneration, this correlation was not statistically significant in

this study (rho = -0.192, p = 0.129). CONCLUSIONS: T2 mapping was correlated with

histological degeneration, and it may be a good biomarker for osteoarthritis in

human articular cartilage. However, the strength of the correlation was weak (rho

= 0.313). Although T2* values showed a decreasing trend with an increase in

cartilage degeneration, the correlation was not statistically significant.

Therefore, T2 mapping may be more appropriate for the initial diagnosis of

articular cartilage degeneration in the knee joint. Further studies on T2*

mapping are needed to confirm its reliability and mechanism in cartilage

degeneration.