T2 and T2* mapping in patients after matrix-associated autologous chondrocyte transplantation: initial results on clinical use with 3.0-Tesla MRI.
OBJECTIVE
To use T2 and T2* mapping in patients after matrix-associated autologous chondrocyte transplantation (MACT) of the knee, and to compare and correlate both methodologies.


METHODS
3.0-Tesla MRI was performed on 30 patients (34.6 +/- 9.9 years) with a follow-up period of 28.1 +/- 18.8 months after MACT. Multi-echo, spin-echo-based T2 mapping using six echoes and gradient-echo-based T2* mapping using six echoes were prepared. T2 and T2* maps were obtained using a pixel-wise, mono-exponential, non-negative least-squares fit analysis. Region-of-interest analysis was performed for mean (full-thickness) as well as deep and superficial aspects of the cartilage repair tissue and control cartilage sites.


RESULTS
Mean T2 values (ms) were comparable for the control cartilage (53.4 +/- 11.7) and the repair tissue (55.5 +/- 11.6) (p > 0.05). Mean T2* values (ms) for control cartilage (30.9 +/- 6.6) were significantly higher than those of the repair tissue (24.5 +/- 8.1) (p < 0.001). Zonal stratification was more pronounced for T2* than for T2. The correlation between T2 and T2* was highly significant (p < 0.001), with a Pearson coefficient between 0.276 and 0.433.


CONCLUSIONS
T2 and T2* relaxation time measurements in the evaluation of cartilage repair tissue and its zonal variation show promising results, although the properties visualised by T2 and T2* may differ.
Welsch
Goetz H
GH
Department of Radiology, Medical University of Vienna, MR Center, Lazarettgasse 14, 1090 Vienna, Austria.
Trattnig
Siegfried
S
Hughes
Timothy
T
Quirbach
Sebastian
S
Olk
Alexander
A
Blanke
Matthias
M
Marlovits
Stefan
S
Mamisch
Tallal C
TC
D000328:Adult; D002357:Cartilage Diseases / Q000175:diagnosis* / Q000601:surgery*; D019902:Chondrocytes / Q000473:pathology* / Q000637:transplantation*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome