Validity of T2 mapping in characterization of the regeneration tissue by bone marrow derived cell transplantation in osteochondral lesions of the ankle.
OBJECTIVE
Bone marrow derived cell transplantation (BMDCT) has been recently suggested as a possible surgical technique to repair osteochondral lesions. To date, no qualitative MRI studies have evaluated its efficacy. The aim of our study is to investigate the validity of MRI T2-mapping sequence in characterizing the reparative tissue obtained and its ability to correlate with clinical results.


METHODS
20 patients with an osteochondral lesion of the talus underwent BMDCT and were evaluated at 2 years follow up using MRI T2-mapping sequence. 20 healthy volunteers were recruited as controls. MRI images were acquired using a protocol suggested by the International Cartilage Repair Society, MOCART scoring system and T2 mapping. Results were then correlated with AOFAS clinical score.


RESULTS
AOFAS score increased from 66.8±14.5 pre-operatively to 91.2±8.3 (p<0.0005) at 2 years follow-up. T2-relaxation time value of 35-45 ms was derived from healthy ankles evaluation and assumed as normal hyaline cartilage value and used as a control. Regenerated tissue with a T2-relaxation time value comparable to hyaline cartilage was found in all the cases treated, covering a mean of 78% of the repaired lesion area. A high clinical score was related directly to isointense signal in DPFSE fat sat (p=0.05), and percentage of regenerated hyaline cartilage (p=0.05), inversely to the percentage of regenerated fibrocartilage. Lesion's depth negatively related to the integrity of the repaired tissue's surface (tau=-0.523, p=0.007), and to the percentage of regenerated hyaline cartilage (rho=-0.546, p=0.013).


CONCLUSIONS
Because of its ability to detect cartilage's quality and to correlate to the clinical score, MRI T2-mapping sequence integrated with Mocart score represent a valid, non-invasive technique for qualitative cartilage assessment after regenerative surgical procedures.
Battaglia
M
M
Service of Ecography and Radiology, Rizzoli Orthopaedic Institute, via Pupilli n. 1, 40136 Bologna, Italy. milva.battaglia@ior.it
Rimondi
E
E
Monti
C
C
Guaraldi
F
F
Sant'Andrea
A
A
Buda
R
R
Cavallo
M
M
Giannini
S
S
Vannini
F
F
D000328:Adult; D000843:Ankle Joint / Q000473:pathology* / Q000601:surgery*; D001182:Arthroscopy; D016026:Bone Marrow Transplantation; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010007:Osteochondritis / Q000473:pathology* / Q000601:surgery*; D018709:Statistics, Nonparametric; D016896:Treatment Outcome