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Multiparametric MR imaging reveals early cartilage degeneration at 2 and 8 weeks after ACL transection in a rabbit model
Author(s) -
Kajabi Abdul Wahed,
Casula Victor,
Ojanen Simo,
Finnilä Mikko A.,
Herzog Walter,
Saarakkala Simo,
Korhonen Rami K.,
Nissi Mikko J.,
Nieminen Miika T.
Publication year - 2020
Publication title -
journal of orthopaedic research®
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.24644
Subject(s) - femur , medicine , anterior cruciate ligament , tibia , anatomy , cartilage , magnetic resonance imaging , t2 relaxation , nuclear medicine , surgery , radiology
In this study, the rabbit model with anterior cruciate ligament transection (ACLT) was used to investigate early degenerative changes in cartilage using multiparametric quantitative magnetic resonance imaging (qMRI). ACLT was surgically induced in the knees of skeletally mature New Zealand White rabbits ( n = 14). ACL transected and contralateral knee compartments—medial femur, lateral femur, medial tibia, and lateral tibia—were harvested 2 ( n = 8) and 8 weeks ( n = 6) postsurgery. Twelve age‐matched nonoperated rabbits served as control. qMRI was conducted at 9.4 T and included relaxation times T 1 , T 2 , continuous‐wave T 1ρ (CWT 1ρ ), adiabatic T 1ρ (AdT 1ρ ), adiabatic T 2ρ (AdT 2ρ ), and relaxation along a fictitious field (T RAFF ). For reference, quantitative histology and biomechanical measurements were carried out. Posttraumatic changes were primarily noted in the superficial half of the cartilage. Prolonged T 1 , T 2 , CWT 1ρ , and AdT 1ρ were observed in the lateral femur 2 and 8 weeks post‐ACLT, compared with the corresponding control and contralateral groups ( P < .05). Collagen orientation was significantly altered in the lateral femur at 2 weeks post‐ACLT compared with the corresponding control group. In the medial femur, all the studied relaxation time parameters, except T RAFF , were increased 8 weeks post‐ACLT, as compared with the corresponding contralateral and control groups ( P < .05). Similarly, significant proteoglycan loss was observed in the medial femur at 8 weeks following surgery ( P < .05). Multiparametric MRI demonstrated early degenerative changes primarily in the superficial cartilage with T 1 , T 2 , CWT 1ρ , and AdT 1ρ sensitive to cartilage changes at 2 weeks after surgery.