Affiliations: Department of Radiology, The Sixth Affiliated Hospital
of Sun Yat-Sen University, Guangzhou, China | Department of Orthopaedic Surgery/Orthopaedic Research
Institute, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou,
China | Orthopaedic Research Laboratory, Aarhus University
Hospital, Aarhus, Denmark | MR Research Center/Institute of Clinical Medicine,
Aarhus University Hospital, Aarhus, Denmark | Department of Orthopaedic Surgery, The Fifth
Affiliated Hospital of Sun Yat-Sen University, Zhuhai, China
Note: [] Corresponding author: Xuenong Zou, Department of Orthopaedic
Surgery/Orthopaedic Research Institute, The First Affiliated Hospital of Sun
Yat-Sen University, 510080 Guangzhou, Guangdong, China. E-mail: zxnong@hotmail.com
Abstract: In order to evaluate the capacity of T1ρ-MRI(Magnetic Resonance Imaging) technique in distinguishing a
four-layered zonal structure of articular cartilage for detecting the
early-onset osteoarthritis (OA), eight 3-month-old female Danish landrace pigs,
weighing 45.3 ± 5.5 kg, were used in this study. Two hind
knees were randomly divided into two groups. IL-1β was
injected into articular cavities in one group while physiological saline into
another as a control one. Six hours later, the patellae were obtained for
T1ρ-MRI and histological examination to distinguish the
four-layered zonal structure of articular cartilages. The thickness of each
layer and their percentages in the entire cartilage were measured on both
T1ρ-MR images and the histological slices.
T1ρ values of every layer were calculated from
T1ρ-mapping images. In the result, the four-layered
zonal structure of articular cartilage was displayed on both T1ρ-MR images and the histological slices. The ICC between these two
methods was 0.981 for single measures (P=0.001), and 0.990
for average measures (P = 0.001). Compared with control
patellae, T1ρ values significantly increased on the
superficial and calcified layers in the IL-1β treated
patellae (P=0.037). Therefore, this study demonstrates that
the four-layered zonal structure of the articular cartilage is visibly
displayed on the T1ρ-MR images. T1ρ-MRI technique can detect the earliest event of cartilage
degeneration while these measurable changes are not shown in the histological
slices. It is possible to use this technique for observing the effects of early
interventions on the early-onset OA.
