T1ρ/T2 mapping and histopathology of degenerative cartilage in advanced knee osteoarthritis

Abstract

AIMTo investigate whether normal thickness cartilage in osteoarthritic knees demonstrate depletion of proteoglycan or collagen content compared to healthy knees.METHODSMagnetic resonance (MR) images were acquired from 5 subjects scheduled for total knee arthroplasty (TKA) (mean age 70 years) and 20 young healthy control subjects without knee pain (mean age 28.9 years). MR images of T1ρ mapping, T2 mapping, and fat suppressed proton-density weighted sequences were obtained. Following TKA each condyle was divided into 4 parts (distal medial, posterior medial, distal lateral, posterior lateral) for cartilage analysis. Twenty specimens (bone and cartilage blocks) were examined. For each joint, the degree and extent of cartilage destruction was determined using the Osteoarthritis Research Society International cartilage histopathology assessment system. In magnetic resonance imaging (MRI) analysis, 2 readers performed cartilage segmentation for T1ρ/T2 values and cartilage thickness measurement.RESULTSEleven areas in MRI including normal or near normal cartilage thickness were selected. The corresponding histopathological sections demonstrated mild to moderate osteoarthritis (OA). There was no significant difference in cartilage thickness in MRI between control and advanced OA samples [medial distal condyle, P = 0.461; medial posterior condyle (MPC), P = 0.352; lateral distal condyle, P = 0.654; lateral posterior condyle, P = 0.550], suggesting arthritic specimens were morphologically similar to normal or early staged degenerative cartilage. Cartilage T2 and T1ρ values from the MPC were significantly higher among the patients with advanced OA (P = 0.043). For remaining condylar samples there was no statistical difference in T2 and T1ρ values between cases and controls but there was a trend towards higher values in advanced OA patients.CONCLUSIONThough cartilage is morphologically normal or near normal, degenerative changes exist in advanced OA patients. These changes can be detected with T2 and T1ρ MRI techniques.

Recent advances in articular cartilage evaluation using computed tomography and magnetic resonance imaging

“…collagen fibre orientation and concentration) can also influence T1ρ times . It is commonly performed in conjunction with T2 mapping to provide information on both proteoglycans and collagen . T1ρ may be more sensitive in detecting early articular cartilage degeneration than T2 mapping .…”

T2 mapping evaluation of changes in cartilage matrix after PRP and HA injection therapy in knee osteoarthritis: a prospective, randomized, double blind, placebo controlled study

“…Quantitative MRI T2 mapping techniques have been used as a non-invasive biomarker of early degenerative changes in knee OA [11,12,20]. MRI relaxation times are translated into quantitative values of tissues [21] in order to show subtle changes in cartilage composition in the early stages [9,10]. In this randomized, double-blind, placebo-controlled study T2 mapping was used speci cally to detect any changes in the cartilage tissue after intraarticular treatment with PRP and HA in patients with knee OA.…”

Utility of T2 mapping in the staging of thyroid-associated ophthalmopathy: efficiency of region of interest selection methods

“…T2 mapping based on multi-echo spin-echo pulse sequences which quantifies native T2 relaxation time (T2RT) is a technique used for enabling visualization as well as quantification of water content and collagen structure, reflecting the histopathological changes of certain diseases (11). It has already been applied in the early assessment of cartilage degeneration and myocardial abnormalities (12–15). Characterized by acute edema and chronic fibrosis, EOMs of TAOs shared the similar microstructural pathological changes which could also be detected by the T2RT derived from T2 mapping.…”