Purpose:To prospectively evaluate the association between clinical features and structural abnormalities found at magnetic resonance (MR) imaging in patients with osteoarthritis (OA) of the knee. Materials and Methods:The study was approved by the institutional medical ethics review board.

This pilot study presents a technique for three-dimensional and quantitative analysis of meniscus shape, position, and signal intensity and compares results in knees with (n 5 20) and without (n 5 11) radiographic osteoarthritis. 3-T MR images with 2mm section thickness were acquired using a proton density-weighted, fat-suppressed, coronal, fast spinecho sequence. Segmentation of the tibial, femoral, and external surface of the medial meniscus and the tibial joint surface was performed. Three-dimensional parameters were computed to describe the shape, position, and signal intensity of the entire meniscus and three subregions (body, anterior, and posterior horn). Key results included a greater size (i.e., volume, surface areas, and thickness), increased medial extrusion (i.e., greater extrusion distance, greater meniscal area uncovered by tibial surface), and elevated signal intensity of the medial meniscus in osteoarthritis than in nonosteoarthritis knees, particularly in the meniscus body. These results need to be confirmed in larger cohorts, preferably under weight-bearing conditions. Magn Reson Med 63:1162-1171, 2010. V C 2010 Wiley-Liss, Inc.Key words: meniscus; osteoarthritis; extrusion; coverageThe meniscus plays an important role in normal knee function by providing a higher degree of joint conformity (congruity) and by distributing loads over a wider area (1). Meniscal pathology (i.e., extrusion and tears) is frequent in the general population, even among asymptomatic individuals, and becomes more common with increasing age (2). Meniscal pathology has also been associated with knee pain (3-6) and osteoarthritis (OA) progression, specifically with increased rates of cartilage loss (7-12). These findings have generally relied on semiquantitative scoring of the meniscus (4,13), and only few studies have utilized quantitative measures of meniscus position (subluxation) or shape (14-16).Gale et al. (14) used coronal fat-saturated proton density and T 2 -weighted images to investigate the relationship between meniscal extrusion (subluxation) and joint space narrowing in 233 participants with symptomatic knee OA and in 58 asymptomatic controls. They determined the degree of extrusion to the nearest millimeter in the image where the greatest distance between the most peripheral aspect of the meniscus and the border of the tibia (excluding osteophytes) was observed. The OA participants displayed more extrusion of the medial meniscus (MM) than controls (5.1 versus 2.8mm; P ¼ 0.001). Modest degrees of meniscal extrusion were common in controls, but severe degrees (>7mm) were unique to OA cases. Hunter et al. (15) explored the role of meniscal tears (semiquantitative scoring (13)), extrusion, and height as risk factors for cartilage loss in 257 subjects. Extrusion and height were measured quantitatively in the coronal MR image showing the maximal medial tibial spine volume and in two sagittal images, one through the medial and one through the lateral tibia. Meniscal coverage and height were smaller in knees with men...

The schuss view is suggested as the most accurate method for the evaluation of JSW in femorotibial OA.

Objective-The performance characteristics of hyaline articular cartilage measurement on magnetic resonance imaging (MRI) need to be accurately delineated before widespread application of this technology. Our objective was to assess the rate of natural disease progression of cartilage morphometry measures from baseline to 1 year in knees with osteoarthritis (OA) from a subset of participants from the Osteoarthritis Initiative (OAI).Methods-Subjects included for this exploratory analysis are a subset of the approximately 4700 participants in the OAI Study. Bilateral radiographs and 3T MRI (Siemans Trio) of the knees and clinical data were obtained at baseline and annually in all participants. 160 subjects from the OAI Progression subcohort all of whom had both frequent symptoms and, in the same knee, radiographic OA based on a screening reading done at the OAI clinics were eligible for this exploratory analysis. One knee from each subject was selected for analysis. 150 participants were included. Using sagittal 3D DESSwe (double echo, steady-state sequence with water excitation) MR images from the baseline and 12 follow-up month visit, a segmentation algorithm was applied to the cartilage plates of the index knee to compute the cartilage volume, normalised cartilage volume (volume normalised to bone surface interface area), and percentage denuded area (total cartilage bone interface area denuded of cartilage).Results-Summary statistics of the changes (absolute and percentage) from baseline at 1 year and the standardised response mean (SRM), ie, mean change divided by the SD change were calculated. On average the subjects were 60.9 years of age and obese, with a mean body mass index of 30. Despite being extraordinarily prevalent OA remains a condition that is poorly understood, and a condition for which available effective therapeutic options are limited to symptomatic treatment. The development of therapies aimed at joint preservation in OA is constrained by the slow progress of the condition, its heterogeneous clinical manifestations and the need for long-term follow-up to observe changes in structure. NIH Public AccessNew technologies may improve the assessment of early disease development, and progression, and could greatly facilitate measurement of structural outcomes in OA clinical trials. Foremost among these is magnetic resonance imaging (MRI), a sensitive non-invasive method for assessing joint morphology. 5 6 MRI is ideally suited for imaging arthritic joints as: (1) it is free of ionising radiation; (2) it defines both calcified as well as soft tissue joint components; and (3) its tomographic viewing perspective obviates morphological distortion, magnification and superimposition. MRI of the knee can directly visualise hyaline articular cartilage and cover the whole joint in one examination, meaning that the cartilage defects in the joint can be visualised directly regardless of their location. 5Although yet to be formally accepted by regulatory authorities, many experts now agree that MRI may b...

Bone marrow edema-like lesions change in volume in the majority of patients with osteoarthritis; associations with clinical features Abstract It has been suggested that bone marrow edema-like (BME) lesions in the knee are associated with progression of osteoarthritis (OA). The purpose of our study in patients with OA was to evaluate prospectively changes of BME lesions over 2 years and their relationship with clinical features. Magnetic resonance (MR) images of the knee were obtained from 182 patients (20% male; aged 43-76 years; mean age 59 years) who had been diagnosed with familial symptomatic OA at multiple joint sites. MR images were made at baseline and at 2 years follow-up. BME lesions in 2 years were associated with clinical features assessed by Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores. A total of 327 BME lesions were recorded. Total size of BME lesions changed in 90 patients (66%). Size of individual lesions changed in 147 foci (45%): new lesions appeared in 69 (21%), existing lesions disappeared in 32 (10%), increased in size in 26 (8%) and decreased in size in 20 (6%) lesions. Increase or decrease of BME lesions, over a 2-year time period, was not associated with severity of WOMAC scores. BME lesions fluctuated in the majority of patients with OA over a 2-year time period. These changes were not associated with severity of WOMAC scores at the study end point.

Objective. Magnetic resonance imaging (MRI) and radiography are established imaging modalities for the assessment of knee osteoarthritis (OA). The objective of our study was to compare the responsiveness of radiographic joint space width (JSW) with MRI-derived measures of cartilage morphometry for OA progression in participants from the Osteoarthritis Initiative (OAI). Methods. This study examined the baseline and 12-month visits of a subset of 150 subjects from the OAI. Measurement of radiographic JSW was facilitated by the use of automated software that delineated the femoral and tibial margins of the joint. Measures of medial compartment minimum JSW and JSW at fixed locations were compared with cartilage morphometry measures derived from MRI. The results were stratified by Kellgren/Lawrence (K/L) scale grade and by tibiofemoral anatomic axis angle. In order to examine the relative responsiveness of various techniques, we calculated the standardized response mean (SRM) between the 2 visits. Results. The SRM for radiographic JSW measured at the optimal location was ؊0.32 compared with ؊0.39 for the most responsive MRI measure. For the subgroup with a K/L scale grade of 2 or 3, the most responsive SRM values were ؊0.34 for radiographic JSW and ؊0.42 for MRI. Conclusion. Our study demonstrates that new measures using a software analysis of digital knee radiographic images are comparable with MRI in detecting OA progression, and potentially superior when considering the cost-effectiveness of the 2 imaging modalities.

Objective To study the longitudinal rate of (and sensitivity to) change of knee cartilage thickness across defined stages of radiographic osteoarthritis (ROA), specifically healthy knees and knees with end-stage ROA. Methods One knee of 831 Osteoarthritis Initiative (OAI) participants was examined: 112 healthy, without ROA or risk factors for knee OA, and 719 ROA knees: 310 calculated Kellgren Lawrence [cKLG] grade 2, 300 cKLG3, and 109 cKLG4. Subregional change in thickness was assessed after segmentation of weight-bearing femorotibial cartilage at baseline and at one year from coronal MRI. Regional and ordered values (OV) of change were compared by baseline ROA status. Results Healthy knees displayed small changes in plates and subregions (±0.7%; standardized response mean [SRM] ±0.15), with OVs being symmetrically distributed around zero. In cKLG2 knees, changes in cartilage thickness were small (≤1%; minimal SRM -0.22) and not significantly different from healthy knees. Knees with cKLG3 showed substantial loss of cartilage thickness (up to -2.5%; minimal SRM -0.35), with OV changes being significantly (p<0.05) greater than those in healthy knees. cKLG4 knees displayed the largest rate of loss across ROA grades (up to -3.9%; minimal SRM -0.51), with OV changes also significantly (p<0.05) greater than in healthy knees. Conclusion MRI-based cartilage thickness showed high rates of loss in knees with moderate and end-stage ROA, and small rates (indistinguishable from healthy knees) in mild ROA. From the perspective of sensitivity to change, end-stage ROA knees need not be excluded from longitudinal studies using MRI cartilage morphology as an endpoint.

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