Cartilage evaluation with biochemical MR imaging using in vivo Knee compression at 3T-comparison of patients after cartilage repair with healthy volunteers.

Magnetic resonance (MR) transverse relaxation time (T2) mapping has been frequently used to evaluate collagen content and its organization. In this study, MR T2 mapping, using the multi-slice, multi-echo Carr-Purcell-Meiboom-Gill technique, was performed in volunteers and patients after matrix-associated autologous chondrocyte transplantation (MACT) under unloading and loading conditions with an MR-compatible compression device. In the volunteer study, a statistically significant decrease in the cartilage MR T2 values was observed during the loading phase when compared to the initial load-free measurement. During the recovery period, a statistically significant increase in the T2 values was found in the central superficial layer (p=0.001), the central deep layer (p=0.005), the posterior deep layer (p=0.001), and in the tibia superficial layer (p=0.01) when compared to measurements under loading. In patients after MACT, during unloading or loading conditions, statistically significant changes in T2 values were observed in the transplant deep zone (p=0.005), in the posterior deep zone (p=0.004), and in the tibia superficial zone (p=0.012). The results of this study show that MR T2 mapping under loading conditions may provide additional information about cartilage repair tissue composition and organization during the postoperative follow-up, and may help to evaluate the efficacy of cartilage-repair surgery techniques.

Alendronate treatment for hip osteoarthritis: prospective randomized 2-year trial.

We examined the clinical efficacy of alendronate treatment for hip osteoarthritis using multiple outcome measures. Fifty patients with symptomatic hip osteoarthritis were enrolled in this prospective trial. The patients were randomly assigned to an alendronate group (35 mg/week alendronate and 600 mg/day calcium lactate) or a control group (600 mg/day calcium lactate) for 2 years. The groups were compared with regard to the following five parameters. The primary outcome measures are the following: (1) the Western Ontario and McMaster Universities (WOMAC) osteoarthritis pain score and the visual analog score (VAS). The secondary outcome measures are the following: (2) joint space width (JSW) measured on radiographs using a semiautomatic computer software, (3) the biochemical markers urinary N-telopeptide of type I collagen (NTX-I) and C-terminal cross-linking telopeptide of type II collagen (CTX-II), (4) dual-energy X-ray absorptiometry of the hip and lumbar spine, and (5) bone marrow edema on magnetic resonance images. The alendronate group showed pain improvement trends in VAS and WOMAC scores, whereas the control group showed worsening of pain. The alendronate group showed significant improvement in WOMAC pain scores after 12 months (p = 0.031) but no significant prevention of structural osteoarthritis progression, defined as a decrease in JSW >0.30 mm or conversion to total hip arthroplasty. There was significantly larger decrease in the biochemical markers and significantly increased bone density in the alendronate group. Alendronate treatment by standard dose for osteoporosis showed clinical efficacy for decreasing pain but failed to show preventive effects for structural progression of hip osteoarthritis.

Three-dimensional topographical variation of femoral cartilage T2 in healthy volunteer knees.

OBJECTIVE: Quantitative knee cartilage T2 assessment on limited two-dimensional midsagittal or midcoronal planes may be insufficient to assess variations in normal cartilage composition. The purpose of this work was to reveal characteristic 3D distribution of T2 values in femoral cartilage in healthy volunteer knees. MATERIALS AND METHODS: Sixteen volunteers were enrolled in this study. One knee joint in each volunteer was imaged using a 3D fast image employing steady-state acquisition cycled phases (FIESTA-C) sequence for modeling distal femoral morphology, as well as a sagittal T2 mapping of cartilage. 3D distribution of cartilage T2 values was generated for the femoral condyles. At each medial and lateral condyle, four regions of interest (ROI) were manually defined based on the cartilage covered by the 3D surface model of the medial and lateral menisci. RESULTS: The 3D maps showed a relatively inhomogeneous distribution of cartilage T2 on the medial and lateral condyles. Cartilage T2 values in the internal half of the weight-bearing zone were significantly higher than those in all other zones on both lateral and medial condyles. CONCLUSIONS: Analysis of 3D distribution of femoral cartilage T2 may be valuable in determining the site-specific normal range of cartilage T2 in the healthy knee joint.

Computational measurement of joint space width and structural parameters in normal hips.

INTRODUCTION: Joint space width (JSW) of hip joints on radiographs in normal population may vary by related factors, but previous investigations were insufficient due to limitations of sources of radiographs, inclusion of subjects with osteoarthritis, and manual measurement techniques. We investigated influential factors on JSW using semiautomatic computational software on pelvic radiographs in asymptomatic subjects without radiological osteoarthritic findings. METHODS: Global and local JSW at the medial, middle, and lateral compartments, and the hip structural parameters were measured in asymptomatic, normal 150 cases (300 hips), using a customized computational software. RESULTS: Reliability of measurement in global and local JSWs was high with intraobserver reproducibility (intraclass correlation coefficient) ranging from 0.957 to 0.993 and interobserver reproducibility ranging from 0.925 to 0.985. There were significant differences among three local JSWs, with the largest JSW at the lateral compartment. Global and medial local JSWs were significantly larger in the right hip, and global, medial and middle local JSWs were significantly smaller in women. Global and local JSWs were inversely correlated with CE angle and positively correlated with horizontal distance of the head center, but not correlated with body mass index in men and women. They were positively correlated with age and inversely correlated with vertical distance of the head center only in men. CONCLUSIONS: There were interindividual variations of JSW in normal population, depending on sites of the weight-bearing area, side, gender, age, and hip structural parameters. For accurate diagnosis and assessment of hip osteoarthritis, consideration of those influential factors other than degenerative change is important.

Loaded cartilage T2 mapping in patients with hip dysplasia.

PURPOSE: To evaluate the change in cartilage T2 values with loading in patients with hip dysplasia. MATERIALS AND METHODS: Fifteen patients with hip dysplasia and nine asymptomatic healthy volunteers were evaluated between April 2008 and February 2009. All subjects provided written informed consent before participation in this prospective, institutional review board-approved study. Midcoronal T2 mapping of hips was performed under unloaded and loaded conditions (with 50% body weight) at 3.0-T magnetic resonance (MR) imaging. Loading was achieved with a mechanical loading system. T2 values under unloaded conditions and the change in T2 values at the weight-bearing area of the acetabular and femoral cartilage with loading were compared between normal and dysplastic hips. The change in T2 with loading was correlated with the patient's age and body mass index as well as with the center-edge angle determined on conventional radiographs. RESULTS: The decrease in cartilage T2 at the outer superficial zones of the acetabular cartilage with loading was significantly greater in patients with hip dysplasia than in healthy volunteers: The mean T2 change with loading was -7.6% +/- 10.6 (+/-standard deviation) for dysplastic hips and 1.2% +/- 10.9 for normal hips (P = .04). Among patients with hip dysplasia, there was a positive correlation between the center-edge angle on anteroposterior radiographs and T2 changes with loading at the outer deep zones of the acetabular cartilage. CONCLUSION: Cartilage T2 mapping with loading during MR imaging enabled the detection of site-specific changes in cartilage T2 in dysplastic hips.

Influence of knee positions on T2, T*2, and dGEMRIC mapping in porcine knee cartilage.

We examined the influence of flexed knee positions on cartilage MR assessments. Sagittal T(2), T*(2), and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) maps of the femoral cartilage were obtained in eight 6-month-old porcine femorotibial joints in the extended knee position (position A: flexion 0 degrees and femoral shaft in parallel with the amplitude of static field), flexed knee position (position B: flexion 40 degrees and femoral shaft oriented at 40 degrees to the amplitude of static field), and oblique-placed knee-extended position (position C: flexion 0 degrees and femoral shaft oriented at 40 degrees to the amplitude of static field). Comparison of the MR parameters between positions A and C showed isolated influence of the magic-angle effect, and comparison between positions A and B showed effects of knee flexion. Proteoglycan and hydroxyproline content in cartilage specimen at each region of interest had no significant correlation with T(2), T*(2), and dGEMRIC values. At the central zone, located on a weight-bearing area and parallel to the amplitude of static field, T(2)/T*(2)/dGEMRIC values increased by 6.8/11/0.8% at position C and by 24/44/31% at position B compared with position A. There was a significant increase in T(2) and T*(2) values at position B compared with those at position A. The substantial changes in T(2), T*(2), and dGEMRIC were shown in response to knee flexion, presumably due to the compounding influence of the magic-angle effect and change in the intra-articular biomechanical condition.