In this study, the investigators seek to validate 3D model-based dGEMRIC (delayed gadolinium enhanced MRI of cartilage) values against histologic grading of cartilage quality, using osteochondral samples of the femoral head collected during hip replacement surgery.
For patients with advanced hip joint degeneration visible on pelvic radiographs, joint-preserving surgery is often not an option, making joint replacement the primary treatment choice. However, for those with moderate signs of degeneration, the choice between joint-preserving surgery and replacement can be challenging. This decision often relies on imaging techniques such as preoperative direct MR arthrography. Recent developments in medical imaging have led to new biochemical MRI sequences, such as dGEMRIC. These sequences are valuable for assessing the condition of cartilage before significant morphologic changes occur. By measuring glycosaminoglycan (GAG) content in cartilage, dGEMRIC provides early insight into cartilage degradation. Incorporating these sequences into standard MRI protocols allows the generation of dGEMRIC indices and the creation of 3D models of hip cartilage, improving the overall assessment of the hip joint. The purpose of this study is to validate 3D model-based dGEMRIC values by comparing them to histologic assessments of cartilage degeneration. The hypothesis is that the dGEMRIC indices from the 3D MRI model will correlate with the histologic grading of cartilage quality in femoral cartilage samples obtained during hip replacement surgery. This study aims to enroll 25 patients scheduled for total hip arthroplasty. Each participant will undergo preoperative biplanar hip radiographs and direct MR arthrography at 3 Tesla, including the dGEMRIC sequence, according the hospital's standard protocol. Surgeries will performed by an experienced orthopaedic hip surgeon. The procedure will involve the femoral neck osteotomy, followed by the removal of the head-neck fragment, and the implantation of the hip prosthesis. Osteochondral samples will be taken from four areas of the femoral head. These will be analyzed using toluidine blue and safranin-O staining to assess cartilage damage. A validated artificial intelligence algorithm will be used for 3D segmentation, visualization and calculation of morphological and biochemical parameters, which will be compared with histological results to determine a dGEMRIC threshold for identifying cartilage damage.
Study Type
OBSERVATIONAL
Enrollment
25
University Hospital of Bern (Inselspital)
Bern, Switzerland
RECRUITINGCorrelation coefficient of dGEMRIC indices and histological cartilage quality
Linear regression analysis will be performed to assess the correlation between dGEMRIC scores and the histological evaluation of cartilage quality.
Time frame: Within 12 months after histological analysis
dGEMRIC indices from 3D MRI cartilage model (T1 relaxation time in milliseconds)
A validated artificial intelligence based algorithm will be used for automated segmentation and visualization of 3D cartilage models and calculation of dGMERIC values. These dGEMRIC values are displayed topographically and color-coded in the 3D model. This allows visual and three-dimensional assessment of cartilage quality.
Time frame: Within 12 months after MRI/patient enrollment
Intensity of Toluidine blue staining as a histological value of cartilage damage (Mankin grading 0-14)
One of the two osteochondral samples from each of the four regions of the femoral head will be fixed for toluidine blue staining to determine the Mankin score. This staining method is used to grade cartilage damage. An experienced histopathologist will evaluate these sections, performing the Mankin grading, which ranges from 0 (indicating no histologic cartilage damage) to 14 (signifying end-stage cartilage damage).
Time frame: Within 1-2 weeks after sample acquisition
Intensity of Safranin-O staining as a histological value of cartilage damage (Relative red fraction of the RGB scale, 0-255)
The other osteochondral sample from each region will be used for the Safranin-O staining. An image analysis software (ImageJ, National Institute of Health, Bethesda Md) will be used to quantify the intensity of the Safranin-O staining. This quantification is represented by the relative amount of red in RGB analysis, with intensity values ranging from 0 to 255. This analysis will be performed without reference to the MRI images to ensure objectivity.
Time frame: Within 1-2 weeks after sample acquisition
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