Purpose-A direct correlation between T 1ρ , T 2 and quantified proteoglycan and collagen contents in human osteoarthritic cartilage has yet to be documented. We aimed to investigate the orientation effect on T 1ρ and T 2 values in human osteoarthritic cartilage; and to quantify the correlation between T 1ρ , T 2 , versus biochemical composition and histology in human osteoarthritic cartilage.Materials and Methods-Thirty-three cartilage specimens were collected from patients who underwent total knee arthroplasty due to severe osteoarthritis, and scanned with a 3T MR scanner for T 1ρ and T 2 quantification. Nine specimens were scanned at three different orientations with respect to the B 0 : 0°, 90°, and 54.7°. Core punches were taken after MRI. Collagen and proteoglycan contents were quantified using biochemical assays. Histology sections were graded using Mankin scores. The correlation between imaging parameters, biochemical contents and histological scores were studied.Results-Both mean T 1ρ and T 2 at 54.7° were significantly higher than those measured at 90°a nd 0°, with T 1ρ showing a less increase compared to T 2 . R 1ρ (1/T 1ρ ) values had a significant, but moderate correlation with proteoglycan contents (R = 0.45, P = 0.002), while R 2 (1/T 2 ) was not correlated with proteoglycan. No significant correlation was found between relaxation times (T 1ρ or T 2 ) and collagen contents. The T 1ρ values of specimen sections with high Mankin scores were significantly higher than those with low Mankin scores (P < 0.05) © 2010 Elsevier Inc. All rights reserved.Corresponding author: Xiaojuan Li, PhD, Department of Radiology and Biomedical Imaging, University of California, San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, xiaojuan.li@radiology.ucsf.edu,. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Competing InterestThe authors declare that they have no competing interests. Conclusions-Quantitative MRI has a great potential to provide non-invasive imaging biomarkers for cartilage degeneration in OA. NIH Public Access

No abstract

Both imaging modalities were found to perform equally well regarding trabecular bone measurements.

The purpose of this study was (1) to evaluate the sensitivity, specificity and accuracy of sagittal in vivo 3-T intermediate-weighted fast spin-echo (iwFSE) sequences in the assessment of knee cartilage pathologies using histology as the reference standard in patients undergoing total knee replacement, and (2) to correlate MR imaging findings typically associated with osteoarthritis such as bone marrow edema pattern (BMEP) and cartilage swelling with histological findings. Tibial plateaus and femoral condyles of eight knees of seven patients were resected during surgery, and sagittal histological sections were prepared for histology. Preoperative MRI findings were compared to the corresponding region in histological sections for thickness, surface integrity and signal pattern of cartilage, and histological findings in areas of BMEP and swelling were documented. The overall sensitivity, specificity and accuracy were 72%, 69% and 70% for thickness, 69%, 74% and 73% for surface and 36%, 62% and 45% for intracartilaginous signal pattern. For all cases of BMEP on MRI subchondral © European Society of Radiology 2008Correspondence to: Thomas M. Link. NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript ingrowth of fibrovascular tissue and increased bone remodeling were observed. MRI using fatsaturated iwFSE sequences showed good performance in assessing cartilage thickness and surface lesions, while signal changes of cartilage were not suited to characterize the severity of cartilage degeneration as validated by histology. NIH Public AccessAuthor Manuscript Eur Radiol. Author manuscript; available in PMC 2010 March 15.