Study: Biochemical MRI can detect early osteoarthritis
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By using these techniques during patient exams to identify OA earlier, clinicians can shift the management of the disease from eventual joint reconstruction to long-term preservation, according to researchers from New York University Langone Medical Center's departments of orthopedic surgery and radiology in New York City.
“Imaging technology is now sensitive and powerful enough to enable detection of subtle changes in the intricate balance of water, chondrocytes and the collagen fibers and protein molecules that make up joint cartilage–which we now know can point to future osteoarthritis,” said Laith Jazrawi, MD, associate professor of orthopedic surgery. “With an active and aging baby boomer population beginning to experience joint pain associated with age, we think there is great potential for bringing these imaging techniques from the lab to the benefit of patients.”
Standard clinical practice employs conventional MRI to assess the quality of cartilage in patients with joint pain, or known arthritis, which focuses on the morphological integrity of the cartilage.
In the lab, however, radiologists, orthopedic surgeons and rheumatologists have used advances in MRI technology and biochemical imaging techniques to assess cartilage damaged by OA.
Damaged cartilage shows distinct changes in the concentration of water and collagen molecules, the micro- and macro-structure of collagen and the concentrations of particular proteins, glycosoaminoglycans, according to the researchers.
Jazrawi and colleagues examined several biochemical-based MRI techniques, including T2 mapping, T1 rho, sodium MRI and delayed gadolinium enhanced MRI of cartilage (dGEMRIC).
According to the researchers, T2 mapping and dGEMRIC may be the first techniques to move into clinical practice. Neither uses intricate pulse sequences or offline reconstruction, and both have short scan times.
“T2 mapping measures the collagen component cartilage by assessing interactions between water and collagen molecules,” wrote Jazrawi et al. It may be used to evaluate articular cartilage after reparative procedures.
dGEMRIC assesses biochemical properties of articular cartilage. Jazrawi and colleagues referred to previous studies underscoring the potential of dGEMRIC in the evaluation and early detection of knee OA. Specifically, one outlined the association between a lower dGEMRIC index at baseline imaging and development of knee OA at average six-year follow-up.
The findings support the use of these MRI techniques in the evaluation of younger patients with joint pain to identify the beginnings of OA, allowing for earlier treatment to halt the progression of the disease.
“The development and optimization of these innovative MR techniques has opened up a new window into the understanding and possible treatment of arthritis before irreversible structural and morphological changes have occurred,” said Michael P. Recht, MD, Louise Marx professor of radiology and chairman of the department of radiology.