Comparison of quantitative imaging of cartilage for osteoarthritis: T2, T1ρ, dGEMRIC and contrast-enhanced computed tomography

Abstract

Evaluation of glycosaminoglycan (GAG) concentration in articular cartilage is of particular interest to the study of degenerative joint diseases such as osteoarthritis (OA). Noninvasive imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT) have demonstrated the potential to assess biochemical markers of cartilage integrity such as GAG content; however, many imaging techniques are available and the optimization of particular techniques in the diagnosis of joint disease remains an active area of research. In order to highlight the differences between these various approaches, this work compares MRI (T1, T2, and T1ρ) and contrast-enhanced CT in human articular cartilage, in both the presence and absence of gadolinium-based contrast agent. Pre-and postcontrast T2 values were found to be similar on a regional level and correlated with each other. As expected, T1 values were shortened significantly on both a global and a spatial basis in the presence of gadolinium (Gd); similar results were found for T1ρ. T2 values were found to correlate mildly with postcontrast T1, T1(Gd), and with precontrast T1ρ values. In addition, contrast-enhanced CT values correlated with both precontrast T1ρ and T1(Gd) more strongly than with precontrast T2. Finally, T1(Gd) and precontrast T1ρ were found to be moderately correlated with CT data. However, T1(Gd) and precontrast T1ρ were found to be almost completely uncorrelated. Together, these results indicate that T1ρ, T2, and contrast-enhanced techniques may provide complementary information about the molecular environment in cartilage during the evolution of OA.

Quantitative parametric MRI of articular cartilage: a review of progress and open challenges

“…T 2 relaxation times are therefore dependent on both the water content and the condition of the surrounding macromolecular structure [32]. Increased hydration of cartilage and breakdown of cartilage collagen are both early indicators of osteoarthritic disease [5]; therefore, there is considerable interest in the potential for T 2 as a predictor of early OA [33]. Early work in this area was conducted by Dardzinski et al [34] in a study of seven asymptomatic adults.…”

“…The spin lattice relaxation time in the rotating frame (T 1r ) is sensitive to low-frequency exchange interactions between water molecules and the large, slow tumbling macromolecules that constitute the cartilage ECM [33]. T 1r measurements are performed using a preparatory spin locking pulse that attenuates T 2 relaxation and causes the magnetisation to evolve according to the T 1r relaxation time of the nuclei [44].…”

An Atlas-Based Approach to Study Morphological Differences in Human Femoral Cartilage Between Subjects from Incidence and Progression Cohorts: MRI Data from Osteoarthritis Initiative

“…These techniques have the power of detecting cartilage loss at an early stage when the damage is still reversible (David-Vaudey et al, 2004;Li et al, 2005;Phan et al, 2006;Regatte et al, 2006;Koff et al, 2007;Li et al, 2007;Link et al, 2007). T2 relaxation time (spin-spin relaxation) is a noninvasive marker of cartilage integrity as it is sensitive to tissue hydration and the collagen-proteoglycan matrix Taylor et al, 2009;Link et al, 2010). In normal cartilage, T2 is low due to the immobilization of the water protons in the collagen-proteoglycan matrix.…”

“…Regression values indicated that the VL/VM CSA values are inversely proportional to the T2 values (Pan et al, 2011). T1 refers to measurement of T1 in the rotating frame and probes very low frequency interactions such as between water and large macromolecules (like proteoglycan) that are present in the extracellular matrix of the cartilage Taylor et al, 2009). T1 has been shown to be correlated with proteoglycan disruption and shows regional variations similar to T2.…”

“…In dGEMRIC studies, the charged contrast agent GdDTPA 2-is injected intravenously into a patient and allowed to diffuse into articular cartilage and imaging is performed 2-3 hours after contrast administration Taylor et al, 2009). The proteoglycan molecule consists of a central protein core to which a large number of negatively charged side chains called glycosaminoglycan (GAG) are attached.…”