Quantitative assessment of morphology, T1ρ, and T2 of shoulder cartilage using MRI

Abstract

Objectives To assess the feasibility of quantifying shoulder cartilage morphology and relaxometry in a clinically feasible scan time comparing different pulse sequences and assessing their reproducibility at 3 Tesla. Methods Three pulse sequences were compared for morphological assessments of shoulder cartilage thickness and volume (SPGR, MERGE, FIESTA), while a combined T1ρ-T2 sequence was optimized for relaxometry measurements. The shoulders of six healthy subjects were scanned twice with repositioning, and the cartilage was segmented and quantified. The degree of agreement between the three morphological sequences was assessed using Bland-Altman plots, while the morphological and relaxometry reproducibility were assessed with root-mean-square coefficients of variation (RMS-CVs) Results Bland-Altman plots indicated good levels of agreement between the morphological assessments of the three sequences. The reproducibility of morphological assessments yielded RMS-CVs between 4.0% and 17.7%. All sequences correlated highly (R>0.9) for morphologic assessments with no statistically significant differences. For relaxometry assessments of humeral cartilage, RMS-CVs of 6.4% and 10.6% were found for T1ρ and T2, respectively. Conclusions The assessment of both cartilage morphology and relaxometry is feasible in the shoulder with SPGR, humeral head, and T1ρ being the more reproducible morphological sequence, anatomic region, and quantitative sequence, respectively.

Biexponential T1ρ relaxation mapping of human knee cartilage in vivo at 3 T

“…As a result of the change in the biochemistry of cartilage and increase in water content caused by OA, an elevated T 1ρ relaxation time is expected. The T 1ρ relaxation time has been measured in vivo and the relationship between the elevation of T 1ρ and cartilage degeneration has been demonstrated in the previous studies . T 1ρ has been found to be sensitive to the slow motional interactions between local macromolecular environments and bulk water, and, as a result, to PG content in articular cartilage …”

“…The T 1ρ relaxation time has been measured in vivo and the relationship between the elevation of T 1ρ and cartilage degeneration has been demonstrated in the previous studies. 8,11,13,[17][18][19][20] T 1ρ has been found to be sensitive to the slow motional interactions between local macromolecular environments and bulk water, 21 and, as a result, to PG content in articular cartilage. 22 Different components of relaxation can be identified by MR relaxation experiments on cartilage, [23][24][25][26] such as T 1ρ from collagen or PG macromolecules, from fragmented PG molecules, from water molecules trapped within collagen fibrils and from free water molecules.…”

T1ρ and T2 mapping for the determination of articular cartilage denaturalization with osteonecrosis of the femoral head: A prospective controlled trial

“…Second, T 2 mapping imaging is susceptible to the effect by the homogeneity of background, magnetic susceptibility, magic angle effect, chemical shift, and partial volume . Conversely, MERGE sequence has a higher signal‐to‐noise ratio and spatial resolution, shows fewer magnetic susceptibility artifacts, and has increased contrast between tissues …”

“…34 Conversely, MERGE sequence has a higher signal-to-noise ratio and spatial resolution, shows fewer magnetic susceptibility artifacts, and has increased contrast between tissues. 25 At present, quantitative analysis of the articular cartilage imaging sequence is still not fully developed. Our study also had some limitations.…”

“…MERGE promotes tissue contrast due to a high signal‐to‐noise ratio and spatial resolution along with a low susceptibility to artifacts. Therefore, this study fit T 1 ρ and T 2 mapping data with MERGE data to improve the spatial resolution and tissue contrast, reduce chemical shift artifacts and image distortion, and obtain higher‐quality T 1 ρ and T 2 mapping . The patients were required to undergo MRI during a fixed period (20:00–23:00) and remain seated for half an hour before the MRI to reduce the mechanical effects on T 2 mapping.…”