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Schoenbauer E.,Medical University of Vienna | Szomolanyi P.,Medical University of Vienna | Szomolanyi P.,Slovak Academy of Sciences | Shiomi T.,Medical University of Vienna | And 8 more authors.
Journal of Biomechanics | Year: 2015

Magnetic resonance (MR) transverse relaxation time (T2) mapping has been frequently used to evaluate collagen content and its organization.In this study, MR T2 mapping, using the multi-slice, multi-echo Carr-Purcell-Meiboom-Gill technique, was performed in volunteers and patients after matrix-associated autologous chondrocyte transplantation (MACT) under unloading and loading conditions with an MR-compatible compression device.In the volunteer study, a statistically significant decrease in the cartilage MR T2 values was observed during the loading phase when compared to the initial load-free measurement. During the recovery period, a statistically significant increase in the T2 values was found in the central superficial layer (p=0.001), the central deep layer (p=0.005), the posterior deep layer (p=0.001), and in the tibia superficial layer (p=0.01) when compared to measurements under loading. In patients after MACT, during unloading or loading conditions, statistically significant changes in T2 values were observed in the transplant deep zone (p=0.005), in the posterior deep zone (p=0.004), and in the tibia superficial zone (p=0.012).The results of this study show that MR T2 mapping under loading conditions may provide additional information about cartilage repair tissue composition and organization during the postoperative follow-up, and may help to evaluate the efficacy of cartilage-repair surgery techniques. © 2015 Elsevier Ltd.

Trattnig S.,Medical University of Vienna | Trattnig S.,CD Laboratory for Clinical Molecular MR Imaging | Ohel K.,Regentis Biomaterials | Mlynarik V.,Medical University of Vienna | And 3 more authors.
Osteoarthritis and Cartilage | Year: 2015

Objective: To evaluate cartilage repair tissue (RT) using MOCART scoring for morphological and T2 mapping for biochemical assessment following implantation of GelrinC, a biosynthetic, biodegradable hydrogel implant. Design: MR imaging (1.5/3T) was performed on 21 patients at six sites. Standard protocols were used for MOCART evaluation at 1 week (baseline) 1, 3, 6, 12, 18 and 24 months. Multi-echo SE was used for T2 mapping. Global (T2 in RT divided by T2 in normal cartilage) and zonal T2 index (deep T2 divided by superficial T2) of RT were calculated. Results: Average MOCART score was 71.8 (95% CI 62.2 to 81.3) at six, 75.2 (95% CI 62.8 to 87.5) at twelve, 71.8 (95% CI 55.4 to 88.2) at eighteen and 84.4 (95% CI 77.7 to 91.0) at twenty-four months. The global T2 index ranged between 0.8 and 1.2 (normal healthy cartilage) in 1/11 (9%) patients at baseline, 8/12 (67%) at 12 months, 11/13 (85%) at 18 months and 13/16 (81%) at 24 months. The zonal T2 index for RT was <20% difference to the zonal T2 index for normal cartilage in: 6/12 patients (50%) at 12 months, 7/13 (53.8%) at 18 months and 10/16 (63.5%) at 24 months. The standard deviation for T2 showed a significant decrease over the study. Conclusions: The increase of MOCART scores over follow-up indicates improving cartilage repair tissue. Global and zonal T2 repair values at 24 months reached normal cartilage in 81% and 63.5% of the patients respectively, reflecting collagen organization similar to hyaline cartilage. © 2015 The Authors.

Zbyn S.,Medical University of Vienna | Zbyn S.,CD Laboratory for Clinical Molecular MR Imaging | Mlynarik V.,Medical University of Vienna | Mlynarik V.,CD Laboratory for Clinical Molecular MR Imaging | And 6 more authors.
NMR in Biomedicine | Year: 2016

The growing need for early diagnosis and higher specificity than that which can be achieved with morphological MRI is a driving force in the application of methods capable of probing the biochemical composition of cartilage tissue, such as sodium imaging. Unlike morphological imaging, sodium MRI is sensitive to even small changes in cartilage glycosaminoglycan content, which plays a key role in cartilage homeostasis. Recent advances in high- and ultrahigh-field MR systems, gradient technology, phase-array radiofrequency coils, parallel imaging approaches, MRI acquisition strategies and post-processing developments have resulted in many clinical in vivo sodium MRI studies of cartilage, even at 3T. Sodium MRI has great promise as a non-invasive tool for cartilage evaluation. However, further hardware and software improvements are necessary to complete the translation of sodium MRI into a clinically feasible method for 3-T systems. This review is divided into three parts: (i) cartilage composition, pathology and treatment; (ii) sodium MRI; and (iii) clinical sodium MRI studies of cartilage with a focus on the evaluation of cartilage repair tissue and osteoarthritis. © 2016 John Wiley & Sons, Ltd.

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