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. Author manuscript; available in PMC: 2015 Feb 10.
Published in final edited form as: Arthritis Care Res (Hoboken). 2014 Aug;66(8):1129–1141. doi: 10.1002/acr.22316

Figure 4.

Figure 4

Glycosaminoglycans (GAGs)–specific chemical exchange saturation transfer (gagCEST) and sodium magnetic resonance imaging (MRI) to followup cartilage repair. Proton density (A), gagCEST (B), and sodium (C) MRIs acquired at 7T of a patient 8.7 years after autologous osteochondral transplantation (white arrow). The color overlay in (B) represents the gagCEST asymmetries in percentages (the lower the values, the less GAGs are present in the cartilage). The color overlay in (C) represents the sodium signal-to-noise ratio values (the lower the values, the less GAGs are present in the cartilage). The transplantation region (white arrow) clearly contains less GAGs compared to the posterior femoral cartilage (B and C). The CEST image (B) has a relatively high spatial resolution compared to the sodium image (C), which makes the technique promising as an outcome measure for cartilage GAG content in future research. (Courtesy of Benjamin Schmitt and Siegfried Trattnig, Medical University of Vienna, MR Center of Excellence, Vienna, Austria [154]).