Cartilage Quality Assessment by Using Glycosaminoglycan Chemical Exchange Saturation Transfer and 23Na MR Imaging at 7 T

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The strong correlation between 23Na imaging and glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging after cartilage repair surgery suggests that gagCEST MR imaging in vivo might be sensitive to cartilage glycosaminoglycan content.


To compare a glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging method, which enables sampling of the water signal as a function of the presaturation offset (z-spectrum) at 13 points in clinically feasible imaging times, with sodium 23 (23Na) magnetic resonance (MR) imaging in patients after cartilage repair surgery (matrix-associated autologous chondrocyte transplantation and microfracture therapy).

Materials and Methods

One female patient (67.3 years), and 11 male patients (median age, 28.8 years; interquartile range [IQR], 24.6–32.3 years) were examined with a 7-T whole-body system, with approval of the local ethics committee after written informed consent was obtained. A modified three-dimensional gradient-echo sequence and a 28-channel knee coil were used for gagCEST imaging. 23Na imaging was performed with a circularly polarized knee coil by using a modified gradient-echo sequence. Statistical analysis of differences and Spearman correlation were applied.


The median of asymmetries in gagCEST z-spectra summed over all offsets from 0 to 1.3 ppm was 7.99% (IQR, 6.33%–8.79%) in native cartilage and 5.13% (IQR, 2.64%–6.34%) in repair tissue. A strong correlation (r = 0.701; 95% confidence interval: 0.21, 0.91) was found between ratios of signal intensity from native cartilage to signal intensity from repair tissue obtained with gagCEST or 23Na imaging. The median of dimensionless ratios between native cartilage and repair tissue was 1.28 (IQR, 1.20–1.58) for gagCEST and 1.26 (IQR, 1.21–1.48) for 23Na MR imaging.


The high correlation between the introduced gagCEST method and 23Na imaging implies that gagCEST is a potentially useful biomarker for glycosaminoglycans.

© RSNA, 2011

Supplemental material:


  • 1 Minas T, Nehrer S. Current concepts in the treatment of articular cartilage defects. Orthopedics 1997;20(6):525–538. Crossref, MedlineGoogle Scholar
  • 2 Trattnig S, Ba-Ssalamah A, Pinker K, Plank C, Vecsei V, Marlovits S. Matrix-based autologous chondrocyte implantation for cartilage repair: noninvasive monitoring by high-resolution magnetic resonance imaging. Magn Reson Imaging 2005;23(7):779–787. Crossref, MedlineGoogle Scholar
  • 3 Trattnig S, Millington SA, Szomolanyi P, Marlovits S. MR imaging of osteochondral grafts and autologous chondrocyte implantation. Eur Radiol 2007;17(1):103–118. Crossref, MedlineGoogle Scholar
  • 4 Trattnig S, Domayer S, Welsch GW, Mosher T, Eckstein F. MR imaging of cartilage and its repair in the knee—a review. Eur Radiol 2009;19(7):1582–1594. Crossref, MedlineGoogle Scholar
  • 5 Welsch GH, Trattnig S, Hughes T, et al.. T2 and T2* mapping in patients after matrix-associated autologous chondrocyte transplantation: initial results on clinical use with 3.0-Tesla MRI. Eur Radiol 2010;20(6):1515–1523. Crossref, MedlineGoogle Scholar
  • 6 Trattnig S, Marlovits S, Gebetsroither S, et al.. Three-dimensional delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) for in vivo evaluation of reparative cartilage after matrix-associated autologous chondrocyte transplantation at 3.0T: preliminary results. J Magn Reson Imaging 2007;26(4):974–982. Crossref, MedlineGoogle Scholar
  • 7 Li X, Benjamin Ma C, Link TM, et al.. In vivo T(1rho) and T(2) mapping of articular cartilage in osteoarthritis of the knee using 3 T MRI. Osteoarthritis Cartilage 2007;15(7):789–797. Crossref, MedlineGoogle Scholar
  • 8 Wheaton AJ, Borthakur A, Shapiro EM, et al.. Proteoglycan loss in human knee cartilage: quantitation with sodium MR imaging—feasibility study. Radiology 2004;231(3):900–905. LinkGoogle Scholar
  • 9 Roughley PJ, Lee ER. Cartilage proteoglycans: structure and potential functions. Microsc Res Tech 1994;28(5):385–397. Crossref, MedlineGoogle Scholar
  • 10 Ling W, Regatte RR, Navon G, Jerschow A. Assessment of glycosaminoglycan concentration in vivo by chemical exchange-dependent saturation transfer (gagCEST). Proc Natl Acad Sci U S A 2008;105(7):2266–2270. Crossref, MedlineGoogle Scholar
  • 11 Ling W, Regatte RR, Schweitzer ME, Jerschow A. Characterization of bovine patellar cartilage by NMR. NMR Biomed 2008;21(3):289–295. Crossref, MedlineGoogle Scholar
  • 12 Ramani A, Dalton C, Miller DH, Tofts PS, Barker GJ. Precise estimate of fundamental in-vivo MT parameters in human brain in clinically feasible times. Magn Reson Imaging 2002;20(10):721–731. Crossref, MedlineGoogle Scholar
  • 13 Marlovits S, Striessnig G, Resinger CT, et al.. Definition of pertinent parameters for the evaluation of articular cartilage repair tissue with high-resolution magnetic resonance imaging. Eur J Radiol 2004;52(3):310–319. Crossref, MedlineGoogle Scholar
  • 14 Bashir A, Gray ML, Boutin RD, Burstein D. Glycosaminoglycan in articular cartilage: in vivo assessment with delayed Gd(DTPA)(2-)-enhanced MR imaging. Radiology 1997;205(2):551–558. LinkGoogle Scholar
  • 15 Bashir A, Gray ML, Burstein D. Gd-DTPA2- as a measure of cartilage degradation. Magn Reson Med 1996;36(5):665–673. Crossref, MedlineGoogle Scholar
  • 16 Stahl R, Luke A, Li XJ, et al.. T1rho, T2 and focal knee cartilage abnormalities in physically active and sedentary healthy subjects versus early OA patients: a 3.0-Tesla MRI study. Eur Radiol 2009;19(1):132–143. Crossref, MedlineGoogle Scholar
  • 17 Reddy R, Li SC, Noyszewski EA, Kneeland JB, Leigh JS. In vivo sodium multiple quantum spectroscopy of human articular cartilage. Magn Reson Med 1997;38(2):207–214. Crossref, MedlineGoogle Scholar
  • 18 Reddy R, Shinnar M, Wang Z, Leigh JS. Multiple-quantum filters of spin-3/2 with pulses of arbitrary flip angle. J Magn Reson B 1994;104(2):148–152. Crossref, MedlineGoogle Scholar
  • 19 Staroswiecki E, Bangerter NK, Gurney PT, Grafendorfer T, Gold GE, Hargreaves BA. In vivo sodium imaging of human patellar cartilage with a 3D cones sequence at 3 T and 7 T. J Magn Reson Imaging 2010;32(2):446–451. Crossref, MedlineGoogle Scholar
  • 20 Tins BJ, McCall IW, Takahashi T, et al.. Autologous chondrocyte implantation in knee joint: MR imaging and histologic features at 1-year follow-up. Radiology 2005;234(2):501–508. LinkGoogle Scholar
  • 21 Welsch GH, Mamisch TC, Marlovits S, et al.. Quantitative T2 mapping during follow-up after matrix-associated autologous chondrocyte transplantation (MACT): full-thickness and zonal evaluation to visualize the maturation of cartilage repair tissue. J Orthop Res 2009;27(7):957–963. Crossref, MedlineGoogle Scholar
  • 22 Dixon WT, Hancu I, Ratnakar SJ, Sherry AD, Lenkinski RE, Alsop DC. A multislice gradient echo pulse sequence for CEST imaging. Magn Reson Med 2010;63(1):253–256. Crossref, MedlineGoogle Scholar
  • 23 Zhu H, Jones CK, van Zijl PC, Barker PB, Zhou J. Fast 3D chemical exchange saturation transfer (CEST) imaging of the human brain. Magn Reson Med 2010;64(3):638–644. Crossref, MedlineGoogle Scholar

Article History

Received September 21, 2010; revision requested November 23; final revision received December 23; accepted January 11, 2011; final version accepted February 3.
Published online: July 2011
Published in print: July 2011