A feasibility study of in vivo T1ρ imaging of the inteirvertebral disc

Purpose: Recent studies have proposed that magnetic resonance (MR) T-1 rho relaxation time is associated with loss of macromolecules. The depletion of macromolecules in the matrix of the intervertebral disc may be an initiating factor in degenerative disc disease. The purpose of this study was to test the feasibility of quantifying T-1 rho relaxation time in phantoms and intervertebral discs of healthy volunteers using in vivo MR imaging at 3 T. Materials and Methods: A multislice T-1 rho spiral sequence was used to quantify T-1 rho relaxation time in phantoms with different agarose concentrations and in the intervertebral discs of 11 healthy volunteers (mean age = 31.3 years; age range = 23-60 years; gender: 5 females, 6 males). Results: The phantom studies demonstrated the feasibility of using spiral imaging at 3 T. The in vivo results indicate that the median T-1 rho value of the nucleus (116.6 +/- 21.4 ins) is significantly greater (P < 0.05) than that of the annulus (84.1 +/- 11.7 ins). The correlations between the age of the volunteers and T-1 rho relaxation time in the nucleus (r(2) = -0.82; P = 0.0001) and the annulus (r(2) = -0.37; P = 0.04) were significant. A trend of decreasing T-1 rho values from L3-4 to L4-5 to L5-S1 was evident. Conclusion: The results of this study suggest that in vivo T-1 rho quantification is feasible and may potentially be a clinical tool in identifying early degenerative changes in the intervertebral disc. (C) 2006 Elsevier Inc. All rights reserved.