Three-dimensional delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) at 1.5T and 3.0T

Purpose: To implement and validate a three-dimension (31) T1 measurement technique that is suitable for delayed gadolinium (Gd)-enhanced MRI of cartilage (dGEMRIC) and can be easily implemented with clinically available pulse sequences at 1.5T and 3.0T. Materials and Methods: A 3D inversion-recovery prepared spoiled gradient-echo (IR-SPGR) imaging pulse sequence with variable TR was used to implement a 3D T1 measurement protocol. The 3D T1 measurements were validated against a gold-standard single-slice 2D IR T1 measurement protocol in both phantoms and in vivo, in both asymptomatic volunteers and volunteers with osteoarthritis (OA). Results: T1 measurements in phantoms showed a statistically significant correlation between the 2D and 3D measurements at 1.5T (R-2 = 0.993, P < 0.001) and 3.OT (R-2 = 0.996, P < 0.001). In vivo application demonstrated the feasibility of using this 3D IR-SPGR sequence to evaluate the molecular status of articular cartilage throughout the knee joint with 0.63 X 0.63 X 3.0 mm spatial resolution within a 20-minute acquisition, even with the measurement parameters set for the higher T1 (Gd) of cartilage at 3T (range = 400-900 msec mean T1 within a region of interest (ROI) in cartilage, compared to 200-600 msec mean T1 at 1.5T). Conclusion: This 3D T1 measurement protocol may prove useful for the evaluation and follow-up of cartilage dGEMRIC indices in clinical studies of OA.