Cartilage T 1ρ and T 2 relaxation times: longitudinal reproducibility and variations using different coils, MR systems and sites

Abstract

OBJECTIVE To evaluate the longitudinal reproducibility and variations of cartilage T1ρ and T2 measurements using different coils, MR systems and sites. METHODS Single-Site study: Phantom data were collected monthly for up to 29 months on four GE 3T MR systems. Data from phantoms and human subjects were collected on two MR systems using the same model of coil; and were collected on one MR system using two models of coils. Multi-site study: Three participating sites used the same model of MR systems and coils, and identical imaging protocols. Phantom data were collected monthly. Human subjects were scanned and rescanned on the same day at each site. Two traveling human subjects were scanned at all three sites. RESULTS Single-Site Study: The phantom longitudinal RMS-CVs ranged from 1.8% to 2.7% for T1ρ and 1.8% to 2.8% for T2. Significant differences were found in T1ρ and T2 values using different MR systems and coils. Multi-Site Study: The phantom longitudinal RMS-CVs ranged from 1.3% to 2.6% for T1ρ and 1.2% to 2.7% for T2. Across three sites (n=16), the in-vivo scan-rescan RMS-CV was 3.1% and 4.0% for T1ρ and T2, respectively. Phantom T1ρ and T2 values were significantly different between three sites but highly correlated (R>0.99). No significant difference was found in T1ρ and T2 values of traveling controls, with cross-site RMS-CV as 4.9% and 4.4% for T1ρ and T2, respectively. CONCLUSION With careful quality control and cross-calibration, quantitative MRI can be readily applied in multi-site studies and clinical trials for evaluating cartilage degeneration.

Reproducibility of in vivo magnetic resonance imaging T1rho and T2 relaxation time measurements of hip cartilage at 3.0T in healthy volunteers

“…Most important, we used a different sequence and it has to be pointed out that the coil used in this study is a 32‐channel body coil. Li et al recently demonstrated significant variations of T 1 ρ and T 2 values with different coils . Moreover, T 1 ρ values are positively related to the spin‐lock frequency and we used a relatively high spin‐lock frequency.…”

Use of 2D U-Net Convolutional Neural Networks for Automated Cartilage and Meniscus Segmentation of Knee MR Imaging Data to Determine Relaxometry and Morphometry

“…The T1 ρ -weighted data set was manually segmented in-house by skilled technicians, with the supervision of radiologists and by using an in-house MATLAB-based program (Mathworks, Natick, Mass), only after they had passed strict training where their segmentations met the metric standard proposed by Carballido-Gamio et al (10) in morphology analysis and the standard of Li et al (19) for relaxation time analysis. The DESS data set was manually segmented; images and segmentation masks are available through the OAI (20).…”

Fully automatic analysis of the knee articular cartilageT1ρrelaxation time using voxel-based relaxometry

“…Both users were trained under the supervision of experienced musculoskeletal radiologists. The procedure for semiautomatic segmentation was evaluated in previous studies reporting processing/reprocessing interobserver intraclass coefficient (ICC) and root mean square / coefficient of variation (RMS‐CV) of the subcompartment T 1ρ quantification equal to 0.961 and 3.9%, respectively, and scan/rescan RMS‐CV of the T 1ρ quantification in compartment equal to 3.1% …”