Assessment of knee cartilage using accelerated 3 T MRI: Evaluation of an isotropic 3D fast spin-echo sequence (CUBE) with compressed sensing technique.

Purpose: Compressed Sensing (CS) is an emerging technique to accelerate MRI acquisitions. The aim of this study was to assess the reliability and accuracy of cartilage thickness measurements in the knee using a CS-enabled isotropic 3D Fast Spin-Echo (FSE) sequence on a 3-T MRI scanner.

Methods: Twenty-eight tibial condyle sections were collected from 14 adult patients who underwent total knee arthroplasty. An isotropic 3D PDw FSE with variable flip-angle (CUBE) sequence with CS was used to acquire MR images of the tibial condyle sections. Minimum cartilage thickness measurements were independently performed by two experienced readers (R1 and R2) on MR images and compared to corresponding anatomical sections measurements. Intraclass correlation coefficients (ICCs) and Bland-Altman analyses, were used to assess agreement between MR and anatomical measurements.

Results: A total of 84 paired cartilage areas were analyzed [cartilage thickness measurements ranged from 0 to 3.40 mm at anatomical evaluation (mean, 1.08 mm ± 0.83)]. The agreements between MR and anatomical measurements were excellent (mean differences, 0.06 ± 0.31 mm for R1 and 0.03 ± 0.43 mm for R2) with respective ICC values of 0.93 and 0.88. Bland-Altman analyses revealed small differences between MR and anatomical measurements, with 95 % Limit of Agreements values falling within clinically acceptable ranges (-0.54 to 0.66 mm for R1, -0.87 to 0.80 mm for R2).

Conclusion: The 3D PDw FSE sequence with Compressed Sensing acceleration technique demonstrated reliable and accurate assessment of cartilage thickness of the tibial condyles within a timeframe suitable for routine clinical practice.