Assessment of bone marrow oedema-like lesions using MRI in patellofemoral knee osteoarthritis: comparison of different MRI pulse sequences.

OBJECTIVE

To compare bone marrow oedema-like lesion (BML) volume in subjects with symptomatic patellofemoral (PF) knee osteoarthritis (OA) using four different MRI sequences and to determine reliability of BML volume assessment using these sequences and their correlation with pain.

METHODS

76 males and females (mean age 55.8 years) with symptomatic patellofemoral knee OA had 1.5 T MRI scans. PD fat suppressed (FS), STIR, contrast-enhanced (CE) W FS, and 3D W fast field echo (FFE) sequences were obtained. All sequences were assessed by one reader, including repeat assessment of 15 knees using manual segmentation and the measurements were compared. We used random-effects panel linear regression to look for differences in the log-transformed BML volume (due to positive skew in the BML volume distribution) between sequences and to determine associations between BML volumes and knee pain.

RESULTS

58 subjects had PF BMLs present on at least one sequence. Median BML volume measured using W FFE sequence was significantly smaller (224.7 mm, interquartile range [IQR] 82.50-607.95) than the other three sequences. BML volume was greatest on the CE sequence (1129.8 mm, IQR 467.28-3166.02). Compared to CE sequence, BML volumes were slightly lower when assessed using PDFS (proportional difference = 0.79; 95% confidence interval [CI] 0.62, 1.01) and STIR sequences (proportional difference = 0.85; 95% CI 0.67, 1.08). There were strong correlations between BML volume on PDFS, STIR, and CE W FS sequences (ρ = 0.98). Correlations were lower between these three sequences and W FFE (ρ = 0.80-0.81). Intraclass correlation coefficients were excellent for proton density fat-suppressed, short-tau inversion recovery, and CE W FS sequences (0.991-0.995), while the ICC for W FFE was good at 0.88. We found no significant association between BML volumes assessed using any of the sequences and knee pain.

CONCLUSION

W FFE sequences were less reliable and measured considerably smaller BML volume compared to other sequences. BML volume was larger when assessed using the contrast enhanced W FS though not statistically significantly different from BMLs when assessed using PDFS and STIR sequences.

ADVANCES IN KNOWLEDGE

This is the first study to assess BMLs by four different MRI pulse sequences on the same data set, including different fluid sensitive sequences and gradient echo type sequence.