• Benjamin Dallaudière, A Trotier, E Ribot, D Verdier, S Lepreux, S Miraux, and O Hauger.
• Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS, Université de Bordeaux, Bordeaux, France.
• J Magn Reson Imaging. 2019 Jul 1; 50 (1): 127-135.

BackgroundDue to the very short T2 of its components, the normal anatomy of Achilles enthesis is impossible to define with "conventional" long echo time (TE) T2 sequences. However, this is a common site affected by rheumatologic disease. Early abnormalities related to inflammatory processes are impossible to detect in this location.PurposeTo assess the feasibility of a 3D-UTE (ultrashort echo time) sequence to evaluate normal and pathological Achilles entheses, determining both anterior fibrocartilaginous and posterior collagenic portions at 4.7T, in a rat model of spondyloarthropathy (SpA) with histological correlation. To assess whether this sequence detects SpA enthesopathy prior to long TE T2 sequences, enabling disease monitoring.Study TypeProspective case-control study.Animal ModelTwelve immunocompetent Wistar male rats imaged before (controls); the model was induced in eight rats (16 tendons) imaged at day 6, day 13, and day 21 with regular sacrifice for ex vivo imaging and histological correlation.Field Strength4.7T Bruker Biospec Systems. 3D balanced steady-state free precession (bSSFP) and 3D-UTE sequences, performed at baseline (day 0, n = 12 animals / 24 tendons), day 6 (n = 8/16), 13 (n = 4/8), and day 21 (n = 2/4).AssessmentVisual analysis and signal intensity measurements (signal to noise ratio, SNR) of both bSSFP and UTE images were performed by two independent musculoskeletal radiologists at different locations of the Achilles enthesis and preinsertional area.Statistical TestsNormal and pathological rat values were compared by Wilcoxon signed-rank tests, as well as interobserver differences. MRI findings were compared against histological data.ResultsThe 3D-UTE sequence identified the anterior fibrocartilage and posterior collagenic areas of Achilles entheses in all cases. Visual analysis and signal intensity measurements distinguished SpA-affected entheses from healthy ones at days 6 and 13 (P = 0.002 and P = 0.006, respectively). Neither the normal anatomy of the enthesis nor its pathological pattern could be identified on T2 bSSFP sequences.Data ConclusionUnlike bSSFP T2 sequences, 3D-UTE sequences enable visualization of normal enthesis anatomy and early detection of abnormalities in pathological conditions.Level Of Evidence2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:127-135.© 2018 International Society for Magnetic Resonance in Medicine.

21 keywords...

hide…