1.5 tesla mri

All individuals were evaluated by MRI, including T1- and T2-weighted axial and sagittal sections of the lumbar spine (T12–S1) and a screening MRI T2-weighted sagittal imaging of the whole spine (1.5 Tesla MRI; Siemens, Munich, Germany). All MRIs were performed according to the standard clinical imaging protocol of each site. All MRI images were viewed using the Advantage Workstation ver. 4.3 (GE Healthcare, Milwaukee, WI, USA), and quantitative measurements were obtained using the digital measuring tools included in the software. Four independent evaluators (I.B.A., H.Y., M.Y.S., and A.G.A.) made quantitative measurements of MRI images using a standardized protocol, and a consensus was negotiated in case of disagreements (Y.K.). Before conducting the measurements, all evaluators underwent training to ensure similar measurement technique. Following training, each evaluator was tested on the same set of five MRI studies to determine interrater reliability (κ=0.82).

We used baseline MRI data, and baseline plus 2-year ldCT data from the whole spine (C3–L5). A standardised protocol was applied in both centres for imaging acquisitions.18 (link) MRI images were acquired in Leiden and Herne, respectively, on a 3 Tesla MRI (Philips Medical systems, Best, The Netherlands) and 1.5 Tesla MRI (Siemens, Erlangen, Germany) using sagittal T1-weighted and short tau inversion recovery (STIR) sequences with a slice thickness of 3 mm. LdCT images were obtained on 64-section and 16-section CT scanners (Leiden: Aquilion 64, Toshiba Medical Systems, Otawara, Japan; Herne: Somatom Emotion 16, Siemens, Erlangen, Germany). Spiral CT scans were performed using automatic exposure control. The effective dose estimates for the whole spine were 3.8 (2.6) mSv and 4.7 (2.4) mSv per ldCT, respectively—further details were previously published.18 (link)

MARS MRI was planned before discharge and after 4 and 12 months. Some participants did not attend all MARS MRI appointments, and there was a variation in time for the examinations (Table 1). In Odense MARS MRI was performed with Philips 1.5T Achieva scanners (Philips Healthcare, Amsterdam, the Netherlands). No contrast agent was administered. The following sequences were performed: coronal STIR, T2W and T1W, and axial T2W and T1W. For some patients axial STIR was also performed. In Malmö MARS MRI was performed using a Siemens 1.5 Tesla MRI. Dotarem (279.3 mg/mL, Guerbet, France), a gadolinium containing contrast agent, was administered intravenously (0.2 mL/kg bodyweight). Before Dotarem was administered the following sequences were performed using view-angle tilting (VAT) for artifact reduction: coronal T1 (Figure 2), coronal STIR (Figure 3), axial T1, and sagittal T2. After Dotarem was administered, axial T1 was performed and axial subtraction images were obtained. Both MRI scanners used commercially available standard sequences for metal artifact reduction, utilizing high bandwidth.