[Modern mid-field magnetic resonance imaging in private practice : Field report]. / Moderne Mittelfeld-Magnetresonanztomographie in der Niederlassung : Erfahrungsbericht.

BACKGROUND: With the 0.55 T magnetic resonance imaging (MRI) scanner "Free.Max", a new device concept in the mid-field sector is being introduced into the market. New technologies and artificial intelligence (AI) applications as well as a new coil concept compensate for the disadvantages of the lower field strength and the widest examination tunnel measuring 80 cm. OBJECTIVES: An initial assessment was made with regard to the suitability of the 0.55 T scanner in the private practise environment. The goal was to analyse whether measurement parameters, examination protocols and image quality meet requirements and expectations. MATERIALS AND METHODS: About 2020 examinations were carried out using the Free.Max scanner. To assess the image quality and measurement parameters, about 20% of those patients had previously undergone comparative examinations of the same body parts with comparable examination protocols based on five different 1.5 T scanners in the same practice. RESULTS: This MRI device has the potential to meet the quality standards and expectations of the assessing radiologists. The measurement time is about 30 min per patient. The signal-to-noise ratio does not achieve that of images obtained using high-field scanners but allows for sufficiently safe diagnosis. Susceptibility to motion artefacts is higher and to metal artefacts lower. The concept of flexible coils and a tunnel width of 80 cm is perceived as comfortable by patients. CONCLUSIONS: The new 0.55 T scanner has the potential to partially replace high-field machines in the private practise setting. The profitability of the device will depend on the cost difference compared to the high-field scanner as longer acquisition times are currently required, which reduces examination frequency. Further developments in the mid-field sector are to be expected.

Decreased femur tunnel widening after augmented suspensory fixation compared to suspensory fixation for single bundle hamstring ACL reconstruction.

Background: Tunnel widening after Anterior cruciate ligament (ACL) reconstruction using a hamstring graft is known to occur at follow-up. Our study aimed to investigate the effect of suspensory fixation augmentation using an interference screw on tunnel widening in single-bundle hamstring ACL reconstruction. Methods: 48 patients who had single bundle ACL reconstruction with femoral fixed loop fixation technique in 15 knees, and, fixed loop with augmented aperture (bio screw) fixation in 33 knees were analyzed. The width of the tunnel was measured using radiographs immediate post-op and at follow-up within 1 year. Computerized Tomogram (CT) measurements of the tunnels and functional scores were also done with overall follow-up for the fixed loop group being 21.33 months (Standard Deviation (SD)11.14) and the Augmentation group 9.12 months (SD 3.83). Results: Midpoint femur tunnel widening was reduced in the augmentation group, with measurements of 0.74 (SD 1.05) mm Antero Posterior (AP) and 1.01 (SD 1.04) mm in the Lateral view, compared to 1.54 (SD 1.48) mm AP and 1.79 (SD1.47 mm) in the Lateral for the fixed button group. The radiological widening was considerably less in the augmentation group with a p-value of 0.07. AP aperture widening in the augmentation group was 1.25(SD 1.10 mm), and 1.09(SD0.98) mm in the lateral view. The fixed button-only group measured 1.53 (SD1.30) mm in the AP, and 1.65 (SD 1.29) mm in the lateral view, both of which were not statistically significant. The follow-up Lysholm and International Knee Documentation Committee (IKDC) scores were similar for the 2 groups. Conclusion: Femoral tunnel midpoint and aperture widening were reduced with the fixed loop with aperture (bio screw) augmentation technique for hamstring grafts in single bundle ACL fixation within 1 year with comparable functional scores. Level of evidence: 4.