[Whole-body ferromagnetic detector systems in clinical MRI]. / Ganzkörperferrodetektorsysteme in der klinischen MRT.

CLINICAL/METHODICAL ISSUE: In spite of technical and organizational measures, ferromagnetic objects still find their way into the magnetic resonance imaging (MRI) room and can cause severe injuries. STANDARD RADIOLOGICAL METHODS: A detailed patient education and MRI safety training for personnel are necessary to avoid MRI incidents with ferromagnetic objects. METHODICAL INNOVATIONS: Whole body ferromagnetic detection systems should increase patient safety and minimize risks for personnel and MRI equipment in the clinical routine. PERFORMANCE: In a clinical MRI setting, a screener system used for outpatients and inpatients (n = 400) identified unknown ferrous objects in 2 % of the cases. In two of these cases patients were found to be in possession of unknown foreign ferrous objects. Furthermore, a door guard system only used for outpatients (n = 2500) detected unknown ferromagnetic objects in 0.3 % of the cases. ACHIEVEMENTS: The number of ferrous objects that are unknowingly brought into the scanner room can be reduced with a whole body ferromagnetic detection system. For an optimal benefit of the system a ferrous-free environment and perfectly ferrous-free clothing for the medical personnel are necessary. In the clinical routine, the benefit of the system is limited particularly for immobile patients who have to remain in a horizontal position. PRACTICAL RECOMMENDATIONS: A whole body ferromagnetic detection system can complement but not replace patient education and MRI safety training.

Magnetic resonance imaging of the active second stage of labour: proof of principle.

OBJECTIVE: To prove that magnetic resonance imaging of foetal anatomy during the active second stage of vaginal delivery is feasible. MATERIALS AND METHODS: Initially, five pregnant volunteers around the 30th week of gestation were examined in an open MRI. Based on the findings, one vaginal delivery was acquired under real-time imaging. To monitor the birth status during image acquisition, an MR-compatible wireless cardiotocography (CTG) system was built. Single-shot sequence parameters were optimised to compensate motion artefacts during labour. RESULTS: Safety requirements to monitor the birth process under real-time MR imaging were met. High-resolution MR images were acquired immediately before and after delivery. In one patient, TSE single-shot cinematic sequences of the active second stage of labour were obtained. All sequences were adapted to tolerate movement of the mother and infant, as well as residual noise from the CTG. Furthermore, the MR imaging during labour showed only minor image artefacts. CONCLUSION: CTG-monitored acquisition of MRI series during the active second stage of delivery is feasible. Image quality should allow various further studies to improve models for birth simulation as well as potential investigation of obstructed labour and obstetric complications.

[A wireless communication system for interventional MRI]. / Ein kabelloses Kommunikationssystem für die interventionelle MRT.

The available MR-compatible communication systems, which are typically designed for diagnostic exams, are mostly based on tubular sound transmission. In other settings, modern commercially available communication systems with ear protection allow wireless communication in noisy environments. The application of MR-compatible wireless headsets in interventional radiology precludes tube contact with sterile surfaces and hindrance of the interventionalist's range of motion. The system introduced here allows wireless communication within the scanner room without influencing MR image quality.