Abstract 1215 Poster Session II, Sunday, 5/2 (poster 41)

Magnetic resonance imaging (MRI) and spectroscopy (MRS) are used frequently to assess in vivo anatomical and metabolic changes within a wide range of pathologies. Until recently it has been difficult to examine neonates in need for life support due to interference of the magnetic field on life support equipment. In addition, the magnetic field, and therefore MR quality may be affected by radiofrequency signals of the medical equipment. In the present study we tested the properties of equipment for neonatal life support and patient monitoring, as well as the effects of this equipment on the quality of MR imaging and proton MRS (1H-MRS).

Materials and Methods: All studies were performed in a 1.5 Tesla Philips ACS-NT whole body system with a standard Helmholtz head coil. For ventilation a Draeger Babylog 2000 was used, positioned at 5 meters of the center of the magnet. With a patient simulator ventilation characteristics using 5 meter tubing and standard 1 meter tubing were compared. Ventilator frequency ranged from 20 to 60 bpm, peak pressure ranged from 14 to 42 mmHg. For infusion an Alaris P3000 series syringe infusion pump was used with an Emdamed 700 × 1 mm line (length × diameter) at flow rates of 0.5 to 5 ml/h. Outcome parameters included time to occlusion alarm and reached infusion pressure. A specially developed MR-incubator (Draeger, Germany) was used. Temperature stability was tested at the head, body, and feet section by an alcohol thermometer at 32-37C. An adapted monitor was used for examination of heart rate and transcutaneous oxygen saturation. For examination of the effects of life support equipment on MRI and 1H-MRS quality, a phantom was used to create fast field echo and turbo spin echo images, followed by 1H-MRS.

Results. Ventilation: Time to reach peak pressure with 5 meter tubes was increased from 100 ms at a peak pressure of 14 mmHg to 200 ms at a peak pressure of 42 mmHg compared to standard tubes. This time to reach peak pressure could be reduced to baseline values by increasing the flow by 6% at 14 mmHg to 10% at 42 mmHg. Expiration time was not affected. Infusion: Infusion pressure until occlusion alarm decreased with an average of 2.6% at 0.5 ml/h to an average of 7% at 5 ml/h, while the average time to occlusion increased with 3 minutes (all within the manufacturer's deviation limits). Incubator: Thermoregulation in the MR-incubator was not affected by the 1.5 T magnetic field. The heart rate and transcutaneous oxygen saturation monitor was unchanged by the magnetic field. All used life support equipment did not show any effect on MRI or 1H-MRS quality.

Conclusions: Neonatal life support and patient monitoring could be performed safely during MRI and 1H-MRS. During ventilation minor increases of air flow rate are necessary to maintain an adequate inspiration time. MRI and 1H-MRS quality was unaffected by the medical equipment tested.

The infusion pump is a donation by Alaris, Amersfoort, Netherlands.