Low field (0.02 T) nuclear magnetic resonance imaging of the brain

Many technical and instrumental alternatives are available to obtain good spatial and contrast resolution in magnetic resonance (MR) imaging. Optimum field strength remains a controversial question. In spite of its inherent low signal-to-noise ratio, low field imaging exhibits some advantages. It is well established that the relaxation times are dependent on the magnetic field strength. In low fields the relaxation times, especially T1, are shorter and the relative differences of T1 between different tissues are larger. Other benefits are the ease of installation of the device, its cost effectiveness, and the obvious avoidance of hazards caused by the magnetic field. In this report we describe six cases of cerebral lesions studied with an MR imager operating at a field strength of 0.02 T (200 G). This is the lowest field strength reported in clinical MR imaging. The information obtained was equal to that of the CT studies performed on the same patients.