The neuroradiology journal
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While the ferromagnetic properties of metallic objects, implantable medical devices, and cosmetics are well known, sand is not generally considered a consequential substance. Beaches in specific geographic regions, including the San Francisco Bay Area, have a propensity for ferromagnetic sand because of their geologic history. We describe a case in which ferromagnetic sand in a patient's hair coated the magnetic resonance imaging (MRI) scanner bore and caused significant imaging artifact, fortunately with no harm to the patient. We recommend that MRI facilities in areas where ferromagnetic sand is found consider educating technologists and screening patients for recent black sand exposure prior to scanning.
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We employed a novel diffusion tensor imaging phantom to study intra- and interscanner reproducibility on two 3T magnetic resonance (MR) scanners. Using a phantom containing thousands of hollow micron-size tubes in complex arrays, we performed two experiments using a b value of 1000 s/ms2 on two Siemens 3T Trio scanners. First, we performed 12-direction scans. ⋯ The difference between median FA values of 12-direction and 64-direction scans was statistically significant ( p < 0.001). We found relatively good reproducibility on any single MR scanner. FA values from one scanner were sometimes significantly below the mean FA of another scanner, which has important implications for clinical use of DTI.