Hair raising artifact: Images in radiology

We present the MRI images of a 41-year-old man who presented to the medical OPD with complaints of headache and was sent for MRI imaging of the brain. MRI revealed no significant brain parenchymal abnormality, but had distortion of the images at the scalp, especially at the vertex. These were present in all sequences [Figures 1-3]. The clinical examination revealed no scalp abnormality. No history of any previous surgery or head trauma was noted. He works as a welder in a factory.Figure 1: Axial T2 (a) and T2 FLAIR (b) images show multiple altered signal intensity foci with central low signal and peripheral high signal in the scalpFigure 2: Axial T1 (a) and T1 SWI (b) images show multiple altered signal intensity foci with central low signal and peripheral high signal in the scalpFigure 3: T2 coronal (a) and T2 sagittal (b) images show scalp artifacts appearing as focal scalloping of the cranial vaultDiagnosis: Susceptibility artifacts caused by iron oxide particles suspended in the patient’s hair. DISCUSSION Metallic objects can be divided according to their magnetic susceptibility into ferromagnetic, paramagnetic, and diamagnetic, where ferromagnetic substances are highly magnetized, paramagnetic moderately magnetized, and diamagnetic only faintly magnetized. Hence, ferromagnetic substances cause the most artifacts and diamagnetic the least artifacts. Iron oxide has a paramagnetic effect. Iron oxide particles cause distortion of the magnetic field homogeneity, resulting in susceptibility artifacts. These particles are not visible to the naked eye and are too small to be visualized on radiographs or computed tomography.[1] A few previous case reports have attributed this phenomenon to “hair twists,” a style popular with the black community in the USA, who use gel or beeswax on their hair that has pigments containing iron oxide.[2] Similar artifacts can be seen with cosmetics containing iron or cobalt pigments. These artifacts can be mistaken for calcified lesions of the scalp or some other pathology. Radiologists should be aware of this entity to prevent misdiagnosis, especially in persons having occupational exposure to iron oxide particles such as welders. Abbreviations MRI: Magnetic resonance imaging, SWI: susceptibility weighted imaging, FLAIR: fluid-attenuated inversion recovery. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.