Fig. 1From: Dynamic interaction of genetic risk factors and cocaine abuse in the background of Parkinsonism – a case reportBrain MRI of the patient. On the axial susceptibility weighted images in the plane of the mesencephalon, the substantia nigra is identifiable both sides. The swallow tail sign is normally present in 3 T imaging at the area indicated by the arrows, but it is absent in the patientBack to article page