Case Report blood products (deoxyhemoglobin, intracellular methemo- globin and hemosiderin) and the surrounding tissue [14]. This all led to an increase in the number of indications to SWI use. It was found that this sequence provides addition- al information, very useful in the diagnostics of brain inju- ries, coagulopathies, vascular malformations, tumors and degenerative diseases accompanied by iron deposits and calcifications [15,16]; but the most valued property of SWI was its sensitivity in diagnosing extravasated blood [17,18]. SWI sequence is a method with the highest sensitiv- ity in detection of foci of microhemorrhage; according to some authors, six times higher than the conventional T2-weighted gradient-echo sequences [19–21]. This con- cerns both the size and the number of foci, as well as the volume of extravasated blood. References: 1. Rauscher A, Sedlacik J, Barth M et al: Magnetic susceptibility sensitive MR phase imaging of the human brain. 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Koeppen AH, Dickson AC, Chu RC et al: The pathogenesis of superficial siderosis of the central nervous system. Ann Neurol, 1993; 34: 646–53 9. McCarron MO, McKinstry CS, Gibson JM: Superficial siderosis 20 years after brain tumour. Lancet Neurol, 2002; 1: 326 10. McCarron MO, Flynn PA, Owens C et al: Superficial siderosis of the central nervous system many years after neurosurgical procedures. J Neurol Neurosurg and Psych, 2003; 74: 1326–28 11. Linn J, Herms J, Dichgans M et al: Subarachnoid Hemosiderosis and superficial cortical hemosiderosis in cerebral amyloid angiopathy. AJNR Am J Neuroradiol, 2008; 29: 184–86 50 © Pol J Radiol, 2010; 75(3): 47-50 Moreover, in the study on MRI presented by us, the appli- cation of the SWI sequence allowed for the detection and imaging of an actual extension and of a precise location of hemosiderin deposits on the surface of the brain, cerebel- lum and ventricular system. Conclusions In the presented case, we found the SWI sequence to be useful in diagnosing the presence and extension of the areas of extravasated blood. MRI with this sequence allowed for the detection of an extremely rare complica- tion of the surgical procedure, i.e. cerebral hemosiderosis. Authors suggest that SWI sequence should be included in the set of routine MRI procedures, especially in the cases of extensive neurosurgical procedures, as well as in many other pathologies of the CNS that may be complicated by intracranial bleeding. 12. Cook SW, Nguyen ST, Hu B et al: Cerebral hemispherectomy in pediatric patients with epilepsy: comparison of three techniques by pathological substrate in 115 patients. J Neurosurg, 2004; 100: 125–41 13. Reichenbach JR, Venkatesan R, Schillinger DJ et al: Small vessels in the human brain: MR venography with deoxyhemoglobin as an intrinsic contrast agent. Radiology, 1997; 204: 272–77 14. 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Tong KA, Ashwal S, Obenaus A et al: Susceptibility-weighted MR imaging: a review of clinical application in children. AJNR Am J Neuroradiol, 2008; 29: 9–17 19. Akter M, Hirai T, Hiai Y et al: Detection of hemorrhagic hypointense foci in the brain on susceptibility-weighted imaging clinical and phantom studiem. Acad Radiol, 2007; 14: 1011–19 21. Babikian T, Frezer MC, Tong KA et al: Susceptibility-weighted MR imaging: neuropsychologic outcome and pediatric head injury. Pediatr Neurol, 2005; 33: 184–94