2015;15 (5): 382-4. 10.1212/WNL.0b013e31826043a9. Google Scholar. Philip J. Kistler Stroke Research Center, Massachusetts General Hospital, 175 Cambridge Street Suite 300, Boston, MA, 02114, USA, Sergi Martinez-Ramirez,Steven M Greenberg&Anand Viswanathan, You can also search for this author in -, Fisher M, French S, Ji P, Kim RC. PubMed 2004, 62: 72-76. The link you have selected will take you to a third-party website. Greenberg SM, Vernooij MW, Cordonnier C, Viswanathan A, Al-Shahi Salman R, Warach S, Launer LJ, Van Buchem MA, Breteler MM: Cerebral microbleeds: a guide to detection and interpretation. By using this website, you agree to our An official website of the United States government. National Library of Medicine For the cortical type, (transient) focal neurological symptoms are found, but also development of dementia (1). 2005, 20: 412-414. The frequency of MRI CMB in 10 cases with highest and lowest burden of putamen haemosiderin, was compared using post mortem 3T MRI. Tidsskriftet redigeres etter redaktrplakaten. Neurology. Iron chelating agents have been tried with limited anecdotal success 6. Arch Neurol. (2010) ISBN: 9780781791861 -. The MRI-CMB concept should take account of brain iron homeostasis, and small vessel ischaemic change in later life, rather than only as a marker for minor episodes of cerebrovascular extravasation. PubMed Accessibility 2016 Dec;139(Pt 12):3151-3162. doi: 10.1093/brain/aww229. PMC Seo SW, Hwa Lee B, Kim EJ, Chin J, Sun Cho Y, Yoon U, Na DL: Clinical significance of microbleeds in subcortical vascular dementia. Ann Neurol. 2012, 43: 1505-1510. Roberts TP, Mikulis D: Neuro MR: principles. 2009, 40: 492-498. From a pathophysiological standpoint, MBs appear to be the expression of a hemorrhage-prone state of the brain, which might carry a greater risk of ICH. Further supporting this observation, PiB retention was shown to rapidly decrease with increasing distance from the MB site [24]. Lancet Neurol. These two factors may explain the impact of baseline identification of MBs on future neurological events and mortality. Cerebral microbleeds as seen on magnetic resonance imaging gradient-recalled echo imaging (arrows). Rinsho Shinkeigaku. The clinical signs of iron toxicity in children are retarded growth, splenomegaly, cardiomyopathy, and endocrinopathies. View Yuranga Weerakkody's current disclosures, see full revision history and disclosures, dural defect with spinal CSF collections/spinal cyst, fragile capillary regrowth after brain surgery, cerebellar bleeding following craniectomy, spinal surgery or lumbar puncture. A few longitudinal studies have investigated the progression of MBs over time, revealing that MBs at baseline are a risk factor for the development of new MBs [3537]. Although the underlying mechanism is still a matter of debate, several clinical reports suggest that MBs might cause acute transient focal neurological episodes (TFNEs) [29, 30]. Neurology. Taken together, these observations strongly support MBs as an additional marker of SVD. Gregoire SM, Brown MM, Kallis C, Jager HR, Yousry TA, Werring DJ: MRI detection of new microbleeds in patients with ischemic stroke: five-year cohort follow-up study. Most cases of renal hemosiderosis do not cause kidney damage. 10.1002/ana.22112. Methods: This was a cross-sectional study involving 37 mountaineers in 4 groups: 10 had . Third, the implementation of more sensitive MRI sequences for MB detection will probably increase the proportion of AD patients with lobar MBs. Dierksen GA, Skehan ME, Khan MA, Jeng J, Nandigam RN, Becker JA, Kumar A, Neal KL, Betensky RA, Frosch MP, Rosand J, Johnson KA, Viswanathan A, Salat DH, Greenberg SM: Spatial relation between microbleeds and amyloid deposits in amyloid angiopathy. However, a larger study using specific neuropsychological assessments did not find any relationship between MBs and worse cognitive performance [50]. Cerebral microbleeds: a guide to detection and interpretation. MBs have extraordinary importance in the context of AD. The association between haemosiderin counts and degenerative and vascular brain pathology, clinical data, and the haemochromatosis (HFE) gene H63D genotype were analysed. Despite this high variability, MB overall prevalence is consistently higher in subjects with AD than in non-demented, older individuals [15, 50]. PLoS One. 2022 Mar 8;10:e13101. 2004, 127: 2265-2275. Epub 2013 May 24. eCollection 2022 Nov. Jordan N, Gvalda M, Cody R, Galante O, Haywood C, Yates P. Front Med (Lausanne). Results: HHS Vulnerability Disclosure, Help Neuropathology of Vascular Brain Health: Insights From Ex Vivo Magnetic Resonance Imaging-Histopathology Studies in Cerebral Small Vessel Disease. An early trial of active immunization reported some cases of severe meningoencephalitis, which prompted its termination [60]. Man fr i denne artikkelen inntrykk av at CT thorax, abdomen og bekken inngr i utredningen av demens hos en pasient i 90-rene med tidligere hjernebldning. Ann N Y Acad Sci. Neurology. 10.1148/radiol.2481071158. An early study prospectively analyzed patients with ischemic stroke, myocardial infarction (MI), or peripheral arterial disease and found evidence of local hemosiderin deposition to be present in 31 of 221 patients (14%). These are biomarkers used to distinguish Alzheimer's disease from normal ageing. 10.1159/000139661. volume6, Articlenumber:33 (2014) Unable to load your collection due to an error, Unable to load your delegates due to an error, Box and whisker plots showing relationship between the density of haemosiderin deposition and both local (. There are two types of SS. Neurology. Indeed, global cognitive tests (like MMSE) may not capture impairment in certain domains such as executive function. 1. Possible sources include brain or spine trauma, neurosurgery, cerebral or . 2013 The Authors. Extensive research has demonstrated the value of MBs as markers of small-vessel disease. 1 While the exact mechanism is unknown, the amount and location of hemosiderin deposition on MR imaging correlate with symptoms and disease burden, with most patients presenting with a combination of . Stroke. 10.1212/WNL.0b013e3182661f91. Keywords: Merritt's Neurology. Nakata Y, Shiga K, Yoshikawa K, Mizuno T, Mori S, Yamada K, Nakajima K: Subclinical brain hemorrhages in Alzheimers disease: evaluation by magnetic resonance T2*-weighted images. Several underlying conditions lead to the development of SS. Overall, there is a male predilection (M:F 3:1) 2,5. Article 2010, 68: 545-548. Causes of Hemosiderin Staining. Provided by the Springer Nature SharedIt content-sharing initiative. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. Article Cite this article. Introduction. As the frequency of MBs varies enormously depending on the MRI study characteristics and the selection of the study subjects, the reported prevalence in different clinical conditions has considerably wide ranges: 47% to 80% in ICH [12, 13], 18% to 71% [12, 14] in ischemic stroke, or 17% to 46% in cognitive decline/dementia [15]. Alz Res Therapy 6, 33 (2014). Stroke. Symptoms of compression neuropathy can be present if the lesion is in the vicinity of peripheral nerves (e.g., carpal tunnel or Guyon's canal). 10.1007/s00401-009-0615-z. It is thus a hopeful treatment option for SS. AJNR Am J Neuroradiol. Hold deg oppdatert om ny forskning og medisinske nyheter. Increase in hemosiderin deposition around the lesion typically represents the hemorrhage transitioning from an acute to chronic phase, and the extent of hemosiderin deposition is related to the number of hemorrhage . However, there is no definitive evidence supporting a high diagnostic value of these MB patterns for CAA/HV. Use to remove results with certain terms 2008, 248: 272-277. Stroke. Before Stephan Johannes Schler (born 1967), specialist in neurology from Germany, from where he has his dr. Also, a high frequency of MBs in severe vascular conditions like ischemic and hemorrhagic stroke has been noticed [17]. Diagnostic Imaging: Head and Neck. In a study of individuals with lobar ICH, a higher number of lobar hemorrhages at baseline (including MBs) predicted an increased risk of not only lobar ICH recurrence but also cognitive decline, functional dependence, or death in those individuals not dependent or demented by the time of admission [38]. 10.1212/01.wnl.0000339060.11702.dd. Cerebral microbleeds in the elderly: a pathological analysis. Hemosiderin staining can also occur after . Brain. 2008, 65: 790-795. This site needs JavaScript to work properly. Disorders that cause inflammation that lasts for an extended period, such as nonalcoholic fatty liver disease Fatty Liver Fatty liver is an abnormal accumulation of certain fats (triglycerides) inside liver cells. The .gov means its official. On returning home, the patient developed symptoms of headache, nausea, and vomiting. Programs & Resources Linn J, Halpin A, Demaerel P et al. 2010, 41: 184-186. Although data are very limited, it is conceivable that lobar MBs could predict progression to AD-type dementia but that deep MBs could anticipate the future development of vascular dementia. 2011, 68: 656-659. Manage cookies/Do not sell my data we use in the preference centre. J Alzheimers Dis. Cognitive impairment (and dementia) represents an increasing source of severe long-term disability and will be the focus of the review in the next sections. 1999;20:637642. Webb AJ, Flossmann E, Armstrong RJ. Disclaimer. Neurology. 10.1007/s00415-008-0967-7. Individuals with MBs had a much higher prevalence of executive dysfunction than those without MBs (60% versus 30%, P=0.03). Lee SH, Bae HJ, Kwon SJ, Kim H, Kim YH, Yoon BW, Roh JK: Cerebral microbleeds are regionally associated with intracerebral hemorrhage. 2009, 40: 1269-1274. Brain Nerve. 10.1093/brain/awq321. 10.1212/01.wnl.0000436609.20587.65. Cerebral amyloid angiopathy itself is associated with an elevated risk of developing dementia. 2003, 24: 88-96. 2006 Apr 25;66(8):1144-52. doi: 10.1212/01.wnl.0000208510.76323.5b. Von Sattel JP, Myers RH, Hedley-Whyte ET, Ropper AH, Bird ED, Richardson EP: Cerebral amyloid angiopathy without and with cerebral hemorrhages: a comparative histological study. Stroke. AJNR Am J Neuroradiol. Inform patients that most people with swelling in areas of the brain do not experience symptoms, however, some people may experience symptoms such as headache, confusion, PubMed Copyright 2023 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. Typical symptoms include 2-5: It is important to realize that the degree of imaging abnormality does not always correlate with the degree of clinical impairment 4. Superficial siderosisis a rare condition which results from the deposition of hemosiderin along the leptomeninges, with eventual neurological dysfunction. Clipboard, Search History, and several other advanced features are temporarily unavailable. Stroke. statement and Mutations in X-chromosomal WDR45 arise de novo; however, the dominant pattern of inheritance is unusual . The https:// ensures that you are connecting to the Analysis of CSF often reveals xanthochromia, red blood cells, and/or elevated protein. Clipboard, Search History, and several other advanced features are temporarily unavailable. Although CNS involvement in hemochromatosis may be asymptomatic and incidentally noted radiographically, patients may present with: movement disorders (e.g. Cordonnier C, van der Flier WM: Brain microbleeds and Alzheimers disease: innocent observation or key player?. 10.1212/01.WNL.0000148604.77591.67. The author has completed the ICMJE form and reports no conflicts of interest. However, these associations were more robust in individuals with strictly lobar MBs (all analyses adjusted for age, sex, education, vascular risk factors, other SVD markers, and brain atrophy). 2009, 17: 599-609. 10.1093/brain/awh253. [Clinical features of superficial siderosis]. BMJ Case Rep. 2019 Jun 8;12(6):e230431. All rights reserved. Tatsumi S, Shinohara M, Yamamoto T: Direct comparison of histology of microbleeds with postmortem MR images: a case report. 2003, 9: 448-452. AJNR Am J Neuroradiol. The long-term bleeding results in a buildup of hemosiderina component of iron storage and deliveryon the brain from circulating CSF. Epub 2011 Aug 7. One of these studies found that the presence of at least one MB yielded a more than twofold increase, but not a significant risk of non-AD dementia [57]. Offenbacher H, Fazekas F, Schmidt R, Koch M, Fazekas G, Kapeller P: MR of cerebral abnormalities concomitant with primary intracerebral hematomas. 1995;118 ( Pt 4)(4):1051-66. -. National Library of Medicine At the time the article was last revised Yahya Baba had Cheng AL, Batool S, McCreary CR, Lauzon ML, Frayne R, Goyal M, Smith EE: Susceptibility-weighted imaging is more reliable than T2*-weighted gradient-recalled echo MRI for detecting microbleeds. 2009, 8: 165-174. AJNR Am J Neuroradiol. Pain and fatigue in the legs Swelling, especially after long periods of sitting or standing still Cramps Varicose veins Itching or flaking skin Sores that don't heal Chronic venous insufficiency is. The main limitation of these studies was the use of the Mini-Mental State Examination (MMSE) as the main cognitive outcome measure. Superficial siderosis. Proper recognition and timely early diagnosis of superficial siderosis allow for early care planning. Associations and implications of cerebral microbleeds. The literature is divided as to whether the term superficial siderosis should be confined to cases where there is no history of symptomatic subarachnoid hemorrhage, or whether it is a blanket term referring to the superficial deposition of hemosiderin, irrespective of cause. People lose small amounts of iron every day, and even a read more . PubMed 2005, 110: 345-359. The clinical and prognostic significance of MBs in all these settings remains poorly understood. Scharf J, Brauherr E, Forsting M, Sartor K: Significance of haemorrhagic lacunes on MRI in patients with hypertensive cerebrovascular disease and intracerebral haemorrhage. 2013, 73: 439-441. 2007, 38: 1949-1951. Goos JD, Henneman WJ, Sluimer JD, Vrenken H, Sluimer IC, Barkhof F, Blankenstein MA, Scheltens PH, van der Flier WM: Incidence of cerebral microbleeds: a longitudinal study in a memory clinic population. 2022 Oct 19;65(4):270-277. doi: 10.33160/yam.2022.11.001. Please confirm that you are not located inside the Russian Federation. Symptoms occur when these hemorrhages cause sufficient irritation in the surrounding brain to produce seizure activity or when the lesions reach sufficient size to compress adjacent neurological structures. Superficial siderosis (SS) of the central nervous system (CNS) is a chronic condition consisting of hemosiderin deposition in the subpial layers of the brain (and spinal cord) due to chronic or intermittent low-grade extravasation of blood into the subarachnoid space. 10.1212/WNL.0b013e3182452928. It was also seen that the combination of multiple MBs and retinopathy increased the odds ratio of vascular dementia: 3.10; 95% confidence interval (CI) 1.11 to 8.62 [46]. -, Poels MM, Vernooij MW, Ikram MA, Hofman A, Krestin GP, van der Lugt A, Breteler MM. PubMed More recently, another study overcame this issue by comparing multiple MB cases with non-MB cases within an AD cohort. Cerebral amyloid angiopathy is caused by cerebrovascular amyloid deposition which leads to microaneurysms and an increased tendency to haemorrhage (microhaemorrhages or larger intracerebral parenchymal haemorrhages). The patient's next of kin have consented to the publication of this article. We discuss this complex interplay between lobar MBs, AD, and CAA in detail below. Epub 2017 Jun 5. Enter search terms to find related medical topics, multimedia and more. Superficial siderosis (SS) is a rare condition in which hemosiderin is deposited on the pial surface of the brain and/or spinal cord. The pathologic study of one of these cases [61] suggested that an inflammatory reaction had been triggered by the immunization agent and targeted -amyloid, both in tissue plaques and vessels [62]. Prevalence of Superficial Siderosis in Patients with Cerebral Amyloid Angiopathy. Soo YO, Yang SR, Lam WW, Wong A, Fan YH, Leung HH, Chan AY, Leung C, Leung TW, Wong LK: Risk vs benefit of anti-thrombotic therapy in ischaemic stroke patients with cerebral microbleeds. 10.1002/jmri.21029. Disorders of the special senses in the elderly. PubMed Central Hao Z, Yang S, Yin R, Wei J, Wang Y, Pan X, Ma A. PeerJ. The site is secure. CAS The body then traps the released iron and stores it as hemosiderin in tissues. 2005, 64: 94-101. One of the initial studies assessing the cognitive impact of MBs compared the performance on multiple cognitive domains between patients with and without MBs from a neurovascular clinic [44]. Martinez-Ramirez, S., Greenberg, S.M. Science. Careers. Privacy A unifying hypothesis for a patient with superficial siderosis, low-pressure headache, intraspinal cyst, back pain, and prominent vascularity. This study showed that AD subjects with multiple MBs had a more severe cognitive impairment (independently of disease duration) and degree of atrophy and WMH [56]. Adv Exp Med Biol. Patients tend to also exhibit other manifestations of hemochromatosis . MBs were distributed mostly in the cortical areas, predominantly in the fronto-temporal lobes, and this might suggest a high prevalence of CAA in this cohort. The site is secure. Unable to load your collection due to an error, Unable to load your delegates due to an error. 2012, 78: 326-333. Kjell Arne Kvistad (born 1960), dr.med., specialist in radiology and senior consultant. Deferiprone, which is a lipid-soluble iron chelator that can penetrate the blood-brain barrier, is reportedly effective at improving the clinical symptoms and deposition of hemosiderin. These results suggested that (a) MBs may actually have a negative effect on cognition, independently of other concurrent vascular lesions, and (b) there seems to be an anatomical correlation between the distribution of MBs and the cognitive domains affected, suggesting a direct damage of MBs over the tissue as the pathogenic mechanism. Conclusions: Differences in baseline characteristics between these two population-based cohorts may explain why deep or lobar location of MBs appears to be more prominent. From a pathological point of view, MBs are tiny deposits of blood degradation products (mainly hemosiderin) contained within macrophages and in close spatial relationship with structurally abnormal vessels. At times, a biopsy is required to distinguish melanin-induced from hemosiderin-induced hyperpigmentation. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. A later study on the same cohort reported that MBs were not associated with a faster rate of cognitive decline, suggesting that the increase in mortality may be related to other clinical events, like ICH [59]. Nat Med. Causes of hemorrhage in the "classical" type include tumor, vascular abnormality, injury, and dural defect. Hemosiderosis is a term used for excessive accumulation of iron deposits called hemosiderin in the tissues. Hemosiderin is a strong paramagnetic material, which allows its detection when a magnetic field is applied [ 1 ]. Bar chart showing distribution of haemosiderin density in the putamen across the cohort. Superficial siderosis of the central nervous system with seizures onset. Brought to you by Merck & Co, Inc., Rahway, NJ, USA (known as MSD outside the US and Canada)dedicated to using leading-edge science to save and improve lives around the world. Magnetic resonance imaging (MRI) cerebral microbleeds (CMB) arise from ferromagnetic haemosiderin iron assumed to derive from extravasation of erythrocytes. official website and that any information you provide is encrypted In contrast, strictly deep MBs were associated with vascular risk factors, lacunar infarcts, and WMH, but not with the APOE-4 allele. 2022 Sep 2;23(17):10018. doi: 10.3390/ijms231710018. Stroke. 2010, 75: 2221-2228. Hemochromatosis more often requires treatment. More recently, small areas of signal loss on T (2)*-weighted images, also called microbleeds (MBs), have been reported. The importance of cumulative MB burden is double: first, it may produce further widespread damage over brain structures; and, second, it highlights the progression of the underlying SVD. Pract Neurol. This deposition of this "foreign" material can occur all along the CNS, including the brain and the spine. 10.1161/STROKEAHA.108.516286. Apart from ICH, the other main neurological outcomes that have been associated with MBs are gait disturbances [41, 42] and cognitive impairment [43]. Greenberg SM, Eng JA, Ning M, Smith EE, Rosand J: Hemorrhage burden predicts recurrent intracerebral hemorrhage after lobar hemorrhage. However, even given the lowest estimates, it appears that MBs are a common phenomenon across different patient populations. As such, MBs are regularly identified in individuals from stroke and memory clinics, where they might have implications in therapeutic management. -, Koennecke HC. 2023 BioMed Central Ltd unless otherwise stated. parkinsonism, Parkinson-plus syndromes, chorea, myoclonus, ataxia, dystonia, or tremor) 3,4. On the other hand, several population-based studies have also reported on MB prevalence in healthy older individuals, which can be as high as 23.5% [16]. Hemosiderin a protein compound that stores iron in your tissues can accumulate under your skin. Brain. 10.1161/STROKEAHA.113.002267. Google Scholar. Ann Neurol. 10.1212/WNL.0b013e3181e396ea. Lippincott Williams & Wilkins. Staekenborg SS, Koedam EL, Henneman WJ, Stokman P, Barkhof F, Scheltens P, van der Flier WM: Progression of mild cognitive impairment to dementia: contribution of cerebrovascular disease compared with medial temporal lobe atrophy. Again, this predominant MB location matched well with the impaired cognitive areas. Mortality was also strongly predicted by MBs (especially when multiple) in another study following patients in a large memory clinic cohort [39]. Stroke. Choi P, Ren M, Phan TG, Callisaya M, Ly JV, Beare R, Chong W, Srikanth V: Silent infarcts and cerebral microbleeds modify the associations of white matter lesions with gait and postural stability: population-based study. Interestingly, MBs are also a common finding in other populations, even in healthy elderly individuals. Regardless of the exact type of lesion involved, the investigation for evidence of chronic hemorrhages in TIA seems crucial, as the simple initiation of anti-thrombotic therapy could have undesirable effects in cases with TFNE. The pathological and radiological relationship between these findings is not resolved. Google Scholar. 10.1159/000088665. Use for phrases Tanaka A, Ueno Y, Nakayama Y, Takano K, Takebayashi S: Small chronic hemorrhages and ischemic lesions in association with spontaneous intracerebral hematomas. Cerebral microbleeds (CMBs) are a crucial radiological marker of cerebral small vessel disease (CSVD) to illustrate the micropathology of perivascular hemosiderin deposition corresponding to past small foci of bleeding ().The prevalence of CMBs increases with age and exceeds 20% in community population over 60 years old (3, 4).More importantly, CMBs are also a common comorbidity . Chrostowski J, Majos M, Walczak A, Wachowski M, Majos A. Pol J Radiol. Beta-amyloid, total tau and phospho-tau in cerebrospinal fluid were consistent with Alzheimer's disease. Vestibulocochlear nerve (CN VIII) dysfunction resulting in a sensorineural hearing loss is believed to be due to the combination of a long cisternal course (thus with ample exposure to the subarachnoid space) and the susceptibility of microglial cells (which have a role in myelination) to be damaged by iron compounds 4. Google Scholar. Interestingly, in individuals with executive dysfunction, MBs were predominantly located in the frontal lobes and basal ganglia, areas classically considered the neuroanatomical substrate for executive function. In this article, we aim to review the current knowledge on the pathophysiology and clinical implications of MBs, with special emphasis on the links between lobar MBs, cerebral amyloid angiopathy, and Alzheimers disease. In this case, low MB counts may have prevented this study from identifying associations. 10.1161/STROKEAHA.109.558197. Federal government websites often end in .gov or .mil. PMC J Magn Reson Imaging. Tidsskrift for Den norske legeforening, Postboks 1152 Sentrum, 0107 OSLO, Sentralbord: 23 10 90 00 Email: redaksjonen@tidsskriftet.no. Lee SH, Ryu WS, Roh JK: Cerebral microbleeds are a risk factor for warfarin-related intracerebral hemorrhage. 8600 Rockville Pike Acta Neuropathol. 2019;1205:25-53. doi: 10.1007/978-3-030-31904-5_3. Nandigam RN, Viswanathan A, Delgado P, Skehan ME, Smith EE, Rosand J, Greenberg SM, Dickerson BC: MR imaging detection of cerebral microbleeds: effect of susceptibility-weighted imaging, section thickness, and field strength. These tumors are often associated with intralesional hemorrhage and hemosiderin deposition; because hemosiderin includes paramagnetic Fe+3 atoms, . Hemosiderin deposition is the consequence of recurrent or persistent hemorrhage in the subarachnoid space. J Neurol. Greenberg SM, Nandigam RN, Delgado P, Betensky RA, Rosand J, Viswanathan A, Frosch MP, Smith EE: Microbleeds versus macrobleeds: evidence for distinct entities. Check for errors and try again. -, Greenberg SM, Vernooij MW, Cordonnier C, Viswanathan A, Al-Shahi Salman R, Warach S, Launer LJ, Van Buchem MA, Breteler MM. PubMed Central (B) Isolated deep microbleed in the lateral aspect of the right thalamus. PubMed represent hemosiderin, calcification, physiological ferritin, melanoma, air, and some paramagnetic contrast agents.7 In particular, T2*-weighted MRI is regarded as a sensitive method for the detection of hemosiderin deposition.8-11 For example, hemosiderin may be detected as an area of signal loss on T2*-weighted images several years after . Three cases of superficial siderosis of the central nervous system and review of the literature.