title: Infratentorial superficial siderosis: Classification, diagnostic criteria, and rational investigation pathway.
abstract: Central nervous system infratentorial superficial siderosis (iSS) is increasingly detected by blood-sensitive magnetic resonance imaging (MRI) sequences. Despite this, there are no standardized diagnostic criteria, and the clinical-radiological spectrum, causes, and optimum investigation strategy are not established. We reviewed clinical and radiological details of patients with iSS assessed at a specialist neurological center during 2004-2016 using predefined standardized radiological criteria. All imaging findings were rated blinded to clinical details. We identified 65 patients with iSS, whom we classified into 2 groups: type 1 (classical) and type 2 (secondary) iSS. Type 1 (classical) iSS included 48 patients without any potentially causal radiologically confirmed single spontaneous or traumatic intracranial hemorrhage, of whom 39 (83%) had hearing loss, ataxia, or myelopathy; type 2 (secondary) iSS included 17 patients with a potentially causal radiologically confirmed spontaneous or traumatic intracranial hemorrhage, of whom none had hearing loss, ataxia, or myelopathy. Of the patients with type 1 (classical) iSS, 40 (83%) had a potentially causal cranial or spinal dural abnormality, 5 (11%) had an alternative cause, and 3 (6%) had no cause identified. Intra-arterial digital subtraction angiography did not identify any underlying causal lesions for type 1 iSS. Type 1 (classical) iSS, defined using simple radiological criteria, is associated with a characteristic neurological syndrome. Rational investigation, including spinal MRI, nearly always reveals a potential cause, most often a dural abnormality. Catheter angiography appears to be unhelpful, suggesting that classical iSS is not associated with macrovascular arterial pathology. Recognition of type 1 (classical) iSS should allow timely diagnosis and early consideration of treatment. Ann Neurol 2017;81:333-343.
authors.affiliation: Stroke Research Centre, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London.
authors.forename: Duncan
authors.initials: D
authors.lastname: Wilson
authors.affiliation: Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London.
authors.forename: Fiona
authors.initials: F
authors.lastname: Chatterjee
authors.affiliation: National Hospital for Neurology and Neurosurgery, London.
authors.forename: Simon F
authors.initials: SF
authors.lastname: Farmer
authors.affiliation: National Hospital for Neurology and Neurosurgery, London.
authors.forename: Peter
authors.initials: P
authors.lastname: Rudge
authors.affiliation: Department of Neurology, Altnagelvin Area Hospital, Derry, United Kingdom.
authors.forename: Mark O
authors.initials: MO
authors.lastname: McCarron
authors.affiliation: Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London.
authors.forename: Peter
authors.initials: P
authors.lastname: Cowley
authors.affiliation: Stroke Research Centre, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London.
authors.forename: David J
authors.initials: DJ
authors.lastname: Werring
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D001927:Brain Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000209:etiology; D001933:Brain Stem / Q000000981:diagnostic imaging*; D005260:Female; D006486:Hemosiderosis / Q000145:classification / Q000000981:diagnostic imaging* / Q000209:etiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009192:Myelography; D012042:Registries; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000209:etiology; D014057:Tomography, X-Ray Computed