Zerebrale Mikroblutungen: Bildgebung, Ursachen und Differenzialdiagnosen

Zusammenfassung

Zerebrale Mikroblutungen (ZMB) sind kleinste Hämosiderinablagerungen im Hirnparenchym, die auf suszeptibilitätsempfindlichen MRT-Sequenzen als kleine, rundliche bis ovale Signalauslöschungen zu erkennen sind. Diese Übersichtsarbeit fasst methodische Aspekte zusammen, die helfen, ZMB sicher zu identifizieren und von anderen Ursachen fokaler Hypointensitäten in diesen Sequenzen abzugrenzen. Wichtige Differenzialdiagnosen und Imitatoren („mimics“) werden vorgestellt. Darüber hinaus wird die klinische Bedeutung der ZMB diskutiert, insbesondere ihre Rolle als MRT-Marker verschiedener zerebraler Mikroangiopathien.

Abstract

Cerebral microbleeds (CMB) represent small hemosiderin deposits, which are surrounded by normal brain tissue and can be depicted as small, rounded or ovoid areas of signal loss on susceptibility-sensitive MRI sequences. This review summarizes helpful methodological considerations to identify CMBs and to differentiate them from other causes of focal hypointensities on these sequences. Important differential diagnoses and „mimics“ are presented and the clinical relevance of CMBs is discussed, in particular their role as important MRI marker of various cerebral small vessel diseases.

Kernaussagen

• Zerebrale Mikroblutungen (ZMB) finden sich bei älteren Patienten und auch in der asymptomatischen älteren Allgemeinbevölkerung in suszeptibilitätsgewichteten MRT-Sequenzen häufig.

• ZMB zeigen eine gewisse erhöhte Blutungsneigung des Hirngewebes an, weshalb ihre Bedeutung als Risikofaktor symptomatischer Hirnblutungen aktuell intensiv beforscht wird.

• Für den Radiologen sind die ZMB vor allem als MRT-Marker verschiedener zerebraler Mikroangiopathien wichtig.

• Konsensuskriterien sind hilfreich, um ZMB von Artefakten und Imitatoren („mimics“) zu unterscheiden.

Keywords

Cerebral microbleeds - imaging - T2*-weighted sequences - susceptibility-weighted imaging - cerebral small vessel disease - cerebral amyloid angiopathy

• Literatur

• 1 Offenbacher H, Fazekas F, Schmidt R et al. MR of cerebral abnormalities concomitant with primary intracerebral hematomas. AJNR Am J Neuroradiol 1996; 17: 573-578
• 2 Fazekas F, Kleinert R, Roob G et al. Histopathologic analysis of foci of signal loss on gradient-echo T2*-weighted MR images in patients with spontaneous intracerebral hemorrhage: evidence of microangiopathy-related microbleeds. AJNR Am J Neuroradiol 1999; 20: 637-642
• 3 Greenberg SM, Vernooij MW, Cordonnier C. Microbleed Study Group et al. Cerebral microbleeds: a guide to detection and interpretation. Lancet Neurol 2009; 8: 165-174
• 4 Schrag M, McAuley G, Pomakian J et al. Correlation of hypointensities in susceptibility-weighted images to tissue histology in dementia patients with cerebral amyloid angiopathy: a postmortem MRI study. Acta Neuropathol 2010; 119: 291-302
• 5 Greenberg SM, Nandigam RN, Delgado P et al. Microbleeds versus macrobleeds: evidence for distinct entities. Stroke 2009; 40: 2382-2386
• 6 Nandigam RN, Viswanathan A, Delgado P et al. MR imaging detection of cerebral microbleeds: effect of susceptibility-weighted imaging, section thickness, and field strength. AJNR Am J Neuroradiol 2009; 30: 338-343
• 7 Stehling C, Wersching H, Kloska SP et al. Detection of asymptomatic cerebral microbleeds: a comparative study at 1.5 and 3.0 T. Acad Radiol 2008; 15: 895-900
• 8 Tatsumi S, Ayaki T, Shinohara M et al. Type of gradient recalled-echo sequence results in size and number change of cerebral microbleeds. AJNR Am J Neuroradiol 2008; 29: e13
• 9 Vernooij MW, Ikram MA, Wielopolski PA et al. Cerebral microbleeds: accelerated 3D T2*-weighted GRE MR imaging versus conventional 2D T2*-weighted GRE MR imaging for detection. Radiology 2008; 248: 272-277
• 10 Haacke EM, Xu Y, Cheng YC et al. Susceptibility weighted imaging (SWI). Magn Reson Med 2004; 52: 612-618
• 11 Kunimatsu A, Suzuki Y, Hagiwara K et al. Clinical value of 3D T2*-weighted imaging with multi-echo acquisition: comparison with conventional 2D T2*-weighted imaging and 3D phase-sensitive MR imaging. Magn Reson Med Sci 2012; 11: 205-211
• 12 Wu Z, Mittal S, Kish K et al. Identification of calcification with MRI using susceptibility-weighted imaging: a case study. J Magn Reson Imaging 2009; 29: 177-182
• 13 Ayaz M, Boikov AS, Haacke EM et al. Imaging cerebral microbleeds using susceptibility weighted imaging: one step toward detecting vascular dementia. J Magn Reson Imaging 2010; 31: 142-148
• 14 Boeckh-Behrens T, Lutz J, Lummel N et al. Susceptibility-weighted angiography (SWAN) of cerebral veins and arteries compared to TOF-MRA. Eur J Radiol 2012; 81: 1238-1245
• 15 Vernooij MW, Ikram MA, Tanghe HL et al. Incidental findings on brain MRI in the general population. N Engl J Med 2007; 357: 1821-1828
• 16 Zabramski JM, Wascher TM, Spetzler RF et al. The natural history of familial cavernous malformations: results of an ongoing study. J Neurosurg 1994; 80: 422-432
• 17 Rigamonti D, Drayer BP, Johnson PC et al. The MRI appearance of cavernous malformations (angiomas). J Neurosurg 1987; 67: 518-524
• 18 Gaviani P, Mullins ME, Braga TA et al. Improved detection of metastatic melanoma by T2*-weighted imaging. AJNR Am J Neuroradiol 2006; 27: 605-608
• 19 Scheid R, Preul C, Gruber O et al. Diffuse axonal injury associated with chronic traumatic brain injury: evidence from T2*-weighted gradient-echo imaging at 3 T. AJNR Am J Neuroradiol 2003; 24: 1049-1056
• 20 Gregoire SM, Jäger HR, Yousry TA et al. Brain microbleeds as a potential risk factor for antiplatelet-related intracerebral haemorrhage: hospital-based, case-control study. J Neurol Neurosurg Psychiatry 2010; 81: 679-684
• 21 Charidimou A, Shakeshaft C, Werring DJ. Cerebral microbleeds on magnetic resonance imaging and anticoagulant-associated intracerebral hemorrhage risk. Front Neurol 2012; 3: 1-13
• 22 Shoamanesh A, Kwok CS, Lim PA et al. Postthrombolysis intracranial hemorrhage risk of cerebral microbleeds in acute stroke patients: a systematic review and meta-analysis. Int J Stroke 2013; 8: 348-356
• 23 Charidimou A, Shoamanesh A, Wilson D et al. Cerebral microbleeds and postthrombolysis intracerebral hemorrhage risk Updated meta-analysis. Neurology 2015; 85: 927-934
• 24 Charidimou A, Werring DJ. Cerebral microbleeds and cognition in cerebrovascular disease: an update. J Neurol Sci 2012; 322: 50-55
• 25 Pantoni L. Cerebral small vessel disease: from pathogenesis and clinical characteristics to therapeutic challenges. Lancet Neurol 2010; 9: 689-701
• 26 Charidimou A, Gang Q, Werring DJ. Sporadic cerebral amyloid angiopathy revisited: recent insights into pathophysiology and clinical spectrum. J Neurol Neurosurg Psychiatry 2012; 83: 124-137
• 27 Samarasekera N, Smith C, Al-Shahi Salman R. The association between cerebral amyloid angiopathy and intracerebral haemorrhage: systematic review and meta-analysis. J Neurol Neurosurg Psychiatry 2012; 83: 275-281
• 28 Linn J, Halpin A, Demaerel P et al. Prevalence of superficial siderosis in patients with cerebral amyloid angiopathy. Neurology 2010; 74: 1346-1350
• 29 Chabriat H, Joutel A, Dichgans M et al. Cadasil. Lancet Neurol 2009; 8: 643-653
• 30 Poels MM, Vernooij MW, Ikram MA et al. Prevalence and risk factors of cerebral microbleeds: an update of the Rotterdam scan study. Stroke 2010; 41: 103-106