Bildgebung beim Schlaganfall – eine Übersicht und Empfehlungen des Kompetenznetzes Schlaganfall

Zusammenfassung

Die bildgebende Diagnostik liefert die Grundlagen für eine spezifische und damit effektive Therapie des Schlaganfalls. Fortschritte in der Technik bildgebender Verfahren haben in den letzten Jahrzehnten viel zum Verständnis der Pathophysiologie der zerebralen Ischämie beigetragen und neue diagnostische und therapeutische Möglichkeiten eröffnet. Die Computertomografie (CT) ist die weltweit am weitesten verfügbare Methode zur bildgebenden Diagnostik beim Schlaganfall. Ihre entscheidende Bedeutung liegt im Ausschluss bzw. Nachweis intrakranieller Blutungen. Damit ermöglicht sie die Indikationsstellung zur intravenösen Thrombolyse. Darüber hinaus lassen sich in der CT in vielen Fällen bereits innerhalb der ersten Stunden nach Schlaganfall sogenannte Ischämiefrühzeichen identifizieren, die differentialtherapeutische und prognostische Bedeutung haben. Die multiparametrische MRT mit diffusionsgewichteter Bildgebung, Perfusionsbildgebung, MR-Angiografie und T2*-gewichteter Bildgebung ist ebenso sensitiv in der Diagnostik intrakranieller Blutungen und liefert darüber hinaus Informationen über das Ausmaß der Ischämie, der Hypoperfusion und den Gefäßstatus. Sie ermöglicht die Darstellung von Risikogewebe als Grundlage für eine Thrombolyse jenseits von 3 Stunden. Die multiparametrische CT mit Perfusions-CT und CT-Angiografie bietet wahrscheinlich vergleichbare Informationen, ist jedoch weniger sensitiv für kleine Infarkte. Neurosonologische Methoden ermöglichen eine Darstellung von arteriosklerotischen und nicht arteriosklerotischen Stenosen und Verschlüssen extrakranieller Hirngefäße. Transkranielle Untersuchungen können „online” Aufschluss geben über Verschlüsse, Rekanalisationen und Reokklusionen der kaliberstarken Hirnbasisarterien einschließlich kollateraler Versorgungswege. Die Positronenemissionstomografie (PET) hat entscheidend zur Entwicklung der pathophysiologischen Modelle der zerebralen Ischämie beigetragen und dient insbesondere als Goldstandard zur Kalibrierung der Untersuchungen mit multiparametrischer CT und MRT. Es ist davon auszugehen, dass die erweiterte Bildgebung mit MRT und CT in Zukunft eine zunehmende Rolle in der Steuerung der Akutbehandlung wie auch in klinischen Studien zur akuten Schlaganfallbehandlung spielen wird. Abschließend werden Empfehlungen für die Bildgebung beim akuten Schlaganfall gegeben.

Abstract

For the past decades, new technical developments in brain imaging have greatly contributed to a better understanding of the pathophysiology of acute stroke und have paved the way for new possibilities in the diagnosis and treatment of acute stroke. Brain imaging provides indispensable information for a specific and effective management of acute stroke patients. Non-contrast CT is the most widely available technique and has its major impact in the diagnosis or exclusion of intracranial hemorrhage. In addition, early ischaemic signs can be identified on CT in a large number of patients already within the first hours of stroke. Non-contrast CT is the only imaging modality that is required prior to treatment with intravenous thrombolysis. Multiparametric stroke MRI including diffusion-weighted imaging, perfusion imaging, MR angiography and T2*-weighted imaging also detects intracranial haemorrhage with high sensitivity, and provides additional information on the extent of the ischaemic lesion, hypoperfused tissue and on the vessel status. Stroke MRI allows the identification of tissue at risk of infarction, which is the target for reperfusion therapies beyond the 3-hour time window. Multiparametric CT combining perfusion CT and CT angiography likely provides comparable information. Doppler and duplex sonography is a reliable method to screen for pathologies of the extracranial arteries. Transcranial sonography additionally enables one to assess large intracranial vessels in the majority of patients. For the future, multiparametric brain imaging with modern CT or MRI techniques is expected to play an increasing role in the management of acute stroke in the routine clinical setting, as well as in clinical trials.

Schlüsselwörter

Schlaganfall - Bildgebung - Computertomografie - Magnetresonanztomografie

Keywords

stroke - imaging - computed tomography - magnetic resonance imaging

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