Case Report of a Diffusion-Weighted Magnetic Resonance Imaging Negative Patient with an Acute Occlusion of a Large Intracranial Artery

Case Report

Austin J Clin Neurol 2017; 4(3): 1108.

Case Report of a Diffusion-Weighted Magnetic Resonance Imaging Negative Patient with an Acute Occlusion of a Large Intracranial Artery

Mackenrodt D1,2 and Kraft P1,3*

¹Department of Neurology, University Hospital Würzburg, Germany

²Institute of Clinical Epidemiology and Biometry, University of Würzburg, Germany

³Klinikum Main-Spessart, Germany

*Corresponding author: Peter Kraft, Department of Neurology, University of Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany

Received: April 25, 2017; Accepted: May 15, 2017; Published: May 29, 2017


Diffusion weighted imaging (DWI) sequences in ischemic stroke (IS) are sensitive and helpful to detect even small vascular lesions. As a restriction, the majority but not all IS patients show a DWI lesion at the time of imaging in the acute stroke setting. We present one of the rare cases of a DWI negative patient with an acute occlusion of a large intracranial artery. We discuss the strengths and limitations of DWI magnetic resonance imaging (MRI) in IS and conclude that negative DWI in patients with a typical clinical presentation for stroke should be a reason to consider a stroke mimic but must not principally restrain the treating physician from thrombolysis.

Keywords: Ischemic stroke; Middle cerebral artery occlusion; Magnetic resonance imaging; Diffusion-weighted imaging; Wake-up stroke


DWI: Diffusion-Weighted Imaging; IS: Ischemic Stroke; MRI: Magnetic Resonance Imaging; rt-PA: Recombinant Tissue Plasminogen Activator; NIHSS: National Institutes of Health Stroke Scale; TOF: Time-of-Flight; MCA: Middle Cerebral Artery; ACA: Anterior Cerebral Artery; DSA: Digital Subtraction Angiography; MT: Mechanical Thrombectomy; FLAIR: Fluid Attenuation Inversion Recovery


Two decades ago large clinical trials led to the approval of recombinant tissue plasminogen activator (rt-PA). While in these trials CT imaging has been mainly or even exclusively used to assess for inclusion and exclusion criteria [1], today MRI including DWI is increasingly available in acute stroke settings. Therefore, on one hand, additional diagnostic information will be generated; on the other hand, novel challenges regarding identification of eligible patients for thrombolysis may arise. This case is intended to sensitize the readers for the underlying pathophysiology as well as the chances and pitfalls of diffusion-weighted MRI in acute IS.

Case Presentation

An 88-year-old woman with past medical history significant for arterial hypertension, hyperlipidemia, and chronic heart failure and ischemic stroke has been found in the morning lying in her bathroom unable to walk. In the emergency room the patient was drowsy, showed a right-sided hemiparesis with central facial palsy and non-fluent aphasia adding up to 15 points on the National Institutes of Health Stroke Scale (NIHSS). The initial computed tomography scan of the brain did not demonstrate hemorrhage or hypodensities suggestive for early signs of IS. Immediately, MRI including DWI and fluidattenuated inversion recovery (FLAIR) sequences, as well as a timeof- flight (TOF) intracranial angiography was performed. Last seen normal and symptom onset remained unclear but between emergency call and first MRI sequence at least 82 minutes elapsed. While there were no signs of acute IS in DWI (not shown) and only moderate white matter lesions in FLAIR images (Figure 1A), TOF angiography revealed an occlusion of the left proximal middle cerebral artery (MCA, Figure 1B). Due to the proximal MCA occlusion and the severe clinical condition we decided to treat the patient with intravenous rt-PA despite unknown symptom onset. In parallel, conventional digital subtraction angiography (DSA) was done according to the bridging-concept and confirmed the MCA-occlusion (Figure 1C). Mechanical thrombectomy using an Acandis Aperio® stent-retriever (4.5x40 mm) was successfully performed under general anesthesia (Figure 1D,E). During the intervention, a clot fragment entered the left anterior cerebral artery (ACA) but was retrieved immediately. A follow-up MRI scan two days later showed a DWI lesion suggestive for an acute IS in the left corpus callosum representing ACA territory (Figure 1F). Despite the proximal MCA occlusion there was no DWI lesion in the left MCA territory. Diagnostic work-up revealed atrial fibrillation as most likely stroke etiology. The patient recovered well and was discharged home to independent living after 6 days without any neurological deficit (NIHSS 0).

Citation: Mackenrodt D and Kraft P. Case Report of a Diffusion-Weighted Magnetic Resonance Imaging Negative Patient with an Acute Occlusion of a Large Intracranial Artery. Austin J Clin Neurol 2017; 4(3): 1108. ISSN:2381-9154