Multimodal Computed Tomography Increases the Detection of Posterior Fossa Strokes Compared to Brain Non-contrast Computed Tomography.

Cecilia Ostman,Mark W Parsons,Andrew Bivard,Shinya Tomari,Carlos Garcia-Esperon,Elizabeth Holliday,Thomas Lillicrap,Neil J Spratt,Christopher Levi

doi:10.3389/fneur.2020.588064

Abstract

Aims: Multimodal computed tomography (mCT) (non-contrast CT, CT angiography, and CT perfusion) is not routinely used to assess posterior fossa strokes. We described the area under the curve (AUC) of brain NCCT, WB-CTP automated core-penumbra maps and comprehensive CTP analysis (automated core-penumbra maps and all perfusion maps) for posterior fossa strokes.Methods: We included consecutive patients with signs and symptoms of posterior fossa stroke who underwent acute mCT and follow up magnetic resonance diffusion weighted imaging (DWI). Multimodal CT images were reviewed blindly and independently by two stroke neurologists and area under the receiver operating characteristic curve (AUC) was used to compare imaging modalities.Results: From January 2014 to December 2019, 83 patients presented with symptoms suggestive of posterior fossa strokes and had complete imaging suitable for inclusion (49 posterior fossa strokes and 34 DWI negative patients). For posterior fossa strokes, comprehensive CTP analysis had an AUC of 0.68 vs. 0.62 for automated core-penumbra maps and 0.55 for NCCT. For cerebellar lesions >5 mL, the AUC was 0.87, 0.81, and 0.66, respectively.Conclusion: Comprehensive CTP analysis increases the detection of posterior fossa lesions compared to NCCT and should be implemented as part of the routine imaging assessment in posterior fossa strokes.

Highlights

The posterior fossa is the area located at the base of the skull which contains the brainstem and the cerebellum, and this region accounts for 13% of all ischemic strokes [1, 2]
Patients were included if they presented with signs and symptoms compatible with posterior fossa stroke, and underwent multimodal CT imaging in the acute setting and follow up diffusion weighted (DWI) magnetic resonance imaging (MRI) within 7 days
From January 2014 to December 2019, 833 consecutive patients who presented with stroke-like symptoms and underwent acute multimodal computed tomography (mCT) and follow up MRI were analysed

Summary

Introduction

The posterior fossa is the area located at the base of the skull which contains the brainstem and the cerebellum, and this region accounts for 13% of all ischemic strokes [1, 2]. Posterior fossa strokes are often misdiagnosed, as some patients present acutely with non-specific symptoms such as vertigo (47%), dysarthria (31%), or nausea (27%) [3] As a result, these patients have longer times to reperfusion therapies compared to anterior circulation strokes [4]. Delays in acute diagnosis may lead to delays in identifying life-threatening complications of ischemic strokes in the posterior fossa such as occlusive hydrocephalus or brainstem compression secondary to ischemia [5]. These complications occur in up to 40% of cerebellar strokes, in particular those with large volumes of ischemic tissue (larger than 5 mL) [2, 5]. This is mostly due to physiological factors, such as the beam hardening artefact created by bony interference of the cranial vault, and technical factors such as limited zaxis coverage and high variability between automated perfusion software and CT vendor software [8,9,10]

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Results

Conclusion