Evidence-based neuroimaging in acute ischemic stroke

Arterial cerebrovascular complications in 94 adults with acute bacterial meningitis

Introduction

Intracranial vascular complications are an important complication of acute bacterial meningitis. Ischemic stroke in meningitis is reported as a result of vasculitis, vasospasm, endocarditis or intraarterial thrombosis. The aim of the study was to identify the value of measuring cerebral blood flow velocity (CBFv) on transracranial doppler (TCD) in the identification of patients at risk for meningitis-associated stroke.

Methods

We retrospectively studied patients with acute bacterial meningitis who were treated in our university hospital from 2000 to 2009. Data were analyzed with the main focus on the incidence of an increase of CBFv on TCD, defined as peak systolic values above 150 cm/s, and the development of stroke.

Results

In total, 114 patients with acute bacterial meningitis were treated, 94 of them received routine TCD studies during their hospital stay. 41/94 patients had elevated CBFv values. This increase was associated with an increased risk of stroke (odds ratio (95% confidence intervall) = 9.15 (1.96-42.67); p < 0.001) and unfavorable outcome (Glasgow Outcome Score < 4; odds ratio (95% confidence intervall) = 2.93 (1.23-6.98); p = 0.018). 11/32 (34.4%) patients with an increase of CBFv who received nimodipine and 2/9 (22.2%) patients with an increase of CBFv who did not receive nimodipine developed stroke (p = 0.69).

Conclusions

In summary, TCD was found to be a valuable bedside test to detect arterial alterations in patients with bacterial meningitis. These patients have an increased risk of stroke.

Computed tomography follow-up imaging of stroke

Due to its widespread availability, computer tomography (CT) scanning continues to be the primary initial imaging modality for assessment of patients with suspected acute stroke. It serves as a screening tool for other structural lesions which can mimic stroke and evaluates for possible hemorrhage prior to potential thrombolytic therapy. Findings seen on the initial CT may also serve as prognostic indicators of patient outcome helping with management decisions. As well, follow-up imaging in the subacute stages of infarct is also valuable for assessment of potential complications such as infarct extension, hemorrhagic transformation (and/or intracranial hemorrhage), and cerebral edema.

Stroke Imaging with Xenon-CT

This article briefly reviews the current literature and implementation of a typically non-firstline methodology to diagnose acute stroke: inhalational-mediated Xenon CT perfusion (Xe-CT). The intent of this article is to provide a short overview of this techniques; the reader is directed to the references for additional information.

Modern Emergent Stroke Imaging: Pearls, Protocols, and Pitfalls

Stroke remains one of the most important clinical diagnoses for which patients are referred to the radiologist for emergent imaging. Timely and accurate imaging guides admission from the emergency department or transfer to a hospital with a dedicated stroke service, triage to the intensive care unit, anticoagulation, thrombolysis, and many other forms of treatment and management. It is important to approach each patient's imaging needs logically and tailor each work-up, and constantly to review the entire process for potential improvements. Time saved in getting an accurate diagnosis of stroke may indeed decrease morbidity and mortality. This article discusses the current management of stroke imaging and reviews the relevant literature.