The roles of CT and MRI techniques in ischemic stroke

Abstract

Background: Ischemic stroke is the second most common cause of death and the leading cause of disability. Imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) are essential in diagnosing the stroke and guiding the treatment strategy. Choosing a specific technique might be challenging in different clinical situations. Material and methods: The study involved searching PubMed database with the following keywords: ischemic stroke, computed tomography, magnetic resonance imaging. The search revealed over 1100 articles, from which 52 were relevant for the studied topic. Results: A head CT scan can quickly exclude the presence of hemorrhage and reveal related signs of ischemia such as the loss of contrast between the gray and white matter, hyperdense vessel sign, etc. CT imaging can also exclude other pathologies that may resemble stroke clinically. MRI is generally more sensitive than CT in the detection of ischemia, although an MRI exam is more complicated and timeconsuming, which can limit its applications in an emergency. The major advantages of MRI are also related to absence of radiation and relatively safer contrast agents. Imaging vertebral and carotid arteries and their branches is an essential part of a stroke protocol and both CT and MR angiography techniques can be used for this purpose, each having its own advantages and disadvantages. A variety of newly emerged techniques such as perfusion computed tomography of the brain can also significantly improve the detection of fresh ischemia. Conclusions: It is most likely that CT and MRI will coexist for decades, and the imaging modality for patients with acute neurological deficits will be decided according to local conditions and patient’s characteristics. Patients are likely to benefit from developmental research of both imaging techniques.