Advanced neuroimaging in stroke patients: prediction of tissue fate and hemorrhagic transformation

Abstract

Stroke is the second greatest cause of mortality worldwide after ischemic heart disease. It is also the leading cause of disability in industrialized countries. According to the WHO, 15 million people worldwide suffer a stroke annually. It is very difficult to distinguish between an ischemic and a hemorrhagic stroke on a clinical basis, therefore imaging (computed tomography or MRI) plays a central role in the evaluation of patients with acute stroke symptoms. Because of significant advances over the last decade, imaging now provides information beyond the mere presence or absence of intracerebral hemorrhage. Comprehensive neurovascular imaging protocols using computed tomography or MRI can be acquired within minutes, helping to distinguish stroke etiology and guiding treatment decisions for acute reperfusion therapies. The purpose of this article is to give an overview of diagnostic information provided by neuroimaging in the setting of acute stroke, especially ischemic stroke, including information about brain tissue viability status and blood–brain barrier permeability. We will discuss the indications of the current treatment options for stroke, and how imaging influences treatment decision. We will organize our discussion around the concept of the ‘four Ps’ (parenchyma, pipes, penumbra and permeability) proposed by Howard Rowley, which is an excellent guide for understanding the underlying causes and pathophysiology of ischemic stroke.

Keywords::

• blood–brain barrier permeability
• computed tomography
• hemorrhagic transformation
• ischemic penumbra
• MRI
• stroke

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Notes

^†Thrombolytic therapy should not be delayed while results are pending, unless there is clinical suspicion of a bleeding abnormality or thrombocytopenia, the patient has received heparin or warfarin, or the use of anticoagulants is not known.

INR: International normalized ratio; PTT: Partial thromboplastin time.