Basics of required neuroimaging for neuroanesthesia

Abstract

Neuroimaging is a very important tool for the neuroanesthesiologist, allowing him or her to grasp intracranial factors influencing intracranial pressure and cerebral hemodynamics in patients with neurologic disease. While computed tomography (CT) provides excellent images of acute hemorrhages and bone and good visualization of neural elements, visualization of the structure of the posterior fossa, spinal cord lesions, early infarction, and subacute hemorrhages is relatively poor. Magnetic resonance imaging (MRI) provides an excellent tool for depiction of all neural elements, including lesions of the posterior fossa and spinal cord. Among MRI sequences, T2-weighted images in particular provide excellent visualization of fluids such as cerebrospinal fluid and brain edema. High intensity in diffusion-weighted images with a low apparent diffusion coefficient is particularly useful in the diagnosis of acute ischemic stroke. Computed tomography angiography and MR angiography provide noninvasive alternatives to conventional angiography. Angiography is playing a new role in interventional neuroradiology. Modern functional and metabolic imaging modalities such as positron emission tomography and single-photon emission tomography provide direct information on cerebral hemodynamics and metabolism. Functional MRI can detect increased blood flow in the brain associated with neuronal activation, which is useful in brain mapping, localizing motor and speech functions, and determining the relationships between various abnormalities in the eloquent regions of the brain.