Diagnostic Fundamentals of Brain Imaging

Abstract

  The brain is located in the bony structure, skull. Computed tomography (CT) and magnetic resonance imaging (MRI) are the modalities of choice to evaluate patients with neurological signs and symptoms.
  Neuroradiologists are the specialists for interpreting neuroimages, and suggesting a diagnosis with alternative possibilities of the disorder involving the central nervous system (CNS) .
  Making a correct diagnosis and narrowing the differential diagnosis are both based on the characteristic clinical and imaging findings. Neuroradiologists interpret images systematically and precisely with integrated insight into the underlying histopathological and pathophysiological changes of the diseases, considering clinical information.
  One of the basic, but essential process of the interpretation is to identify the normal macroscopic anatomical structures in the skull: the brain, vessels running in the subarachnoid spaces, and cerebrospinal fluid. The brain parenchyma is constituted of the gray matter and white matter. The cortex, basal ganglia and thalamus are the gray matter. The cerebral cortex is 2～5 mm in thickness. The cerebral white matter extends into the gyri as the medullary branches. These anatomical structures can be identified on both CT and MRI with different contrasts.
  It can be applied to CT images from patients with acute ischemic stroke, namely “early CT signs”.
  With careful identification of these normal anatomical structures, lesions with isodensity on CT or isointensity on MRI could be detected.
  Linear enhancement along the cortex (enhancement of gyral pattern) suggests non-neoplastic lesions, such as the subacute stage of the ischemic stroke and cerebral contusion.
  The aim of this article is to show how a neuroradiologist interprets CT and MR images and narrows the differential diagnosis of the CNS disorder for better understanding of the medical workers in the field of the neurological diseases and their related clinical issues.