Bacterial Infections of the Brain and Spine

Medical University of Vienna Bacterial Infections of the Brain and Spine The fact that delay in diagnosis of CNS infections may lead to irreversible neurological deficits increases the responsibility of radiologists to promptly recognize different infections in the brain and also in the spinal canal. Magnetic resonance imaging (MRI) is the primary imaging method for the evaluation and monitoring of infection. Newer imaging techniques, such as diffusion-weighted MR imaging (DWI) diffusion-weighted imaging ), diffusion-tensor MR imaging (diffusion tensor imaging (DTI)), and pperfusion, MR and MR spectroscopy (MRS) show promising results in the differentiation between infectious and neoplastic diseases. Based on location of the brain involved bacterial infections can divided into: a) bacterial meningitis, b) encephalitis and brain abscess, c) ventriculitis, and d) subdural / epidural empyema. In the spinal canal bacterial infections can be located in the extradural (spondylitis, discitis, epidural phlegmone/abscess), intradural-extramedullary (arachnoiditis, polyradiculitis) and intramedullary (spinal cord abscess, myelitis) compartments. Cerebritis is characterized by nonspecific features on CT scans (ill-defined low density area with peripheral enhancement) and cannot reliably be distinguished from neoplasms. Cerebral abscess account for up to1-2% of all intracranial mass lesions in developed countries, with potentially high mortality rate. After the formation of a collagenous capsule, a thin-walled, markedly hypointense ring on T2-weighted MR images, with prominent surrounding edema will be recognized on MRI. Pyocephalus is an