Pyogenic Cerebritis and Brain Abscess

Abstract

Despite essential proceedings in diagnosis and therapy during the past decades, pyogenic cerebritis and brain abscesses remain severe, potentially life-threatening diseases of the CNS that should be diagnosed without delay. The spectrum of pathogens differs considerably depending on the route of infection, on the one hand, and the status of the immune system of the host, on the other. In addition to the clinical examination, imaging studies are the main diagnostic clues for an early diagnosis. The different histological stages of abscess formation from early cerebritis to a mature encapsulated abscess are reflected in nonenhanced and contrast-enhanced CT and MR imaging findings. Magnetic resonance imaging is the imaging procedure of choice, not only in the primary diagnosis, but also in planning surgical or stereotactic procedures, and in the follow-up of patients with pyogenic brain infections. In addition to the morphological information, DWI, PerfMRI, and MRS add valuable metabolic information that may help to differentiate pyogenic infections from other disease processes. The main differential diagnoses of cerebritis include arterial or venous infarction, and nonpyogenic inflammations. Abscesses have to be discriminated from autochthonous and metastatic brain tumors.