Editing Brain abscess (section)

== Diagnosis ==
[[File:Brain Abscess at MRI (T1 + contrast) -- showing a small ring-enhancing lesion with mild surrounding edema adjacent to the ventricular catheter and ventricular dilatation..jpg|thumb|MRI (T1 with contrast) showing the ring-enhancing lesion. From a rare case report of an abscess formed as a complication of the CSF shunt. Jamjoom et al., 2009.<ref name="jamjoom09"/>]]
The diagnosis is established by a [[CT scan|computed tomography]] (CT) (with contrast) examination. At the initial phase of the inflammation (which is referred to as [[cerebrit]]is), the immature lesion does not have a capsule and it may be difficult to distinguish it from other space-occupying lesions or infarcts of the brain.  Within 4–5 days the inflammation and the concomitant dead brain tissue are surrounded with a capsule, which gives the lesion the famous [[ring-enhancing lesion]] appearance on CT examination with contrast (since intravenously applied contrast material can not pass through the capsule, it is collected around the lesion and looks as a ring surrounding the relatively dark lesion). [[Lumbar puncture]] procedure, which is performed in many infectious disorders of the central nervous system is contraindicated in this condition (as it is in all space-occupying lesions of the brain) because removing a certain portion of the [[cerebrospinal fluid]] may alter the concrete intracranial pressure balances and causes the brain tissue to move across structures within the skull ([[brain herniation]]).{{cn|date=March 2022}}

Ring enhancement may also be observed in cerebral hemorrhages (bleeding) and some brain [[tumor]]s. However, in the presence of the rapidly progressive course with fever, focal neurologic findings (hemiparesis, aphasia etc.) and signs of increased intracranial pressure, the most likely diagnosis should be the brain abscess.{{cn|date=March 2022}}