Experimental brain abscess evolution: computed tomographic and neuropathologic correlation.

Brain abscess evolution was studied in dogs by correlating the CT appearance with the neuropathologic findings. The abscess, produced by direct inoculation, progressed from an area of cerebritis to a well encapsulated abscess over 14 days. Ring enhancement was seen in the cerebritis stage prior to capsule formation. The ring reached its maximum size at this stage and correlated best with the area of cerebritis surrounding the developing necrotic center; the rim of this ring increased in thickness, resulting in progressive diminution of the central lucent area on scans delayed up to 60 min. The diameter of the ring decreased as cerebritis receded. Once the capsule had formed, the central lucent area was similar and no longer filled in on delayed scans.