The differential of an established abscess is essentially that of a ring enhancing lesion, and therefore includes:
Metastasis or high-grade glioma (e.g. GBM)
abscesses tend to have smoother inner wall
satellite lesions favour infection
abscesses may have low intensity capsule
rCBV elevated in high grade gliomas, reduced in abscesses
low intensity SWI rim of GBM
incomplete and irregular in 85%
within (rather than overlapping) the peripheral enhancement
absent dual rim sign
subacute infarction, haemorrhage or contusion
demyelination
When a lesion demonstrates both ring enhancement and central restricted diffusion the differential is very much narrowed, and although cerebral abscess is by far the most likely diagnosis, the following should also be included on the differential diagnosis:
cerebral metastases
necrotic adenocarcinoma.
ADC whole lesion histogram profiling provides a valuable tool to differentiate between morphologically indistinguishable mass lesions. Among the investigated parameters, the 10th percentile of the ADC volume distinguished best between GBM and BA 1).