Brain abscess differential diagnosis

Differential Diagnosis

 * Some studies suggest that indium scans can help differentiate abscess from CA, and thallium SPECT scans can distinguish CNS toxo from lymphoma.
 * A CT scan with contrast will show a ring-enhancing mass that surrounds an area of hypodensity (necrosis or edema).
 * The big differential is metastatic tumor: abscesses are often located in watershed regions, and tumors often enhance diffusely with contrast.
 * Despite these differences, the true Dx is sometimes not made until biopsy.
 * MRI is generally thought to be the imaging modality of choice and can more accurately stage the abscess and gauge the response to therapy.
 * T1 images are similar to CT, with a central hypodense signal and surrounding ring-enhancement.
 * T2 images reveal a central hyperintense area surrounded by a well-defined hypointense capsule with surrounding edema.