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| Stage | Description | Histology | MRI | MR spectroscopy | CT | CT perfusion |
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| I | Early cerebritis, intermediate cerebritis | Early infection, inflammation. Poorly demarcated, toxic changes, and perivascular infiltrates | T1 isointensity to hypointensity. T2 hyperintensity without a defined margin; ill-defined nodular enhancement | | Ill-defined low attenuation, variable contrast enhancement (no enhancement, nodular, or ring enhancement) | |
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| II | Late cerebritis | Reticular matrix (collagen precursor), developing necrotic center | Increasing edema, development of rim of granulation tissue. T1 hypointensity. T2 isointensity to hyperintensity with surrounding edema; incomplete to complete zone of enhancement | | Poorly defined low attenuation edema; thick ring or nodular enhancement | |
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| III | Early capsule | Neovascularity, necrotic center, and periphery reticular matrix | Peripheral zone of enhancement is thinner, more uniform in contour, and relative to mesial thinning. No persistent central enhancement | | Core is round or ovoid low attenuation, sometimes faint surrounding capsule ring. Ring enhancement corresponds to granulation tissue of capsule; medial or ventricular thinner than lateral wall due to differences in capsule blood supply | |
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| IV | Late capsule | Collagen capsule, necrotic center, and gliosis around capsule | Loss of capsular hypointensity on T2-weighted images, reduction in size of central necrotic cavity. Enhancement may persist for several months, but progressively decreases on serial examination | | Same as III above | |
| Increased signal intensity of DWI, decreased signal intensity on ADC map | Metabolites identified in abscess: lactate, succinate, acetate, amino acids (valine, leucine, and isoleucine), and aspartate | Increase in cerebral blood flow, cerebral blood volume seen in 24 hours, and peak in 48–72 hours |
| Increased fractional anisotropy and reduced mean diffusivity | Late capsule: necrotic center lack normal brain metabolites of NAA, choline, and creatine. Elevated cytosolic amino acids (valine, leucine, and isoleucine), lactate, acetate, and succinate | |
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