Cerebral abscess

Centered on the grey-white matter junction of the right frontal lobe is a ring enhancing lesion (which is slightly hyperdense pre-contrast) surrounded by low density white matter change, consistent with vasogenic edema.  This has moderate local mass effect. 

Low density in the left occipital region with volume loss is consistent with an old area of gliosis. No other abnormality. 

Centered on the grey-white matter junction of the right frontal lobe is a ring enhancing lesion (which is slightly hyperdense pre-contrast) surrounded by low density white matter change, consistent with vasogenic edema.  This has moderate local mass effect. 

Low density in the left occipital region with volume loss is consistent with an old area of gliosis. No other abnormality. 

Lobulated mass measuring 22 x 17 x 17 mm centered on the grey-white matter junction in the right posteroinferior frontal lobe demonstrates isointense FLAIR signal, hyperintense central T2 signal with a rim which is T2 hypointense, and slightly T1 hyperintense signal with thick peripheral contrast enhancement.  The lesion involves the cortex and appears to have ruptured through the cortex with adjacent meningeal enhancement. It is surrounded by increased FLAIR signal, most in keeping with vasogenic edema.  There is associated mass effect with effacement of adjacent sulci and leftward midline shift of 4 mm at the level of the third ventricle.  The mass demonstrates restricted diffusion and reduced ADC. There is an area of restricted diffusion involving the adjacent cortex also.

MRI spectroscopy in voxel at the medial margin of the lesion demonstrates depleted NA-A, decreased choline, increased lactate and slightly increased myo-inositol.  Possible increased amino acids.

There is an old infarct in the left parieto-occipital region extending to the ventricular surface, with ex-vacuo dilatation of the posterior aspect of left lateral ventricle.

Slightly hyperdense (on pre-contrast CT) peripherally enhancing lesion (blue dotted line) is associated with meningeal enhancement (yellow arrows, MRI, T1 C+) and is surrounded by vasogenic edema. The center of the lesion demonstrates vivid restricted diffusion (MRI, DWI) (green arrow).