Brain abscess and brain tumor: discrimination with in vivo H-1 MR spectroscopy

To determine the ability to differentiate brain abscess from cystic or necrotic brain tumor with hydrogen-1 magnetic resonance (MR) spectroscopy.

H-1 MR spectroscopy was prospectively performed in seven consecutive patients with pyogenic brain abscess and in seven consecutive patients with necrotic or cystic brain tumor (five patients with glioblastoma and one each with pilocytic astrocytoma and metastasis from lung cancer) in whom radiologic images depicted ring-shaped areas of contrast material enhancement (indicative of a cystic or necrotic mass). Assignment of resonance peaks to metabolites was based on reports in the literature.

In six of seven patients with abscess, there were various resonances attributed to lactate, valine, alanine, leucine, acetate, succinate, and unidentified metabolites (2.2, 2.9, 3.2, 3.4, and 3.8 ppm). In six of seven patients with tumor, there was only a resonance attributed to lactate. One patient with a tumor had an unidentified peak at 0.9 ppm (presumably attributed to lipid) in addition to the peak attributed to lactate.

Spectral patterns from in vivo H-1 MR spectroscopy may permit differentiation of brain abscess from necrotic or cystic tumor.