BRAIN-ABSCESS AND BRAIN-TUMOR - DISCRIMINATION WITH IN-VIVO H-1 MR SPECTROSCOPY

PURPOSE: To determine the ability to differentiate brain abscess from cystic or necrotic brain tumor with hydrogen-1 magnetic resonance (MR) spectroscopy. MATERIALS AND METHODS: H-1 MR spectroscopy was prospect ively performed in seven consecutive patients with pyogenic brain absc ess and in seven consecutive patients with necrotic or cystic brain tu mor (five patients with glioblastoma and one each with pilocytic astro cytoma and metastasis from lung cancer) in whom radiologic images depi cted ring-shaped areas of contrast material enhancement (indicative of a cystic or necrotic mass). Assignment of resonance peaks to metaboli tes was based on reports in the literature. RESULTS: In six of seven p atients with abscess, there were various resonances attributed to lact ate, valine, alanine, leucine, acetate, succinate, and unidentified me tabolites (2.5, 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 pati ent with a tumor had an unidentified peak at 0.9 ppm (presumably attri buted to lipid) in addition to the peak attributed to lactate. CONCLUS ION: Spectral patterns from in vivo H-1 MR spectroscopy may permit dif ferentiation of brain abscess from necrotic or cystic tumor.