Utility of in vitro proton magnetic resonance spectroscopy in aetiological characterisation of brain abscesses.

Purpose: Brain abscesses often present an aetiological dilemma. Microscopy is insensitive and culture techniques are time consuming. Hence, a new rapid technique in vitro Proton Magnetic Resonance Spectroscopy (1HMRS) was evaluated for its usefulness in the identification of aetiology of brain abscesses.

Materials And Methods: A total of 39 pus specimens from brain abscesses were subjected to in vitro 1HMRS. These pus specimens were also processed by conventional culture methods. The spectral patterns generated by in vitro 1HMRS were further correlated with culture results.

Results: Pus specimens which showed the presence of anaerobes on culture revealed the presence of multiplet at 0.9 ppm (100%), lactate-lipid at 1.3 ppm (100%), acetate at 1.92 ppm (100%) and succinate at 2.4 ppm (75%). Pus specimens that revealed the presence of facultative anaerobes on culture showed a pattern B, i.e., the presence of lactate-lipid at 1.3 ppm (100%), acetate at 1.92 ppm (88.88%) along with the multiplet at 0.9 ppm (100%). Pattern C was seen in aerobic infection which showed the presence of lactate-lipid at 1.3 ppm (100%) along with the multiplet at 0.9 ppm. Pus from two tuberculous abscesses showed the complete absence of multiplet at 0.9 ppm.

Conclusions: We observed in this study that it was possible to differentiate bacterial and tuberculous brain abscesses using in vitro 1HMRS. Further, it was also possible to distinguish between aerobic and anaerobic brain abscesses on the basis of spectral patterns. In vitro 1HMRS of fungal and actinomycotic brain abscess are also presented for its unusual spectra.