In-vivo 1H MR Spectroscopy in Abscessess Induced in Rabbit Thighs: Evaluation of Treatment Effect

ABSTRACT

PURPOSE: To analyze the serial changes of proton magnetic resonance (MR) spectra in the abscess and to determine the effect of the antibiotic treatment on the metabolite patterns. MATERIALS AND METHODS: MR imaging and MR spectroscopy of an experimentally induced abscess were performed sequentially for four weeks at interval of one week in both the control group (n=5) and the antibiotic treatment group (n=5). On MR imaging, the shape and the size of the abscess were analyzed. On MR spectroscopy, the resonance peaks of metabolites were assigned on the basis of reported peaks in the literature. The metabolite ratios measured by using N-acetyl alanine as an external reference and by using lipid as an internal reference were compared in both the control and treatment groups. RESULTS: The abscesses were seen as cystic masses on MR imaging. On MR spectroscopy, the variable peaks of acetate, succinate and various amino acids, which are the metabolites of infection, were identified in the control and antibiotic treatment groups. The most frequent peak was that of acetate at 1.92 ppm (70%). Both the peak ratios of acetate to lipid and acetate to external reference tended to decrease in the treatment group while the ratios did not change significantly in the control group. CONCLUSION: MR spectroscopy is useful not only for the diagnosis of abscess but also for monitoring the evolution of the abscess by using the acetate peak.