Article

Brain abscesses: etiologic categorization with in vivo proton MR spectroscopy.

Dept of Radiodiagnosis, Sanjay Gandhi Post-Graduate Institute of Med Sciences, Lucknow-226014, India.
Radiology (impact factor: 5.73). 03/2004; 230(2):519-27. DOI:10.1148/radiol.2302021317
Source: PubMed

ABSTRACT To compare the metabolite patterns observed at in vivo proton magnetic resonance (MR) spectroscopy of brain abscesses in patients for whom bacteriologic information was obtained from cultures and to categorize the MR spectral patterns with respect to the underlying etiologic agents.
MR imaging and in vivo single-voxel proton MR spectroscopic data obtained from 75 patients with brain abscesses were retrospectively analyzed. Ex vivo spectroscopic experiments with the pus from 45 of these patients also were performed, and the data were further categorized on the basis of bacteriologic information. Quantification of various metabolites and metabolite ratios and statistical analyses of lactate and lactate/amino acid (AA) ratio levels were performed by using one-way analysis of variance.
On the basis of in vivo proton MR spectroscopic and bacteriologic analysis findings, data were classified into three categories: Group 1 data showed resonances of lactate, AAs, and acetate, with or without succinate at proton MR spectroscopy; cultures for this group showed obligate anaerobes or a mixture of obligate and facultative anaerobes. The metabolite patterns in the group 2 and group 3 data were similar to the pattern of the group 1 data, with the exception that acetate and succinate resonances were absent. Culture was positive for either obligate aerobes or facultative anaerobes in group 2 and was sterile in group 3. At analysis of variance, in vivo data showed significant differences in lactate/AA ratios (P =.008), and ex vivo data showed significant differences in lactate levels (P =.001) among the three groups.
It is possible to differentiate anaerobic from aerobic or sterile brain abscesses on the basis of metabolite patterns observed at in vivo proton MR spectroscopy. This information may be useful in facilitating prompt and appropriate treatment of patients with these abscesses.

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Keywords

75 patients
 
appropriate treatment
 
bacteriologic information
 
differentiate anaerobic
 
Ex vivo spectroscopic experiments
 
group 2
 
group 3
 
group 3 data
 
lactate/AA ratios
 
lactate/amino acid
 
metabolite patterns
 
metabolite ratios
 
MR imaging
 
MR spectral patterns
 
proton MR spectroscopy
 
statistical analyses
 
underlying etiologic agents
 
various metabolites
 
vivo proton MR spectroscopic
 
vivo proton MR spectroscopy