Lactate and T 2 measurements of synovial aspirates at 1.5 T: differentiation of septic from non-septic arthritis.

Abstract Objective  The aim of this study was to differentiate septic from non-septic arthritis by measuring lactate concentration with 1H magnetic resonance spectroscopy (HMRS) and by estimating total protein content with the assessment of T 2 values. Materials and methods  In 30 patients with acute arthritis, synovial fluid was aspirated. Lactate concentrations were analyzed with single voxel HMRS at 1.5 T. T 2 relaxation times were mapped with a multi-spin echo sequence. All samples underwent microbiological testing and routine laboratory analysis to quantify lactate concentration and total protein content. Values obtained in septic and non-septic arthritis were compared with a Mann–Whitney U test. Results  Synovial fluid from patients with septic arthritis (n = 10) had higher concentrations of lactate (11.4 ± 4.0 mmol/L) and higher total protein content (51.8 ± 10.7 g/L) than fluid obtained in non-septic arthritis (n = 20; 5.2 ± 1.1 mmol/L and 40.4 ± 6.9 g/L, respectively, p T 2 relaxation times (as an indicator of total protein content) were moderately correlated to laboratory-confirmed lactate concentration (r 2 = 0.71) and total protein content (r 2 = 0.73). Markedly increased lactate concentrations (>6 mmol/L) in combination with low T 2 values ( Conclusion  Spectroscopic measurements of lactate concentration in combination with the estimation of protein content using T 2 may be of value in the differentiation of septic from non-septic arthritis. [ABSTRACT FROM AUTHOR]