Role of MRI and cerebrospinal fluid analysis in early differential diagnosis of central nervous system infection

Abstract

Objective To investigate the significance of cerebrospinal fluid pressure,cytology and biochemistry,and MRI features in the early differential diagnosis of central nervous system infections.Methods The clinical data of 274 patients with central nervous system infections (viral encephalitis/meningitis in 166 patients,purulent meningitis in 45,tuberculous meningitis in 47 and cryptococcal meningitis in 16),admitted to our hospital from January 2007 to December 2011,were analyzed retrospectively.The cerebrospinal fluid pressure,cytology,biochemistry and MRI parameters were compared,and stepwise discriminant analysis was performed to evaluate the diagnostic value of these parameters in these four types of infections.Results Seventy six patients (27.74％) had abnormal MRI results; viral meningitis/encephalitis,purulent meningitis,tubercular meningitis and cryptococcal meningitis were found in 38,10,26 and 2 patients,respectively.Cerebrospinal fluid pressure,protein content,chloride and sugar level,and neutrophil percent were significantly different among the patients of four types of infections (P＜0.05).And cerebrospinal fluid pressure,protein content,chloride level,neutrophil percent and MRI lesions were included in the discriminant functions by stepwise discriminant analysis; the total accurate rate of the discriminant functions for diagnosis was 59.1％.The sensitivity,specificity and accurate rate of the discriminant functions were 24.4％,73.4％ and 65.3％ in purulent meningitis,61.7％,80.6％ and 77.4％ in tubercular meningitis,62.5％,56.9％ and 57.3％ in cryptococcal meningitis and 67.5％,75.0％ and 70.4％ in viral meningitis/encephalitis,respectively.Conclusion Cerebrospinal fluid pressure,protein content and chloride level,neutrophil percent,and MRI lesions are important for differentially diagnosing central nervous system infection; the disscriminant functions produced by stepwise discriminant analysis are somewhat valuable for the differential diagnosis,and the final diagnosis still based on the etiology. Key words: Central nervous system infection; Magnetic resonance imaging; Cerebrospinal fluid