Single photon emission computed tomography in tuberculous meningitis.

INTRODUCTION: Data on single photon emission computed tomography (SPECT) in tuberculous meningitis are lacking and prompted this study. SPECT findings in tuberculous meningitis are reported and correlated with clinical and radiological findings. PATIENTS AND METHODS: Seventeen patients with tuberculous meningitis that was diagnosed on clinical, radiological, and laboratory criteria have been included. Their age ranged between 5 and 62 years and four of them were female. Computed tomography and/or magnetic resonance imaging (MRI) and SPECT using (99m)Tc-ethylene cystine dimer were performed in all the patients. On the basis of Barthel index (BI) score the patients' outcome was defined as complete (BI = 20), partial (BI = 19-12), and poor recovery (BI<12). RESULT: Eleven patients were in stage III and three each in stage II and stage I tuberculous meningitis. Two patients had hemiplegia and five quadriplegia. Computed tomography was abnormal in 11 out of 16 patients and revealed hydrocephalus in nine, basal exudates, infarction in subcortical white matter and basal ganglia in six patients each, frontal cortical infarction in one, and granulomata in three patients. Cranial MRI was carried out in four patients and revealed multiple granulomata, hydrocephalus, and brainstem infarction in two patients each. SPECT studies were abnormal in all except two patients and revealed hypoperfusion of the basal ganglia in 14, cortical hypoperfusion in 10, and midbrain hypoperfusion in one patient. At the three month follow up four patients had died, five had poor, three partial, and five complete recovery. The SPECT studies were more frequently abnormal compared with computed tomography but did not correlate with stage of meningitis or outcome.
CONCLUSION: In tuberculous meningitis subcortical and cortical hypoperfusion is common but it does not correlate with stage of meningitis or three month outcome.