MRI perfusion findings in patients with tuberculous meningitis

Abstract

Background

Tuberculous meningitis (TBM) is a devastating infection in the world. The primary objective of the study was to evaluate magnetic resonance imaging (MRI) perfusion cerebral changes in the patients with tuberculous meningitis (TBM) before and after anti-tuberculous therapy. We aimed to compare the MRI changes between cerebral infarcts in TBM patients with normal appearing contralateral brain in the same patients. The secondary objective was to compare MRI perfusion changes in TBM patients with/without infarcts with control subjects.

Methods

MRI perfusion of brain (Dynamic susceptibility contrast-enhanced) was performed at diagnosis and repeated one month after treatment. The study was conducted on both TBM patients and age-matched control subjects. Perfusion parameters were obtained by placing the region of interest (ROI) at the cerebral infarcts, normal appearing contralateral brain and TBM without infarction group. Relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV) and mean transit time (MTT) were assessed. Perfusion parameters pre-treatment and post-treatment were compared.  

Results

18 TBM patients and six age-matched control subjects were recruited. Acute cerebral infarctions were demonstrated in 10 (55.6%) patients.  Comparison  of pre-treatment MRI perfusion studies showed significantly reduced rCBF of the infarcted regions compared to the normal appearing contralateral brain (279.0ml/100g/min vs 615.2 ml/100g/min, p < 0.05), and age-matched control subjects (279.0 ml/100g/min vs 754.1 ml/100g/min, p < 0.05). There was significantly reduced rCBV of the infarcted regions compared to the normal appearing contralateral brain (45.0ml/100g vs 96.8ml/100g, p < 0.05), and age-matched control subjects (45.0ml/100g vs 82.9ml/100g, p<0.05). There was significantly increased MTT of the infarcted regions compared to age-matched control subjects (9.8sec vs 6.7sec,  p< 0.05).

There was also significantly reduced rCBF of the normal appearing contralateral brain (615.2ml/100g/min vs 754.1ml/100g/min, p<0.05) and TBM patients without cerebral infarction (554.9ml/100g/min vs 754.1ml/100g/min, p<0.05) compared to age-matched control subjects. Increased MTT was significantly present in the normal appearing contralateral brain (9.6sec vs 6.7sec, p<0.05) and TBM patients without cerebral infarction (7.8sec vs 6.7sec, p<0.05) compared to age-matched control subjects.

Comparison of pre and post-treatment MRI perfusion study showed significant increased rCBF (501.4ml/100g/min vs 279.0ml/100g/min, p<0.05) and rCBV (104.0ml/100g vs 45.0ml/100g, p<0.05) in the infarcted regions.  Significant increased in rCBV (104.2ml/100g vs 77.1ml/100g, p<0.05) and MTT (9.0sec vs 7.8sec, p<0.05) were also demonstrated in TBM patients without cerebral infarction following treatment.

Conclusion

In conclusion, perfusion parameters of the infarcted regions were consistent with infarcted tissue. Perfusion parameters of the normal appearing contralateral brain and TBM without infarction group showed ischaemic changes.