ABSTRACT
PURPOSE: Tuberculous meningitis (TBM) is associated with borderzone necrosis (BZN) of the brain parenchyma in areas adjacent to meningeal inflammation. Diffusion-weighted MRI (DWI) allows for accurate detection of cytotoxic oedema associated with necrosis. Detection and characterisation of BZN using DWI to explain its pathogenesis in TBM have not been performed previously in children. Our objective was to identify the prevalence and characteristics of BZN using DWI in children with TBM and to correlate it with the presence, degree and distribution of basal meningeal enhancement (BE) in the absence of large-vessel thrombosis. METHODS: A retrospective descriptive MRI DWI study of 34 children with TBM was conducted. The topography of BZN was compared with the presence and severity of BE on specific MRI sequences. RESULTS: BZN was identified on MRI DWI in 50% of patients of which 82% had involvement of the temporal lobes. The severity and extent of BE in either middle cerebral artery cistern correlated with the presence of BZN (P = 0.02). BZN did not correlate with radiologically detectable vascular occlusion. CONCLUSION: BZN is common in TBM occurring in 50% of children. Detection and confirmation of cytotoxic oedema associated with BZN using DWI, and its clear relation to BE supports existing pathogenetic descriptions. The pathogenesis of BZN differs to that of topographical infarction on the basis of distribution as well as an absent statistical relationship between vascular occlusion and BZN.
Subject(s)
Brain/pathology , Cerebral Infarction/complications , Cerebral Infarction/pathology , Diffusion Magnetic Resonance Imaging/methods , Tuberculosis, Meningeal/complications , Tuberculosis, Meningeal/pathology , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Male , Necrosis/pathology , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
INTRODUCTION: The Western Cape in South Africa has one of the highest incidences of tuberculous meningitis (TBM) in the world. Despite therapy, the outcome in children with advanced TBM remains dismal. Magnetic resonance imaging (MRI) has been shown to be superior to computed tomography (CT) in demonstrating ischemia in TBM, especially of the brainstem. The objective of this study was to characterize brainstem lesions and association with clinical findings in children with TBM by using MRI. MATERIALS AND METHODS: CT and multiplanar MRI scans were performed in 30 children with proven TBM. From this group, a subgroup with radiological ischemic changes of the brainstem were identified. Radiological findings in these patients were then correlated with severity of disease, motor deficit, and outcome after 6 months. RESULTS: Radiological brainstem abnormalities were identified in 14 out of 30 children. Thirty-eight brainstem lesions were confirmed to be ischemic. The severity of disease at presentation, degree of motor deficit, and developmental outcome after 6 months of the children with ischemic brainstem lesions was poorer compared to those children without brainstem involvement. However, both sensitivity and specificity of the MRI brainstem lesion detection for clinical outcome proved low. CONCLUSION: A significant percentage of children with TBM have ischemic brainstem lesions. These are poorly visualized on conventional CT. MRI scanning is more sensitive in detecting these lesions and localizing them. There appears to be some association between MRI-detected brainstem lesions and clinical outcome. The exact meaning of these lesions and their implication for the patient's management require further clarification.
Subject(s)
Brain Ischemia/etiology , Brain Ischemia/pathology , Brain Stem/pathology , Tuberculosis, Meningeal/complications , Tuberculosis, Meningeal/pathology , Adolescent , Brain Ischemia/diagnostic imaging , Brain Stem/diagnostic imaging , Child, Preschool , Diffusion Magnetic Resonance Imaging , Disease Progression , Female , Follow-Up Studies , Humans , Male , Movement Disorders/diagnostic imaging , Movement Disorders/etiology , Movement Disorders/pathology , Sensitivity and Specificity , Tomography, X-Ray Computed , Tuberculosis, Meningeal/diagnostic imagingABSTRACT
BACKGROUND: Computed tomography (CT) findings in children with tuberculous meningitis (TBM) often do not explain the clinical presentation and may even be normal. Magnetic resonance imaging (MRI) has the potential to diagnose TBM with greater sensitivity than CT and also to detect more infarcts. AIM: The aim of this study was to determine whether MRI demonstrates features and complications of TBM not present on CT. MATERIALS AND METHODS: Retrospective, blinded evaluation and comparison of CT and MRI findings in children with TBM were performed. RESULTS: Of 30 children included, MRI demonstrated eight more with basal enhancement and four more with infarctions. Overall, MRI demonstrated an additional 104 sites of infarction (of a total 172) than CT. Of these, 89 were acute and visualized only on diffusion-weighted image. MRI showed five more patients with unilateral and two more with bilateral basal ganglia infarcts than CT as well as 19 brainstem infarcts. Hydrocephalus was equally detected by MRI and CT. CONCLUSION: MRI is superior to CT for diagnosing TBM (by detecting basal enhancement in more patients) and prognosis (by detecting many more infarcts in strategic locations). The role of CT is defined for the acute setting in detecting hydrocephalus for surgical management.
Subject(s)
Brain/pathology , Tuberculosis, Meningeal/pathology , Adolescent , Brain/diagnostic imaging , Brain Infarction/diagnosis , Brain Infarction/diagnostic imaging , Brain Infarction/pathology , Child , Child, Preschool , Female , Granuloma/diagnosis , Granuloma/diagnostic imaging , Granuloma/pathology , Humans , Hydrocephalus/diagnosis , Hydrocephalus/diagnostic imaging , Hydrocephalus/pathology , Infant , Magnetic Resonance Imaging , Male , Prognosis , Retrospective Studies , Tomography, X-Ray Computed , Tuberculosis, Meningeal/diagnosis , Tuberculosis, Meningeal/diagnostic imagingABSTRACT
BACKGROUND: Tuberculous meningitis (TBM) is closely associated with miliary tuberculosis and a pathogenetic relationship is suspected, although it has been proposed that the two processes are unrelated. OBJECTIVE: To describe miliary tuberculosis of the central nervous system (CNS) on MRI in children with TBM. MATERIALS AND METHODS: A retrospective descriptive study of 32 paediatric TBM patients referred for MRI. The presence of miliary nodules in the CNS was recorded. Lesions were categorized according to their distribution, enhancement pattern, size and signal characteristics. RESULTS: A miliary distribution of nodules was present in 88% of patients. All patients with a miliary distribution had leptomeningeal nodules and 18% of these patients had deep parenchymal nodules in addition. At least one tuberculoma with central T2 hypointensity was identified in 39% of patients. CONCLUSION: The high prevalence of miliary leptomeningeal nodules in the CNS of children with TBM is significant because it points to a pathogenetic relationship that has long been suspected on epidemiological grounds. Our findings challenge the concept that miliary tuberculosis is only an incidental finding in TBM patients and suggest that it plays an integral part in the pathogenesis.