Manana Pienaar

MRI to demonstrate diagnostic features and complications of TBM not seen with CT.

BackgroundComputed 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.AimThe aim of this study was to determine whether MRI demonstrates features and complications of TBM not present on CT.Materials and methodsRetrospective, blinded evaluation and comparison of CT and MRI findings in children with TBM were performed.ResultsOf 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.ConclusionMRI 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.

Magnetic resonance imaging of miliary tuberculosis of the central nervous system in children with tuberculous meningitis

BackgroundTuberculous 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.ObjectiveTo describe miliary tuberculosis of the central nervous system (CNS) on MRI in children with TBM.Materials and methodsA 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.ResultsA 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.ConclusionThe 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.

Diffusion-weighted magnetic resonance imaging of borderzone necrosis in paediatric tuberculous meningitis

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.

Meningioma presenting as an oropharyngeal mass--an unusual presentation.

ArtCITATION: Dekker, G. et al. 2007. Meningioma presenting as an oropharyngeal mass: An unsual presentation. South African Medical Journal, 97(5):242.

Unusual midline neck mass

CITATION: Louw, H.B., et al. 2007. Unusual midline neck mass. South African Medical Journal, 97 (1):30-31.

Elbow fracture in a child

We present a case of a 2-year-old child who fell and injured his elbow. Plain films were taken and had the appearance of an elbow dislocation (Fig. 1). Subsequent MRI confirmed a Salter Harris I fracture of the distal humeral epiphysis (Figs 2a & b).

Subarachnoid or subdural effusion

42 SA JOURNAL OF RADIOLOGY • September 2006 Often one is confronted with an extracerebral fluid collection/effusion when interpreting computed tomography (CT) of the brain in children. To determine whether the effusion is subarachnoid or subdural, a few basic principles should be kept in mind. Subdural effusions are crescent-shaped, especially over the frontal and parietal lobes, with the vessels ‘pasted’ against the cerebral surface (Fig. 1). The interhemispheric fissure anteriorly can be V-shaped or asymmetrical, as the hemisphere is displaced away from the falx at an angle (Figs 2a and b).