Diferenciación entre absceso cerebral y tumor necrótico o quístico mediante secuencias de difusión

INTRODUCTION: The diagnosis of a cerebral abscess is a real challenge since the clinical and radiological findings are often non-specific and undistinguishable from those seen with cystic or necrotic tumours. Recently it has been suggested that diffusion sequences may be useful in the differential diagnosis of a necrotic or cystic mass. PATIENTS AND METHODS: Nine patients with cystic or necrotic intracranial masses were studied. The diagnoses were: three pyogenic abscesses, three metastases and three high grade gliomas. The diffusion images were evaluated visually and by means of maps based on the apparent diffusion coefficient (CDA). RESULTS: All lesions showed fine iso-intense or slightly hyperintense walls in T1 potentiated sequences, and isointense or slightly hypointense walls in T2 potentiated sequences. In all cases the wall took up gadolinium intensity, with a well-defined smooth edge (ring uptake). In the diffusion sequences the abscesses showed a very strong central signal, as compared with the low signal of other lesions. The CDA were significantly lower in the abscesses than in the tumours. CONCLUSIONS: Since cerebral abscesses are potentially curable, early diagnosis should be made. A cerebral abscess should be suspected in all cases of cystic or necrotic masses with hypersignals in diffusion sequences and low CDA.