title: Subtentorial cerebral nocardiosis in immunocompetent patients: CT and MR imaging findings.
abstract: OBJECTIVE
  To describe the clinical presentation and computed tomography (CT) and magnetic resonance imaging (MRI) appearances of subtentorial nocardia cerebral abscesses developing in immunocompetent patients.
  
  
  METHODS
  The clinical findings and the results of CT and MRI examinations of three immunocompetent patients with nocardiosis located initially only in the subtentorial region were studied. Three patients underwent CT examination and two patients had MRI.
  
  
  RESULTS
  Clinically, two patients had cerebellar syndrome and the third had meningism with fever. The diagnosis of nocardiosis was bacteriologically confirmed by demonstrating the organism in lumbar puncture fluid in one patient and by an aspiration biopsy of the abscess in the other two. Two of the patients improved under targeted antibiotic therapy whereas the third patient died. The main imaging features of the lesions were a multiloculated appearance with peripheral enhancement after intravenous administration of iodinated contrast material on CT and a multicystic appearance on MRI, with a peripheral hypointense rim on T2-weighted images, a relatively minor mass effect and a multiloculated appearance on gadolinium-chelate enhanced T1-weighted images.
  
  
  CONCLUSIONS
  The clinical presentation of cerebral nocardiosis is relatively non-specific. A microcystic lesion surrounded by hypointensity on T2-weighted MR images with a multiloculated pattern after gadolinium chelate administration on T1-weighted MR images in association with a relatively minor mass effect should suggest this diagnosis even if the lesion is single and in the absence of immunosuppression.
authors.affiliation: Université de Lorraine, 54000 Nancy, France; Department of Diagnostic and Therapeutic Neuroradiology, hôpital Central, 29, avenue Maréchal-de-Lattre-de-Tassigny, 54035 Nancy cedex, France. Electronic address: flobeuret@hotmail.fr.
authors.forename: F
authors.initials: F
authors.lastname: Beuret
authors.affiliation: Department of Diagnostic and Therapeutic Neuroradiology, hôpital Central, 29, avenue Maréchal-de-Lattre-de-Tassigny, 54035 Nancy cedex, France.
authors.forename: E
authors.initials: E
authors.lastname: Schmitt
authors.affiliation: Université de Lorraine, 54000 Nancy, France; Department of Diagnostic and Therapeutic Neuroradiology, hôpital Central, 29, avenue Maréchal-de-Lattre-de-Tassigny, 54035 Nancy cedex, France.
authors.forename: S
authors.initials: S
authors.lastname: Planel
authors.affiliation: Department of Diagnostic and Therapeutic Neuroradiology, hôpital Central, 29, avenue Maréchal-de-Lattre-de-Tassigny, 54035 Nancy cedex, France.
authors.forename: G
authors.initials: G
authors.lastname: Lesanne
authors.affiliation: Université de Lorraine, 54000 Nancy, France; IADI-Inserm U 947, Vandœuvre-lès-Nancy, France; Department of Diagnostic and Therapeutic Neuroradiology, hôpital Central, 29, avenue Maréchal-de-Lattre-de-Tassigny, 54035 Nancy cedex, France.
authors.forename: S
authors.initials: S
authors.lastname: Bracard
mesh_terms: D000368:Aged; D001922:Brain Abscess / Q000175:diagnosis*; D002526:Cerebellar Diseases / Q000175:diagnosis* / Q000276:immunology; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007121:Immunocompetence / Q000276:immunology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009617:Nocardia Infections / Q000175:diagnosis* / Q000276:immunology; D013116:Spinal Cord / Q000473:pathology*; D014057:Tomography, X-Ray Computed
keywords: Cerebral abscess; Computed tomography; Immunocompetent; MRI; Nocardia