title: Cerebral abscesses and necrotic cerebral tumours: differential diagnosis by perfusion-weighted magnetic resonance imaging.
abstract: OBJECTIVE
  This study was undertaken to evaluate the usefulness of perfusion-weighted imaging (PWI) in the differential diagnosis of ring-enhancing cerebral lesions, including abscesses, high-grade gliomas and metastases.
  
  
  METHODS
  Nine cerebral abscesses (five pyogenic, four from Toxoplasma gondii), ten glioblastomas and five cerebral metastases in 19 patients were studied with gadolinium-enhanced magnetic resonance imaging, diffusion-weighted imaging (DWI) including calculation of mean apparent diffusion coefficient (ADC) of the lesion core, and PWI. At PWI, the mean of the maximum regional cerebral blood volume (rCBV) was calculated in the gadolinium-enhancing peripheral solid areas and compared with that of the contralateral normal-appearing white matter [ratio=rCBV (lesion)/rCBV (contralateral normal-appearing white matter)].
  
  
  RESULTS
  DWI achieved the differential diagnosis in all cases except for the four Toxoplasma abscesses. At PWI, the mean ratio of the rCBV of the capsular portion was 0.72+/-0.08 (range 0.60-0.82) in the pyogenic abscesses, 0.84+/-0.07 (range 0.75-0.91) in the Toxoplasma abscesses, 4.45+/-1.5 (range 2.9-8.0) in the high-grade gliomas and 3.58+/-0.68 (range 3.28-4.27) in the metastases.
  
  
  CONCLUSIONS
  PWI seems to be useful in the differential diagnosis of ring-enhancing cerebral lesions. High rCBV values in the peripheral areas appear to indicate the possibility of a necrotic tumour, whereas low values tend to indicate an abscess.
authors.affiliation: U.O. Neuroradiologia, Dipartimento di Neuroscienze, A.O. "G. Rummo", Via dell'Angelo 1, 82100 Benevento, Italy. cfmuccio@yahoo.it
authors.forename: C F
authors.initials: CF
authors.lastname: Muccio
authors.forename: G
authors.initials: G
authors.lastname: Esposito
authors.forename: A
authors.initials: A
authors.lastname: Bartolini
authors.forename: A
authors.initials: A
authors.lastname: Cerase
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001922:Brain Abscess / Q000175:diagnosis*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D005682:Gadolinium; D005909:Glioblastoma / Q000175:diagnosis; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009942:Organometallic Compounds; D016781:Toxoplasmosis, Cerebral / Q000175:diagnosis
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol; D005682:Gadolinium