title: The role of diffusion-weighted imaging in the differential diagnosis of intracranial cystic mass lesions: a report of 147 lesions.
abstract: BACKGROUND
  The objective of this study is to evaluate the sensitivity and specificity of DWI in differentiating brain abscesses from other intracranial cystic lesions.
  
  
  METHODS
  One hundred fifteen patients with 147 cystic lesions (mean age, 26.4 year) were prospectively studied with DWI on a 1.5-T magnetic resonance imaging. Lesions appearing hyperintense on DWI with the ADC values of lower than 0.9 +/- 0.13 x 10(-3) mm(2)/s (mean +/- SD) were considered as brain abscess, whereas hypointense lesions on DWI with the ADC values 2.2 +/- 0.9 x 10(-3) mm(2)/s were categorized as nonabscess cystic lesions.
  
  
  RESULTS
  Ninety-three of 97 brain abscess lesions were hyperintense on DWI, with significantly low (P = .0001) ADC value (0.87 +/- 0.05 x 10(-3) mm(2)/s) (mean +/- SEM), compared with 48 nonabscess lesions (2.89 +/- 0.05 x 10(-3) mm(2)/s). Four of 97 brain abscess lesions in 65 patients were false negative, and 2 of 50 nonabscess lesions in 50 patients were false positive for the diagnosis of brain abscess. The ADC value of the tumor cysts (2.9 +/- 0.05 x 10(-3) mm(2)/s) was significantly lower (P = .02) compared with benign cysts and neurocysticercosis (3.2 +/- 0.05 x 10(-3) mm(2)/s) among nonabscess group. The sensitivity of DWI for the differentiation of brain abscesses from nonabscesses was 96%; specificity, 96%; positive predictive value, 98%; negative predictive value, 92%; and accuracy of the test, 96%.
  
  
  CONCLUSIONS
  Diffusion-weighted imaging has high sensitivity and specificity for the differentiation of brain abscess from other nonabscess intracranial cystic lesions.
authors.affiliation: Department of Neurosurgery, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow-226014, India.
authors.forename: Jaypal Sangala
authors.initials: JS
authors.lastname: Reddy
authors.forename: Asht Mangal
authors.initials: AM
authors.lastname: Mishra
authors.forename: Sanjay
authors.initials: S
authors.lastname: Behari
authors.forename: Mazhar
authors.initials: M
authors.lastname: Husain
authors.forename: Vikas
authors.initials: V
authors.lastname: Gupta
authors.forename: Manu
authors.initials: M
authors.lastname: Rastogi
authors.forename: Rakesh Kumar
authors.initials: RK
authors.lastname: Gupta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001834:Body Water / Q000378:metabolism; D001921:Brain / Q000473:pathology; D001922:Brain Abscess / Q000175:diagnosis* / Q000503:physiopathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000503:physiopathology; D020863:Central Nervous System Cysts / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000378:metabolism / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies