title: Diagnostic value of apparent diffusion coefficient hyperintensity in selected patients with acute neurologic deficits.
abstract: OBJECTIVE
  A pattern of decreased intensity on apparent diffusion coefficient (ADC) maps is useful in the early detection of ischemic brain injury. Less information exists with regard to patients with acute neurologic deficits in whom there is abnormal conventional magnetic resonance imaging (MRI) and increased ADC intensity.
  
  
  METHODS
  The authors identified 13 patients with acute neurologic deficits who underwent diffusion MRI and had calculated ADC maps demonstrating hyper-intensity in regions characterized by computed tomography hypodensity and MRI T2 hyperintensity. The initial and follow-up imaging characteristics and clinical syndromes were recorded.
  
  
  RESULTS
  Clinical syndromes included hypertensive encephalopathy, posterior leukoencephalopathy, hyperperfusion following carotid endarterectomy, venous sinus thrombosis, HIV encephalopathy, and brain tumor. Diffusion-weighted imaging (DWI) was hyperintense in 3 of 13 patients, isointense in 4 of 13 patients, heterogeneous in 3 of 13 patients, and hypointense in 3 of 13 patients. The ADC values in these regions were significantly higher than those in control regions (P < .0001). At early follow-up, MRI abnormalities resolved completely in 3 of 13 patients and partially in 9 of 13 patients. MRI abnormalities were unchanged in 1 patient.
  
  
  CONCLUSIONS
  In the evaluation of patients with acute neurologic deficits, ADC hyperintensity may identify a subset of patients with vasogenic edema of nonischemic etiology. Frequently, these conditions are potentially reversible if appropriately managed. DWI and conventional images alone are not sufficient to identify these neurologic conditions.
authors.affiliation: Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors.forename: P W
authors.initials: PW
authors.lastname: Schaefer
authors.forename: R G
authors.initials: RG
authors.lastname: Gonzalez
authors.forename: G
authors.initials: G
authors.lastname: Hunter
authors.forename: B
authors.initials: B
authors.lastname: Wang
authors.forename: W J
authors.initials: WJ
authors.lastname: Koroshetz
authors.forename: L H
authors.initials: LH
authors.lastname: Schwamm
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis; D001931:Brain Mapping; D002561:Cerebrovascular Disorders / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004058:Diffusion; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors