title: Diffusion-weighted MRI in patients with non-diagnostic CT in the post-acute phase of cerebral ischemia.
abstract: BACKGROUND
  Unenhanced computed tomography (CT) is the imaging technique used in acute stroke. In some cases it is unable to detect damage even 24-48 h after symptom onset. The aim of our work was to evaluate the diagnostic value of diffusion-weighted imaging (DWI) in the post-acute phase of cerebral ischemia in patients in whom CT did not yield a definitive diagnosis.
  
  
  METHODS
  We retrospectively evaluated DWI findings in 214 patients, out of a series of 1,680 patients admitted to our hospital following the acute onset of focal neurological symptoms, in whom non-contrast CT, performed within 30 h of symptom onset, was normal (123), incongruous, i.e. a marked hypodensity indicative of an old infarct or a slight hypodensity not consistent with the clinical findings (66), or leukoaraiotic, i.e. diffuse chronic hypodensities in the periventricular white matter (25).
  
  
  RESULTS
  DWI showed signs of recent brain ischemia in 125/214 (58%) patients: 64/123 (52%) with a normal CT, 41/66 (62%) with an incongruous CT, and 20/25 (80%) with leukoaraiosis (p=0.027). Multiple lesions were detected in 16/125 (16%) patients, while single lesions were <or=2 cm in 83/109 (76%) cases. DWI showed signs of ischemia in 22/91 (24%) patients with TIA and in 103/123 (84%) patients with stroke (p=0.0001).
  
  
  CONCLUSIONS
  In a quite high proportion of patients with recent symptoms of transient ischemic attack/ischemic stroke and a repeat non-diagnostic CT, DWI may help in the diagnosis of ischemic stroke and in shedding light on the underlying pathogenic mechanism.
authors.affiliation: Section of Neuroradiology, Department of Neurological Sciences, La Sapienza University, Rome, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Totaro
authors.forename: D
authors.initials: D
authors.lastname: Toni
authors.forename: L
authors.initials: L
authors.lastname: Durastanti
authors.forename: L
authors.initials: L
authors.lastname: Bozzao
authors.forename: G F
authors.initials: GF
authors.lastname: Gualdi
authors.forename: E
authors.initials: E
authors.lastname: Raz
authors.forename: A
authors.initials: A
authors.lastname: Kouleridou
authors.forename: P
authors.initials: P
authors.lastname: Pantano
mesh_terms: D000368:Aged; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed