title: Diffusion-weighted MRI and 99mTc-HMPAO SPECT in delayed relapsing type of carbon monoxide poisoning: evidence of delayed cytotoxic edema.
abstract: BACKGROUND
  Carbon monoxide (CO) is a common cause of poisoning, and its sequelae include a progressive (25%) and a delayed relapsing form (75%). We report the diffusion-weighted MRI (DWI) findings in the delayed relapsing form of CO poisoning and characterize the types of edema.
  
  
  METHODS
  From November 1, 2000 to June 1, 2003, 5 consecutive patients (2 men, 3 women, range of age: 54-67 years), who had the delayed relapsing type of CO poisoning, underwent DWI, conventional MRI, MR angiography and SPECT. CO poisoning was diagnosed by the presence of a typical clinical history, an abnormally increased level of serum carboxyhemoglobin and MRI findings. Apparent diffusion coefficient (ADC) values were measured in all of the abnormal lesions with visual inspection of DWI and T(2)-weighted echo-planar imaging.
  
  
  RESULTS
  DWI showed high signal intensities in bilateral periventricular white matter, in the splenium of the corpus callosum, in internal capsules, and brainstem showing moderately decreased ADC values. In the globus pallidus, the ADC values were rather increased with low signal intensities on DWI. Brain SPECT showed decreased perfusion in bilateral white matter and some parts of the cerebral cortex, which correlated well with the DWI findings.
  
  
  CONCLUSIONS
  We suggest that prominent, symmetric restricted diffusion can occur in periventricular white matter, brainstem, and corpus callosum after the delayed relapsing type of CO poisoning. Delayed cytotoxic edema can occur in this setting, which provides a new guidance for the pathogenesis of CO poisoning and the differential diagnosis of white matter diseases.
authors.affiliation: Stroke and Neural Stem Cell Laboratory, Clinical Research Institute, Seoul National University Hospital, 28 Yongon-Dong, Chongro-Gu, Seoul 110-744, South Korea.
authors.forename: Kon
authors.initials: K
authors.lastname: Chu
authors.forename: Keun-Hwa
authors.initials: KH
authors.lastname: Jung
authors.forename: Han-Joon
authors.initials: HJ
authors.lastname: Kim
authors.forename: Sang-Wuk
authors.initials: SW
authors.lastname: Jeong
authors.forename: Dong-Wha
authors.initials: DW
authors.lastname: Kang
authors.forename: Jae-Kyu
authors.initials: JK
authors.lastname: Roh
mesh_terms: D000368:Aged; D001929:Brain Edema / Q000097:blood / Q000175:diagnosis / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D002248:Carbon Monoxide / Q000097:blood*; D002249:Carbon Monoxide Poisoning / Q000097:blood / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: D019690:Technetium Tc 99m Exametazime; D002248:Carbon Monoxide