title: Diffusion-weighted and gradient echo magnetic resonance findings of hemichorea-hemiballismus associated with diabetic hyperglycemia: a hyperviscosity syndrome?
abstract: BACKGROUND
  The magnetic resonance (MR) imaging findings of hemichorea-hemiballismus (HCHB) associated with hyperglycemia are characterized by hyperintensities in the striatum on T1-weighted MR images and computed tomographic scans, with a mechanism of petechial hemorrhage considered to be responsible. Diffusion-weighted MR imaging (DWI) has been reported to detect early ischemic damage (cytotoxic edema) as bright areas of high signal intensity and vasogenic edema as areas of heterogeneous signal intensity. We report various DWI findings in 2 patients with hyperglycemic HCHB.
  
  
  OBJECTIVE
  To describe the DWI and gradient echo findings and characterize the types of edema in HCHB associated with hyperglycemia.
  
  
  METHODS
  A tertiary referral center neurology department.
  
  
  METHODS
  Two patients with HCHB associated with hyperglycemia underwent DWI, gradient echo imaging, and conventional MR imaging with gadolinium enhancement. The patients had an elevated serum glucose level on admission and a long history of uncontrolled diabetes, and the symptoms were controlled by dopamine receptor blocking agents. Initial DWIs were obtained 5 to 20 days after symptom onset. Apparent diffusion coefficient (ADC) values were measured in the abnormal lesions with visual inspection of DWI and T2-weighted echo planar images.
  
  
  RESULTS
  T1- and T2-weighted MR images and brain computed tomographic scans showed high signal intensities in the right head of the caudate nucleus and the putamen. Gradient echo images were normal. The DWIs showed bright high signal intensity in the corresponding lesions (patient 1), and the ADC values were decreased. The decrease in ADC and the high signal intensity on DWI persisted despite the disappearance of HCHB, even after 70 days.
  
  
  CONCLUSIONS
  Gradient echo MR imaging findings were normal in HCHB with hyperglycemia, whereas DWI and the ADC map showed restricted diffusion, which suggests that hyperviscosity, not petechial hemorrhage, with cytotoxic edema can cause the observed MR abnormalities.
authors.affiliation: Department of Neurology, 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: Dong-Wha
authors.initials: DW
authors.lastname: Kang
authors.forename: Dong-Eog
authors.initials: DE
authors.lastname: Kim
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Park
authors.forename: Jae-Kyu
authors.initials: JK
authors.lastname: Roh
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000473:pathology; D002819:Chorea / Q000175:diagnosis / Q000209:etiology*; D003920:Diabetes Mellitus / Q000097:blood*; D020820:Dyskinesias / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000150:complications* / Q000209:etiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D011699:Putamen / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed