Diffusion-weighted and gradient echo magnetic resonance findings of hemichorea-hemiballismus associated with diabetic hyperglycemia: a hyperviscosity syndrome?
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.
Chu
Kon
K
Department of Neurology, Seoul National University Hospital, 28, Yongon-Dong, Chongro-Gu, Seoul 110-744, South Korea.
Kang
Dong-Wha
DW
Kim
Dong-Eog
DE
Park
Seong-Ho
SH
Roh
Jae-Kyu
JK
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