Unilateral putaminal CT, MR, and diffusion abnormalities secondary to nonketotic hyperglycemia in the setting of acute neurologic symptoms mimicking stroke

Abstract

A 75-year-old Asian man presented with two episodes of chorea associated with nonketotic hyperglycemia. His chorea rapidly resolved after restitution of a normal serum glucose level, although an MR image obtained at the time of acute symptoms demonstrated high signal intensity on T1-weighted images, low signal intensity on T2-weighted images, and restricted diffusion, all involving the left putamen. A CT scan obtained 1 month later demonstrated faint hyperattenuation of the involved putamen. The reported pathophysiologic considerations for these imaging features are reviewed, and an original explanation is proposed.

Fig 1.

MR images of the brain obtained during the patient’s first admission. The left putamen is hyperintense on T1-weighted images (A) and hypointense on T2-weighted (B) and FLAIR images (C). The left putamen (circles [D and E]) appears hyperintense on the exponential DW images (b = 1000-s/mm² images divided by b = 0-s/mm² images [5]) (D) and hypointense on the ADC maps (E). A subtle focus of reduced ADC is also present in the posterior aspect of the right putamen (arrows). Lipoma of the corpus callosum is incidentally noted (C, arrowhead).

Fig 2.

Noncontrast cranial CT scan obtained during the patient’s second admission shows faint hyperattenuation of the entire left putamen, without evidence of mass effect, edema, or volume loss and with no sign of brain ischemia.