Diffusion-weighted imaging of hyperacute cerebral hypoglycemia

Abstract

Background and purpose: Cerebral hypoglycemia can result in reversible metabolic brain insults and can be associated with impaired diffusion disturbances. Our aim was to evaluate possible changes in DWI of the human brain during hyperacute short-term severe hypoglycemia.

Materials and methods: Ten individuals scheduled for a clinical IST were examined with DWI while the test was performed. Venous blood glucose was continuously measured, and sequential DWI sequences were performed without interruption. Hypoglycemia was terminated with intravenous glucose administration when glucose levels were at ≤2.0 mmol/L.

Results: Blood glucose levels were lowered to a mean nadir of 1.75 ± 0.38 mmol/L. No alterations of cerebral diffusion could be observed in any individuals on DWI.

Conclusions: Hyperacute short-term severe hypoglycemia does not induce visible changes in DWI of the human brain.

Fig 1.

Example of region-of-interest setting on ADC maps. The circular region of interest of 0.68 cm² was set for the bilateral thalamus and splenium. ADC values were calculated before (left image) and after (right image) insulin was administered.

Fig 2.

Blood glucose levels of subjects during the procedure. The horizontal line indicates the lower threshold of physiologic postprandial blood glucose concentration (4.0 mmol/L); the vertical line indicates the end of hypoglycemia by administering 40 mL of glucose 40% intravenously.

Fig 3.

Duration of hypoglycemia during DWI. The blood glucose level was lowered to <4.0 mmol/L for a mean of 43.8 ± 10.85 minutes for all subjects, to <3 mmol/L for 31.5 ± 12.0 minutes, to <2.5 mmol/L for 20.5 ± 10.7 minutes, and to a level <2.0 mmol/L for 10 ± 5.3 minutes.