Perfusion scanning using 99mTc-HMPAO detects early cerebrovascular changes in the diabetic rat

Cerebral perfusion studies were performed on both control and streptozotocin-(STZ) induced diabetic male Wistar rats. Rat brain imaging using a gamma camera was performed for each group 0.5, 2, 4, and 24 hours post 99mTc-HMPAO injection. Data processing for each cerebral perfusion scan was performed by drawing a region of interest (ROI) circumferentially around the brain (B). Background (BKG) due to signal from the soft tissue of each rat was subtracted. Brain 99mTc-HMPAO uptake minus background counts (net brain counts; NBC) were then compared between the two groups.The NBC (mean ± SD) for the STZ group were statistically significantly higher (p = 0.0004) than those of the control group at each of the time points studied.99mTc-HMPAO brain scan may be useful in the detection of early atherosclerotic changes in the diabetic rat brain.Diabetes leads to early atherosclerotic changes through a number of mechanisms, including the formation of advanced glycosylation end products and its influence on serum lipid composition. The vascular complications of diabetes are significant, and can lead to a severe arteriopathy prominently affecting the heart, kidneys and eyes. The brain can also be affected, causing impairments in memory and learning.Nuclear medicine studies have previously been utilized for the functional investigation of diabetic pathophysiology. For example, in the podiatric literature, nuclear medicine imaging has been shown to be helpful in the management of the diabetic foot [1]. The role of cerebral nuclear medicine imaging techniques in the detection of CNS manifestations of diabetes has been studied previously using 18F fluorodeoxyglucose (18F-FDG) positron emission tomography (PET), to assess brain glucose metabolism [2,3] in diabetic patients. Four studies have examined cerebral perfusion in diabetes using SPECT [4-7], three in type 1 diabetics and one in type 2 diabetics.Technetium 99m-hexamethylpropylene amine oxime (99mTc-HMPAO) cerebral perfusion scan