Influence of diabetes mellitus on regional cerebral glucose metabolism and regional cerebral blood flow

Abstract

Previous studies have shown both increased and decreased regional cerebral glucose metabolism-blood flow (rMRGlu-rCBF) values in diabetes. We sought to elucidate the influence of diabetes on rMRGlu-rCBF in 57 patients with pure cerebral microangiopathy. Sixteen of 57 patients had diabetes requiring therapy (11 NIDDM, 5 IDDM). Using a special head-holder for exact repositioning, rMRGlu (PET) and rCBF (SPET) were imaged and measured in slices, followed by MRI. White matter and cortex were defined within regions of interest taken topographically from MRI (overlay). Diabetic and non-diabetic microangiopathy patients were compared to 19 age-matched controls. The diabetic patients showed significantly lower rMRGlu-rCBF values in all regions than controls, whereas non-diabetic patients did not. There were no significant NIDDM-IDDM differences. rMRGlu-rCBF did not depend on venous blood glucose levels at the time of the PET examination. However, analysis of variance with the factors diabetes, atrophy and morphological severity of microangiopathy showed that lowered rMRGlu-rCBF in the diabetic group was due to concomitant atrophy only (P < 0.005), while neither diabetes nor microangiopathy had any influence on rMRGlu-rCBF (all P > 0.2). These results were confirmed by multivariate factor analysis. It can thus be concluded that a supposed decrease in rMRGlu-rCBF in diabetes mellitus is in fact only an artefact produced by the concomitant atrophy. All previous studies failed to correct for atrophy, and a critical reappraisal is required.

The resting perfusion pattern associates with functional decline in type 2 diabetes

“…Some studies did not have similar gender distributions between T2DM and non-diabetic control groups, but female subjects had higher CBF than male subjects (Pirson, Vander Borght, and Van Laere 2006; Gur and Gur 1990), which may obscure the CBF difference between the groups. Some studies also did not account for brain volume difference, which has been shown to largely explain reduced CBF (Sabri et al 2000). …”

Diffusion Tensor Imaging Identifies Deficits in White Matter Microstructure in Subjects With Type 1 Diabetes That Correlate With Reduced Neurocognitive Function

“…If such a biomarker can be developed, future study could focus on identifying interventions that can prevent the appearance or slow the progression of white matter microstructural changes in patients with diabetes. Over the last 10 years, investigators have used a variety of imaging techniques, including MRI, single photon emission computed tomography (30,31), and positron emission tomography (32), to determine whether structural abnormalities could be identified in the brains of patients with (36), and decreased cerebral gray matter density (37,38) in type 1 diabetic subjects. Some of these structural abnormalities have corresponded to age of diabetes onset (35), A1C levels, hypoglycemia (37), and the presence of retinopathy (38).…”

Type 2 Diabetes and Cognitive Impairment

“…Several studies have attempted to link T2D to alterations in CBF, but with mixed results. Initial studies using single photon emission computed tomography found a reduction in CBF in patients with T2D relative to control participants 38,39 . Later studies with larger sample sizes have had difficulty identifying consistent patterns of CBF change in individuals with T2D.…”