technetium-tc-99m-exametazime and Diabetic-Angiopathies

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.

Topics: Aged; Blood Glucose; Brain Chemistry; Cerebrovascular Circulation; Diabetes Mellitus; Diabetic Angiopathies; Female; Fluorodeoxyglucose F18; Follow-Up Studies; Glucose; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed

This study aimed to assess if activation with acetazolamide increases the diagnostic capacity of baseline SPECT with (99m)Tc-HMPAO in the study of brain perfusion in type I diabetic patients with no history of neurological symptoms.. A baseline SPECT was carried out in 11 diabetes mellitus type I patients with no neurological symptoms with 555 MBq of (99m)Tc-HMPAO; 1 g of acetazolamide was administered during the examination and a second SPECT was obtained 20' later with the same methodology used in the baseline SPECT. The images were visually analyzed. The post-acetazolamide studies were analyzed with (CBS) and without (WBS) baseline image subtraction and both methods were compared.. The baseline SPECT showed 48 hypoperfused cortical areas. The post-acetazolamide SPECT analyzed without baseline image subtraction detected 14 new hypoperfused areas and those analyzed with it detected 26 areas. 69% of the baseline hypoperfused areas were hyporeactive in the WBS analysis and 54% in the CBS analysis.. The perfusion SPECT with acetazolamide improves the diagnostic capacity of the baseline perfusion (99m)Tc-HMPAO SPECT, and makes it possible to classify the abnormalities as metabolic or vascular, with a preference for the post-acetazolamide CBS imaging analysis.

Topics: Acetazolamide; Adult; Brain; Brain Diseases, Metabolic; Cerebrovascular Circulation; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Diabetic Neuropathies; Diagnosis, Differential; Female; Humans; Injections, Intravenous; Male; Middle Aged; Perfusion; Premedication; Radiopharmaceuticals; Subtraction Technique; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vasodilator Agents

The detection of subclinical abnormalities in cerebral blood flow could be of great value in identifying diabetic patients at risk of stroke. The aim of this study was to assess the contribution of semiquantified post-acetazolamide technetium-99m hexamethylpropylene amine oxime single-photon emission tomography (99mTc-HMPAO SPET) in 15 diabetic patients with no clinical history of central neurological disease. After baseline 99mTc-HMPAO SPET, a second SPET scan was acquired after activation of the cerebrovascular reserve (CVR) with an injection of 1 g of acetazolamide (post-ACZ SPET). Semiquantitative analysis was made in 16 regions of interest (ROIs) drawn for each of the three supratentorial slices selected, and in two ROIs in the infratentorial slice. The CVR was calculated in each ROI by subtracting the decay-corrected baseline images from those obtained in the post-ACZ SPET and expressed as the percent increase in the average counts between the two scans. Baseline perfusion and CVR values in the study group were compared with the corresponding values in a control group. Of 750 cortical ROIs studied, 332 showed a decreased CVR (44.3%). The baseline perfusion SPET study showed hypoperfusion in 65 ROIs (8.6%) and hyperperfusion in 56 (7.4%). Of the 65 hypoperfused regions, 66.2% had a normal CVR and 33.8% had a decreased CVR, whereas of the 56 hyperperfused regions, 51.8% had a CVR within normal limits and 48.2% showed a decreased CVR. In conclusion, in comparison with baseline 99mTc-HMPAO SPET, the ACZ activation test provided additional information in the study of cerebrovascular impairment, and allowed characterisation of the subclinical abnormalities in the population studied. The technique may therefore prove useful in evaluating future preventive strategies for stroke in diabetic patients.

Topics: Acetazolamide; Adult; Carbonic Anhydrase Inhibitors; Cerebrovascular Circulation; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Female; Humans; Male; Middle Aged; Radiopharmaceuticals; Risk Factors; Stroke; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

We assessed cerebral blood flow in 78 diabetic patients (40 Type 1 and 38 Type 2) with no previous history of central nervous system disease using 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) single photon emission tomography (SPET) and found areas of severe hypoperfusion in 36% of them. All cerebral anatomical regions showed abnormalities related to hypoperfusion, but they were most frequently seen in the fronto-temporal region, followed by the occipital and parietal regions. 99Tcm-HMPAO SPET has been shown to be able to detect subclinical alterations in blood flow in diabetes, a finding that may account for the high prevalence of cerebrovascular disease seen in these patients. This technique could, therefore, play an important role in future preventative strategies.

Topics: Adult; Aged; Cerebrovascular Circulation; Cerebrovascular Disorders; Diabetes Complications; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Neuropathies; Humans; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon