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

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

We combined behavioral testing with brain imaging using (99m)Tc-HMPAO (Amersham Health) to identify CNS structures reflecting alterations in pain perception in the streptozotocin (STZ) model of type I diabetes. We induced diabetic hyperglycemia (blood glucose >300 mg/dl) by injecting male Sprague-Dawley rats with STZ (45 mg/kg i.p.). Four weeks after STZ-diabetic rats exhibited behaviors indicative of neuropathic pain (hypersensitivity thermal stimuli) and this hypersensitivity persisted for up to 6 weeks. Imaging data in STZ-diabetic rats revealed significant increases in the activation of brain regions involved in pain processing after 6 weeks duration of diabetes. These regions included secondary somatosensory cortex, ventrobasal thalamic nuclei and the basolateral amygdala. In contrast, the activation in habenular nuclei and the midbrain periaqueductal gray were markedly decreased in STZ rats. These data suggest that pain in diabetic neuropathy may be due in part to hyperactivity in somatosensory structures coupled with a concurrent deactivation of structures mediating antinociception.

Topics: Amygdala; Animals; Behavior, Animal; Brain; Cerebrovascular Circulation; Diabetes Mellitus, Experimental; Diabetic Neuropathies; Habenula; Hyperglycemia; Male; Neuralgia; Periaqueductal Gray; Prosencephalon; Radiopharmaceuticals; Rats; Rats, Sprague-Dawley; Reaction Time; Somatosensory Cortex; Technetium Tc 99m Exametazime; Thalamic Nuclei

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