technetium-tc-99m-exametazime and Brain-Concussion

The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography (99mTc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using 99mTc-HMPAO SPET is reliable in clinical evaluations.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Brain Concussion; Brain Neoplasms; Cerebrovascular Circulation; Cerebrovascular Disorders; Child; Consciousness Disorders; Humans; Middle Aged; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The purposes of this study were: (1) to determine the prevalence of abnormal 99mTc-HMPAO SPECT scans in patients suffering from persistent post-concussive syndrome (PPCS) after mild closed head injury (CHI); (2) to compare SPECT with structural neuroimaging (MRI and CT) in patients with mild CHI; and (3) to investigate correlations between SPECT and clinical data obtained from the patient sample (neuropsychological testing, demographics, psychiatric diagnoses). Forty-three patients were included. SPECT was read as abnormal in 53% of patients and showed a total of 37 lesions while MRI was read as abnormal in 9% and CT scan in only 4.6% of patients after mild CHI. SPECT appears to be more sensitive in detecting cerebral abnormalities after mild CHI, especially in patients with PPCS symptoms, than either CT or MRI. No statistically significant relationship was found between SPECT scan abnormalities and age, past psychiatric history, history of substance abuse, or history of multiple CHI. Education level did not differ between patients with normal and abnormal SPECT. Current neuropsychiatric symptoms did not seem to have any impact on the results of SPECT scan.

Topics: Adolescent; Adult; Brain Concussion; Brain Damage, Chronic; Cerebral Cortex; Dominance, Cerebral; Energy Metabolism; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Neuropsychological Tests; Organotechnetium Compounds; Oximes; Regional Blood Flow; Syndrome; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

We are proposing a new method for correcting of scattered photons in technetium-99m (99mTc) imaging by means of photopeak dual-energy window acquisition. This method consists of the simultaneous acquisition of two images and estimation of a scatter image included in the symmetric energy window (SW) image by the difference between these images. The scatter corrected image is obtained by subtracting the scatter image from the SW image. In order to evaluate this method, we imaged a planar and a SPECT phantom with cold lesions and calculated the contrast value with and without the scatter correction. In addition, we performed asymmetric energy window (ASW) imaging to compare with this scatter correction method for planar images. In the planar image with the tissue-equivalent material of 10 cm, the scatter correction method removed 32% of the counting rate of the SW image and improved from 0.81 to 0.94 of the contrast value for a 4 cm-diameter cold lesion, while the contrast value with the ASW was 0.87 for such a cold lesion. The scatter corrected SPECT image had a reduction of 18% of the counting rate of the SW SPECT image and improvement of approximately 11% in contrast for cold spot sizes larger than a 3 cm-diameter, compared with the SW SPECT image. In addition, a perfusion defect could be well visualized by this scatter correction method on 99mTc-HMPAO regional cerebral blood flow SPECT of a patient. Our proposed scatter correction method can improve both planar and SPECT images qualitatively and quantitatively.

Topics: Brain Concussion; Humans; Models, Structural; Organotechnetium Compounds; Oximes; Scattering, Radiation; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Focal post traumatic mass lesions such as contusions and intracerebral haematomas are common, and often difficult for neurosurgeons to manage, because little is known of their pathophysiology. We have mapped cerebral blood flow, and studied small vessel ultrastructure at different time points within the first three weeks of head injury, in patients with these lesions. A zone of ischaemic brain is always present around these lesions, and persists for weeks or months. This accords with astrocyte swelling and microvascular compression seen on electron microscopy. Focal zones of hyperaemia were also present in 42% of patients, within the first two weeks of injury, and this appeared only within apparently normal tissue as judged by late MRI or CT.

Topics: Astrocytes; Biopsy; Blood-Brain Barrier; Brain; Brain Concussion; Brain Damage, Chronic; Brain Injuries; Capillaries; Cerebral Hemorrhage; Endothelium, Vascular; Follow-Up Studies; Humans; Hyperemia; Microscopy, Electron, Scanning; Muscle, Smooth, Vascular; Neurologic Examination; Organotechnetium Compounds; Oximes; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

123I-IMP and Tc-PAO SPECT were performed in 20 cases of cerebral concussion ranging in age from 4 to 20 years old, including six cases of the juvenile head trauma syndrome (JHTS). The SPECT findings were divided into two main types: six cases in the normal group with no blood flow abnormalities, and 14 cases in abnormal group showing reduced blood flow, mainly in cerebellum and occipital lobe except in one case. In 10 cases with reduced blood flow which could be analyzed, calculation of the blood flow ratio in the temporal and occipital lobes and the cerebellum with the frontal lobe taken as 100 showed values of 93.5% for the temporal lobe, 82.7% for the occipital lobe and 76.8% for the cerebellum. A statistically significant reduction in blood flow occurred in the occipital lobe and cerebellum. In blood examination, abnormally high values of white blood cell counts were observed transiently in 94% of cerebral concussion cases. Abnormalities in brain stem and hypothalamus appeared to cause these abnormal WBC values. From these findings, it was suggested that the blood flow regions of the basilar and posterior cerebral arteries, i.e., the brain stem and hypothalamus are closely connected with the lesions responsible for cerebral concussion. It also appeared that the JHTS occurs in cerebral concussion cases where recovery of the abnormal blood flow in these regions in poor.

Topics: Adolescent; Adult; Amphetamines; Brain Concussion; Cerebrovascular Circulation; Child; Child, Preschool; Female; Humans; Iodine Radioisotopes; Iofetamine; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon