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The History of Nuclear Medicine
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
In 1961, David H. Ingvar (1924–2000) and Niels A. Lassen (1926–1997) introduced 133Xe for quantitative measurements of regional cerebral blood flow (rCBF) using a system of multiple single NaI(Tl)-detectors [1]. In 1962, David Kuhl (1929–2017) introduced emission reconstruction tomography, which was later further developed and became the basis for image reconstruction in SPECT, PET and CT. Its reconstruction method was relatively simple, and the rapid development of computer tomography, CT, by Godfrey Hounsfield (1919–2004) benefitted PET significantly.
Positron Emission Tomography Imaging Systems And Applications
Published in Bhagwat D. Ahluwalia, Tomographic Methods in Nuclear Medicine: Physical Principles, Instruments, and Clinical Applications, 2020
Regional cerebral blood flow and oxygen utilization has been investigated by Lenzi et al.46 and Ito et al.47 Positron emitters as gaseous 15O labeled carbon dioxide and oxygen-labeled 15O were continuously inhaled by subjects and brain images were taken at equilibration. Continuous inhalation of carbon dioxide gas labeled with 15O tracer has been noninvasively used by Ackerman et al.43-45 to study stroke patients. Tracer activity patterns were observed in areas of ischemic injury.
Cerebral Metabolic Impairments
Published in Zaven S. Khachaturian, Teresa S. Radebaugh, Alzheimer’s Disease, 2019
Reductions in cerebral metabolic rate in AD are incontrovertable. Data supporting this statement have been gathered since the late 1940s, by invasive methods, measurement of regional cerebral blood flow (rCBF), and more recently by positron emission tomography (PET), single photon emission computerized tomography (SPECT), and other more modern techniques.2,3,5,17 The reduction affects glucose utilization, oxygen uptake, and cerebral blood flow. Indeed, the diminutions in glucose utilization (with positron-emitting fluorodeoxyglucose as label), or in oxygen uptake or cerebral blood flow, are commonly used to study in vivo the location and degree of brain impairment in AD.
Unilateral akathisia and choreoathetosis as an unusual presentation of a frontal lobe dermoid cyst
Published in British Journal of Neurosurgery, 2021
Lindsey Bulleid, Christopher Wilcox, Tom Hughes, Paul A Leach
Pressure effects may also damage other key structures in the nigrostriatal pathway, including the substantia nigra of the midbrain and the thalamus, with subsequent implications for effective transmission and modulation of motor impulses. Supporting evidence includes recent F-fluoro-deoxyglucose-positron emission tomography (FDG-PET) imaging of olanzapine-induced akathisia, suggesting that akathisia may be related to reduction in metabolic activity in the thalamus.5 Furthermore, mass effect seems a reasonable explanation given that choreoathetosis and akathisia have been reported as presenting feature in cases of subdural haematoma and hydrocephalus, and resolved following surgical treatment.6 Further FDG-PET studies measuring regional cerebral blood flow have suggested that impaired tissue perfusion may be a contributory mechanism in such cases, especially in large tumours with significant peritumoural oedema.7
Resveratrol promoted the M2 polarization of microglia and reduced neuroinflammation after cerebral ischemia by inhibiting miR-155
Published in International Journal of Neuroscience, 2020
Shan Ma, Lingling Fan, Junchao Li, Bei Zhang, Zhongjun Yan
The cerebral ischemia model was constructed through transient middle cerebral artery occlusion (MCAO). First, the adult mice were anesthetized by 3.5% chloral hydrate (1 ml/100g) through intraperitoneal (IP) injection. Then, a ventral midline neck incision was performed to expose the right external carotid artery (ECA), right common carotid artery (CCA) and right internal carotid artery (ICA). Later, the branches of ECA were cut off at 2.0 mm from the bifurcation of CCA, and a nylon suture with heparin-dampened monofilament and a rounded tip was gently inserted 18–20 mm in ECA to occlude the right middle cerebral artery (MCA). The filament was then withdrawn to restore blood flow after occlusion for 2 h. A decrease in the regional cerebral blood flow to 20% and recovered to more than 80% of the baseline was used to confirm the occlusion was successful. Mice in sham group only underwent the same surgical procedures, but the monofilament was not inserted to the MCA. During the surgery process, the temperature of mice was maintained at 37.0 ± 0.5 °C by a thermostatically controlled infrared lamp.
Alien hand syndrome – a rare presentation of stroke
Published in Journal of Community Hospital Internal Medicine Perspectives, 2020
Kelly Le, Christine Zhang, Lisa Greisman
The frontal variant of AHS is theorized to occur when the primary motor cortex controlling hand movement is isolated from the premotor cortex’s influence. Therefore, the brain is still able to command some body movements but cannot generate self-control over these movements, leading to disinhibited movements. The posterior variant of AHS is believed to occur when disruptions develop between the parietal and temporal cortices. This theory is supported by regional cerebral blood flow (rCBF) studies using single-photon emitted computed tomography (SPECT) and functional MRI (fMRI). In normal patients, fMRI shows activation of multiple extensive neural networks upon initiation of motor activity, whereas isolated activation of the contralateral primary motor cortex is seen in patients with posterior AHS[3]. In a case study reported by Delrieu et al., seven patients with corticobasal degeneration underwent rCBF. Six of the seven patients demonstrated reduced rCBF in the right parietal region compared with controls, and three patients were diagnosed with AHS[4]. In our patient, involvement of the parietal area along with proprioception deficits correlated most closely with posterior-variant AHS. However, signs and symptoms of the three variants commonly overlap, making it difficult to determine precisely which AHS variant is present.