Imaging Angiogenesis
Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman in Molecular Imaging in Oncology, 2008
Some experimental designs such as indicator fractionation methods and indicator washout methods simplify the relationship such that Ci or Ce is equal to zero. Indicator washout studies rely on direct administration of tracer to the tissues or a large artery, e.g., the carotid artery for hemicerebral studies. For this purpose, [133Xe]xenon can be used because effectively all tracer is exhaled at first pass through the lungs without recirculation. Therefore, Ca can be disregarded and Ci can be modeled as the concentration in tissue fluid (Ct) and Ce as regional venous concentration (Cv). However, this model is sensitive to assumptions including the profile of lymphatic drainage and sequestration of the tracer in fat. Its main application in humans is the measurement of regional cerebral blood flow (63).
Clinical Applications and Protocols of Single Photon Emission Computed Tomography
Bhagwat D. Ahluwalia in Tomographic Methods in Nuclear Medicine: Physical Principles, Instruments, and Clinical Applications, 2020
Measurement of regional cerebral blood flow (rCBF) with SPECT appears promising, even though it is restricted to special purpose instrumentation since most SPECT systems are too insensitive for this application. Invasive intracarotid injection of 133Xe24 and 15O-labeled water25 were the early approaches to rCBF studies. High sensitivity is required to perform 133Xe tomographic studies because of the fast washout of the radionuclide. Special instrumentation such as a bar-camera array system was developed to overcome this problem;26, 27 this approach failed, however, because of poor spatial resolution. Fazio et al.28 studied rCBF using intracarotid infusion of 81mKr and a rotating SPECT camera; however, this approach is somewhat impractical because of its invasiveness. With the introduction of N-isopropyl-123I-iodoamphetamine (123I-IMP)29-31 and, lately, other 123I-labeled compounds such as hydroxyiodopropyldiamine (HIPDM)32-35 and iodobenzene (IBZ),36 some of the sensitivity problems can be overcome. Since 123I-IMP remains a long time (≃2 days) in the brain parenchyma,29 the sensitivity of the imaging device becomes less problematic compared to the use of 133Xe with its fast washout.
Advances in the Prevention and Treatment of Age-Related Organic Memory Disorders
José León-Carrión, Margaret J. Giannini in Behavioral Neurology in the Elderly, 2001
Different authors have proposed that there is a fall in cerebral blood flow and oxygen metabolism from childhood to adolescence, followed by a more gradual reduction throughout the remaining age span. An interesting study was done by Hagstadius and Risberg,8 measuring the regional cerebral blood flow (rCBF) of 97 normal subjects aged 19 to 68 years old while resting. Results showed that the mean CBF level decreased progressively with age. The decrease was more pronounced in frontotemporal and inferior Rolandic areas bilaterally. Frontal areas showed the highest values in all age groups. This hyperfrontality weakened somewhat with age. Mean CBF in the right hemisphere was significantly higher than in the left, as was flow in superior frontal, inferior frontal, and parietal areas. These asymmetries were age invariant. The age-related decrease of rCBF is interpreted by the author as reflecting aging of the brain per se, although the influence of asymptomatic brain disease cannot be ruled out. The flow asymmetries are interpreted as related to functional lateralization of some aspects of attentional activation.
Hypnotic Automaticity in the Brain at Rest: An Arterial Spin Labelling Study
Published in International Journal of Clinical and Experimental Hypnosis, 2019
Pierre Rainville, Anouk Streff, Jen-I Chen, Bérengère Houzé, Carolane Desmarteaux, Mathieu Piché
In the present study, we assessed resting-state brain activity using arterial spin labelling (ASL), a functional magnetic resonance imaging method sensitive to brain perfusion (van Osch et al., 2018). This approach allows direct comparisons of regional cerebral blood flow between states and individuals. We tested the hypothesis that increases in self-reports of hypnotic automaticity at rest (i.e., without any stimulus or task) are positively associated with activity in the parietal operculum (Blakemore et al., 2003), and are related to a fronto-parietal network involved in phenomenological aspects of self-agency and volition (Darby, Joutsa, Burke, & Fox, 2018). In order to verify that automaticity-related effects did not simply reflect nonspecific aspects of hypnosis phenomenology, brain activity was also examined in relation to hypnotic depth and hypnotizability scores to highlight putative distinctive neural associations. Importantly, participants were not selected a priori based on their scores to allow conducting regression analyses examining individual differences in hypnosis-related effect across a representative range of hypnotizability (see Jensen et al., 2017).
Diversity in clinical manifestations and imaging features of neurosyphilis: obstacles to the diagnosis and treatment (report of three cases)
Published in International Journal of Neuroscience, 2018
Hui Liu, Zong-Bo Zhao, Nian-Xing You
These three patients received cerebral blood flow perfusion examination by SPECT. In case 1, the patient underwent surgical exairesis, so he had nonperfusion in right parietal lobe. The patients in cases 2 and 3 showed regional cerebral blood flow hypoperfusion. The hypoperfused lesions of SPECT imaging are consistent with abnormal signals of MRI imaging. Pichler and some other researchers performed SPECT to investigate the cerebral blood flow of syphilis patients. They observed that all subjects showed general or patchy hypoperfusion of regional cerebral blood flow [3]. Ide reported a case of neurosyphilis patient whose MRI imaging showed normal. But his cerebral blood flow of SPECT imaging improved predominately after norm antisyphilitic treatment [6]. Evidence above shows TP invades into central nervous system (CNS) and affects the whole brain in the early infecting stage. But at this stage, Computed Tomography (CT) or MRI imaging is normal. In a word, SPECT imaging can be of benefit to the diagnosis of early neurosyphilis and assessment after treatment [4].
Genistein attenuates brain damage induced by transient cerebral ischemia through up-regulation of Nrf2 expression in ovariectomized rats
Published in Neurological Research, 2018
Zhong-Yan Miao, Xu Xia, Lu Che, Yan-Tao Song
The intraluminal filament model of MCAO was used to induce transient focal cerebral ischemia as described previously (n = 30 per group) [13]. In brief, a heat-blunted 3–0 nylon suture was inserted into the right common carotid artery to obstruct the middle cerebral artery. The right external carotid artery and the common carotid artery were both simultaneously ligated. After 1.5 h of transient occlusion, cerebral blood flow was restored by removing the nylon suture for 72 h. Regional cerebral blood flow was measured via transcranial laser Doppler flowmetry (PeriFlux 5000, Perimed AB, Sweden). Rats with >80% flow reduction during the ischemic period and >70% flow recovery within the first 10 min of reperfusion were included in the study. Physiological variables monitored included rectal temperature, blood pressure, heart rate, blood gas, and glucose levels and were monitored as previously described [14]. Data are shown in Supplementary Table 1. The animals in the sham group were subjected to the same operation; however, no suture was inserted into the right common carotid artery to obstruct the middle cerebral artery. And the rats in Con, OVX, and Genistein group were all received obstruction of the middle cerebral artery.