<i>In vivo</i> Measurement of Regional Cerebral Haematocrit Using Positron Emission Tomography

Lammertsma, Adriaan A.; Brooks, David J.; Beaney, R. P.; Turton, David R.; Kensett, M.J.; Heather, J. D.; Marshall, John; Jones, Terry

doi:10.1038/jcbfm.1984.47

Cited by 146 publications

(66 citation statements)

References 17 publications

(19 reference statements)

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“…It is interesting to note that some of these studies were performed using generator-produced radionuclides including 68 Ga, 82 Rb and 62 Cu [38][39][40][41].…”

Section: Final Remarksmentioning

confidence: 99%

The new FDG brain revolution: the neurovascular unit and the default network

Sestini¹,

Castagnoli²,

Mansi³

2009

Eur J Nucl Med Mol Imaging

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"Our aim is, more than see new things, to see with new eyes what has already been seen" Baruch SpinozaThe first FDG brain revolutionThe first revolution was explosive. Using 18 F-fluorodeoxyglucose (FDG), it was possible to see and study the living brain in humans! Pioneers were top experts who provided different specialized expertise, but strictly cooperating between themselves [1]. Physicists, engineers and mathematicians were actively involved in producing the best hardware and software. The research on crystals, in identifying the most effective electronics, in defining accurate methods for attenuation and scatter correction and so on, was nevertheless limited by the relatively poor technology, with the main consideration being limited computer power. These developments stimulated a major interest in the brain. Satisfactory sensitivity and resolution, together with reliable solutions to the technical problems, were only achieved with dedicated cerebral PET scanners which had a field of view that permitted exclusive analysis of the brain.Basic scientists had the possibility of realizing a scientific dream: the transfer of data on cerebral glucose metabolism acquired in animals by quantitative autoradiography to humans. Another issue in the original FDG PET research was to consider mandatory absolute quantification. Thus arterial (or arterialized) sampling, to obtain data to be included in mathematical models, was routinely performed. However, because the equations included nonmeasurable parameters, the presence of a lumped constant affected absolute measurement in an individual [2][3][4]. PET teams included (and were directed by) clinical experts including not only nuclear physicians, but also other professionals such as neuroradiologists, neurologists and psychiatrists, who frequently cooperated with psychologists, anatomists and physiologists.Because of the unsatisfactory spatial resolution and the negative influence of the partial volume effect, in presence of glucose uptake in the normal brain, only a low lesion/background ratio was achievable, except for hot spots, i.e. the presence of focal areas of increased uptake determined by physiological and/or pathological causes. Therefore, the use of FDG as a positive indicator was restricted in the first studies and in the search for hot spots, many studies involved physiological stimulation tests (closed/open eyes, auditory system, etc.) in normal subjects [5,6]. Similarly, major interest in pathological analysis was directed to the evaluation of brain tumours, starting from Warburg's hypothesis of higher FDG uptake in malignant lesions with respect to benign ones [7]. With further clinical experience, in the analysis of patients with epilepsy, a higher sensitivity was clearly demonstrated during the ictal phase, the focus being seen as a hot spot, with respect to the interictal period when the lesion was not easily detectable, being an area with a slightly reduced overall FDG uptake [8,9]. Discrepant results in epilepsy clearly demonstrate how, in the absenc...

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“…It is interesting to note that some of these studies were performed using generator-produced radionuclides including 68 Ga, 82 Rb and 62 Cu [38][39][40][41].…”

Section: Final Remarksmentioning

confidence: 99%

The new FDG brain revolution: the neurovascular unit and the default network

Sestini¹,

Castagnoli²,

Mansi³

2009

Eur J Nucl Med Mol Imaging

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“…Thus, to avoid systematic errors in quantification of the paramagnetic contrast agent induced by susceptibility contrast in the vicinity of vessels and the fact that the hematocrit is higher in big vessels as compared with capillaries, we did not attempt to quantify c t (t) in absolute units. Instead, we assumed that the microvascular hematocrit was constant across the brain (16), and used normal white matter as an internal standard in our measurements (17).…”

Section: Quantitative Analyses Of Cbf Cbv and Mttmentioning

confidence: 99%

Quantitative cerebral perfusion using the PRESTO acquisition scheme

Pedersen

Klarhöfer

Christensen

et al. 2004

Magnetic Resonance Imaging

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Purpose:To evaluate the feasibility of using the rapid principles of echo shifting with a train of observations (PRESTO) sequence for measurements of cerebral hemodynamic parameters based on first pass of a contrast agent. Materials and Methods:Simulations were performed to investigate potential resolution loss due to relaxation effects. Experimental evaluation was conducted in healthy monkey brains using PRESTO and echo-planar imaging (EPI).Results: For short echo trains, an insignificant contribution of the longitudinal and transversal relaxation rates to the signal amplitude in white matter and gray matter was found, whereas a contribution as large as 40% was found in large vessels. Simulations of the point spread function demonstrated that PRESTO, despite its shorter readout trains, only has a small advantage in terms of maintenance of image resolution during bolus passage compared to EPI as long as the EPI echo train can be kept similar to the T2* value at the top of the bolus. Experimental studies revealed that the PRESTO and EPI gray matter to white matter ratio were similar with respect to cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). Conclusion:The study showed that PRESTO and EPI led to comparable quantitative perfusion parameters.

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“…d L ' , D is brain density in g.mL-', and R is the large vesse1:cerebral hematocrit ratio. For this study, we assumed values of 64 500 for MW, 1.05 for D (23) and 0.69 for R (24). These values give the formula:…”

Section: Materlals and Methodsmentioning

confidence: 99%

Response of Cerebral Blood Volume to Changes in Arterial Carbon Dioxide Tension in Preterm and Term Infants

et al. 1991

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ABSTRACT. The response of cerebral blood volume (CBVR) to a small induced change in arterial carbon dioxide tension was studied by near-infrared spectroscopy in 17 newborn infants born from 26 wk of gestation to term. All 17 infants were undergoing mechanical ventilation but had apparently normal brains. The CBVR per kPa change in arterial carbon dioxide tension within the range 3.9 to 9.6 kPa was calculated from the change in total cerebral Hb concentration (

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In vivo Measurement of Regional Cerebral Haematocrit Using Positron Emission Tomography

Cited by 146 publications

References 17 publications

The new FDG brain revolution: the neurovascular unit and the default network

The new FDG brain revolution: the neurovascular unit and the default network

Quantitative cerebral perfusion using the PRESTO acquisition scheme

Response of Cerebral Blood Volume to Changes in Arterial Carbon Dioxide Tension in Preterm and Term Infants

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