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Functional imaging and emerging techniques in CT
Published in Anju Sahdev, Sarah J. Vinnicombe, Husband & Reznek's Imaging in Oncology, 2020
Vicky Goh, Christian Kelly-Morland, Davide Prezzi
Perfusion CT techniques were first described in the late 1970s. Ladurner et al. described the measurement of regional cerebral blood volume (CBV) using an EMI CT 1010 scanner in 14 patients (3). However, the limitations of CT for measuring regional blood flow and blood volume at the time were acknowledged (4,5). In particular, the slow sequential acquisition speed and limited coverage of single-slice CT were problematic. MDCT and computed parametric mapping of perfusion (6) were a necessary step-change, and with current MDCT, high temporal resolution perfusion CT can be achieved for the whole organ.
Radioisotopes in Biology and Medicine
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
99Tc-labeled sodium pertechnetate or 99Tc-labeled glucoheptonate is commonly used for the study of a damaged blood-brain barrier (BBB). Cerebral blood volume is determined by the use of 99mTc-labeled red blood cells or 99mTc-labeled serum albumin. 133Xe, an inert and diffusable gas, is commonly used to determine cerebral blood flow.
The nervous system and the eye
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
James A.R. Nicoll, William Stewart, Fiona Roberts
An increase in the volume of the brain due to oedema or increased cerebral blood volume contributes to raised ICP. Vasodilatation leading to an increase in cerebral blood volume may occur due to hypoxia or hypercapnia, or as a result of loss of vasomotor tone which may complicate acute brain damage.
Dural venous sinus stenting in patients with idiopathic intracranial hypertension: report of outcomes from a single-center prospective database and literature review
Published in Expert Review of Ophthalmology, 2022
Matthew J Kole, Juan Carlos Martinez-Gutierrez, Francisio Sanchez, Rosa Tang, Peng Roc Chen
No consensus based on large, randomized, controlled trials exist comparing the numerous medical and surgical treatment modalities for IIH to one another. However, the main goals of treatment are relieving intracranial pressure and optic nerve edema, as well as headache relief [57]. As intracranial pressures are a product of the collective volumes of brain, CSF, and blood, and cerebral blood volume is not readily addressed, treatments have been devised to reduce the volume of the first two constituents. The order in which treatments are selected, and the length of time for which any of them may be trialed before selecting a more invasive option are often related to the time course of symptom onset and severity of symptoms. At our own institution, patients with a ‘fulminant’ course of disease progression (that which occurs over a period of several days) often forgo medical management in favor of surgical options, whereas those with several years of symptom progression prior to diagnosis may reasonably undergo a trial of medical management prior to considering more invasive therapies. Here, we will briefly touch on these therapies and focus on endovascular stenting.
Atrial fibrillation as an important clinical condition of cognitive decline; diagnosis, comorbidities and severity of symptoms in patients with dementia
Published in Neurological Research, 2020
Natalia Niedziela, Maria Magdalena Nowak, Martyna Lis, Maria Blaszkowska, Rozalia Kośmider, Monika Adamczyk-Sowa
A number of mechanisms are considered to account for cognitive impairment in AF. One of them assumes that small thrombi from the fibrillating left atrium cause microembolization which results in subclinical infarction and subsequent brain atrophy. Another hypothesis assumes that reduced cerebral blood flow resulting from atrial beat-to-beat variability is connected with cerebral atrophy in patients with permanent AF [38,39]. Moreover, AF is a known risk factor for heart failure, which may further aggravate cerebral hypoperfusion [7]. An important aspect of decreased cerebral blood volume in dementia is related to the location of cerebrovascular changes with unfavorable outcomes in the Circle of Willis, which is crucial for the distribution of cerebral blood flow. This mechanism could explain sudden cognitive impairment in patients after the onset of AF [40]. An association between cerebral microbleeds and reduced cerebral blood flow is also observed. In patients on anticoagulants due to AF, some microbleeds may result in an increased risk of dementia. Reduced blood volume and hippocampal atrophy are reported in microbleeds [41]. Furthermore, AF and dementia are symptoms of a degenerative process related to increased vascular stiffness in hypertension, which adversely affects microvascular function of many internal organs.
Improvement of cerebral blood perfusion in certain cerebral regions after cranioplasty could be monitored via tympanic membrane temperature changes
Published in Brain Injury, 2018
Ying Jiang, Yun-Kun Wang, Xiao-Lei Shi, Shen-Hao Wang, Yi-Ming Li, Jun-Yu Wang, Dan-Feng Zhang, Chao Ma, Ming-Kun Yu, Li-Jun Hou
All brain CTP examinations were carried out on a 64-section CT scanner (Philips Healthcare, Cleveland, OH, USA). The CTP scan was started 5 s after the injection of 35 mL of non-ionic contrast agent (Iomeron 300 mg/mL, Bracco Imaging S.p.A. Milan, Italy) at the rate of 4 mL/s with a power injector (Medrad Inc., Indianola, PA, USA). The cerebral blood volume (CBV), mean transit time (MTT) and CBF maps were generated and underwent measurement by an independent technician with the CT scanner including software package. The regions of interest (ROIs) were located at eight different loci, including the frontal lobe, parietal lobe, occipital lobe, temporal lobe, thalamus, basal ganglia, mesencephalon and epencephalon of the primary injured side, which then were automatically ‘reflected’ onto the contralateral hemisphere about the midline by the software. The CBV value was calculated from the area under the time-attenuation curves during the first contrast material bolus passage, while the MTT was calculated by using a deconvolution operation (15). According to the central volume principle (CBF = CBV/MTT), the CBF was calculated from the measured CBV and MTT as previously demonstrated (16).