Brain temperature in volunteers subjected to intranasal cooling

Covaciu, Lucian; Weis, Ján; Bengtsson, Caroline; Allers, Mats; Lunderquist, Anders; Åhlström, Håkan; Rubertsson, Sten

doi:10.1007/s00134-011-2264-7

Cited by 35 publications

(30 citation statements)

References 33 publications

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“…Regardless of its limited capacity for air convective cooling, the nasal mucosa remains a target for clinical SBC, primarily through the insertion of cold saline perfused balloon catheters [for review, see (190)]. Using the intranasal balloon catheter, Covaciu et al, (107) report rapid cerebral cooling measured by magnetic resonance. However, Springbord et al, (432) later found that the cerebral cooling from intranasal cold balloon insertion parallels reductions in esophageal temperature, and therefore, does not provide a functional means for SBC.…”

Section: Can the Brain Selectively Cool?mentioning

confidence: 98%

Cerebral Vascular Control and Metabolism in Heat Stress

Bain

Nybo

Ainslie

2015

Comprehensive Physiology

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This review provides an in-depth update on the impact of heat stress on cerebrovascular functioning. The regulation of cerebral temperature, blood flow, and metabolism are discussed. We further provide an overview of vascular permeability, the neurocognitive changes, and the key clinical implications and pathologies known to confound cerebral functioning during hyperthermia. A reduction in cerebral blood flow (CBF), derived primarily from a respiratory-induced alkalosis, underscores the cerebrovascular changes to hyperthermia. Arterial pressures may also become compromised because of reduced peripheral resistance secondary to skin vasodilatation. Therefore, when hyperthermia is combined with conditions that increase cardiovascular strain, for example, orthostasis or dehydration, the inability to preserve cerebral perfusion pressure further reduces CBF. A reduced cerebral perfusion pressure is in turn the primary mechanism for impaired tolerance to orthostatic challenges. Any reduction in CBF attenuates the brain's convective heat loss, while the hyperthermic-induced increase in metabolic rate increases the cerebral heat gain. This paradoxical uncoupling of CBF to metabolism increases brain temperature, and potentiates a condition whereby cerebral oxygenation may be compromised. With levels of experimentally viable passive hyperthermia (up to 39.5-40.0 °C core temperature), the associated reduction in CBF (∼ 30%) and increase in cerebral metabolic demand (∼ 10%) is likely compensated by increases in cerebral oxygen extraction. However, severe increases in whole-body and brain temperature may increase blood-brain barrier permeability, potentially leading to cerebral vasogenic edema. The cerebrovascular challenges associated with hyperthermia are of paramount importance for populations with compromised thermoregulatory control--for example, spinal cord injury, elderly, and those with preexisting cardiovascular diseases.

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Section: Can the Brain Selectively Cool?mentioning

confidence: 98%

Cerebral Vascular Control and Metabolism in Heat Stress

Bain

Nybo

Ainslie

2015

Comprehensive Physiology

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“…Targeting a specific tissue makes it possible to reduce temperature more rapidly without altering core body temperature and producing unwanted side effects. Current cooling methods include cooling helmets, nasopharyngeal cooling, local cooling coils, and cerebrospinal fluid exchange (Andrews et al, 2005;Covaciu et al, 2011;Harris et al, 2007). However, the brain is supplied by 15% of the cardiac output, and the high blood flow continuously warms the brain, which in addition to the invasiveness of the method, undermines the utility of selective head cooling (Esposito et al, 2014).…”

Section: From Whole Body To Selective Head Coolingmentioning

confidence: 99%

Therapeutic hypothermia for stroke: Where to go?

Han

Liu

Luo

et al. 2015

Experimental Neurology

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“…This MR thermometry method largely eliminates field drift or non-uniform field distribution by using the internal reference. Magnetic resonance spectroscopic imaging (MRSI), or sometimes referred to as chemical shift imaging (CSI) of temperature mapping has been further developed after the success of the single voxel MRS absolute temperature quantification technique (15,16,24,75). Although these MR spectroscopy methods have demonstrated promising potential for accurate mapping of absolute temperature in biological systems, they unfortunately still have many disadvantages preventing their use in real time temperature monitoring: (I) relatively long acquisition time (typically on the order of a couple of minutes), thus low temporal resolution and poor spatial resolution comparing to other thermal imaging methods; (II) highly dependent on a homogeneous magnetic field to obtain accurate frequency measurement; (III) rely on accurate measurement of low concentration metabolites, thus, not applicable under some pathological conditions (e.g., tumor necrosis).…”

Section: Proton Frequency Referenced By Lipid or Naa In Magnetic Resomentioning

confidence: 99%

Image-guided thermal ablation with MR-based thermometry

Zhu

Sun

2017

Quant. Imaging Med. Surg.

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Thermal ablation techniques such as radiofrequency, microwave, high intensity focused ultrasound (HIFU) and laser have been used as minimally invasive strategies for the treatment of variety of cancers. MR thermometry methods are readily available for monitoring thermal distribution and deposition in real time, leading to decrease of incidents of normal tissue damage around targeted lesion. HIFU and laser-induced thermal therapy (LITT) are the two widely accepted tumor ablation techniques because of their compatibility with MR systems. MRI provides multiple temperature dependent parameters for thermal imaging, such as signal intensity, T1, T2, diffusion coefficient, magnetization transfer, proton resonance frequency shift (PRFS, including phase imaging and spectroscopy) as well as frequency shift of temperature sensitive contrast agents. Absolute temperature mapping techniques, including both spectroscopic imaging using metabolites as a reference and phase imaging using fat as a reference, are immune to susceptibility effects and are not dependent on phase differences. These techniques are intrinsically more reliable than relative temperature measurement by phase mapping methods. If the limitation of low temporal and spatial resolution could be overcome, these methods may be preferred for MR-guided thermal ablation systems.As of today, the most popular MR thermal imaging method applied in tumor thermal ablation surgery is, however, still PRFS based phase mapping technique, which only provides relative temperature change and is prone to motion artifacts.

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Brain temperature in volunteers subjected to intranasal cooling

Abstract: Both MR techniques revealed brain temperature reductions after 60 min of intranasal cooling with balloons circulated with saline at 20°C in awake, unsedated volunteers.

Cited by 35 publications

References 33 publications

Cerebral Vascular Control and Metabolism in Heat Stress

Cerebral Vascular Control and Metabolism in Heat Stress

Therapeutic hypothermia for stroke: Where to go?

Image-guided thermal ablation with MR-based thermometry

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