Abstract
BACKGROUND AND PURPOSE: Brain temperature is critical for homeostasis, relating intimately to cerebral perfusion and metabolism. Cerebral thermometry is historically challenged by the cost and invasiveness of clinical and laboratory methodologies. We propose the use of noninvasive MR thermometry in patients with cerebrovascular disease, hypothesizing the presence of a measurable brain thermal response reflecting the tissue hemodynamic state.
MATERIALS AND METHODS: Contemporaneous imaging and MR thermometry were performed in 10 patients (32–68 years of age) undergoing acetazolamide challenge for chronic, anterior circulation steno-occlusive disease. Cerebrovascular reactivity was calculated with blood oxygen level–dependent imaging and arterial spin-labeling methods. Brain temperature was calculated pre- and post-acetazolamide using previously established chemical shift thermometry. Mixed-effects models of the voxelwise relationships between the brain thermal response and cerebrovascular reactivity were computed, and the significance of model coefficients was determined with an F test (P < .05).
RESULTS: We observed significant, voxelwise quadratic relationships between cerebrovascular reactivity from blood oxygen level–dependent imaging and the brain thermal response (x coefficient = 0.052, P < .001; x2coefficient = 0.0068, P < .001) and baseline brain temperatures (x coefficient = 0.59, P = .008; x2 coefficient = −0.13, P < .001). A significant linear relationship was observed for the brain thermal response with cerebrovascular reactivity from arterial spin-labeling (P = .001).
CONCLUSIONS: The findings support the presence of a brain thermal response exhibiting complex but significant interactions with tissue hemodynamics, which we posit to reflect a relative balance of heat-producing versus heat-dissipating tissue states. The brain thermal response is a potential noninvasive biomarker for cerebrovascular impairment.
ABBREVIATIONS:
- ACZ
- acetazolamide
- ASL
- arterial spin-labeling
- BOLD
- blood oxygen level–dependent
- BTR
- brain thermal response
- CMRO2
- cerebral metabolic rate of oxygen
- CVR
- cerebrovascular reactivity
- MRSI
- MR spectroscopic imaging
- OEF
- oxygen extraction fraction
Footnotes
Disclosures: Candace C. Fleischer—UNRELATED: Grants/Grants Pending: National Institutes of Health, Comments: National Institutes of Health postdoctoral fellowship (F32CA199834); Support for Travel to Meetings for the Study or Other Purposes: International Society for Magnetic Resonance in Medicine, Comments: International Society for Magnetic Resonance in Medicine travel award to attend the annual meeting in Singapore to present this work. Deqiang Qiu—UNRELATED: Grants/Grants Pending: Medtronic and Siemens Healthcare, Comments: research support*. Fadi Nahab—UNRELATED: Expert Testimony: Grant Law Firm, Comments: pertains to cases of stroke treatment, not imaging of stroke; Payment for Lectures Including Service on Speakers Bureaus: Medtronic, American Heart Association/American Stroke Association, Genzyme, Comments: lectures on cryptogenic stroke, Fabry disease; Payment for Development of Educational Presentations: Imedex, Comments: education on cryptogenic stroke. Seena Dehkharghani—UNRELATED: Travel/Accommodations/Meeting Expenses Unrelated to Activities Listed: Society of Vascular and Interventional Neurology and All India Institute of Medical Sciences, Comments: travel expenses paid by the Society of Vascular and Interventional Neurology and All India Institute of Medical Sciences as an invited speaker. *Money paid to the institution.
Deqiang Qiu is supported by National Institutes of Health grants AG25688, AG42127, AG49752, and AG51633.
Abstract previously presented at: Annual Meeting and Exhibition of the International Society for Magnetic Resonance in Medicine, May 7–13, 2016; Singapore; and the Annual Meeting of the American Society of Neuroradiology, May 21–26, 2016; Washington, DC.
- © 2017 by American Journal of Neuroradiology
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