title: Cerebral Effects of Targeted Temperature Management Methods Assessed by Diffusion-Weighted Magnetic Resonance Imaging.
abstract: The aim of this randomized porcine study was to compare surface targeted temperature management (TTM) to endovascular TTM evaluated by cerebral diffusion-weighted magnetic resonance imaging (MRI): apparent diffusion coefficient (ADC), and by intracerebral/intramuscular microdialysis. It is well known that alteration in the temperature affects ADC, but the relationship between cerebral ADC values and the cooling method per se has not been established. Eighteen anesthetized 60-kg female swine were hemodynamically and intracerebrally monitored and subsequently subjected to a baseline MRI. The animals were then randomized into three groups: (1) surface cooling (n = 6) at 33.5°C using EMCOOLSpad®, (2) endovascular cooling (n = 6) at 33.5°C using an Icy®cooling catheter with the CoolGard 3000®, or (3) control (n = 6) at 38.5°C using a Bair Hugger™. The swine were treated with TTM for 6 hours followed by a second MRI examination, including ADC. Blood and microdialysate were sampled regularly throughout the experiment, and glucose, lactate, pyruvate, glycerol, and the lactate/pyruvate ratio did not differ among groups, neither intracerebrally nor intramuscularly. Surface cooling yielded a significantly lower median ADC than endovascular cooling: 714 (634; 804) × 10-6mm2/s versus 866 (828; 927) × 10-6mm2/s, (p < 0.05). The surface cooling ADC was lowered to a range usually attributed to cytotoxic edema and these low values could not be explained solely by the temperature effect per se. To what extent the ADC is fully reversible at rewarming is unknown and the clinical implications should be further investigated in clinical studies.
authors.affiliation: 1 Research Center for Emergency Medicine, Aarhus University Hospital , Aarhus C, Denmark .|2 Department of Anesthesiology and Intensive Care Medicine, Aarhus University Hospital , Aarhus N, Denmark .|3 Department of Clinical Medicine, Aarhus University Hospital , Aarhus N, Denmark .
authors.forename: Anders Morten
authors.initials: AM
authors.lastname: Grejs
authors.affiliation: 2 Department of Anesthesiology and Intensive Care Medicine, Aarhus University Hospital , Aarhus N, Denmark .
authors.forename: Jakob
authors.initials: J
authors.lastname: Gjedsted
authors.affiliation: 3 Department of Clinical Medicine, Aarhus University Hospital , Aarhus N, Denmark .
authors.forename: Michael
authors.initials: M
authors.lastname: Pedersen
authors.affiliation: 3 Department of Clinical Medicine, Aarhus University Hospital , Aarhus N, Denmark .
authors.forename: Hanne
authors.initials: H
authors.lastname: Birke-Sørensen
authors.affiliation: 1 Research Center for Emergency Medicine, Aarhus University Hospital , Aarhus C, Denmark .
authors.forename: Andreas
authors.initials: A
authors.lastname: Rauff-Mortensen
authors.affiliation: 3 Department of Clinical Medicine, Aarhus University Hospital , Aarhus N, Denmark .
authors.forename: Kristian Kjær
authors.initials: KK
authors.lastname: Andersen
authors.affiliation: 1 Research Center for Emergency Medicine, Aarhus University Hospital , Aarhus C, Denmark .
authors.forename: Hans
authors.initials: H
authors.lastname: Kirkegaard
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D001833:Body Temperature Regulation; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D001929:Brain Edema / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D038524:Diffusion Magnetic Resonance Imaging; D057510:Endovascular Procedures / Q000009:adverse effects; D005260:Female; D007036:Hypothermia, Induced / Q000009:adverse effects / Q000379:methods*; D017551:Microdialysis; D023421:Models, Animal; D034421:Sus scrofa; D013997:Time Factors
chemical_list: D015415:Biomarkers
keywords: MRI; apparent diffusion coefficient; body temperature regulation; targeted temperature management; temperature; therapeutic hypothermia