Brain physiology studied with functional imaging methods
Fundamental understanding of brain physiology is interesting both for fundamental scientific reasons and a prerequisite for understanding and treatment of many neurological diseases. We study the brain with advanced functional imaging methods, use pharmacological as well as respiratory perturbations, and develop new quantitative methods to extract physiological information on the resting and working brain.
Vestergaard MB, Larsson HBW. Cerebrovascular reactivity and oxygen consumption during breath-hold and hypoxic challenge in freedivers and healthy controls. Journal of Cerebral Blood Flow and Metabolism. May 2019 . 39(5):834-848.
Vestergaard MB, Lindberg U, Aachmann-Andersen NJ, Lisbjerg K, Christensen SJ, Law I, Rasmussen P, Olsen NV, Larsson HBW. Acute hypoxia increases the cerebral metabolic rate - a magnetic resonance imaging study. Journal of Cerebral Blood Flow and Metabolism. December 2016. 36(6); 1046-1058.
Perfusion measurements using T1 weighted imaging
Determination of the vascular parameters of the brain is important both in disease and for basic understanding of brain physiology. Prof. Henrik Larsson has pioneered a T1 weighted perfusion imaging method based on bolus-tracking. This approach gives a better quantitative determination of cerebral blood flow and has less image distortions than other MR methods. The activities range from optimization of MR sequences and processing algorithms with regard to precision, spatial coverage and speed, to clinical applications in e.g. brain tumor patients.
Larsson HBW, Hansen AE, Berg HK, Rostrup E, Haraldseth O. Dynamic contrast-enhanced quantitative perfusion measurement of the brain using T1-weighted MRI at 3T. J Magn Reson Imaging. April 2008. 27(4):754-62.
EEG-fMRI for studies of neurovascular coupling in humans
Functional MR imaging (fMRI) of brain activity is in most cases based on the BOLD effect, which measures the change in deoxy-hemoglobin. This vascular response is only an indirect measure of neuronal activity. To investigate the coupling between the neuronal activity and the BOLD signal we use both EEG and fMRI measurement. We study the coupling both in healthy volunteers and neurological patients.
Lindberg U, Kruuse C, Witting N, Jørgensen SL, Vissing J, Rostrup E, Larsson HBW. Altered somatosensory neurovascular response in patients with Becker muscular dystrophy. Brain Behav. 2018 Jun;8(6):e00985.
Blood-brain barrier permeability and multiple sclerosis
The permeability of the blood-brain barrier as measured by dynamic contrast-enhanced MRI (DCE-MRI) is a novel in-vivo marker of neuroinflammation in the brain and is a useful tool in the clinical evaluation of multiple sclerosis patients. We investigate this along with brain perfusion and metabolic changes in relapsing-remitting and primary progressive multiple sclerosis patients.
Cramer SP, Modvig S, Simonsen HJ, Frederiksen JL, Larsson HBW. Permeability of the blood-brain barrier predicts conversion from optic neuritis to multiple sclerosis. Brain. September 2015. 138(9); 2571-2583.
SP Cramer, H Simonsen, JL Frederiksen, E Rostrup, HBW Larsson. Abnormal blood–brain barrier permeability in normal appearing white matter in multiple sclerosis investigated by MRI.NeuroImage: Clinical. December 2013. 4, 182-189.
Ageing is a main risk factor for the development of neurodegenerative disease and consequently cognitive decline. As part of population-based cohort studies we investigate the changes of the brain seen in normal ageing and its association with cognition, brain function and health status.
Vestergaard MB, Jensen MLF, Arngrim N, Lindberg U, Larsson HBW. Higher physiological vulnerability to hypoxic exposure with advancing age in the human brain. Journal of Cerebral Blood Flow and Metabolism. November 2018. doi: 10.1177/0271678X18818291.
Functional and structural imaging in neurological diseases
Functional imaging methods may give a better understanding of brain diseases, and eventually lead to better diagnostics and treatment. We perform functional imaging on patients with diseases such as optic neuritis, migraine, Tourettes syndrome, epilepsy, schizophrenia, brain tumors and stroke.
Functional imaging of heart disease
Tracerkinetic modeling of myocardial perfusion when using an MR contrast agent allows absolute quantification of perfusion with a high regional spatial resolution. We have during years developed these tracerkinetic methods and lately used this in an evaluation exercise effect on myocardial perfusion in pre- and post menopausal women.
Egelund J, Nyberg M, Mandrup CM, Abdulla J, Stallknecht B, Bangsbo J, Hellsten Y, Larsson HBW. Cardiac perfusion and function after high-intensity exercise training in late premenopausal and recent postmenopausal women: an MRI study. J Appl Physiol. May 2019. 1;126(5):1272-1280.
Using perfusion and T2* weighted imaging the dynamic of renal perfusion and oxygenation is studied. Renal function during physiological challenges in healthy individuals and in disease is investigated.
Haddock BT, Francis ST, Larsson HBW, Andersen UB. Assessment of Perfusion and Oxygenation of the Human Renal Cortex and Medulla by Quantitative MRI during Handgrip Exercise. J Am Soc Nephrol. October 2018 .29(10):2510-2517.