Reserch On Brain Function Changes Of Pilots In Simulated Weightlessness Based On ASL Sequence

During civil aviation flight or complex flight training,pilots are often in a state of slight weightlessness.In this paper,from the influence of mild weightlessness on pilots,combined with the characteristics of magnetic resonance experimental equipment,an experiment of-10°head low simulated weightlessness is designed.ASL technology has the advantages of non-destructive and reproducible,and can directly and quantitatively analyze the changes of cerebral blood flow?CBF?.It has its own unique advantages compared with PET technology and CT technology,and is the key research sequence of this paper.Firstly,the article introduces the technical principle of the ASL sequence and the image quantization process of the multi-delay pCASL sequence.Then,with ASL as the core research sequence,the changes of human CBF under simulated weightlessness and the advantages of multi-delay ASL technique in measuring CBF are discussed.On the basis of simulated weightlessness experiment,the change of cerebral oxygen metabolism rate?CMRO₂?is studied based on ASL sequence and T2-Relaxation-Under-Spin-Tagging?TRUST?sequence.Based on ASL sequence and blood oxygen level dependent?BOLD?sequence,the voxel-based ratio of CBF and functional connection strength is calculated to study the change of blood supply per unit functional connection strength?FCS?under simulated weightlessness.The experimental results show that under simulated weightlessness,CBF changes,brain regions such as thalamus and central anterior gyrus rise,and the medial frontal gyrus and other brain regions decrease.By including arterial transit times?ATT?calculation,the detection signal of ASL sequence is reached at ATT,improving the measurement accuracy of CBF;the CMRO₂ measured by the TRUST sequence and the ASL sequence is elevated under simulated weightlessness,and the brain is in a relatively more active state than the lying state;By calculating the ratio of CBF and FCS based on voxel,It is found that there is a positive correlation between the CBF and FCS,and the ratio is reduced under the simulated weightlessness state,indicating that the blood supply capacity under the unit connection strength of the brain has been affected to some extent.On the basis of the research,this paper makes a new discussion on pilot training and physical examination mode.Based on the above results,it can be concluded that mild weightlessness will have a certain impact on the brain function parameters of pilots,and ASL sequence can become an important tool for pilots in the field of brain function changes and physical training.