MRIMagnetic resonance imaging
• NMR = Nuclear Magnetic Resonance
• MRI = Magnetic Resonance Imaging
• ESR = Electron Spin Resonance
• Basic principles• while in the magnetic field, radio waves redirect
the axes of spinning nuclei or electrons
• Electron magnetic radiation is used to flip the alignment of nuclear or electron spin
• from low energy spin aligned state to high energy spin opposed state
• Radio frequency is absorbed, that is what is measured
• MRI: spin of nuclei of an odd mass or odd atomic number (usually H)
• ESR: spin of electrons of most fundamental particles
• ESR: particles will do as many as possible to pair up electrons
• MRI: nuclei also do, but not that many
• MRI is used for body examination.
• MRI can help in visualizing the human body. It can form structure images of tissues and bones in high definition.
• Also, they can detect problems such as tumors and gores.
Basic MRI scans
T1 Weighting with gadolinium
• T1,T2 are the time constant values.
• they determine the physical property changes of a specific tissue when it receives a series of radial pulse from the machine .
• Different type of tissue may have different T1, T2 values. This is due to the difference in behaviors of the H’s protons in a particular tissue when a radial pulse is transmitted to it by the magnetic field.
• Images that contains both the T1,T2 properties can be formed by adjusting TR,TE variables.
Side Effect of MRI
• MRI Side-effects are mostly temporary effects. The MRI scan itself does not usually have any physical side-effects.
• Projectile or missile effect
• Peripheral nerve stimulation (PNS)
• Radio frequency energy
• Acoustic noise• Contrast agents
• Our government is investing money on MRI technology to solve following problems
1. Wait List
2. Side Effect
Work cites• http://www.magnet.fsu.edu/usershub/scientificdivisions/emr/overview.html• http://www.chem.ucalgary.ca/courses/351/Carey/Ch13/ch13-nmr-1.html• http://www.radiologyinfo.org/en/info.cfm?pg=bodymr#part_five• http://www.chinamedi.cn/bbs/dispbbs.asp?boardID=17&ID=160&page=5• http://answers.yahoo.com/question/index?qid=20060902235859AAjZ7gx
• Simon, Merrill; Mattson, James S (1996). The pioneers of NMR and magnetic resonance in medicine: the story of MRI. Ramat Gan, Israel: Bar-Ilan University Press. ISBN 0-9619243-1-4.
• Haacke, E Mark; Brown, Robert F; Thompson, Michael; Venkatesan, Ramesh (1999). Magnetic resonance imaging: physical principles and sequence design. New York: J. Wiley & Sons. ISBN 0-471-35128-8.