T1 Relaxation & T2 Relaxation ll magnetic resonance imaging ll Radiography simplified

Hi friends... Welcome to Radiography Simplified. #T1_relaxation #T2_relaxation #NMR MRI uploaded video. mri principle    • MRI principle ll Magnetic Resonance Imagin...   mri components    • MRI ( components ) ll Magnetic resonance i...   mri introduction    • MRI introduction ll Magnetic resonance ima...   Old video links Focal spot.    • Focal Spot in an x-ray tube  ll Effective ...   IVP    • IVP ll Intravenous pyelography ll Intraven...   Automatic processor    • Automatic film Processor  l components l D...   X ray beam restrictor.    • X-ray beam restrictors ll Cone , Cylinder ...   Coherent scattering.    • COHERENT SCATTERING ll interaction of x-ra...   X- ray tube    • x-ray tube l components & type l Radiograp...   Dark room    • Dark Room in radiography l feature l const...   Processing chemical    • x-ray film processing chemical l developer...   Intensifying screen    • Intensifying screen part -1 l construction...   X ray film    • Radiographic / x- Ray films l construction...   Today topic is... T1 relaxation & T2 relaxation ( magnetic resonance imaging) T1 relaxation-: 1) it is a loss of longitudinal. magnetization along the axis. 2) it happens along z axis 3) hydrogen nuclei return to restingl state that is from higher energy state to lower energy state. 4) it is also known as spin lattice relaxation. 5) There is an energy transfer. 6) T1 is a time constant. " It is the time it take longer chooral meditation to recover to 63% of it maximum value" T2 relaxation:- 1) it is loss of transverse magnetization along xy plane. 2) it is also known as spin-spin relaxation. 3) T2 is a time constant. 'It is the time taken to reduce the transverse magnetisation to 37% of the peak value' It depends on -: 1) external magnetic field inhomogeneities. 2) intrinsic magnetic inhomogeneities of tissues. MRI principle -: " It States that certain atomic nuclei demonstrate the ability to absorb and re-emit radio frequency when it is placed in the magnetic field" Hydrogen is consist of a single proton. Proton as spinning charged particle produces a magnetic field so hydrogen act like a tiny magnet. In a normal state all the hydrogen protons are oriented randomly and cancel out each other so there will be no net magnetization. When patient is placed in the magnetic field, Most of the hydrogen proton line up in the direction of magnetic field Bo and few line up in antiparallel direction resulting in net magnetization . Precession frequency is represented by a formula called larmor equation. It states that precession frequency is equal to Gamma multiplied by Bo. When our pulse is applied perpendicular to the main magnetic field. Then absorption of energy takes place which flips the longitudinal magnetization in the direction of xy plane and there will be a loss of longitudinal magnetization. And when RF pulse is switched off two things happen at the same time. 1) regain longitudinal magnetization called T1 relaxation. 2) lose of transverse magnetization known as T2 relaxation. T1 relaxation :- 1) it is also known as spin- lattice relaxation. 2) it is is occur along the z axis. 3) it involve transfer of energy. 4)it is a slower process. T2 relaxation:- 1) it is also called spin spin relaxation. 2) it's occur along xy plane 4) it is a faster process. Gradient coils are used to produce deliberate variation in the magnetic field. There are three set of gradient coil for each directions. The variation the magnetic field permit localisation of image slices as well as phase encoding and frequency encoding. It is also responsible for the loud noise generated by the MR scanner. During relaxation that is T1 and t2 signal are emitted out from the patient body. Which is detected by the the RF receiver coils Once the signal are are detected by the the RF receiver coil. the signals are are turned to digital signal by analogue to digital converter. the digital signal is then sent for image processing ( Fourier transform )and the the images displayed on the monitor. Thanks for watching 🙏 Please like, share & subscribe. bye . Take care.