2 Objectives: Advantages of MRI over other Modalities Discuss the MRI historical development, and to know the significant person who discovered MRI.MRI discovery time linePersons involvedWhat are their ContributionsOverview of the basic principle of MRIAdvantages of MRI over other ModalitiesDifferent Components of MRI
5 DemocritusIn early 400B.CFirst to theorize that all matter consist of both invisible and indivisible particlesGreeksAlso noted and observed that a piece of amber, when rubbed by fur, would attract specific particles or object.
7 MAGNESIA TURKEY City of Magnesia is the origin of the term magnetism. Observed that when certain rock formation were spun on their axes, they always and immediately returned to their original orientation. These magnetize structure, which are called lodestone.
13 Michael FaradayStated and successfully demonstrated that electricity can produce magnetism.In 12 years later, michael faraday statedFor his contribution, and many others michael faraday is regarded by many as the father of electricity.
14 Michael FaradayCalculated the velocity and propagation of electromagnetic waves and predicted the existence of other waves in addition to the ultraviolet and infrared regions.In 12 years later, michael faraday statedFor his contribution, and many others michael faraday is regarded by many as the father of electricity.
15 Sir James Clerk Maxwell In 1860 discovered magnetic lines of force could be mathematically expressed.
16 Heinrich Hertz of Germany In 1868 discovered that invisible electromagnetic wave do exist and that all electromagnetic waves are identifiable by their characteristic wave frequency values.
17 Heinrich Hertz of Germany Electromagnetic spectrum – the categorical arrangement of the wave energies corresponding to their properties, began to take form.
19 Wilhelm Conrad Roentgen Marie Curie Nov. 8, 1895 discovered the x-rayMarie CurieIn 1896 discovered the gamma rays by experimenting on radioactive phosphors.Their discoveries soon demonstrated that high frequency wave energies were identifiable, detectable, measurable and often biologically damaging.
20 Post WORLD WAR IISome of the technology advances associated with the world war 2 laid the groundwork for utilizing sonograpghy (submarine detection) and nuclear medicine (atomic energy) for human.
21 Felix Bloch & Edward Purcell 1946Explore the mystery of atom.They noted that when a test tube sample of a pure substance was magnetically energized and RF bombarded the excited atoms themselves would respond by singing their own atomic ‘’tune’’.
23 Felix bloch & edward purcell These tune signal were detected and recorded into spectroscopic images, corresponding to their frequency values.Virtually overnight Nuclear Magnetic Resonance (NMR). The prelude to MRI, was about to be born.
24 Felix bloch & edward purcell Bloch and Purcell were recipients of the Novel Price in 1952 for their major contribution in uniquely discovering and implementing the use of atomic energy for analytical purposes.
29 Basic Principle of MRA certain atomic nuclei, if placed in a magnetic field, can be stimulated by (absorb energy from) radio waves of the correct frequency.Following this stimulation, the nuclei release the extra absorbed energy by transmitting radiowaves (the MR) signal, which can be received by an antenna and analyzed.
31 Advantages of MRI over other Modalities Contrast ResolutionMulti-Planar ImagingNo Radiation
32 CONTRAST RESOLUTION Principal advantage of MRI Allows visualization of low- density objects with similar soft tissue characteristics, such as liver- spleen or white matter – gray matterIt is a function of several intrinsic properties of the tissue being imaged.
38 NO Radiation MRI does not use Ionizing radiation MRI uses RF electromagnetic radiation and magnetic fields, which do not cause ionization and therefore do not have associated potentially harmful effects of ionizing radiation
39 MRI Hardware3 main components:GantryComputerOperating Console
40 GantryIs the large, usually cylindrical device that accommodates the patient during imagingMRI gantry does not have moving parts- everything is electronically controlledThe patient aperture is usually cm in diameter
42 RF COILSRF coils which is called the RF probe, surrounds the patient in this apertureGradient coils, shim coils, and in the case of an electromagnetic, primary coils all surrounds the RF probe to produce the static magnetic field
48 MRI OverviewThe hydrogen nuclei in the Patient- protons- behave like tiny magnetsHydrogen makes up 80 % of all atoms found in the human body, making hydrogen extremely useful for MRI.Because Hydrogen is a single- charge spinning nucleons, the hydrogen nucleus exhibit relatively strong magnetism