MRI- Magnetic resonance imaging

1. MRI-Magnetic resonance imaging By Prashil Patel

2. What is MRI •  Test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the body. • Body is placed inside a special machine that contains a strong magnet.

3. Cont… • An MRI is similar to a (CT) scanner in that it produces cross-sectional images of the body • MRI uses a strong magnetic field and radio waves to produce very clear and detailed computerized images of the inside of the body.

4. Early History of MRI •  Felix Bloch of Stanford University and Edward Purcell of Harvard University made the first successful nuclear magnetic resonance, NMR, experiment to study chemical compounds in 1946 • NMR creates magnetic fields and radio waves cause atoms to give off tiny radio signals.  •  In the early 1980s, the first "human" magnetic resonance imaging (MRI) scanners became available, producing images of the inside of the body.

5. Why Is MRI Done Used to find problems such as •  Tumors • Bleeding • Injury • Blood vessel diseases • Infection MRI scan can be done for • Head • Chest • Blood vessels • Abdomen and pelvis • Bones and joins • spine

6. Current technology T1 vs T2 MRI T1MRI • T1 MRI is known as Spin-lattice relaxation time • It differentiates fat from water - with water darker and fat brighter • T1-weighted MRI is best for looking at brain structures • The strength of the magnets used in T1 are in the 0.5-tesla to 2.0 -tesla range

7. T1 vs T2 conti… T2 MRI • T2 MRI is known as spin-spin relaxation time • Like T1 MRI, T2 also differentiates fat from water, but fat shows darker, and water lighter • T2 is better for looking at non-enhancing brain lesions • The strength of the magnets used in T2 are in the 0.5-tesla to 2.0 -tesla range

8. T1 Image T2Image T1 MRI Scan 1.5 Telsa T2 MRI Scan 1.5 Telsa

9. Proton Density weighted MRI •  Concentration of protons in the tissue in the form of water and macromolecules.(Far, Protein, etc) •  Utilizes the difference in proton densities of two materials when T1 and T2 characteristics are similar.

10. T1-Weighted T2-weighted Proton Density Weighted

11. limitations of the MRI • Because of the small space given, some patients experience claustrophobia have difficulty in cooperating during the study. • Some obese patients cannot be examined • Patients with pacemakers and certain ferromagnetic appliances cannot be studied • MRI equipment is expensive to purchase, maintain, and operate

12. Future direction of the MRI • Very small scanners for imaging specific body parts are being developed • Researchers at the University of Zurich, has recently demonstrated a novel way of enticing hydrogen atoms to produce images. This will produce images of larger portionsof the body and at the same time free up some space around the patient.  • The usage of the stronger magnets, 7 tesla will produce high definition images but has not yet been approved due to high magnetic field.

13. Citations: • Department of Health and Human Services • University of Zurich article • Discovery Fit & Health • Pubmed.gov • http://www.medhelp.org • http://srinivasarao.webs.com