MRI Basics Principles - PDF

MRI Basics principles Why MRI ???? No radiation HISTORY Phenomenon of Nuclear Induction later termed as NMR (Nuclear Magnetic Resonance) first described by Bloch and Purcell in 1946. They won Nobel Prize for Physics in year 1952. In 1971 Damadian (father of MRI) noted that tumors have ele...

MRI Basics principles Why MRI ???? No radiation HISTORY Phenomenon of Nuclear Induction later termed as NMR (Nuclear Magnetic Resonance) first described by Bloch and Purcell in 1946. They won Nobel Prize for Physics in year 1952. In 1971 Damadian (father of MRI) noted that tumors have elevated MR Relaxation Times and filed a patent 'Apparatus and methods for detection of cancer in tissues.' Human in vivo images first published in 1977 by Damadian et al A pilot look on the events occurring in MRI: 1) Patient is put into the bore of a strong magnet. 2) Radiofrequency waves are transmitted into the patient for an extremely short time [2~10 ms], then turned off. 3) Radio waves re-transmitted by the patient are then received in the Receive coil. 4) Measured RF data are then transformed to image. Father of MRI First to perform a full body scan of a human being in 1977 to diagnose cancer. Raymond Damadian Damadian died on August 3, 2022, at the age of 86 from cardiac arrest. Raymond said that he first became interested in detecting cancer when, as a boy of 10, he saw his maternal grandmother, with whom he was very close, die painfully of breast cancer In a 1971 paper in the journal Science SUNY Downstate Medical Center professor Damadian reported that tumors can be detected in vivo by nuclear magnetic resonance (NMR) because of much longer relaxation times than normal tissue. He suggested that these differences could be used to detect cancer, even in the early stages where it would be most treatable, though later research would find that these differences, while real, are too variable for diagnostic purposes. Damadian's research into sodium and potassium in living cells led him to his first experiments with nuclear magnetic resonance (NMR) which caused him to first propose the MR body scanner in 1969. Damadian discovered that tumors and normal tissue can be distinguished in vivo by nuclear magnetic resonance (NMR) because of their prolonged relaxation times, both T1 (spin-lattice relaxation) or T2 (spin-spin relaxation). Damadian was the first to perform a full-body scan of a human being in 1977 to diagnose cancer. Damadian invented an apparatus and method to use NMR safely and accurately to scan the human body, a method now well known as magnetic resonance imaging (MRI). 1- CLOSE 2. OPEN 3.EXTRIMETS 4.DYNAMIC 5.Stress test MRI for spine Whats is MRI 1.Magnetic Field: 1.MRI machines contain powerful magnets that create a strong magnetic field, typically around 1.5 to 3 Tesla (the unit of magnetic strength). When a patient enters the MRI machine, the magnetic field aligns the hydrogen nuclei (protons) in the body's water molecules. 2.Radiofrequency Pulses: 1.Once the protons are aligned, the machine sends radiofrequency (RF) pulses to the area being examined. These pulses temporarily disturb the alignment of the protons. When the RF pulse is turned off, the protons return to their original alignment, releasing energy in the process. Signal Detection: 1.The released energy is detected by the MRI scanner, which converts the signals into images. The differences in the signals are due to the varying properties of different tissues (e.g., fat, muscle, and fluid) in the body. Image Formation: 1.A computer processes the data collected from the signals to create cross-sectional images (slices) of the body. These images can be stacked together to form 3D representations of the anatomy. tissues. Contrast Agents: Sometimes, a contrast agent (usually gadolinium-based) is injected into the patient's bloodstream to enhance the visibility of certain structures or abnormalities. This can help differentiate between healthy and diseased Applications of MRI: Neurology: MRI is often used to detect tumors, stroke, and degenerative diseases in the brain. Orthopedics: It can visualize injuries to muscles, ligaments, and cartilage. Cardiology: MRI can assess the structure and function of the heart and blood vessels. Oncology: It's valuable for detecting and monitoring cancers and their spread. Advantages of MRI: Non-invasive: MRI does not involve ionizing radiation, making it safer than some other imaging methods, such as CT scans. High-resolution images: It provides detailed images of soft tissues, allowing for accurate diagnoses. Functional imaging: Advanced techniques like fMRI (functional MRI) can measure brain activity by detecting changes in blood flow. MRI detect H basesd tissue , not calcium based one ,so for tissues not bone. Imaging in varius planes. Unlike CT PLANES MRI ONLY SEE H2 PRACTICAL Thank you