History - fundamental - development of MRI system

DR. NGUYEN XUAN THUC MRI History Damadian created the world's first magnetic resonance imaging machine in 1972 Damadian, along with Larry Minkoff and Michael Goldsmith, performed the first MRI body scan of a human being on July 3, 1977 Paul Christian Lauterbur shared the Nobel Prize in Physiology in 2003 with Peter Mansfield for his work which made the development of magnetic resonance imaging (MRI) possible (researched from 1963 until 1985). The magnet ss the most important component of the MRI scanner The magnet currently used are in the 0.2 to 3.0-tesla range (2,000 to 30,000-gauss). Higher values are used for research Earth magnetic field : 0,5-gauss There are three types of magnets used in MRI systems: - Resistive magnets : no more used - Permanent magnets: 0.2 to 1.0-tesla - Super conducting magnets: 1.0 to 3.0-tesla Magnetic field The lower field strengths can be achieved with permanent magnets, which are often used in "open" MRI scanners Higher field strengths can be achieved only with superconducting magnets [...]...-T1WI - T2WI - PDWI - DWI - ADC - GE - BOLD images - MRA - MRV - Post-Gd images - Volumetric images - FLAIR - Perfusion images - STIR - f MRI - Etc… T1W T2W T1W + CE T1W T2W T2W T1W T2W Fluid signal ↓ Fluid signal ↑ Signal of Lipid ↑ Signal of Lipid ↑ T1W (+-FS) + CE T2W – FS (STIR) T2W-FS Advantages - Greater differentiation of soft tissue structures - Can be acquired in any planes - Can provide... models), passive implants (depending on its ferromagnetic status) - Pregnancy : No known risks, how ever MRI ACCIDENTS MRI ACCIDENTS Patterns of Contrast Enhancement in Brain Tumors Differential diagnosis of ring-enhancing brain lesions: Neoplasm : Primary neoplasm (high-grade glioma, meningioma, lymphoma, acoustic schwannoma, cranio-pharyngioma) .Metastatic tumor Abscess Bacterial, fungal, parasitic... vascular study without use of IV contrast Disadvantages - Longer time of scanning - Motion artifacts from respiration, cardiac pulsation Generally, MRI is very safe and adverse reactions to contrast agent (gadolinium) are extremely rare Absolute contraindications: Cardiac pacemakers, implanted cardiac defibrilations, otic/inner ear/ cochlear implantsm metal fragments in the eye Others: - Heart valve, aneurysm... subdural, orintraventricular) Hemorrhagic-ischemic lesion • Resolving infarction • Aging hematoma Demyelinating disorder Radiation necrosis Patterns of Contrast Enhancement in Brain Tumors Cyst with enhancing mural nodule 1.Pilocytic astrocytoma 2.Hemangioblastoma 3.Pleomorphic xanthoastrocytoma 4.Ganglioglioma This 44-year-old woman presented with an epileptic seizure Low-grade diffuse astrocytoma (WHO grade . XUAN THUC MRI History Damadian created the world's first magnetic resonance imaging machine in 1972 Damadian, along with Larry Minkoff and Michael Goldsmith, performed the first MRI body. the development of magnetic resonance imaging (MRI) possible (researched from 1963 until 1985). The magnet ss the most important component of the MRI scanner The magnet currently used are in. in "open" MRI scanners Higher field strengths can be achieved only with superconducting magnets