Magnetic Resonance Imaging Abstract

MRI uses the body’s natural magnetic properties to formulate an image of the soft tissues. It does this by using the hydrogen atom nucleus which has a single proton and is a spinning charged particle. The human body is made up of 70% water, which is hydrogen and oxygen. Those hydrogen nuclei (protons) spin inside the body, creating their own magnetic field. They are orientated randomly and cancel each other out when no field is applied.

MRI machines can detect “tumors, cancers, traumatic brain injuries, developmental anomalies, multiple sclerosis, stroke, dementia, infection, and causes of a headache.” (MRI and MR Angiography). According to Mayfield Clinic “An MRI scan works by using a powerful magnet, radio waves, and a computer to create detailed images. Your body is made up of millions of hydrogen atoms (the human body is 80% water), which are

The MRI scanner is a large magnet that is 30,000 times stronger than the earth’s magnetic field. The force increases as a person or a ferromagnetic object move closer to the magnet. The strong magnetic field of the MR scanner is Always on even when the MR scanner is not in use.

Magnetic Resonance Imaging is also known as MRI. This computerized device is used for scanning the

The singlet that appeared up field with an integration value of 3 was the Hd peak and its appearance here was due to the oxygen deshielding it from seeing any other neighbors besides itself. The protons in the benzene ring were observed to be further downfield due to the benzene ring as opposed to the proton that is bonded to the nitrogen. The proton bonded to the nitrogen, Hc, was observed as a singlet around 7.218, which is still downfield. The aromatic protons, Hb and Ha, showed up as doublets and they can be distinguished by the substituents they are closest to, as these substituents determine the chemical shifts of Hb and Ha. The protons closest to the acetamide group, Hb, appeared more upfield and this is because the nitrogen atom donates electrons to the ring that would allow for Hb to not have its electron drawn as much.

The best feature of this instrument is that it was capable of taking images in four different spectral positions and the rotating polarizer was capable of measuring magnetic fields.

The simplest type of separation is known as the imaging slice. Protons only exchange energy efficiently if the frequency of the energy matches frequency of precession. So, the 90 and 180 degree pulses must be sent at the Larmor frequency of the proton. Hence, by combining this with gradients, a selected slice of the body can then be imaged. By altering the frequency of the 90 and 180 degree pulses, different protons will then experience excitation. Certain slices to be imaged can be selected by turning on the gradient fields and altering the excitation pulses (0°, 180°) frequency to match the frequency of the slice in the desired position. Protons that are not within the slice will not experience excitation by the gradient fields as their Larmor frequency will not be the same as the frequency of the pulse, thus the energy of the pulse will not be

the body and makes use of the property of nuclear magnetic resonance (NMR) to image

Basic idea Hydrogen nuclei are subjected to a pulse of radio waves, which causes them to briefly emit low-intensity radio waves. These are detected by the MRI scanner, which measures the signal as the patient is scanned by a changing magnetic field. The signal is processed, producing an image of where the hydrogen atoms in water molecules and lipids are located. Nuclei used in NMR contain an odd number of protons or neutrons and so possess intrinsic spin. (Spin is an inherently quantum property.

The scanner also produces a radio frequency current that create a magnetic field. When the field is turned off the protons slowly return to the normal spin, this process is called precession. Protons are found in different body tissues to return to their normal spins at different rates, so the scanner can separate between tissues. The scanner can be adjusted to produce contrast between different body tissues. By going into further, magnetic fields are also used to focus body structures

Tissue that contains a lot of hydrogen, which happens bounteously in the human body as water, creates a splendid picture, while tissue that contains practically zero hydrogen (e.g., bone) seems dark. The brilliance of a MRI picture is encouraged by the utilization of a difference operator, for example, gadodiamide, which patients ingest or are infused with preceding the methodology. These operators can enhance

Magnetic Resonance Imaging (MRI) is a diagnostic procedure technique that uses a magnetic field and radio waves to create detailed images of the organs and the tissues within the body (Mayo Clinic 2013 par.1). When the human body lies inside the MRI machine, the magnetic field temporarily

The MRI is possible in the human body because our bodies are filled with small biological ?magnets?, the most abundant and responsive of these are the protons. The principal of the MRI is that it utilizes the random distribution of protons, which have basic magnetic properties. Once the patient is placed in the cylindrical magnet, the diagnosis process follows 3 steps. First, MRI

An MRI (magnetic resonance imaging) is a scan that uses a system of techniques, involving magnetism, radio waves and a computer to generate detailed images of the human body. Essentially, it is a tube encased by a large circular magnet. The patient would be placed on a moveable bed, which is then inserted into the tube. The magnet then creates a strong magnetic field that aligns the protons of hydrogen atoms. These hydrogen atoms come from the human body, which is 50-65% H2O. These atoms are exposed to a beam of radio waves. This spins the various protons of the body. As they spin, they produce a slight

Magnetic Resonance Angiography (MRA) is a technique in which magnetic pulses are used to image pictures of blood vessels inside the body. A MRA can be achieved using two techniques phase contrast and time of flight. A phase contrast can be done using complex subtraction and phase subtraction. A time of flight (TOF) can be done using dark blood and bright blood. A dark blood imaging is visualized using inversion recovery, saturation and dephasing. A bright blood imaging is analyzed using rephased /dephased, in-flow, use of contrast agents. Once a required MRA is processed, it is envisioned using a maximum intensity projection (MIP).