Summary
Magnetic resonance imaging (MRI) is ”an imaging method that is used in hospitals to diagnose and evaluate the extent of a given disease” (Guevara 472). It can be considered to be a test that is based on the application of radio wave pulses, as well magnetic field in making drawings of different parts of the body according to investigation needs. Magnetic resonance imaging has become more popular than X-ray due to its ability to provide detailed information during the investigation of various body parts and structures (Lampa 423). Additionally, MRI technology can identify major problems in the human body that other types of imaging methods cannot.
Principles of magnetic resonance imaging
Guevara (474) asserted that magnetic resonance imaging relies on the magnetic properties, which exist naturally in the body to provide clear pictures of any given aspects of the body under investigation. The test uses a hydrogen nucleus in achieving the images required. The hydrogen proton spins on its axis and maintains the south and north poles. During the spin, the properties of the proton are similar to those of a bar magnet (Guevara 474). During normal conditions of the body, the proton shows a random alignment of its axes. However, after placing the body under investigation in a magnetic field, it results in alignment of the axes of the protons creating a magnetic vector that orients itself along the scanner’s axes. Thus, a deflection is expected upon the introduction of more energy in the magnetic moment created by the spinning nucleus. However, the resonance of the element being investigated is determined by how strong the magnetic field is, as well as the strength of the element under investigation. For this reason, whenever the magnetic field’s strength is varied the body resonance also varies with respect to the applied frequency. Lampa (434) observed that switching off the source of the radiofrequency energy pushes the magnetic vector to its initial position, and is accompanied by the emission of a radio wave signal. The creation of MRI images is done with the help of the emitted radio wave signal after the source of the radio frequency is switched off. Often, during this process, the area under investigation is surrounded by receiver coils that play the role of aerials in improving the precision with which the emitted signal is detected.
Role of the spin of atoms
Atoms have various characteristics including a magnetic property referred to as spin, electrical charge, and mass. For any given atomic nuclei with protons numbers that are odd, there is a magnetic moment that can be used in the description of the direction as well as the strength of the magnetic field that can be traced around the given nuclei (Lampa 423). In a case where the magnetic field is constant and very strong, it is expected that a fraction of the nuclei will align with respect to the magnetic field and thus will result in the production of a sizeable magnetic moment that can be measured (Harms 350). Additionally, the interplay of the external field and the nucleus’ magnetic moment results in the precession of each spinning nucleus. As such, the spinning of atoms is significant for imaging to occur.
Magnetic field
The functionality of the MRI is dependent on the magnetic field around the body under examination (Lampa 423). As noted earlier, the magnetic field is responsible for the reflection of the magnetic vector and the spin of the element under investigation. The variation of the strength of the magnetic field affects the alignment of the nuclei creating a magnetic moment that can be measured. As such, the spinning of the nucleus, which determines the occurrence of images during MRI, depends on the magnetic field.
Relaxation in medical imaging
Relaxation in magnetic resonance imaging occurs whenever the source of the radio frequency is removed, causing the magnetic vector to return to its initial position (Harms 350). However, the relaxation times of different body tissues differ. In MRI, relaxation is used to identify various types of tissues based on the difference in relaxation times (Lampa 423). Often, fat and water suppressions are used to help in the removal of pulses from either fat or water for a chance to examine any other signals that might be coming from the tissue under investigation. Thus, relaxation helps in the detection of different diseases during MRI diagnosis and evaluation.
Benefits of MRI
The magnetic resonance imaging procedure is carried out for several reasons. For example, MRI is commonly used in identifying diseases within the blood vessel, injury, bleeding, as well as tumors in the body (Harms 349). There are numerous benefits of magnetic resonance imaging. First, MRI uses no radiation, is non-invasive, and is suitable where detailed information is needed since the test provides images that are very clear and detailed. Besides, MRI can create numerous images according to the required orientation and direction (Harms 350). For these reasons, magnetic resonance imaging is used in the early detection of cancer; due to the test’s ability to provide detailed images even of the structure of the soft tissues of the human body.
Works Cited
Guevara, Lin. “FRI0247 Black Blood MRI/A For Diagnosis Of Large Vessel Vasculitis”. Annals of the Rheumatic Diseases 73. 2 (2014): 472-473. Print.
Harms, Susan. “4–7 MRI for diagnosis of pure ductal carcinoma in situ: a prospective observational study”. Breast Diseases: A Year Book Quarterly 18.4 (2008): 349-350. Print.
Lampa, John. “MRI Guided Muscle Biopsy Confirmed Polymyositis Diagnosis in A Patient With Interstitial Lung Disease”. Annals of the Rheumatic Diseases 60.4 (2010): 423-426. Print.