How does an MRI scan work?
The MRI is a large, cylindrical (tube-shaped) system that generates a powerful magnetic field around the patient and sends radio wave pulses from a scanner. The intense magnetic field allows the body’s hydrogen atoms to align themselves around the same axis. Out of this balanced location the radio waves knock the nuclei of the atoms in your body. They send out radio signals as the nuclei realign back into proper position. A device that analyzes and translates these signals into an picture of the part of the body being studied receives those signals. This picture will appear on a display for viewing. You can get cross-sectional views to show additional information. Some MRI machines look like narrow tunnels, and others are more widespread.
In cases where organs or soft tissue are being examined, magnetic resonance imaging ( MRI) can be used instead of computed tomography ( CT), since MRI is better at telling the difference between different types of soft tissue and the difference between normal and abnormal soft tissue. There is no chance of exposure to ionizing radiation during an MRI operation since ionizing radiation is not used.
MRI can not be done on most patients with implanted pacemakers, older intracranial aneurysm films, cochlear implants, some prosthetic devices, implanted drug infusion pumps, neurostimulators, bone growth stimulators, some intrauterine contraceptive devices, or any other type of iron-based metal implants, due to the usage of the powerful magnet. Also, MRI is not approved for people who have internal metal items such as bullets or shrapnel and certain surgical sticks, pins, plates, screws, metal sutures or wire mesh in their bodies. Colouring used in tattoos may contain iron and can heat up during an MRI, but this is an uncommon occurrence.
Newer MRI uses, and signs have helped improve new magnetic resonance technology.
Magnetic resonance angiography (MRA) is a non-invasive (the skin is not pierced) technique used to measure blood flow across arteries. MRI can also be used to diagnose brain aneurysms and vascular malformations (blood vessel defects within the brain, spinal cord, or other parts of the body).
Magnetic resonance spectroscopy (MRS) is another non-invasive technique used in the assessment of chemical anomalies in body tissues, including the brain. MRS may be used to evaluate disorders such as brain HIV infection, stroke, headache, coma, Alzheimer’s disease, tumours, and multiple sclerosis.
Functional brain magnetic resonance imaging (fMRI) is used to determine the specific place within the brain where there is a specific function, such as speech or memory. The general areas of the brain where such functions occur are known, but the exact location can vary from individual to individual. You may be asked to perform a particular task during functional resonance imaging of the brain, such as reciting the Pledge of Allegiance while the scan is being performed. Doctors may prepare Surgery or other therapies for a particular brain condition by determining the precise position of the functional core within the brain.
The “accessible” MRI is yet another development in MRI technology:
- Standard MRI units are equipped with a closed cylinder-shaped tunnel into which the patient is put. Open MRI units do not cover the patient entirely, and certain units may be open on all sides.
- Open MRI units are especially useful for procedures which involve children. Parents or other caregivers may stay with a child during the procedure to provide comfort and security.
- Claustrophobia: Before the development of open MRI units, persons with severe claustrophobia often required a sedative medication prior to the procedure.
- Very large or obese persons. Almost anyone can be accommodated in most open MRI units.
How is an MRI performed?
An MRI can be done on an outpatient basis, or as part of hospital treatment. Although each facility may have unique protocols in place, this method usually follows an MRI procedure:
- The patient has to remove all jewelry and metal items, such as hairpins or barrettes, hearing aids, eyeglasses, and dental bits, because of the strong magnetic field.
- If an intravenous line (IV) is to deliver a contrast drug and/or sedative, an IV line is initiated in the hand or arm. If the contrast is to be taken by mouth, then the contrast to swallow is offered to the patient.
- The patient will be lying on a table in the scanner, which slides into a tunnel.
- The MRI team will be in another room where the controls of the scanner are stored. The patient would also be through a window in constant sight of the workers. Speakers inside the scanner enable the staff to communicate with the patient and listen to him. The patient will have a call bell to let the staff know if he or she is having any concerns during the operation.
- A clicking noise can sound during the scanning process, as the magnetic field is generated and radio wave signals are transmitted from the scanner. To help block the sounds from the MRI scanner and hear any signals or orders from the technologist, the patient may be given headphones to wear.
- During the examination, it is necessary for the patient to remain very still.
- At intervals, depending on the part of the body being examined, the patient may be advised to hold his or her breath, or not breathe, for a few seconds. When he or she can breathe the patient will then be told. The patient should have no more than a few seconds to catch his or her breath, so this should not be painful.
- The technologist will always observe the patient and will be in continuous contact.
Role of MRI Scan for cancer detection and treatment:
MRI (Magnetic Resonance Imaging) plays a crucial role in the detection, diagnosis, and treatment of cancer. Here are some key aspects:
a) Cancer detection: MRI scans are highly effective in visualizing soft tissues, making them valuable in detecting various types of cancers. MRI can help identify tumors, determine their size, location, and extent of spread, and provide information to guide further diagnostic procedures or treatment planning.
b) Staging and evaluation: MRI scans provide detailed images that help in staging cancer, which involves assessing the extent of the disease and determining its progression. This information is vital for developing an appropriate treatment strategy.
c) Treatment planning: MRI scans aid in treatment planning by precisely delineating tumor boundaries and their proximity to critical structures. This helps oncologists determine the optimal approach, such as surgery, radiation therapy, or chemotherapy.
d) Monitoring treatment response: MRI scans can be used to monitor the effectiveness of cancer treatment over time. They can detect changes in tumor size and characteristics, helping physicians assess the response to therapy and make necessary adjustments.
Advantages of MRI Scan for cancer detection and treatment:
a) Excellent soft tissue visualization: MRI provides detailed images of soft tissues, allowing for accurate identification and characterization of tumors. This is particularly beneficial for detecting cancers in organs like the brain, liver, prostate, and breast.
b) Multiplanar imaging: MRI scans can produce images in multiple planes, enabling a comprehensive evaluation of tumor size, location, and relationships with adjacent structures. This helps in precise treatment planning and surgical guidance.
c) Non-ionizing radiation: Unlike other imaging techniques such as CT scans or X-rays, MRI does not use ionizing radiation, making it a safer option for repeated imaging, especially for younger patients and those who require frequent follow-ups.
d) Contrast-enhanced imaging: MRI scans can be performed with the use of contrast agents, which help in highlighting specific areas of concern, such as tumor vascularity. This enhances the sensitivity and accuracy of cancer detection and evaluation.
Risk factors of MRI Scan:
MRI scans are generally considered safe, but there are a few risk factors to be aware of:
a) Contraindications: Certain individuals may not be eligible for MRI scans due to the presence of metallic objects in their body, such as pacemakers, cochlear implants, or certain types of metal implants. It is important to inform the healthcare provider about any metallic implants or foreign bodies before undergoing an MRI.
b) Claustrophobia: Some individuals may experience claustrophobia or anxiety inside the narrow MRI scanner. Open MRI machines or sedatives can be considered for patients who find the traditional MRI machine uncomfortable.
c) Allergic reactions: In rare cases, individuals may experience allergic reactions to the contrast agents used during an MRI scan. It is important to inform the healthcare provider about any known allergies or previous reactions to contrast agents.
d) Potential harm to the fetus: MRI scans are generally safe during pregnancy, especially when essential. However, it is crucial to inform the healthcare provider if you are pregnant or suspect you might be, as certain precautions may need to be taken.
Instructions before, during, and after MRI Scan:
Before the MRI scan: Follow any specific instructions provided by your healthcare provider, such as fasting for a certain period before the scan, especially if contrast agents will be used.
Inform your healthcare provider about any metallic implants or devices in your body.
Remove any metal objects such as jewelry, watches, or clothing with metal components.
During the MRI scan: You will be asked to lie down on a movable table that slides into the MRI scanner. It is important to remain still during the scan to ensure clear images.
You may be given.
