Everything You Need To Know About MRIs
Table of Contents
- What is an MRI scan?
- MRI Image quality & signal-to-noise ratio
- Why are MRI scans ordered?
- Are there different types of MRI machines?
- What type of MRI machine is best for me?
- How are MRI scans different from X-ray & CT Scans?
- What are the risks of an MRI?
- Additional precautions
- Why choose ExpertMRI?
It’s October, and COVID-19 restrictions are having an unfortunate effect on everyone’s usual Halloween plans. This year, memories of Halloweens past will likely have to take the place of venturing out for any parties or neighborhood trick-or-treating. Depending on your age, past Halloween adventures may have involved a long night of trick-or-treating concluding with a stop at the local hospital for a quick X-ray of that big bag of candy. Since the 1980s, in an effort to screen for any potentially dangerous materials hidden within those tasty treats, many concerned parents across the country have made a final stop to an X-ray facility a mandatory part of their child’s trick-or-treating routine.
Just as X-rays can look inside Snickers and Milky Way bars and produce an image to help detect dangerous foreign objects, MRI scans can generate detailed pictures of the human body that help detect and diagnose injuries or disease. Let’s take a look at what an MRI scan entails, and how it can help diagnose countless conditions which may be affecting you and your quality of life.
What is a MRI scan?
Magnetic resonance imaging (MRI) is a medical diagnostics technique utilizing magnetic field and computer-generated radio wave scans to produce detailed pictures of various organs and tissues within the human body. MRI scanning machines are commonly identified by their magnetic field strength. The magnetic fields utilized in MRI machines are measured in units called Tesla.
Today’s MRI machines typically operate at strengths between 0.5T (or Tesla) and 3.0T (or Tesla). 3.0T MRI machines provide some advantages for medical diagnostics when compared to machines utilizing lower strengths. For example, 1.5T MRI machines require longer scans to produce clear images, while 3.0T machines can produce superior images in a shorter period of time due to increased signal strength. 3.0T machines, therefore, allow a larger number of patients to be scanned in an equal amount of time. The increased 3.0T magnet strength can be essential for certain medical diagnostics tests where increased clarity and better detail is necessary, such as MRI of the prostate, MR spectroscopy, arterial spin labeling, and functional MRI.
MRI machines which operate using stronger Tesla units are mostly utilized in research protocols rather than imaging of the human body. Such MRI machines can be used at strengths up to 60T.
MRI image quality and signal-to-noise ratio
Signal-to-noise ratio (SNR) is a term used to indicate the performance of an MRI machine. A greater SNR indicates a higher image quality.The signal is what emanates from a patient’s body during an MRI. The patient’s signal is received by coils along the areas of the body that are scanned during a procedure. As coils vibrate in response to the magnetic field, noise is produced. A higher magnetic field means the signal that is read by the coils and transmitted to the computer is increased. This allows for a higher-quality image, as there is less noise obstruction.
Why are MRI scans ordered?
Your doctor may order an MRI scan for any number of reasons, but the goal is to identify what is causing a specific health issue, provide an accurate diagnosis, and then prescribe an effective treatment plan. Your individual symptoms will determine which areas of the body are scanned. Some common types of MRI scans that are used to identify certain disorders include:
-MRI of the brain/spinal cord
MRI of the brain and spinal cord is the most common type of magnetic resonance imaging test ordered. It can be used to help diagnose myriad ailments including:
- Blood vessel damage (e.g. aneurysms of cerebral vessels)
- Spinal cord injuries or disorders
- Brain injury from trauma (commonly known as traumatic brain injury or TBI)
- Multiple sclerosis (MS)
- Eye problems
- Inner ear problems
- Pituitary gland disorders
- Epilepsy or seizure disorders
- Fluid in the brain (hydrocephalus)
- Herniation or degeneration of disks of the spine
- Inflammation or infection of the brain (encephalomyelitis)
- Lack of oxygen to the brain (hypoxic encephalopathy)
- Bleeding under the brain (subdural hematoma)
MRI of the brain and spinal cord may also be conducted prior to common spinal surgical procedures, such as decompression of a pinched nerve or spinal fusion. This type of MRI can also be used to discover common problems after surgery, such as scarring or infection.
Moreover, this type of MRI can aid in treating conditions of the brain by identifying the specific part which controls certain functions, such as speech or memory.
–MRI of the circulatory system
For patients with poor circulation, constriction, clots or other related issues, your doctor may order an MRI of the blood vessels (also known as MRA) to examine and screen for:
- Inflammation or blocked blood vessels
- Constricted or tortuous vessels
- AVM’s, aneurysms and other vascular conditions
-MRI of the bones/joints/soft tissues:
MRI scans can also examine the bones, joints, and soft tissue areas of the body (including cartilage, muscles, and tendons). These types of MRI scans can be used to detect abnormalities and injuries such as:
- Bone infections
- Damage to joints
- Disc problems in the spine
- Neck or low back pain with symptoms of nerve damage
- Bone diseases and conditions
-MRI of internal organs:
Doctors may order MRI scans to examine other particular internal organs and screen for tumors or abnormalities. MRI scans can look at individual organs within the body such as:
- Liver and bile ducts
- Adrenal glands
- Lymph nodes
Are there different types of MRI machines?
If you’ve undergone an MRI test in the past, you may be familiar with closed MRI machines (also known as traditional MRIs). A traditional MRI machine is made of a long, capsule-like tube with a hole on either end. A patient is inserted into the tube, where images of various areas of the body are captured.
Another type of MRI system is the FONAR “Front Open” machine. The Front Open MRI system can be referred to by many names, such as Stand-Up MRI, Upright MRI, or Sit MRI. The Front Open system allows for additional types of positional scans beyond those available through a traditional MRI machine.
At Expert MRI, all of our advanced machines utilize state-of-the-art technology to ensure you receive a precise diagnosis for your individual ailment.
What type of MRI system is best for me?
Expert MRI offers traditional and FONAR “Front Open” MRI systems, providing patients with premier medical diagnostics options for enjoying a more comfortable, stress-free examination. Our Front Open machine offers advantages for certain patients with specific needs. Some of the Front Open MRI system’s features include:
- Multi-positional imaging: Front Open MRIs offer patients the option to be scanned while standing, sitting, or lying down.
- Weight-bearing (axial loading) imaging: Front Open MRIs allow radiologists the option to view weight displacement along the spine and joints. The spine can be imaged in flexion and extension positions, and joints can also be rotated into various positions.
Front Open MRIs can be ideal for patients who may suffer from claustrophobia, anxiety, or panic attacks, as well as patients of larger size, children, and senior citizens.
Traditional MRI’s have a higher magnetic field strength and can scan faster and at higher resolution. These machines are useful for smaller body parts like elbow & wrist and for brain and body/vascular scans.
–The Front Open MRI system allows for sitting, standing, recumbent, prone, and supine positioning during a scan.
–The traditional MRI system allows for recumbent, prone, and supine positioning during a scan and offers higher resolution, better signal-to-noise and shorter scan times.
Both machines generate high quality images of various areas within the body to accurately detect and diagnose disease. Individual symptoms and type of injury or disease will help your doctor decide which type of MRI system should be used during your specific scan (and in which position(s) the test should be administered)
How are MRI scans different from X-ray and CT scans?
Unlike X-rays and computed tomography (CT) scans, MRIs do not subject a patient to any ionizing radiation (which can be damaging at high levels).
CT scans take multiple X-rays at various angles and then process those X-rays to produce a three-dimensional image of the particular area of the body that is being examined. A computer analyzes the various X-rays taken from multiple angles and then synthesizes those images to create a three-dimensional computer model of the body’s internal organs.
When compared to CT and X-ray scans, MRI is considered a more-accurate method of detecting and diagnosing disease and is often used when these aforementioned methods fail to provide sufficient information.
Although CT and X-ray scans expose patients to a relatively low doses of radiation, certain types may not be appropriate during pregnancy. Patients are advised to consult with a general physician prior to undergoing such scans, advising the practitioner if pregnancy may be a factor.
What are the risks of undergoing an MRI scan?
There is no risk of exposure to ionizing radiation during an MRI procedure. However, due to the use of strong magnets in MRI machines, certain precautions must be taken for patients with implanted devices such as:
- Metallic joint prostheses
- An implantable heart defibrillator
- Implanted drug infusion pumps
- Implanted nerve stimulators
- Metal clips
- Metal wires, pins, screws, plates, stents, or surgical staples
- Cochlear implants
- A bullet, shrapnel, or any other type of metal fragment
- Artificial (prosthetic) metal heart valves
- Brain aneurysm clips
- Dentures/teeth with magnetic keepers
- Eye implants
- IUDs (intrauterine device)
- Medication patches (transdermal patch) that contain metal foil
- Metallic fragments in or near the eyes or blood vessels
- Penile implants
- Permanent cosmetics or tattoos
- Tubal ligation clips
If you have a metal implanted device, the MRI technologist will need some additional information, such as the make and model number, to determine whether or not it is safe for you to undergo an MRI. Patients who have certain internal metal objects might not be eligible for an MRI exam.
Additional precautions for patients prior to undergoing an MRI
Patients who are claustrophobic or experience anxiety during medical procedures should advise their physician prior to an MRI. Your physician may provide you with anti-anxiety medication to be taken before the examination. If you are prescribed this type of medication, you should plan to have someone drive you home following your MRI test.
If you are pregnant (or suspect that you may be pregnant), you should notify your health care provider. While there is no information indicating that an MRI scan is harmful to an unborn child, testing during the first trimester is typically discouraged as a matter of precaution. Expert MRI will only screen for pregnancy when performing a contrast scan.
Some MRI exams involve an intravenous contrast or dye that is injected during the procedure. This allows the radiologist to better view internal tissues and blood vessels on the completed images. If contrast is used, there can be a rare but potentially serious risk of allergic reaction in certain patients. Patients who are allergic or sensitive to contrast, dye, or iodine should notify the radiologist or technologist before the exam.
Additionally, if you have severe kidney disease or are undergoing kidney dialysis treatment, you may be at risk for a rare but serious condition called nephrogenic systemic fibrosis (NSF). Although NSF is a very rare complication of MRI with contrast, it can be quite serious. Patients with a history of kidney disease, kidney failure, kidney transplant, or liver disease must inform the MRI technologist or radiologist of their specific condition(s) prior to their scan.
MRI contrast may have an effect on other conditions, such as allergies, asthma, anemia, hypotension (low blood pressure), and sickle cell disease. There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.
Why choose Expert MRI for your MRI Scan?
Expert MRI is California’s leading diagnostic imaging provider and foremost network of innovative and cutting edge equipment including Front Open and traditional MRI systems. We are accredited by the American College of Radiology (ACR) and have over 20 specialized MRI centers located conveniently throughout California.
You can easily find the Expert MRI center that is closest to you and schedule an appointment through our website portal. Our cooperative and friendly staff members will guide you through the entire process – from the MRI appointment scheduling stage until you complete and receive your personalized MRI report.