Magnetic Resonance Imaging (MRI) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. MRI uses a very strong magnetic field and radio waves to create images of the body. The hydrogen atoms in the body react to the magnetic field and emit signals that are analyzed by a computer to produce images.
MRI reveals more details than other imaging modalities and is able to differentiate between healthy and diseased tissue. It does not use any ionizing radiation and is painless with no known permanent side effects.
Detailed MR images allow physicians to better evaluate various parts of the body and certain diseases that may not be assessed adequately with other imaging methods such as x-ray, ultrasound or computed tomography (also called CT or CAT scanning).
Each exam can take from 20 minutes to 1 hour and is very motion sensitive. If a patient moves during the sequence scans, there is risk of distorting the images and the scan may need to be repeated.
Some MRI exams require the injection of contrast into the veins. This is to help better visualize the anatomy and will show more detail about that particular part of the body. MRI uses a different type of contrast which works differently than that in X-ray or CT. Contrast agents may be injected intravenously to enhance the appearance of blood vessels, tumors or inflammation. Contrast agents may also be directly injected into a joint in the case of arthrograms, MR images of joints.
The blood filters out the contrast through the urinary system naturally, so it is crucial that the kidneys are functioning properly. For all patients receiving intravenous contrast and are 60 years of age or older; or diabetic and/or with known renal insufficiency/compromise creatinine levels/GFRs are required. Lab results must be within 30 days prior to the procedure. Patients currently receiving dialysis will not receive Gadodiamide (Omniscan) for MRI.
The safety questionnaire must be filled out entirely and accurately to ensure you do not have anything in or on the body that could cause injury or problems during the MRI.
As part of the safety screening,you may be required to have an x-ray before an MRI to determine if there are any metal foreign objects in a particular area of anatomy prior to going into the magnet. Most often, it is the orbits (eyeballs) that are imaged if a you have a history of working with metal or have had metal removed from your eyes in the past.
Please complete the MRI Safety Questionnaire (PDF) before your scheduled appointment. You may have your ordering physician’s office print this for you to complete during your office visit. The completed questionnaire can be faxed with your order when scheduling your imaging services. Your technologist will review your screener form with you prior to your imaging study. It is important to remember to bring the completed form with you to your appointment along with any literature or documentation regarding any implants or prostheses you may have.
How does MRI work?
Radio frequency (RF) pulse is applied to protons in body tissue, and excites the protons. When the protons return to the equilibrium state, they emit energy as RF signal. These RF signals are picked up and analyzed and using a computer, creates an image. By varying the sequence of RF pulse applied & collected, different types of images are created. MRI DOES NOT USE IONIZING RADIATION (X-RAY).
Why is safety important?
Because the Magnet is over 45,000 times stronger than the earth's magnetic field, safety screening is very important. The safety questionnaire must be filled out entirely and accurately. This will ensure that the patient does not have anything in or on his/her body that could cause problems during the MRI. Patients should please empty pockets prior to the MRI, as metal objects may become projectiles in the magnetic field.
Why would I need Pre-MRI orbit x-rays?
If the patient has ever done any welding, machinist work or metal work in his/her lifetime or had metal removed from his/her eyes, pre-MRI orbit x-rays may be required. The magnetic force of the machine is so strong that if there is any metal in the eyes, it could move and cut the optic nerve. An x-ray needs to be done at WDH before 5 pm on the day of the MRI or sooner to ensure there is no metallic foreign body in the eyes.
Pre-MRI orbit x-rays are part of the MRI charge and does not cost extra. If there is shrapnel or metal of any kind in any other area of the body that could cause harm or injury if exposed to a powerful magnetic field, a separate order for x-ray of that part of the body, must be obtained from the ordering physician. There may be additional charges for this x-ray, but it is the interest of patient safety and if not performed, the patient may not be permitted to have an MRI.
Will I be comfortable during the MRI?
The patient will be made as comfortable as possible for the duration of his/her scan. A cushion is placed under the knees and a blanket is provided for comfort. Please let the requesting physician know if something is needed for pain management or anxiety. They can prescribe some medication prior to the MRI. This medication is not provided by Wentworth-Douglass Hospital.
Is the machine loud?
Yes, the machine is very loud. It makes a loud knocking and banging noise. Patients must wear earplugs or headphones to block out the noise and protect his/her hearing. Wentworth-Douglass' MRI offers cinema vision. It is a system that allows patients to view a show or movie on a special virtual reality headset. Patients can bring a DVD or pick one from the hospital's large selection. Also, patients may listen to music, which may be their own selection, or something from the WDH MRI music library.
What if I am claustrophobic?
The technologist will be in contact with the patient continuously during the MRI. They can see, hear and communicate with each patient during the exam. Patient safety, comfort and privacy are of top priority. Many exams (NOT all) can be performed feet first allowing the head to be out of the scanner or not have to go through the machine.
Please tell the ordering physician if there is a chance of claustrophobia or heightened anxiety. The ordering doctor can prescribe some medication to help relax you during the MRI. It is the patient's responsibility to obtain the medications at their local pharmacy and to follow the directions on the label.
Wentworth-Douglass now offers wide bore MRI scanners in Dover, Portsmouth and Lee. These scanners are shorter and wider than the traditional MRI magnets. We also offer an ambient experience which includes relaxing lighting, videos and your choice of music.
When will I get the results?
The radiologists at Wentworth-Douglass Hospital will interpret the MRI and dictate a report which is transcribed and sent to the ordering physician. The ordering physician will inform you of the results.
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