The MRI personnel will ask you many questions to determine if you can safely be imaged. You will also be asked you weight and height. This information will allow the pulse sequence to adhere to the specific absorption rate (SAR) limitations described in Chapter 9, and the proper choice of imaging hardware.
You will be weighed before your scan. For some scans, a small plastic tube called a cannula will be inserted into your arm so that contrast dye (see 'Contrast injections' section) or medication can be given during the scan. The radiographer will explain what will happen during your scan.
Yes, the table weight limit is 400 lb. or 180 kg., with a maximum width restriction of 60 cm. For optimal images it is necessary for the area being examined to be within the magnets isocentre which is located directly in the centre of the scanner.
Wide bore scanners can hold up to 550 pounds, which is also a greater weight limit than typical traditional scanners.
MRIs of obese patients are typically challenging because of the effects of a large field of view on image quality and the increased risk of thermal burns from contact with the bore.
The weight limitation is 350 to 400 pounds. It fits most people, but not all. "Patients who won't fit in an MRI, in a conventional MRI, are in the small minority, in the few per cent, perhaps up to five per cent," said Edward Kendall, a medical technologist at Memorial University.
Obese patients cannot fit comfortably in a standard MRI scanner, which has an enclosed tube of only 60cm. Wide MRI scanners, often referred to as wide bore MRIs, have a slightly larger opening of 72cm on average, but still don't offer enough space for obese patients.
Some MRIs are called "wide-bore," which means the machine has a wider tunnel-like opening than other MRI systems. This creates more headroom and space around the patient. A wide-bore MRI system offers a more comfortable exam for people with wide shoulders or who weigh up to 550 pounds.
Scientists at the University of Minnesota have become the first in the world to perform magnetic resonance imaging of the human body at 10.5 Tesla—a magnetic field strength 10 times greater than a standard MRI and topping even the most advanced scanners elsewhere in the world.
MRI is also contraindicated in the presence of internal metallic objects such as bullets or shrapnel, as well as surgical clips, pins, plates, screws, metal sutures, or wire mesh. If you are pregnant or suspect that you may be pregnant, you should notify your physician.
Jewelry, piercings, buckles or keys
You shouldn't go into an MRI scanning room wearing jewelry or clothing with metal parts. At Yale Medicine, patients are required to change into a hospital gown before undergoing an MRI.
Items that need to be removed by patients and individuals before entering the MR system room include: Purse, wallet, money clip, credit cards, cards with magnetic strips. Electronic devices such as beepers, cell phones, smartphones, and tablets. External hearing aids.
Since the MRI machines are magnets, it is best to not apply deodorants, antiperspirants, perfumes, or body lotions before the examination. These items contain metals that might interfere with the magnetic field inside the MRI machine and cause you to have distorted images and wrong results.
Cotton, polyester, and wool are best. Don't worry about the snaps or zippers on pants, as that metal can be allowed into the scanning facility. If you have questions about these procedures, please feel free to contact the study coordinator.
“Your test needs to be read by a diagnostic radiologist, and the results go back to your physician. Your physician reads the report and then discusses it with you,” Edwards said. The biggest reason for that policy is that only a medical doctor has the training and experience to make a diagnosis.
Traditional MRI: A traditional MRI machine is a large tube, roughly 23.5 inches in diameter that a patient lays in. Wide Bore MRI: Essentially this is the same as the traditional MRI machine, but it is a little wider—roughly 27.5 inches. The wide bore is ideal for larger patients and those who are claustrophobic.
How long does an MRI scan take? A single scan may take a few seconds or 3 to 8 minutes. You may be asked to hold your breath during short scans. The total scan lasts 15 to 90 minutes, depending on the size of the area being scanned and how many images are needed.
Compact Superconducting Magnets – a key enabling technology
Our high / very high field compact superconducting magnets are smaller, lighter, and help to deliver more economical and smaller MRI systems, whilst maintaining the gold standard of imaging quality expected by clinicians.
MRI is a very safe procedure. As noted above, MRI does not use x-rays. In theory, you could undergo many MRI examinations without any cumulative effects.
Individuals undergoing a magnetic resonance imaging (MRI) scan often need to minimize movements for up to 10 minutes at a time to maximize scan quality. That can be challenging for many people. In fact, between 10 to 15% of all MRI scans need to be redone because of excessive movement during the scan.
They have an opening with a diameter around 50-60 centimeters (most typically around 60 cm). Most people describe the bore, which is the opening to the MRI machine, as an entrance into a long, narrow tunnel.
If the patient can be supported by the table and is able to fit into the gantry, Uppot believes that CT is the best modality for imaging obese patients. An obese person's fat typically causes the internal structures to be more separated, so radiologists can see all the spaces between them.
Instead of an enclosed capsule, the open MRI uses a magnet top and bottom and is open on all four sides. These decrease the risk of claustrophobia and panic attacks exponentially and allows patients of all shapes and sizes to be able to make use of an MRI to accurately diagnose their problems.