Protect the health of the elderly, MRI can help - Preparation before the examination

Author: Wang Xuan, deputy chief physician, Peking Union Medical College Hospital

Reviewer: Feng Feng, Chief Physician, Peking Union Medical College Hospital

Magnetic resonance imaging (MRI) is an advanced medical imaging technology that can help diagnose and monitor a variety of common diseases and protect the health of the elderly. Understanding the necessity, precautions and process of the examination will help the elderly and their families cooperate with doctors to better complete the examination. Today, the "Xieying Puhui" science popularization team of the Department of Radiology of Peking Union Medical College Hospital (the original plan of Xiehexing) will take you to understand the things about MRI examinations for the elderly, so that the elderly can be worry-free and their families can feel at ease.

Our introduction is divided into three parts: the principle of magnetic resonance imaging, common situations in which the elderly need to undergo MRI examinations; preparations before MRI examinations for the elderly; and the specific process of MRI examinations for the elderly.

In the previous article, we introduced the principles and indications of the examination. In this article, we will introduce the preparations that the elderly need to make before undergoing an MRI examination.

Figure 1 Staff position an elderly patient with low back pain (head first) (copyright image not authorized for reproduction)

1. Health assessment : Elderly people often suffer from chronic diseases, such as hypertension and diabetes. Before undergoing an MRI examination, it is necessary to ensure that these chronic diseases are well controlled to avoid emergencies during the examination. Enhanced MRI examinations are contraindicated for patients with severe renal insufficiency, and should be used with caution for patients with mild to moderate renal insufficiency.

2. Medical history disclosure : The elderly and their families need to inform the medical staff of their medical history in detail, including any surgical history, allergy history, whether they have electronic implants [such as cardiac pacemakers and implantable cardioverter defibrillators (ICDs) and other cardiac implantable electronic devices, cochlear implants, deep brain stimulators, etc.] and metal implants (such as arterial stents, venous filters, mechanical valves, cardiac suture and occlusion devices, floating catheters, orthopedic implants, etc.) and metal foreign bodies in the body to avoid potential risks. Some electronic implants in the patient's body may malfunction or fail due to radio frequency interference; ferromagnetic implants may change their position due to magnetic fields; implants may also introduce image artifacts and affect the observation of surrounding tissues; in addition, there is also a risk of thermal burns. Therefore, patients with electronic or metal implants in their bodies should consult the surgeon before undergoing an MRI examination, or check the surgical records and implant instructions. The MRI examination can only be performed with the support of the instructions and the patient's signed informed consent.

In addition, if you know that you have claustrophobia, you can communicate with your doctor in advance and use sedatives if necessary. If conditions permit, you can also choose an open magnetic resonance imaging device.

3. Psychological preparation : MRI examinations usually require patients to remain still for a long time, which may be difficult for some elderly people. Some elderly people may have cognitive dysfunction, such as memory loss or dementia. Medical staff and family members should provide more explanations and support to ensure that the elderly understand the process in advance and are mentally prepared.

4. Medication management : Elderly people may take certain medications for a long time. Most medications will not affect the test results and do not need to be stopped. Oral iron supplements or Chinese medicine containing iron will affect the imaging of the digestive tract, and some medications will affect the imaging of brain function tests, etc., which require attention.

5. Dietary precautions : Abdominal and pelvic examinations and enhanced MRI require fasting 4 hours in advance, and you can drink water appropriately before the examination. Some digestive tract examinations require fasting for 6 to 8 hours, but water is not required.

6. Special preparation : For examinations to observe the small intestine, 2.5% mannitol solution will be taken orally 1 hour in advance to fill the intestine. For examinations involving the colon, Heshuang (compound polyethylene glycol electrolyte powder) will be taken orally 1 day in advance to clean the intestine. For observations of the small intestine and colon, drugs that inhibit intestinal motility will be injected 10 minutes before the scan. For rectal examinations, enema will be applied 1 hour before the examination. Most examinations involving the pelvic cavity and urinary system require appropriate urine retention before the scan. Before other special examinations, the staff will inform you of the specific preparation requirements and precautions when making an appointment. If you are not sure, please confirm with the doctor in advance.

7. Dress requirements : Elderly people should wear loose clothing without metal objects, and should not wear magnetic therapy underwear and bras with metal buckles. At the same time, avoid wearing clothing that is easy to generate static electricity, such as chemical fiber materials and some sweaters. In addition, it should be noted that not only metallic substances will cause artifacts and affect the imaging effect. As long as the difference in magnetic susceptibility between tissues and tissues/substances is large enough, magnetic sensitivity artifacts visible to the naked eye will appear on the image. Therefore, try to choose clothes without decorations, do not wear tights that increase skin wrinkles, and remove the accessories on your body. Please try not to wear makeup before scanning, because some cosmetics contain metal substances, which will affect the examination image effect. Plasters, heat packs, knee pads, waist protectors, sandbags and other items may contain metal substances, so please remember to remove them in advance. If you have tattoos, permanent eyeliner, subcutaneous metal foreign bodies or accessories that cannot be removed, please inform the medical staff in advance. The medical staff will take thermal protection measures or terminate the examination according to the actual situation. If you feel a tingling sensation on your skin during the examination, you should also inform the medical staff immediately and stop the examination.

Figure 2 Staff position the patient with abdominal pain (head first) (copyright image not authorized for reproduction)

In the following articles, we will continue to introduce the third part - the magnetic resonance imaging examination process. We look forward to your attention.

MRI is a safe and non-invasive examination method that can provide important information for the diagnosis of diseases in the elderly, especially in cases where high-resolution soft tissue imaging is required. I hope that this series of articles can help the elderly and their families better understand and prepare for MRI examinations, so as to obtain the best health protection.