Magnetic Resonance Imaging, Abdomen
To visualize and assess abdominal and hepatic structures toward diagnosis of tumors, metastasis, aneurysm, and abscess. Also used to monitor medical and surgical therapeutic interventions.
Area Of Application:
Liver and abdominal area.
Can be done with or without IV contrast medium (gadolinium).
Magnetic resonance imaging (MRI) uses a magnet and radio waves to produce an energy field that can be displayed as an image. Use of magnetic fields with the aid of radiofrequency energy produces images primarily based on water content of tissue. The magnetic field causes the hydrogen atoms in tissue to line up, and when radio waves are directed toward the magnetic field, the atoms absorb the radio waves and change their position. When the radio waves are turned off, the atoms go back to their original position; this change in the energy field is sensed by the equipment, and an image is generated by the attached computer system. MRI produces cross-sectional images of the abdomen in multiple planes without the use of ionizing radiation or the interference of bone.
Abdominal MRI is performed to assist in diagnosing abnormalities of abdominal and hepatic structures. Contrast-enhanced imaging is effective for distinguishing peritoneal metastases from primary tumors of the gastrointestinal (GI) tract. Primary tumors of the stomach, pancreas, colon, and appendix often spread by intraperitoneal tumor shedding and subsequent peritoneal carcinomatosis. MRI uses the noniodinated contrast medium gadopentetate dimeglumine (Magnevist), which is administered IV to enhance contrast differences between normal and abnormal tissues.
Magnetic resonance angiography (MRA) is an application of MRI that provides images of blood flow and diseased and normal blood vessels. In patients who are allergic to iodinated contrast medium, MRA is used in place of angiography (see monograph titled “Magnetic Resonance Angiography”).
- Detect abdominal aortic diseases
- Detect and stage cancer (primary or metastatic tumors of liver, pancreas, prostate, uterus, and bladder)
- Detect chronic pancreatitis
- Detect renal vein thrombosis
- Detect soft tissue abnormalities
- Determine and monitor tissue damage in renal transplant patients
- Determine the presence of blood clots, cysts, fluid or fat accumulation in tissues, hemorrhage, and infarctions
- Determine vascular complications of pancreatitis, venous thrombosis, or pseudoaneurysm
- Differentiate aortic aneurysms from tumors near the aorta
- Differentiate liver tumors from liver abnormalities, such as cysts, cavernous hemangiomas, and hepatic amebic abscesses
- Evaluate postoperative angioplasty sites and bypass grafts
- Monitor and evaluate the effectiveness of medical or surgical interventions and the course of the disease
Normal Findings In:
- Normal anatomic structures, soft tissue density, and biochemical constituents of body tissues, including blood flow
Abnormal Findings In:
- Acute tubular necrosis
- Internal bleeding
- Masses, lesions, infections, or inflammations
- Renal vein thrombosis
- Vena cava obstruction
- Acute GI bleed
- Aortic aneurysm
- Tumor with significant mass effect
It is essential that critical diagnoses be communicated immediately to the appropriate health-care provider (HCP). A listing of these diagnoses varies among facilities. Timely notification of critical values for lab or diagnostic studies is a role expectation of the professional nurse. Notification processes will vary among facilities. Upon receipt of the critical value the information should be read back to the caller to verify accuracy. Most policies require immediate notification of the primary HCP, hospitalist, or on-call HCP. Reported information includes the patient’s name, unique identifiers, critical value, name of the person giving the report, and name of the person receiving the report. Documentation of notification should be made in the medical record with the name of the HCP notified, time and date of notification, and any orders received. Any delay in a timely report of a critical value may require completion of a notification form with review by Risk Management.
This procedure is contraindicated for:
- Patients with certain ferrous metal prostheses, valves, aneurysm clips, inner ear prostheses, or other metallic objects.
- Patients with metal in their body, such as shrapnel or ferrous metal in the eye.
- Patients with cardiac pacemakers, because the pacemaker can be deactivated by MRI.
- Use of gadolinium-based contrast agents (GBCAs) is contraindicated in patients with acute or chronic severe renal insufficiency (glomerular filtration rate less than 30 mL/min/1.73 m2). Patients should be screened for renal dysfunction prior to administration. The use of GBCAs should be avoided in these patients unless the benefits of the studies outweigh the risks and if essential diagnostic information is not available using non-contrast-enhanced diagnostic studies.
- Patients with intrauterine devices.
- Patients with iron pigments in tattoos.
- Patients who are claustrophobic.
- Patients who are pregnant or suspected of being pregnant, unless the potential benefits of the procedure far outweigh the risks to the fetus and mother.
Factors that may impair clear imaging:
- Metallic objects (e.g., jewelry, body rings, dental amalgams) within the examination field, which may inhibit organ visualization and cause unclear images.
- Inability of the patient to cooperate or remain still during the procedure because of age, significant pain, or mental status.
- Patients with extreme cases of claustrophobia, unless sedation is given before the study or an open MRI is utilized.
- If contrast medium is allowed to seep deep into the muscle tissue, vascular visualization will be impossible.
Nursing Implications Procedure
- Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
- Patient Teaching: Inform the patient this procedure can assist in assessing the abdominal organs and structures.
- Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex, iodine, seafood, contrast medium, anesthetics, or dyes.
- Obtain a history of the patient’s gastrointestinal, genitourinary, and hepatobiliary systems; symptoms; and results of previously performed laboratory tests and diagnostic and surgical procedures. Obtain a history of renal dysfunction if the use of GBCA is anticipated.
- Ensure the results of BUN, creatinine, and eGFR (estimated glomerular filtration rate) are obtained if GBCA is to be used.
- Determine if the patient has ever had any device implanted into his or her body, including copper intrauterine devices, pacemakers, ear implants, and heart valves.
- Obtain occupational history to determine the presence of metal in the body, such as shrapnel or flecks of ferrous metal in the eye (which can cause retinal hemorrhage).
- Note any recent procedures that can interfere with test results, including examinations using barium- or iodine-based contrast medium.
- Record the date of the last menstrual period and determine the possibility of pregnancy in perimenopausal women.
- Obtain a list of the patient’s current medications including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values).
- Review the procedure with the patient. Address concerns about pain related to the procedure and explain that no pain will be experienced during the test, but there may be moments of discomfort. Reassure the patient that if contrast is used, it poses no radioactive hazard and rarely produces side effects. Inform the patient the procedure is performed in an MRI department by an HCP specializing in this procedure, with support staff, and takes approximately 30 to 60 min.
- Inform the patient that the technologist will place him or her in a supine position on a flat table in a large cylindrical scanner.
- Tell the patient to expect to hear loud banging from the scanner and possibly to see magnetophosphenes (flickering lights in the visual field); these will stop when the procedure is over.
- Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
- Explain that an IV line may be inserted to allow infusion of IV fluids, contrast medium, or sedatives.
- Instruct the patient to remove jewelry and all other metallic objects from the area to be examined prior to the procedure.
- There are no food, fluid, or medication restrictions unless by medical direction.
- Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient.
- Ensure that the patient has removed all external metallic objects from the area to be examined prior to the procedure.
- If the patient has a history of allergic reactions to any substance or drug, administer ordered prophylactic steroids or antihistamines before the procedure.
- Have emergency equipment readily available.
- Instruct the patient to void prior to the procedure and to change into the gown, robe, and foot coverings provided.
- Instruct the patient to cooperate fully and to follow directions. Instruct the patient to remain still throughout the procedure because movement produces unreliable results.
- Supply earplugs to the patient to block out the loud, banging sounds that occur during the test. Instruct the patient to communicate with the technologist during the examination via a microphone within the scanner.
- Establish an IV fluid line for the injection of emergency drugs and of sedatives.
- Administer an antianxiety agent, as ordered, if the patient has claustrophobia. Administer a sedative to a child or to an uncooperative adult, as ordered.
- Place the patient in the supine position on an examination table.
- If contrast is used, imaging can begin shortly after the injection.
- Ask the patient to inhale deeply and hold his or her breath while the images are taken and then to exhale after the images are taken.
- Instruct the patient to take slow, deep breaths if nausea occurs during the procedure.
- Monitor the patient for complications related to the procedure (e.g., allergic reaction, anaphylaxis, bronchospasm).
- Remove the needle or catheter and apply a pressure dressing over the puncture site.
- Observe/assess the needle/catheter insertion site for bleeding, inflammation, or hematoma formation.
- A report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
- Observe for delayed allergic reactions, such as rash, urticaria, tachycardia, hyperpnea, hypertension, palpitations, nausea, or vomiting
- Instruct the patient to immediately report symptoms such as fast heart rate, difficulty breathing, skin rash, itching, chest pain, persistent right shoulder pain, or abdominal pain. Immediately report symptoms to the appropriate HCP.
- Instruct the patient in the care and assessment of the injection site.
- Instruct the patient to apply cold compresses to the puncture site as needed to reduce discomfort or edema.
- Recognize anxiety related to test results. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate.
- Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
- Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
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