Liver MRI is a method of noninvasive visual examination of the liver and biliary tract, based on the change in the polarity of hydrogen atoms in the body under the influence of radio waves and a constant magnetic field. It is used to obtain information about the uniformity and density of the hepatic parenchyma, as well as to study blood vessels and bile ducts. It is used for the diagnosis of volumetric formations of various nature, inflammatory processes, atrophy, structural changes, confirmation of developmental anomalies, the presence of concretions and assessment of the general condition of the organ.
Indications
Liver MRI is prescribed for many diseases of the hepatobiliary system. Indications for examination are diffuse liver lesions, which include hemochromatosis and many others. Scanning is required for differential diagnosis of intrahepatic formations, in particular, benign and malignant tumors, cystic cavities. Focal lesions are also detected on liver MRI. In addition to the parenchyma of the organ, the liver vessels are visualized on the images with the possibility of assessing their patency. The examination is used to clarify the results of other diagnostic procedures, and is also prescribed in the postoperative period, for example, after surgery for a tumor.
Congenital anomalies of the hepatobiliary system are also an indication for liver MRI. It can be hepatoptosis, congenital liver cyst, doubling, dystopia and other defects. Metastases of various extrahepatic tumors are often found in the liver, and an examination is prescribed to identify or exclude them. As a result of some congenital and acquired diseases, the iron content in the liver may increase, which has a detrimental effect on hepatocytes. An increase in the concentration of a trace element is determined using MRI. Scanning is also indicated if organ transplantation is planned, there is a need for a thorough assessment of its general condition and structure.
The study is used to visualize the bile ducts and diagnose pathologies associated with a decrease in their lumen up to complete obstruction. In this case, an liver MRI is required to determine the cause of the patient’s complaints. Examination may reveal choledocholithiasis or a tumor in the bile duct, which is the cause of stasis. Scanning is used in the diagnosis of congenital anomalies and inflammatory processes of the biliary tract. In addition, MRI is prescribed for suspected pancreatic cancer, pseudocysts and some malformations. The study is carried out after liver surgery to exclude iatrogenic changes in the anatomy of the ducts.
Contraindications
The procedure is not performed if there are any metal-containing structures in the patient’s body, except for titanium products. In a magnetic field, the operation of complex electronic devices, for example, a hearing aid, can be disrupted, so in this case, liver MRI is also contraindicated. Scanning is not recommended during pregnancy, especially in the first trimester, however, if the rejection of MR diagnostics may entail high risks to health and life, the procedure is allowed. MRI is not prescribed to patients in a general serious condition, because during the examination it is not possible to monitor the patient’s vital signs.
There are also contraindications to liver MRI with contrast. These include chronic renal failure, since the contrast agent is excreted by the kidneys. The examination is not carried out with a confirmed allergy to gadolinium and its compounds. With caution, MRI is prescribed to patients with a burdened allergic history, usually the procedure is performed after drug hyposensitization. The lactation period is a relative contraindication, since the contrast agent is absent in breast milk within 1-2 days after the study. In many clinics, breast-feeding women are not scanned. MRI in most clinical forms of epilepsy is possible with the use of anesthesia.
Preparation
The pre-examined area is studied using ultrasound and laboratory diagnostic methods. Retrograde pancreatocholangiography may be performed. The excretory function of the kidneys is being clarified, since the study is almost always performed with contrast. Two days before the procedure, products that increase gas formation are excluded from the diet: black bread, legumes, dairy, etc. liver MRI is performed on an empty stomach, 4-6 hours after eating. 1-2 hours before the examination, an antispasmodic drug is usually prescribed, this contributes to better visualization of the biliary tract.
Methodology of conducting
Before the start of the procedure, a system of intravenous contrast is installed for the patient, in order to avoid thrombosis, a drip of saline solution is often administered. The recommended position for liver MRI is lying on your back. During the administration of the contrast agent, the subject may feel fever in the body, dizziness, dry mouth. The symptoms go away on their own within a few minutes. The duration of the scan is about 30 minutes. During operation, the device emits loud sounds and clicks, and earplugs or headphones are provided to the patient at will.
During the examination, communication is carried out via a two-way communication system. The patient can report any changes in his condition, the doctor informs about the periods of breath retention, during which many pictures are taken. Complications occur with allergies to contrast media and chronic renal failure, and may also be associated with the presence of metal elements in the body of the subject. Liver MRI results are prepared within a few hours. The patient receives printed images with the conclusion of the radiologist. If desired, the data is duplicated to a CD-ROM or USB.
