MRI examination of liver, gallbladder, pancreas and spleen

MRI examination of liver, gallbladder, pancreas and spleen can determine the extent, extent and characteristics of the lesion and can be differentiated from other tumors. It has a diagnostic effect on liver, spleen cyst and cavernous hemangioma. Basic Information Specialist Category: Digestive Examination Category: Nuclear Magnetic Resonance Applicable gender: whether men and women apply fasting: fasting Tips: Do not wear underwear with metal materials. Patients with head and neck should wash their hair one day before the test. Do not wipe any hair care products. Normal value Scope of application: 1. Primary or metastatic tumors of the liver, gallbladder, pancreas, and spleen, and hepatic cavernous hemangioma. 2. Hepatic parasitic diseases such as liver echinococcosis. 3. Diffuse liver disease such as cirrhosis, fatty liver, hyperpigmentation. 4. Congenital dysplasia of liver, gallbladder, pancreas and spleen. 5, liver abscess. 6, liver localized nodular hyperplasia and hepatitis pseudotumor. 7. Follow-up and observation of surgery, radiotherapy, chemotherapy and other therapeutic effects. 8, pancreatitis and its complications. Clinical significance 1, can determine the extent, extent and characteristics of the lesion, and can be identified with other tumors. 2, the diagnosis of liver, spleen cysts, cavernous hemangioma. 3. MRI is mainly used as a tumor diagnosis for the study of the physiology, pathology and biliary tract of the gallbladder. 4. MRI is more meaningful than CT for the diagnosis of disease. Precautions Requirements for inspection: 1. Those with magnets in the body, such as those equipped with cardiac pacemakers, aneurysms, etc., artificial valves, metal foreign body residues beside important organs, and pregnant women within 3 months of pregnancy, can not do this check. 2. Explain the following to the technician: (1) Whether there is a history of surgery. (2) Whether any metal or magnetic substance is implanted in the body, including a metal tube. (3) Whether there are dentures, electronic ears, prosthetic eyes, etc. (4) Whether there is drug allergy. (5) There are no metal foreign objects splashing into the body in the near future. 3, do not wear underwear with metal materials, patients with head and neck should wash their hair one day before the inspection, do not wipe any hair care products. Preparation before inspection: 1. Before the inspection, remove all the clothes outside the underwear and replace the special clothes for the magnetic resonance room. Remove the metal items such as necklaces, earrings, watches and rings. Remove cosmetics and dentures, prosthetic eyes, glasses and other items on your face. 2, magnetic resonance examination time is longer, and the environment in which the patient is located is dark and noisy. Be mentally prepared, don't be impatient, don't be afraid, keep your position under the guidance of a doctor. Patience. 3. Provide the doctor with all medical history, examination data and all X-ray films and CT films before the examination. Inspection process 1. Fasting for 4-6 hours before the examination, oral MRI gastrointestinal contrast agent 500~1000ml 15min before the examination, common contrast agents are: 0.1～0.2mmol/L iron citrate solution, 5% mannitol solution or 1.0～2.0mmol /L Gd-DTPA solution, etc., to help the difference between the upper abdominal parenchyma and the gastrointestinal tract. If necessary, intramuscular injection of 10 mg of anisodamine can reduce gastrointestinal motility. 2. Take the supine position, aim the xiphoid at the center of the body coil, and gently snoring the patient. Pressing the upper abdomen with the abdominal band can reduce the breathing artifacts. 3. Positioned by the coronal plane, the cross section is the basic section, and T1, proton and T2 weighted images are made. The layer thickness is 8 to 10 mm, the layer spacing is 1 to 2 mm, and the matrix is ​​160 to 256×256. 4. Conventional body coil, FOV is 35 ~ 42cm. 5. SE sequence is the most commonly used, scanning the wild head and tail to add saturation zone to suppress pulsation and respiratory artifacts, T1 weighted TR350 ~ 600ms, TE15 ~ 20ms, 3 ~ 4 times to collect signals. Proton and T2 weighted images were acquired using a double echo sequence, TR1500 ~ 2000ms, TE20, 90ms, or three echo sequences, TR2000 ~ 2200ms, TE22, 60, 120 ~ 150ms. Fat-suppressed protons and T2-weighted images help to show edge lesions and distinguish them from surrounding organs. Gradient echo sequence quasi-T1-weighted screen gas scanning can be used for patients with obvious respiratory artifacts, TR100 ~ 180ms, TE4 ~ 8ms, flip angle 80 ° ~ 90 °, 1 breath holding 15 ~ 21s can scan 6 ~ 14 layers, layer thickness 8 ~ 10mm, layer spacing 1 ~ 2mm, can be pre-saturation on the head side to suppress aortic beat artifacts. Although the fast SE sequence can shorten the T2-weighted image scanning time, it has the disadvantage of increasing motion artifacts and signal atypicality, and should be used with caution. 6. Coronal and sagittal planes are mainly used for lesion localization, usually only T1 weighted images. In order to save time, gradient echo sequence scanning is generally used, and the parameters are the same as the cross section, and the FOV is 42-45 cm. 7. There are many kinds of contrast agents in liver enhanced scan. Gd-DTPA is a non-specific extracellular distribution contrast agent, which is mainly used to observe the hemodynamics of the lesions. The enhanced performance and significance are similar to those of CT iodine, emphasizing dynamic enhancement. For scanning, the gradient echo sequence quasi-T1-weighted image should be selected, and the lesion should be used as the center for multiple breath-holding scans to show the dynamic enhancement of the lesion. The SE-sequence T1-weighted image is only used for delayed scanning. Other types of contrast agents include hepatobiliary contrast agents, such as manganese-pyridoxal bisphosphate (Mn-DPDP), which can be taken up by liver cells and secreted into bile. Normal liver cells are fortified, setting off no strengthening. Liver occupying. There are also reticular cell-targeting contrast agents, such as superparamagnetic iron oxide particles (representing the product AMI25), which are engulfed by the liver, spleen, lymphatic system, etc., which are rich in the reticuloendothelial system, so that normal liver tissue is strengthened in T2. The signal on the weighted image is reduced, and the contrast shows a lesion with no enhanced high signal, which has certain tissue specificity. Enhanced scans of these contrast agents should be selected for optimal contrast between the liver tissue and the lesion. Not suitable for the crowd 1. Those who have an electrocardiograph. 2. Use various rescue tools with metal and cannot remove them. 3. Those who have metal clips in the body after surgery. There is a metal implant that cannot be removed adjacent to the body at the examination site. 4. Women with early pregnancy (within 3 months) should avoid MRI scans. Adverse reactions and risks A small number of people may have transient facial flushing, sore back, chest tightness, palpitations and other reactions.

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