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Renal scintigraphy is an exam done with magnetic resonance imaging that allows you to assess the shape and functioning of the kidneys. For this, it is necessary that a radioactive substance, called a radiopharmaceutical, be administered directly into the vein, which is shiny in the image obtained during the examination, allowing the visualization of the inside of the kidneys.
Renal scintigraphy can be classified according to how images are obtained in:
- Static renal scintigraphy, in which images are obtained in a single moment with the person at rest;
- Dynamic renal scintigraphy, in which dynamic images are obtained from the production to the elimination of urine.
This test is indicated by the urologist or nephrologist when changes in the type 1 urine test or 24-hour urine test are identified that could be indicative of changes in the kidneys. Here's how to recognize the symptoms of kidney problems.
How to prepare for the exam
The preparation for renal scintigraphy varies according to the type of examination and what the doctor intends to evaluate, however, it is common that it is necessary to keep the bladder full or empty. If the bladder needs to be full, the doctor can indicate the intake of water before the test or put serum directly into the vein. On the other hand, if it is necessary to have an empty bladder, the doctor may indicate that the person urinates before the test.
There are also some types of scintigraphy in which the bladder must always be empty and, in such cases, it may be necessary to introduce a bladder probe to remove any urine that is inside the bladder.
It is also very important to remove any kind of jewelry or metal materials before starting the exam, as they can interfere with the result of the scintigraphy. Generally for dynamic renal scintigraphy, the doctor orders to suspend diuretic medications 24 hours before the exam or on the same day.
How kidney scintigraphy is done
The way of doing renal scintigraphy varies according to its type:
Static scintigraphy:
- The radiopharmaceutical DMSA is injected into the vein;
- The person waits about 4 to 6 hours for the radiopharmaceutical to accumulate in the kidneys;
- The person is placed in the MRI machine if they obtain images of the kidneys.
Dynamic renal scintigraphy:
- The person urinates and then lies down on the stretcher;
- The radiopharmaceutical DTPA is injected through the vein;
- A drug is also administered through the vein to stimulate the formation of urine;
- Kidney images are obtained through magnetic resonance imaging;
- The patient then goes to the toilet to urinate and a new image of the kidneys is obtained.
While the exam is being done and the images are being collected it is very important that the person remains as immobile as possible. After the injection of the radiopharmaceutical, it is possible to feel a slight tingling in the body and even a metallic taste in the mouth. After the examination, it is allowed to drink water or other liquids except alcoholic beverages and to urinate frequently to eliminate the rest of the radiopharmaceutical.
How scintigraphy is done on the baby
Kidney scintigraphy in a baby is usually done after a urinary infection of the baby or child to assess the function of each kidney and the presence or absence of kidney scars that are a consequence of the urinary infection. To do renal scintigraphy, fasting is not necessary and about 5 to 10 minutes before the exam the child should drink 2 to 4 glasses or 300 - 600 ml of water.
Scintigraphy should not be performed on pregnant women and those who are breastfeeding should discontinue breastfeeding and avoid contact with the baby for at least 24 hours after the examination.
Created by: Tua Saúde Editorial Team