Renal scintigraphy is an MRI scan that allows the kidney shape and function to be assessed by injecting a radioactive substance into the vein, called a radiopharmaceutical, which is bright in the image and kidney.
There are two main types of renal scintigraphy:
- Static renal scintigraphy: the images are obtained in a single moment with the person at rest;
- Dynamic renal scintigraphy: dynamic images are obtained from production to elimination of urine.
Then there are renal scintigraphy with DMSA and renal scintigraphy with DTPA, which have this name according to the radiopharmaceutical used to produce the image during the examination. Each radiopharmaceutical also allows the evaluation of different functions of the kidney.
Depending on the type of scintigraphy, the value of the exam can vary from 600 to 1300 reais, but in some cases, it is also possible to make renal scintigraphy by the SUS for free.
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 may indicate water intake before the test or put serum directly into the vein.
If it is necessary to have an empty bladder, it may be advisable to urinate before the exam. There are also some types of scintigraphy where the bladder must always be empty and in such cases it may be necessary to introduce a bladder catheter to remove any urine that is inside the bladder.
It is still very important to remove any jewelry or metal materials before starting the exam, as they may interfere with the result of scintigraphy. Generally for dynamic renal scintigraphy, the doctor has to suspend the diuretic medications 24 hours before the exam or on the day itself.
How is renal scintigraphy done?
How to perform 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 put on the resonance machine if they get the pictures of the kidneys.
Dynamic Renal Scintigraphy:
- The person urinates and then lies down on the stretcher;
- The DTPA radiopharmaceutical is injected into the vein;
- A drug is also given into the vein to stimulate the formation of urine;
- Images of the kidneys 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 examination is being done and the images are being collected it is very important that the person remains as still as possible. After the injection of the radiopharmaceutical it is possible to feel a slight tingling in the body and even the metallic taste in the mouth.
After the test, you should drink water or other liquids except alcoholic beverages and urinate frequently to eliminate the rest of the radiopharmaceutical.
How the scintigraphy is done on the baby
Kidney scintigraphy in a baby is usually done following a baby's urinary infection to assess the function of each kidney and the presence or absence of renal scars that are a consequence of urinary tract infection.
For renal scintigraphy, fasting is not necessary and about 5 to 10 minutes before the examination the patient should drink 2 to 4 cups or 300-600 ml of water.
Scintigraphy should not be performed on pregnant women and breastfeeding women should discontinue breastfeeding and avoid contact with the baby for at least 24 hours after the examination.
