Renal scintigraphy is an exam done with magnetic resonance that allows to evaluate the shape and functioning of the kidneys through the injection, through the vein, of a radioactive substance, called radiopharmaceutical, which is brilliant in the image and, therefore, allows to evaluate the inside the kidneys.
There are two main types of renal scintigraphy:
- Static renal scintigraphy: images are obtained in a single moment with the person at rest; Dynamic renal scintigraphy: dynamic images are obtained from the production to the elimination of urine.
Then, there is also renal scintigraphy with DMSA and renal scintigraphy with DTPA, which have this name according to the radiopharmaceutical that is used to produce the image during the exam. Each radiopharmaceutical also allows you to evaluate different kidney functions.
Depending on the type of scintigraphy, the value of the exam can vary between 600 to 1300 reais, but in some cases, it is also possible to do renal scintigraphy by SUS free of charge.
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.
If it is necessary to have an empty bladder, it may be advisable to urinate 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 insert a bladder probe to remove any urine that is inside the bladder.
It is also very important to remove any type of jewelry or metal materials before starting the exam, as they can interfere with the result of the scintigraphy. Usually 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 the images of the kidneys are obtained.
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; Images of the kidneys are obtained through magnetic resonance imaging; The patient then goes to the toilet urinate and a new kidney image 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 baby's urinary infection 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 patient 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.
