This is a medical question of type : exams and tests 
 How to diagnose Urinary Tract Infections in Children ? 
 Once the infection has cleared, more tests may be recommended to check for abnormalities in the urinary tract. Repeated infections in an abnormal urinary tract may cause kidney damage. The kinds of tests ordered will depend on the child and the type of urinary infection. Because no single test can tell everything about the urinary tract that might be important, more than one of the tests listed below may be needed.
                
- Kidney and bladder ultrasound. Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. The procedure is performed in a health care providers office, outpatient center, or hospital by a specially trained technician, and the images are interpreted by a radiologista doctor who specializes in medical imaging; anesthesia is not needed. The images can show certain abnormalities in the kidneys and bladder. However, this test cannot reveal all important urinary abnormalities or measure how well the kidneys work.  - Voiding cystourethrogram. This test is an x-ray image of the bladder and urethra taken while the bladder is full and during urination, also called voiding. The childs bladder and urethra are filled with a special dye, called contrast medium, to make the structures clearly visible on the x-ray images. The x-ray machine captures images of the contrast medium while the bladder is full and when the child urinates. The procedure is performed in a health care providers office, outpatient center, or hospital by an x-ray technician supervised by a radiologist, who then interprets the images. Anesthesia is not needed, but sedation may be used for some children. This test can show abnormalities of the inside of the urethra and bladder. The test can also determine whether the flow of urine is normal when the bladder empties.  - Computerized tomography (CT) scan. CT scans use a combination of x rays and computer technology to create three-dimensional (3-D) images. A CT scan may include the injection of contrast medium. CT scans require the child to lie on a table that slides into a tunnel-shaped device where the x rays are taken. The procedure is performed in an outpatient center or hospital by an x-ray technician, and the images are interpreted by a radiologist; anesthesia is not needed. CT scans can provide clearer, more detailed images to help the health care provider understand the problem.  - Magnetic resonance imaging (MRI). MRI machines use radio waves and magnets to produce detailed pictures of the bodys internal organs and soft tissues without using x rays. An MRI may include the injection of contrast medium. With most MRI machines, the child lies on a table that slides into a tunnel-shaped device that may be open ended or closed at one end; some newer machines are designed to allow the child to lie in a more open space. The procedure is performed in an outpatient center or hospital by a specially trained technician, and the images are interpreted by a radiologist; anesthesia is not needed, though light sedation may be used for children with a fear of confined spaces. Like CT scans, MRIs can provide clearer, more detailed images.  - Radionuclide scan. A radionuclide scan is an imaging technique that relies on the detection of small amounts of radiation after injection of radioactive chemicals. Because the dose of the radioactive chemicals is small, the risk of causing damage to cells is low. Special cameras and computers are used to create images of the radioactive chemicals as they pass through the kidneys. Radionuclide scans are performed in a health care providers office, outpatient center, or hospital by a specially trained technician, and the images are interpreted by a radiologist; anesthesia is not needed. Radioactive chemicals injected into the blood can provide information about kidney function. Radioactive chemicals can also be put into the fluids used to fill the bladder and urethra for x ray, MRI, and CT imaging. Radionuclide scans expose a child to about the same amount or less of radiation as a conventional x ray.  - Urodynamics. Urodynamic testing is any procedure that looks at how well the bladder, sphincters, and urethra are storing and releasing urine. Most of these tests are performed in the office of a urologista doctor who specializes in urinary problemsby a urologist, physician assistant, or nurse practitioner. Some procedures may require light sedation to keep the child calm. Most urodynamic tests focus on the bladders ability to hold urine and empty steadily and completely. Urodynamic tests can also show whether the bladder is having abnormal contractions that cause leakage. A health care provider may order these tests if there is evidence that the child has some kind of nerve damage or dysfunctional voidingunhealthy urination habits such as holding in urine when the bladder is full.