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Preface and Contents

Diagnosis of Kidney Diseases

Radiological Tests

3. Radiological Tests

  • Ultrasound of the kidneys A kidney ultrasound is a simple, useful, quick and safe (no radiation exposure) test which provides valuable information such as the size of kidney and the presence of cysts, stones and tumors. An ultrasound can also detect blockage to urine flow in the urinary tract. In advanced stage of CKD or ESKD both kidneys may be found to be small in size.
  • X-ray of abdomen This test is useul for the diagnosis of calcium containg stones in the urinary system urinary tract.
  • Intra venous urography (IVU) IVU (also known as intra venous pyelography-IVP) is a specialized X- ray test. In this test, a radio opaque iodine containing dye (fluid which can be seen on X-ray films) is injected into a vein in the arm. This dye then passes through the kidney and gets excreted in to the urine. The urinary tract (kidneys, ureters and bladder) are rendered radio-opaque, and this allows visualization of the entire urinary tract. A series of X-ray pictures are taken at specific time intervals which give a comprehensive view of the anatomy of the urinary system. IVU can reveal problems such as stone, obstruction, tumor and abnormalities in structure and function of the kidneys.

    In cases of advanced CKD, IVU is usually not recommended because the injected dye can damage the already poorly functioning kidneys. In kidney failure, excretion of dye during test may be inadequate. This test is also not recommended during pregnancy. Because of availability of ultrasound and CT scan, this test is used much less frequently nowadays.

The most important screening tests for kidney diseases are the urinalysis, serum creatinine and ultrasound of kidney.
  • Voiding cystourethrogram (VCUG) Voiding cystourethrogram - VCUG (previously known as Micturating cystourethrogram - MCU) test is most commonly used in the evaluation of urinary tract infection in children. In this special X - ray test, under sterile conditions, the bladder is filled with contrast medium via the urinary catheter. After the bladder is filled, urinary catheter is removed and the patient is asked to urinate. X -rays taken at intervals during urination show the outline of the bladder and urethra. This test is helpful to diagnose backflow of urine into the ureters, and up to the kidneys (known as vesicoureteric reflux VUR) as well as identifying structural abnormalities of urinary bladder and urethra.
  • Other radiological tests In special circumstances for the diagnosis of certain kidney diseases, other tests such as CT scan of kidney and urinary tract, renal doppler, radionuclear study, renal angiography, antegrade and retrograde pyelography etc. can be useful.
A kidney ultrasound is a simple and safe test used to assess the size, shape, and location of the kidneys.

4. Other Special Tests

Kidney biopsy, cystoscopy and urodynamics are special tests which are necessary for the exact diagnosis of certain kidney problems.