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Introduction ⬇

A renal scan, also known as a kidney scan or renogram, is performed in both adult and pediatric patients to study the function of the kidneys and to detect renal parenchymal or vascular disease or defects in excretion. The radiopharmaceutical of choice, 99mTc mertiatide, permits visualization of renal clearance. In pediatric patients, this procedure is done to evaluate hydronephrosis, obstruction, reduced kidney function (premature neonates), kidney trauma, and urinary tract infections. A renal scan is ideal for pediatric evaluation because of the nontoxic nature of the radiopharmaceuticals, compared with the contrast media used in radiology procedures. Post–kidney transplantation scans, which assess perfusion and excretory function as a reflection of glomerular filtration rate (GFR), are done when the serum creatinine level increases and determine kidney damage leading to acute tubular necrosis.

A renal scan may also be performed using drugs, such as furosemide or captopril, as well as 99mTc mertiatide, based on the reason for the scan. A diuretic renal scan, using furosemide, is performed to rule out obstructive hydronephrosis, whereas a captopril renal scan is performed to evaluate for the presence of renal artery stenosis and renovascular hypertension.

  1. To detect the presence or absence of unilateral kidney disease

  2. For long-term follow-up of hydroureteronephrosis

  3. To study the patient with hypertension to evaluate for renal artery stenosis or renovascular hypertension (captopril test)

  4. To study the patient with azotemia when urethral catheterization is contraindicated or impossible

  5. To evaluate upper urinary tract obstruction (diuretic renal scan)

  6. To assess kidney transplant efficacy

Procedure ⬆ ⬇

  1. Place the patient in either an upright sitting or supine position for imaging; the supine position is preferred for pediatric patients.

  2. Inject the radiopharmaceutical intravenously. An IV diuretic (such as furosemide) or angiotensin-converting enzyme (ACE) inhibitor (such as enalapril/captopril) may also be administered during a second phase of the renal scan.

  3. Start imaging immediately after injection.

  4. Alert the patient that total examination time is approximately 45 minutes for a routine, one-phase renal scan.

  5. See Chapter 1 guidelines for safe, effective, informed intratest care.

Procedural Alert

  1. The test should be performed before an IV pyelogram.

  2. A renal scan may be performed in a pregnant woman if it is imperative to assess kidney function.

Clinical Implications ⬆ ⬇

Abnormal distribution patterns may indicate:

  1. Hypertension

  2. Obstruction due to stones or tumors

  3. Kidney disease

  4. Decreased kidney function

  5. Diminished blood supply

  6. Kidney transplant rejection

  7. In pediatric patients, urinary tract infections in male neonates; the finding shifts to females after 3 months of age

Interventions ⬆ ⬇

Pretest Patient Care

  1. Explain the purpose, procedure, benefits, and risks of the procedure. Pediatric patients have a detectible GFR after 6 months of age. In the neonate, ultrasound is used in combination with nuclear medicine procedures for a more complete kidney assessment. Refer to standard NMI pretest precautions. An IV line is placed before imaging. Check for history of previous transplantation.

  2. Unless contraindicated, ensure that the patient is well hydrated with two to three glasses of water (10 mL/kg of body weight) before undergoing the test.

  3. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Encourage fluids and frequent bladder emptying to promote excretion of radioactivity.

  2. Review test results; report and record findings. Modify the nursing care plan as needed. Counsel the patient appropriately.

  3. Refer to standard NMI posttest precautions.

  4. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Clinical Alert

Some kidney transplant recipients may have more than two kidneysfor example, the transplanted kidney, their native kidney or kidneys, and an older, failing transplant. Sometimes, two pediatric kidneys will both be transplanted

Interfering Factors ⬆ ⬇

Diuretic agents, ACE inhibitors, and beta-blockers are medications that may interfere with the test results.

Reference Values ⬆

Normal

Equal blood flow in right and left kidneys

In 10 minutes, 50% of the radiopharmaceutical should be excreted.