Nuclear Medicine Procedures made easy

1. Renal: Renogram,
Diuretic, and Captopril:
Tubular Function, ERPF,
and GFR
BY
DR. ASHRAF ANAS ZYTOON MD, PHD, FJRS
MENOUFIYA UNIVERSITY - EGYPT

2. Radiopharmacy
Radionuclide
99mTc
t1/2: 6 hours
Energies: 140 keV
Type: IT, γ, generator
Radiopharmaceutical
• 99mTc-DTPA (diethylenetriaminepentaacetic acid)
• 99mTc-MAG3® (mercaptoacetyltriglycine)

3. Adult Dose Range
99mTc:3–20 mCi (111–740 MBq) generally 10 mCi
(370 MBq) for most studies.
Method of Administration
• Bolus intravenous injection
• If study includes a diuretic use butterfly or IV
catheter (furosemide).
• ACE inhibitor study:
– Captopril (Capoten®) is given PO 1 hour before exam.
– Enalapril maleate (Vasotec® intravenous over 3–5 minutes).

4. Indications
• Evaluation for renal artery stenosis, obstruction,
and/or trauma.
• Evaluation of renal tubular function and perfusion
(glomerular filtration) for blood flow, parenchyma, and
excretion.
• Evaluation of renal vascular flow (effective renal
plasma flow).
• Evaluation of renal obstructive nephropathy and/or
hydronephrosis (study with furosemide).

5. Indications
• Evaluation for renal (renovascular) hypertension
(captopril study).
• Evaluation of renovascular hypertension therapy.
• Evaluation of abdominal or flank bruits, azotemia,
pulmonary edema, retinopathy, and unexplained renal
dysfunction.
• Detection of acute tubular necrosis.
• Evaluation of a kidney transplant.

6. Contraindications
• Iodine IV contrast study on same day.
• Patient still on adrenal cortical extract (ACE, or
angiotensin-converting enzyme) inhibitors or
angiotensin receptor blocker (ARB).
• Food intake too close to a captopril study will decrease
the sensitivity of the test and slow the absorption of
the ACE inhibitor.
• Beta blockers may affect production of renin.

7. Patient Preparation
• Identify the patient. Verify doctor's order. Explain the
procedure.
• Instruct patient to hydrate well (water) and void just
before test.
• Physician is to instruct patient to discontinue ACE
inhibitors for several days (3–7) before examination.
• Instruct patient to be NPO for at least four hours on
morning before captopril study.
• Post study voiding is recommended to lessen bladder
exposure.

8. Equipment
Camera
Large field of view
Collimator
low energy, all purpose, or low energy, high resolution

9. Normal Results
• Assuming two kidneys, both kidneys visualizing about
the same size and intensities.
• Excretion at the same rate.
• Smooth renal contour.
• Time-to-peak concentration is 3 to 5 minutes.
• Clearance t1/2 is 12 to 15 minutes.
• GFR (glomerular filtration rate) = 125 mL/minute.

10. Artifacts
• Some patients do not have both kidneys.
• Injection problems for flow or bad start.
• Infiltration at the injection site can alter renography
curves, food within 4 hours of study, pelvic retention,
dehydration, hypotension, or full bladder at the start of
the study.
• False-positives of mechanical obstruction: poor
hydration.

11. Patient History 1 (The patient should answer the following questions).
• Do you have a history of kidney disease (e.g., stones,
infections)?
• Do you have both kidneys?
• Are there any recent or planned operations?
• Do you have any renal pain?
• Are you experiencing urinary frequency or urgency?

12. Patient History 2 (The patient should answer the following questions).
• Do you have any blood in your urine?
• Do you have high blood pressure?
• Do you have the results of any recent renal
laboratory tests?
• What medications are you currently taking
(please list)?
• Female: Are you pregnant or nursing?