I. Purpose

The purpose of this guideline is to assist nuclearmedicine practitioners in recommending, perform-ing, interpreting, and reporting the results of di-uretic renography in children.

II. Background Information and Definitions

Hydronephrosis (distension of the pelvicalyceal sys-tem) is one of the most common indications for ra-dionuclide evaluation of the kidneys in pediatric pa-tients. The etiology of the hydronephrosis can be anobstructed renal pelvis, an obstructed ureter, vesi-coureteral reflux, the bladder itself or the bladderoutlet, infection or congenital in nature.

Contrast intravenous urography, ultrasonogra-phy and conventional radionuclide renographycannot reliably differentiate obstructive from nonob-structive causes of hydronephrosis and hydroure-teronephrosis (distension of the pelvicalyceal sys-tem and ureter).

The pressure perfusion study (Whitaker test), whichmeasures collecting system pressure under conditionsof increased pelvic infusion, is relatively invasive.

The evaluation of function in the presence of ob-struction does not give reliable indication of poten-tial for recovery following surgical correction. Highpressure in the collecting system results in reductionof renal blood flow and function.

The most common cause of unilateral obstructionis the presence of a ureteropelvic obstruction. Ob-structions can also occur more distally at theureterovesical junction. Bilateral hydronephrosis canbe produced by posterior urethral valves, bilateralureteropelvic obstructions or even a full bladder.

The purpose of diuretic renography is to differen-tiate a true obstruction from a dilated nonobstructedsystem (stasis) by serial imaging after intravenousadministration of furosemide (Lasix).

Hydronephrosis detected in utero may resolve

spontaneously and is related to physiologic changeduring early development. The diagnosis of ob-struction often requires sequential scintigraphic ex-a m i n a t i o n s .

III. Common Indications

A. Ureteropelvic or ureterovesical obstructionB . Prenatal ultrasound diagnosis of hydronephrosisC. Post-surgical evaluation of a previously ob-

structed systemD. Distension of pelvicalyceal system as an etiology

of back pain

IV. Procedure

A. Patient Preparation1. Preparation prior to arrival in department

Preparation is usually not necessary. If the pa-tient is not going to receive intravenous flu-ids, oral hydration is encouraged prior to ar-rival and while in the department.

2. Preparation prior to injection of the radio-pharmaceuticala. The procedure is explained to parents and

all children old enough to understand.b. Continual communication and reassurance

with explanation of each step is essentialfor cooperation and successful intravenousinjection of the radiopharmaceutical andcatheterization of the bladder.

c. Oral hydration may be sufficient in certainsituations. Intravenous hydration is morereliable in the diagnosis of questionablecases of urinary obstruction. An in-dwelling venous catheter may be insertedto maintain sufficient hydration for a gooddiuretic effect and obviate the necessity forrepeated traumas from multiple percuta-neous injections.

Society of Nuclear Medicine Procedure Guideline forDiuretic Renography in Childrenversion 2.0, approved February 7, 1999

Authors: Gerald A. Mandell, MD (DuPont Hospital for Children, Wilmington, DE); Jeffrey A. Cooper, MD (Albany Med-ical Center, Albany, NY); Joe C. Leonard, MD (Oklahoma Children’s Memorial Hospital, Oklahoma City, OK); MassoudMajd, MD (Children’s National Medical Center, Washington, DC); John H. Miller, MD (Children’s Hospital Los Angeles,Los Angeles, CA); Marguerite T. Parisi, MD (Children’s Hospital Los Angeles, Los Angeles, CA); and George N.Sfakianakis, MD, PhD (University of Miami School of Medicine, Miami, FL).

d . Bladder catheterization is not always nec-essary, but is suggested. In some cases,the diagnosis of obstruction may be morereliable with bladder catheterization.Older children, who are not catheterized,are requested to void completely prior tothe study.i. Sterile urethral catheterization should

be performed with the largest size Fo-ley or feeding catheter that will com-fortably pass the meatus (a 2.6 mm di-ameter catheter [French #8] for mostpatients and 1.8 mm diameter [French#6] for infants). A #8 French feedingcatheter may also be used for continualbladder drainage.

ii. Continual drainage by catheterizationof bladder is required in patients withhydroureter, vesicoureteral reflux,neurogenic bladder, a small capacitybladder, dysfunctional bladder, or pos-terior urethral valves.

iii. The diuretic effect can be assessed bycomparing the volume of urine ex-creted during the dynamic phase andthe volume of urine excreted duringthe diuretic phase.

e. The patient is usually hydrated intra-venously (10–15 ml/kg of D5 0.22% NS forunder 1 yr of age and D5 0.45% NS for over1 yr of age) for thirty min prior to adminis-tering the diuretic. The slow administra-tion of fluid is continued during the re-mainder of the study.

f. If the rate of urine flow is low during hy-dration, a larger amount of fluid (up to 40ml/kg) can be administered.

g. Some laboratories do not use intravenoushydration or catheter bladder drainage forthe initial evaluation (particularly in olderchildren) so that kidneys can be evaluatedwithout intervention.

B. Information Pertinent to Performing theProcedure1 . A prenatal history of urinary tract obstruction,

history of prior surgery to the urinary tractand congenital urinary abnormalities (duplexsystems, renal fusion, etc.) are important foraccurate interpretation of the study.

2 . The review of available past radiographic, ul-trasound and radionuclide studies adds to theaccuracy of interpretation of the current study.

3. Nonlatex materials should be used in patientsprone to latex allergy (e.g. congenital spinaldefects and chronic urethral catheterization).

4. An allergy to sulfa drugs may prevent usageof furosemide (cross reactivity between sulfaand furosemide) in a small percentage of pa-tients. Urethral anesthesia with xylocaineshould not be used in patients with an allergichistory to lidocaine or its derivatives.

C. Precautions1. The examination table is covered with plastic-

lined absorbent paper to contain spilled tracerand reduce contamination of the table duringdrainage and catheterization.

2. Gentle catheterization by a qualified individ-ual can prevent an overly traumatic andpainful experience and results in better coop-eration during follow-up examinations.

3. Slow, deep breathing and a gentle forwardmotion of the catheter should be used to relaxthe spastic external sphincter.

4. An application of urethral anesthesia (3 to 5ml of lidocaine jelly) in the male urethra 2 to 5min before catheterization helps decrease thepatient’s discomfort.

5. A Foley balloon is only inflated after catheterand its balloon are confirmed to be in thebladder. Urine return can be appreciated withballoon still positioned in the posterior ure-thra. The balloon must be deflated prior to re-moval from the patient’s bladder. When afeeding tube is used for bladder drainage,premeasurement of catheter length may pre-vent excessive instillation.

6. Caution should be observed with posturalchanges because of possible diuresis-inducedhypotension.

7. Sudden abdominal or flank pain can ariseduring acute distension of the pelvicalycealsystem in some patients.

8. There is a small risk of catheter-inducedtrauma and infection.

D. Radiopharmaceuticals1. Technetium-99m diethylene triamine pen-

taacetic acid (Tc-99m DTPA) is a glomerularagent. The biological half life is under 2.5 hr.95% of the administered dose is cleared by24 hr.

2. Tc-99m mercaptoacetyltriglycine (Tc-99mMAG3) is cleared by tubular secretion. Afterabout three hr, 90% of the injected dose can berecovered in the urine.

3. Tc-99m MAG3 has a high initial renal uptake,providing high kidney/background ratioswith good temporal resolution. It is recom-mended for neonatal renography and for vi-sualization of kidneys in patients with com-promised renal function.

160 • PEDIATRIC DIURETIC RENOGRAPHY

4. Iodine-131 orthoiodohippurate (OIH) (Hip-puran) is cleared by tubular excretion (80%)and glomerular filtration (20%) with ninetypercent clearance in the first pass through thekidney. The patient must be premedicatedwith several drops of potassium iodide oralsolution (SSKI).

5. The minimal administered activity for Tc-99mDTPA is about 20 MBq (0.5 mCi). The maxi-mum administered activity for Tc-99m DTPAis about 375–750 MBq (10–20 mCi) inteenagers who weigh over 70 kg.

6. The minimal administered activity for Tc-99mMAG3 is about 20 MBq (0.5 mCi). The maxi-mum administered activity for Tc-99m MAG3is about 375–750 MBq (10–20 mCi) inteenagers who weigh over 70 kg.

7. The minimal administered activity for I-131-OIH is about 1.0 MBq (0.025 mCi). The maxi-mum administered activity for I-131-OIH isabout 7 MBq (0.2 mCi).

E. Interventions1. The dose of furosemide (Lasix) is 1.0 mg/kg

with a usual maximum dose of 40 mg. Ahigher diuretic dose may be necessary in casesof severe renal failure.

2. There are two validated, but different ap-proaches for the time of injection of the di-uretic furosemide (F).a. In the method endorsed by the American

Society of Fetal Urology, the diuretic is in-

jected at 20 min or later after the radio-pharmaceutical (F + 20 or later) when therenal pelvis and ureter become maximallydistended in hydronephrosis and hy-droureter respectively. Maximal disten-sion is usually determined by visual in-spection of the images.

b. In the method developed in Europe, the di-uretic is injected 15 min prior to the injec-tion of the radiopharmaceutical (F–15) andimaging is continued for thirty min afterthe injection of the radiopharmaceutical.

F. Image Acquisition1 . The preliminary study is a dynamic renal scan

with the patient supine with his/her back tothe camera and acquisition for 20 to 30 min asserial 15 to 30 sec images (64 x 64 or 128 x 128matrix format). After the first few min, 30 to 60sec images may be acquired. This format can beused for the pre-diuretic phase of F + 20 orlater, or F–15 acquisition.

2. For the diuretic phase, the supine positionpermits the least motion and is recommendedfor infants and most children. The sitting po-sition is occasionally necessary but can resultin motion, even in the most cooperative child.

3. The diuretic effect usually begins within 1 to 2min after the administration of the diuretic.

4. For the diuretic phase of F + 20 or later, con-tinuous computer and analog acquisitions arebegun one to two min prior to the administra-

SOCIETY OF NUCLEAR MEDICINE PROCEDURE GUIDELINES MANUAL JUNE 2002 • 161

Radiation Dosimetry in Children*(5 year old)

Tc-99m DTPA 3.2 – 4.2 0.086 0.012bladder wall

(0.08 – 0.12) (0.32) (0.044)Tc-99m MAG3 3.2 – 4.2 0.17 0.015

bladder wall(0.08 – 0.12) (0.63) (0.056)

I-131 OIH 0.08 – 0.12 1.7 0.12bladder wall

(0.002 – 0.004) (6.3) (0.44)

Radiopharmaceutical Effective Dose+

mSv (rem)

Organ Receiving the L a r g e s t Radiation Dose+

mGy ( r a d )

Administered Activity

M B q / k g( m C i / k g )

*Treves ST. Pediatric Nuclear Medicine. 2nd Edition. Springer-Verlay, 1995, pp. 567-569.+Per MBq (per mCi)

tion of the diuretic (the baseline phase) andfor the rest of the study.

5. The computer is set to record 15 to 60 secframes for the baseline phase and for the ad-ditional 30 min with a 64 x 64 or 128 x 128 ma-trix format.

G. Processing1. From the dynamic renal study, careful evalu-

ation of the parenchymal phase reveals renalfunction, size and position. Cortical transittime and dilatation of the collecting systemare examined on the excretory phase.

2. Baseline images of the diuretic phase are usedfor the assessment of the diuretic effect.

3. Cinematic viewing of the diuretic phase as-sesses patient movement. If there is consider-able patient motion, regions of interestaround the collecting systems of individualframes will have to be compared at varioustime intervals of the study to assess drainage.

4. Regions of interest are drawn around the di-lated pelvicalyceal system for curve analysisand calculation of the T 1/2. One to two back-ground regions can also be drawn. The readeris referred to a standardized technique of the“well-tempered” diuretic renogram.

5. The diuretic half-time is the time at which thetime-activity curve decreases to half of itsmaximal activity.

6. Residual activity can be reported by estimat-ing the percentage of the initial tracer activitythat remains at 30 min after the injection of theradiopharmaceutical.

H. Interpretation Criteria1. The diuretic effect usually begins within 1 to 2

min after the administration of the diuretic.2. In absence of obstruction, there is rapid and

almost complete washout of the radiotracer.3. Obstructed systems can result in delayed

drainage from the collecting system. Theamount of activity proximal to the obstructioncan also increase in time.

4 . With the injection of the diuretic after the ra-diopharmaceutical (F + 20 or later), a T 1/2 l e s sthan 10 min usually means the absence of ob-struction, where a T 1/2 greater than 20 minidentifies obstruction. The T 1/2 with a valuebetween 10 and 20 min is an equivocal result.However, some observers consider T 1/2 of 10to 15 min as probably normal.

5. With the injection of the diuretic prior to theradiopharmaceutical (F–15), the T 1/2 greaterthan 20 min is compatible with obstruction.

6. The shape of the resulting time activity curves

of the washout study has been used for differ-entiation of stasis from obstruction.

I. Reporting1. The procedure, date of the study, amount and

route of administration of the radiopharma-ceutical, and previous study for comparisonare included.

2 . The history includes symptoms and/or di-a g n o s i s .

3. The technique includes catheter size and typeif implemented, amount and kind of i.v. fluidif administered, the imaging sequence, theamount and time of diuretic administration,and the urine volumes pre- and post-diureticif measured.

4. The findings may include renal perfusion,split renal function, progression of activity,and the T 1/2 of collecting system emptyingpost-diuretic.

J. Quality ControlThere are no issues of quality control.

K. Sources of Error1. Infiltration of the radiopharmaceutical or di-

uretic may invalidate the results.2. Insufficient hydration can result in delayed

uptake and excretion, simulating poor func-tion, or demonstrate a normal response in thepresence of significant obstruction.

3. If the diuretic is administered prior to themaximum distension of the collecting system,the response may not reflect the true physio-logic state.

4 . Poor renal function from prolonged severe ob-struction can result in slow tracer accumula-tion in the dilated collecting system and resultin difficult interpretation of the diuretic phase.

5. With severe compromise of function (lessthan 20%), the diuretic response tofurosemide (a tubular effect) may be difficultto evaluate when using Tc-99m DTPA, aglomerular agent.

6 . A large, unobstructed collecting system withrelatively good renal function can exhibit slowdrainage of the radiotracer (prolonged T 1/2) .

7. When the obstruction is at both pelvicalycealand ureterovesical junctions, it may be diffi-cult to detect the ureterovesical junction ob-struction. A repeat evaluation may need to beperformed following the surgical correctionof the ureteropelvic junction obstruction.

8 . Patient movement may invalidate curvea n a l y s i s .

9. Urinary systems considered normal on thedynamic study should not be evaluated fordrainage. A prolonged T 1/2 can be obtained

162 • PEDIATRIC DIURETIC RENOGRAPHY

because of the relatively small amount ofresidual activity in the collecting system to re-spond to the diuretic challenge.

V. Issues Requiring Further Clarification

A. The calculation method of the diuretic half-timeis variable, but a standardized technique is avail-able in the literature.

B. The curve analysis has been questioned becauseof poor correlation with pressure perfusion stud-ies in children.

C. The results of alternative method of simultane-ous injection of the radiopharmaceutical and di-uretic remain to be validated.

D. Guidelines for doses of Lasix above usual maxi-mums.

VI. Concise Bibliography

Conway JJ. Radionuclide cystography. In: Tauxe WN,Dubovsky EV, eds. Nuclear Medicine in ClinicalUrology and Nephrology. East Norwalk, CT: Apple-ton, Century & Crofts; 1985:305–320.

Conway JJ. “Well-tempered” diuresis renography: itshistorical development, physiological and technicalpitfalls, and standardized technique protocol. SemNucl Med 1992;22:74–84.

Foda MM, Garfield CT, Matzinger M, et al. A prospec-tive randomized trial comparing 2 diuresis renog-raphy techniques for evaluation of suspected upperurinary tract obstruction in children. J Urol1998;159:1691–1693.

Kass EJ, Majd M. Evaluation and management of theupper urinary tract obstruction in infancy andchildhood. Urol Clin NA 1985;12:122–141.

Meller ST, Eckstein HB. Renal scintigraphy: quantitativeassessment of upper urinary tract dilatation in chil-d r e n . J Pediatr Surg 1 9 8 1 ; 1 6 : 1 2 3 – 1 2 6 .

Senac MO, Miller JH, Stanley P. Evaluation of obstruc-tive uropathy in children: radionuclide renographyversus the Whitaker test. AJR 1984;143:11–15.

Wackman J, Brewer E, Gelfand MJ, et al. Low gradepelviureteric obstruction with normal diureticrenography. Br J Urol 1986;58:364–367.

Whitaker RH, Buxton TMS. A comparison of pressureflow studies and renography in equivocal uppertract obstruction. J Urol 1 9 8 6 ; 1 3 1 : 4 4 6 – 4 4 9 .

VIII. Disclaimer

The Society of Nuclear Medicine has written andapproved guidelines to promote the cost-effectiveuse of high quality nuclear medicine procedures.These generic recommendations cannot be appliedto all patients in all practice settings. The guidelinesshould not be deemed inclusive of all proper proce-dures or exclusive of other procedures reasonablydirected to obtaining the same results. The spec-trum of patients seen in a specialized practice set-ting may be quite different than the spectrum of pa-tients seen in a more general practice setting. Theappropriateness of a procedure will depend in parton the prevalence of disease in the patient popula-tion. In addition, the resources available to care forpatients may vary greatly from one medical facilityto another. For these reasons, guidelines cannot berigidly applied.

Advances in medicine occur at a rapid rate. Thedate of a guideline should always be considered indetermining its current applicability.

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