Radionuclide studies in paediatric nephro-urology

doi:10.1016/S0720-048X(02)00111-0

European Journal of Radiology

Volume 43, Issue 2, August 2002, Pages 146-153

https://doi.org/10.1016/S0720-048X(02)00111-0 Get rights and content

Abstract

The main tool of radionuclide techniques applied to paediatric uro-nephrology is the quantitation of function, which is an information not easily obtained by other diagnostic modalities. The radiation burden is low. Drug sedation is only rarely needed, whatever the age of the patient. Accurate determination of glomerular filtration rate can be obtained by means of an intravenous injection of Cr-51 EDTA and one or two blood samples. Tc-99m DMSA scintigraphy is an accurate method for evaluation of regional cortical impairment during acute pyelonephritis and later on, for detection of permanent scarring. Tc-99m MAG3 renography is nowadays a well-standardized method for accurate estimation of the split renal function and of renal drainage with or without furosemide challenge. This technique is particularly indicated in uni- or bilateral uropathies with or without renal and/or ureteral dilatation. Direct and indirect radionuclide cystography are two alternative modalities for X-ray MCUG. Their relative place in the strategy of management of vesicoureteral reflux is discussed.

Introduction

The main tool of radionuclide techniques applied to paediatric uro-nephrology is the quantitation of function, which is an information not easily obtained by other diagnostic modalities. The radiation burden for all these procedures is below 1 mSv and often much lower [1]. It compares favourably to the radiation dose related to intravenous urography, computed tomography (CT) scan and VCUG. Drug sedation is only rarely needed, whatever the age of the patient. A friendly environment, an adequate attitude toward the child, a technologist well-trained for paediatric procedures and involved parents before and during the procedure generally allow good collaboration of the child during the procedure.

Section snippets

Tracer and methods

Measurement of GFR can be obtained after a bolus injection of a radioactive tracer exclusively eliminated by the glomerulus, such as Tc-99m DTPA (diethylenetriamine pentaacetic acid) or Cr-51 EDTA (ethylenediamine tetraacetic acid). It has been shown that the plasma disappearance curve of such tracer allows an accurate determination of the glomerular clearance. The drawback of this method is that it necessitates a rather large number of blood samples, in order to define accurately the plasma

Tracer and methods

The most appropriate tracer for that purpose is Tc-99m DMSA (dimercaptosuccinic acid). The tracer is taken up by the proximal tubular cells, directly from the peritubular vessels.

The technical aspects of the procedure as well as the field of application have been described in detail in an international consensus on Tc-99m DMSA scintigraphy [6] and in two recent guidelines [7], [8]. Images should be acquired 2–3 h after tracer injection. The collimator should be turned side up and the patient

Tracers and procedure

The ideal tracers for renography are those exclusively excreted by the kidney, without any retention into the renal cells. They allow estimation of two aspects of renal function: the first one is renal clearance, i.e. the capacity of the kidney to clear the tracer from the blood; the second one is excretion, or disappearance of the tracer from the kidney into the bladder. Tc-99m DTPA, filtered by the glomerulus, has been for years the most widely used tracer for that purpose. Tubular excreted

Procedure

The procedure is comparable to the X-ray micturating cystourethrography (MCUG). A tracer (generally Tc-99m colloid) is instilled in the bladder through an indwelling catheter and the entire filling phase and voiding phase are recorded. An example is given in Fig. 5.

The technical details can be found in a recent guideline [15].

Advantages

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Favourable dosimetry compared to MCUG.
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Complete recording of filling and voiding phases available, thus providing a higher sensitivity for reflux detection than with MCUG

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Radionuclide Tools in Clinical Management of Febrile UTI in Children
2020, Seminars in Nuclear Medicine
The optimal imaging strategy for febrile urinary tract infections in children is not yet satisfactorily defined, mainly because of the different clinical scenarios in which these acute illnesses are framed. This is overall true for radionuclide imaging, whose well-known advantages and weaknesses have a weight that can change according to the characteristic of the patients (age, sex, anatomical features, and clinical history). Cortical renal scan with 99mTc-dimercaptosuccinic acid, direct radionuclide cystography, and dynamic renal scan with MAG3 plus indirect radionuclide cystography should be ever taken into account whenever doubts arose during clinical evaluation, mainly looking for their right use in the right child at the right time, having the necessary flexibility in applying published guidelines, being aware of the debate still running about.
Voiding cystourethrography and <sup>99M</sup>TC-MAG3 renal scintigraphy in pediatric vesicoureteral reflux: what is the role of indirect cystography?
2019, Journal of Pediatric Urology
Citation Excerpt :
Voiding cystourethrography is an invasive examination that carries a risk of radiation exposure and iatrogenic UTI, so many efforts have been and are being made to develop an equally informative but non-invasive diagnostic technique for VUR in children [17]. Dynamic renal (using technetiated tracers as 99mTc-DTPA or 99mTc-MAG3) scintigraphy with indirect cystography has been developed and used in clinical practice as a valid alternative to VCUG [18]. This method requires the intravenous injection of a radiolabeled agent that is extracted by the kidney and proceeds into the urinary system and can be tracked with a gamma camera.
Primary vesicoureteral reflux (VUR) is the most common urological anomaly in children. Voiding cystourethrography (VCUG) is considered the reference standard for the diagnosis of VUR. Even if it is a secure and standardized technique, it is still an invasive method, hence, the effort to find an alternative method to diagnose VUR. The aim of the study is to evaluate the diagnostic accuracy of ^99mTC-MAG3 scintigraphy with indirect cystography in detecting VUR and to estimate any interobserver variability in ^99mTC-MAG3 scintigraphy interpretation.
The authors retrospectively reviewed all the pediatric patients who underwent both a VCUG and a ^99mTC-MAG3 renal scintigraphy at the study institution between 2012 and 2016.
A total of 86 children (and 168 renal units) were included. MAG3 scan revealed a sensitivity of 54% and a specificity of 90% with positive predictive value of 79% and negative predictive value of 73%. Each MAG3 scintigraphy was then independently and blindly evaluated by a pediatric urologist and two nuclear physicians. After revision, the concordance between VCUG and MAG3 in reflux cases dropped from 54% to 27% (on average), and the reviewers reclassified most examinations as non-conclusive.
^99mTC-MAG3 renal scintigraphy with indirect cystography showed low sensitivity in detecting VUR of any grade and cannot, therefore, be proposed as completely alternative to VCUG in the diagnosis of VUR. Moreover, MAG3 scintigraphy interpretation for the diagnosis of VUR has a very high interobserver variability, mostly because of the lack of a correct and complete voiding phase.
Standardization of pediatric uroradiological terms: A multidisciplinary European glossary
2017, Journal of Pediatric Urology
To promote the standardization of nephro-uroradiological terms used in children, the European Society of Pediatric Radiology uroradiology taskforce wrote a detailed glossary. This work has been subsequently submitted to European experts in pediatric urology and nephrology for discussion and acceptance to improve the quality of radiological reports and communication among different clinicians involved in pediatric urology and nephrology.
Renal pelvis reduction during dismembered pyeloplasty: Is it necessary?
2013, Journal of Pediatric Urology
To compare treatment results in patients who underwent pyeloplasty with and without pelvic reduction for ureteropelvic junction obstruction (UPJO).
This randomized prospective study involved 40 patients, all diagnosed with unilateral UPJO; 20 each were randomly selected to undergo open dismembered pyeloplasty with pelvic reduction (group A) or pelvis-sparing pyeloplasty (group B). Patients were evaluated with ultrasound and DPTA renography scans 6 months postoperatively. Mean follow-up was 9 months.
The mean age in group B was 5.71 ± 6.36 years; in group A it was 4.81 ± 6.78 years. There was a decrease in mean anteroposterior renal pelvic diameter (from 49.9 to 26.35 ± 0.949 mm in A and 50.9 to 30.8 ± 1.556 mm in B) with improvement of split renal function (from 39 ± 22.47% to 42.4 ± 22.13% in A and 34.92 ± 16.79% to 38.8 ± 19.66% in B), glomerular filtration rate (from 37.25 ± 15.33 to 41.7 ± 19.34 ml/min in A and 31.3 ± 18.50 to 38.1 ± 23.23 ml/min in B) and draining curves on the 6-month scans, but without any significant difference between groups (p > 0.05). Two cases in group A and three in group B needed redo pyeloplasty, but without any significant difference in failure rate.
Excision of the pelvis is not necessary in dismembered pyeloplasty procedures. We had similar surgical outcomes for patients with or without pelvis reduction.
Indirect radionuclide cystography coupled to renal cortical scintigraphy and vesico-renal reflux detection in infants and children with pyelonephritis
2012, Medecine Nucleaire
Le reflux vésico-urétéro-rénal (RVR) est étroitement lié aux infections des voies urinaires hautes. Non traité, il peut se compliquer d’une néphropathie de reflux avec ses conséquences : hypertension artérielle et insuffisance rénale. L’enjeu est donc de pouvoir assurer un diagnostic précoce et fiable du RVR. Notre étude a été menée rétrospectivement sur 33 enfants présentant une pyélonéphrite aiguë (PNA), ayant bénéficié d’une cystographie isotopique indirecte au MAG3-99mTc (CII) couplée le même jour à une scintigraphie rénale corticale au DMSA-99mTc, et d’une cystographie radiologique directe (CRD). Nous avons analysé l’apport de la CII comparativement à l’examen de référence qu’est la CRD, la scintigraphie rénale corticale étant l’un des critères objectifs de jugement. L’analyse principale a donc consisté à évaluer l’existence ou l’absence d’un RVR homolatéral à une encoche corticale à la scintigraphie au DMSA-99mTc, détecté par la CII et par la CRD. La CII détecte un RVR homolatéral chez 52 % des patients et la CRD 33 % ; en considérant chaque rein lésé, la CII détecte un RVR homolatéral dans 59 % des reins contre 38 % pour la CRD (p < 0,05). Dans ce dernier cas, la différence entre les résultats obtenus avec la CII et la CRD est donc statistiquement significative. La CII, examen physiologique, non intrusif et peu irradiant, démontre ici une bonne capacité de détection des reflux vésico-urétéro-rénaux chez des patients à haut risque de complications rénales ultérieures. Couplée à une étude fonctionnelle rénale et urétérale, la CII présente des atouts non négligeables par rapport à la CRD.
Vesico-uretero-renal reflux (VRR) and urinary tract infection are closely linked. Without any treatment, reflux nephropathy, hypertension and renal dysfunction are very often encountered. That is why a precocious and reliable diagnosis of RVR should be made. Our retrospective study included 33 infants and children suffering from acute pyelonephritis (APN). They were explored by both 99mTc-MAG3 indirect isotopic cystography (IIC), 99mTc-DMSA cortical renal scintigraphy performed on the same day, and radiological retrograde cystography (RRC). A VRR was expected on the same side than the pyelonephritic kidney. Results from IIC versus RRC and versus renal cortical acute pyelonephritis lesions, which were proved by the “gold standard” DMSA scan, were obtained. IIC detected a same-sided VRR in 52% and CRR in 33% of our patients. Some of them had bilateral lesions. IIC detected an homolateral VRR in 59% instead of 38% with RRC (P < 0.05). IIC is a physiological noninvasive examination with a convenient sensitivity and dosimetry to search a VRR. Moreover, it gives in the same time interesting functional information on the kidneys and the urinary tract. Each of these characteristics can be favorably compared with RRC.
Postnatal evaluation and management of fetal pyelectasis on prenatal ultrasound
2011, Journal de Radiologie
La dilatation des voies urinaires est l’anomalie fœtale la plus fréquente. Les critères diagnostiques échographiques sont précis : nature des structures anatomiques dilatées, ampleur de la dilatation, aspect échographique des reins, quantité de liquide amniotique. L’échographie permet aussi de préciser s’il s’agit d’une anomalie isolée ou non, ce qui est important dans la prise en charge et le pronostic de la grossesse. La mise au point postnatale repose a priori sur une confirmation échographique néonatale. La prise en charge sera ensuite fonction du diagnostic suggéré. Dans les cas où l’une des échographies postnatales est évocatrice de reflux vésico-urétéral, une cystographie sera réalisée. Dans les cas d’uropathies obstructives ou malformatives complexes (duplications), une IRM sera réalisée vers l’âge de six mois afin de préciser exactement l’anatomie de l’arbre urinaire. La scintigraphie réalisée dans la plupart des cas permet d’évaluer la fonction rénale isolée. Le suivi échographique est important pour apprécier la croissance rénale, l’évolution de la dilatation et l’aspect du parenchyme. Le suivi fonctionnel se fera plutôt par scintigraphie. Cette prise en charge attentive est préconisée en vue de prévenir les complications et la détérioration progressive de la fonction rénale.
Fetal pyelectasis is the most frequently encountered anomaly on prenatal ultrasound. The ultrasound diagnostic criteria are well established: nature of dilated structures, degree of dilatation, ultrasound appearance of the kidneys, volume of amniotic fluid. Ultrasound can also determine if the anomaly is isolated or not, which is important for the management and prognosis of the pregnancy. Ultrasound is the initial postnatal study to evaluate the urinary tract. Further management will be based on suspected diagnosis. In cases of suspected vesico-ureteral reflux, VCUG is performed. In cases of obstructive uropathy or complex malformation (duplications), MRI is performed at 6 months of age to further define the anatomy of the urinary tract. Radionuclide renogram, performed in most cases, allows evaluation of split renal function. Follow-up ultrasound is important to monitor renal development, urinary tract dilatation and appearance of the renal parenchyma. Functional follow-up is assured by radionucline renography. This comprehensive follow-up is recommended to prevent complications and progressive loss of renal function.

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Radionuclide studies in paediatric nephro-urology

Abstract

Introduction

Section snippets

Tracer and methods

Tracer and methods

Tracers and procedure

Procedure

Advantages

Semin. Nucl. Med.

Semin. Nucl. Med.

J. Urol.

J. Urol.

An update of radiopharmaceutical schedules in children

Nucl. Med. Commun.

Report of the radionuclides in nephrourology committee on renal clearance

J. Nucl. Med.

Guideline for glomerular filtration in children

Eur. J. Nucl. Med.

Estimation of glomerular filtration rate in infants and children using a simple plasma sample method

J. Nucl. Med.

Estimation of normal 51Cr-EDTA clearance in children

Eur. J. Nucl. Med.