MAGNETIC
RESONANCE IN DIAGNOSIS OF URETEROCELE
(
Download pdf )
HUMBERTO DO NASCIMENTO, MAURÍCIO HACHUL, ANTÔNIO MACEDO JR
Division of Urology, Federal University of São Paulo, UNIFESP, São Paulo, SP, Brazil
ABSTRACT
Ultrasonography is the main non-invasive technique for screening of ureterocele, but presents some difficulties for its diagnosis. Other supplementary diagnostic methods have the disadvantage of being invasive or using ionizing radiation. Magnetic resonance (MR) has a high sensitivity for diagnosing urinary tract malformations in adults and children. We report one case of ureterocele in a 1-year old child with the purpose of presenting its diagnosis through MR
Key
words: ureter; infant; ureterocele; diagnosis; magnetic resonance
Int Braz J Urol. 2003; 29: 248-50
INTRODUCTION
The study of urinary tract anatomy and pathology in pediatric patients can be obtained by a number of imaging methods. Ultrasonography represents the main screening technique, but rarely it enables an accurate analysis of the entire urinary tract. Other diagnostic methods such as voiding urethrocystography, excretory urography, computerized tomography, ascending pyelography, cystoscopy and renal scintigraphy complement the diagnosis, but have the disadvantage of exposing the patient to invasive procedures or to ionizing radiation. Uro-resonance has a high sensibility for the diagnosis of urinary tract malformations in adults and children (1), and can be performed by 2 distinct techniques: one that uses images of the body’s static fluids (the technique employed in this case) and the other using a paramagnetic contrast medium associated with a diuretic. The technique that employs paramagnetic contrast and diuretic, do not require the dilatation of the excretory system, presenting a better contrast in image and a higher sensitivity.
CASE REPORT
We
studied a female, 1-year old patient, with a clinical history of recurrent
urinary tract infection since birth. Ultrasonography evidenced severe
bilateral pyelocaliceal dilatation and left pyelocaliceal duplication,
with an image inside the bladder suggesting ureterocele. Voiding urethrocystography
demonstrated absence of vesicoureteral reflux, excretory urography showed
functional exclusion of the right kidney, and scintigraphy with DMSA showed
9% of function on the right side. The diagnosis of left ureterocele was
confirmed by uro-resonance (Figure-1). An endoscopic punction of the ureterocele
was performed without intercurrences and the child evolved with clearing
of the ipsilateral renal unit.
COMMENTS
Ultrasonography
is a good examination for viewing pyelocaliceal duplicity; however, it
is limited for a complete study of the ureter. In the dilated urinary
tract, the ureterovesical junction can be easily localized by ultrasound,
but it is impaired in ectopic or slightly dilated ureters. Computerized
tomography can be employed as an alternative diagnostic technical modality;
however, the exposure to high doses of radiation restricts its use in
pediatrics (2).
Uro-resonance can be employed in cases of
dilated ureters and functional exclusion, because it provides an adequate
visualization of the entire urinary tract. It defines the morphology and
the thickness of the renal parenchyma, and additionally it provides an
indirect analysis of renal function concerning urinary excretion. It is
a rapid technique, which contributes substantially to the diagnosis of
ureterocele, since its performance does not depend on the patient’s
respiratory rate and offers images with high definition and quality.
Recently, the utilization of uro-resonance
in the prenatal diagnosis of ureterocele has significantly decreased morbidity,
potential lesions due to repeated urinary infections, and the need of
secondary surgical interventions (3). Magnetic resonance can be an alternative
in relation to conventional diagnostic techniques, since it does not expose
the patient to ionizing radiation or the use of an iodinated intravenous
contrast medium.
Uro-resonance images are acquired in weighted
sequences in T2, in frontal (coronal) or sagital sections, presenting
very prolonged echo time and repetition time, promoting an adequate analysis
of the urinary tract’s morphology. Uro-resonance weighted in T2
can be performed with administration of furosemide before the examination,
but the identification of urinary tract can be impaired if those are no
dilated. Adding a paramagnetic contrast medium (gadolinium), favors the
adequate study of kidneys and urinary tract, even in the absence of dilatation,
promoting a more sensitive and more specific diagnosis.
REFERENCES
- Borthne A, Pierre-Jerome C, Nordshus T, Reiseter T: MR urography in children: current status and future development. Eur Radiol. 2002; 10: 503-11.
- Staatz G, Rohrmann D: Magnetic resonance urography in children: evaluation of suspected ureteral ectopia in diplex systems. J Urol. 2002; 166: 2346-50.
- Upadhyay J, Bolduc S, Braga L, Farhat W, Bagli DF, McLorie GA, et al: Impact of prenatal diagnosis on the morbidity associated with ureterocele management. J Urol. 2002; 167: 2560-5.
______________________
Received: January 8, 2003
Accepted after revision: May 6, 2003
_______________________
Correspondence address:
Dr. Humberto do Nascimento
Disciplina de Urologia, UNIFESP
Rua Napoleão de Barros, 715 – 2o andar
São Paulo, SP, 04024-002, Brazil
E-mail: humbertojr1@aol.com