Saudi Journal of Kidney Diseases and Transplantation

ORIGINAL ARTICLE
Year
: 2011  |  Volume : 22  |  Issue : 3  |  Page : 488--491

Accuracy of cystosonography in the diagnosis of vesicourethral reflux in children


Hasan Otukesh1, Rozita Hoseini1, Ashkan Heshmatzade Behzadi2, Mahsa Mehran2, Ali Tabbaroki3, Behnaz Khamesan3, Reza Farjad3, Violet Amirjalai3,  
1 Pediatric Nephrology, Labafi-Nejad Hospital, Tehran, Iran
2 Medical Faculty Research Center, Tehran, Iran
3 Tehran University of Medical Science, Tehran, Iran

Correspondence Address:
Ashkan Heshmatzade Behzadi
Medical Faculty Research Center, Tehran University of Medical Science, Tehran
Iran

Abstract

Vesicoureteric reflux (VUR) is found in 1% of all children and in 30%-50% of those with urinary tract infection. Furthermore, VUR in childhood is the main reason for pyelonephritis, hypertension and chronic kidney disease. Recently, a variety of procedures with low radiation have been recommended for diagnosis of VUR. Therefore, in this study, voiding urosonography (VUS) or cystosonography was performed for evaluation of VUR and for comparing it with radio nucleotide cystography (RNC). We studied 25 children admitted with initial diagnosis of VUR in our center in the year 2007. Simultaneously, RNC and VUS were performed for all the patients. VUR was detected in eight patients with the VUS procedure and in nine children with RNC. Another patient was diagnosed only by RNC, and two other patients by only VUS. The two methods were concordant in detection and exclusion of urinary reflux in 87% (P: 0.000, r: 0.728). Furthermore, the diagnosis of various grades of reflux by these two schemes were comparable (P: 0.0000, r: 0.724). Sensitivity and specifity of VUS was determined as 87% and 88%, respectively, with a 94% positive predictive value and a 77% negative predictive value. We conclude that VUS is a highly accurate, safe and inexpensive tool for the screening, diagnosis and follow-up of VUR.



How to cite this article:
Otukesh H, Hoseini R, Behzadi AH, Mehran M, Tabbaroki A, Khamesan B, Farjad R, Amirjalai V. Accuracy of cystosonography in the diagnosis of vesicourethral reflux in children.Saudi J Kidney Dis Transpl 2011;22:488-491


How to cite this URL:
Otukesh H, Hoseini R, Behzadi AH, Mehran M, Tabbaroki A, Khamesan B, Farjad R, Amirjalai V. Accuracy of cystosonography in the diagnosis of vesicourethral reflux in children. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2020 Jul 15 ];22:488-491
Available from: http://www.sjkdt.org/text.asp?2011/22/3/488/80485


Full Text

 Introduction



From 1990 until now, there have been several attempts for finding an efficient, practical and with less-imposing radiation technique for screening of children with different grades of vesicoureteric reflux (VUR). Upon this, sonography with echo contrast materials, which has been introduced as a routine and safe diagnostic method in some centers. [1]

Essential substances for filling up the bladder in voiding ultrasonography (VUS) are normal saline, air bubbles and radio opaque derivatives. In two different studies, air was emphasized as a validate material for accentuating the diagnosis of VUR in VUS. [2],[3] Furthermore, Haburg et al demonstrated that the combination of air and normal saline enhance the accuracy of diagnosis of all of grades of VUR. [4]

Some studies compared VUS with other methods such as radio nucleotide cystography (RNC), of which many claimed a high specificity of VUS in distinguishing a variety of VUR, particularly the transitional one (pseudo VUR).

In this study, VUS was evaluated for safety, sensitivity and specificity in the diagnosis of VUR in children referred to our center.

 Materials and Methods



We studied 25 children under the age of 15 years with first episode of urinary tract infection evaluated at the Labafai Nejad Education and Treatment Center in the year 2007. All patients suffering from acute pyelonephritis or any complication of malfunction and/or anatomical defects related to the lower urinary tract system were excluded.

RNC and VUS tests were performed sequentially on all the study patients. RNC was considered as the gold standard diagnostic method. Before performing any diagnostic tests, a negative result of urine culture in the cases should be obtained.

VUS was accomplished by using a real-time equipment (Hitachi, 7.5 MHTZ transducer) under the supervision of an expert specialist in a double-blind fashion. The echo contrast solution used was Levovist suspension, an echo contrast substance composed of glucose and air bubbles with Pamtic acid.

Initially, the kidneys, ureters and bladder were evaluated by using ultrasonography, followed by measuring the urine residue in the bladder after voiding. In the final step, 10-20 mL of normal saline with a 5 mL/kg of Levovist suspension in children and 1 mL/kg in infants were entered into the bladder by a urine catheter. The diagnostic images were obtained during the loading and unloading periods of the contrast suspension in the bladder. The different grades of reflux were classified similar to the RNC. Accordingly, grade I was considered as mild, grades II and III as moderate and grades IV and V as severe. [5]

 Statistical Analysis



All the study findings were analyzed by SPSS (Version; 14). Specifically, sensitivity and negative and positive predictive values were determined for all the outcomes obtained from both the tests. A P-value < 0.05 was set as significant.

 Results



The study patients had an average age of 4.5 years (min, 6 months; max, 13 years). Twenty percent of the patients were male and the rest were female.

VUR was found in eight cases when using RNC and in nine cases with VUS. Another patient was diagnosed only by RNC, and two other patients by only VUS. In these two cases, Di Mercapto Succynil Acid (DMSA) scan demonstrated scarring damage [Table 1].{Table 1}

VUS showed a sensitivity of 87%, a specificity of 88%, a positive predictive value of 77%, a negative predictive value (NPV) of 94%, and accuracy of 88%.

The results gathered from performing VUS and RNC were compared and a significant correlation was found (P: 0.000, r: 0.728). In addition, there was a positive correlation between various grades of reflux diagnosed by these two techniques (P: 0.000, r: 0.724).

 Discussion



VUR is one of the most common findings among children suffering from recurrent urinary tract infection. Congenital defects of the urinary tract are the main reasons for VUR. [6] The risk of fibrosis due to pyelonephritis is increased according to the severity of VUR. [7],[8],[9],[10],[11]

VUR is considered as one of the major predisposing factors for elevated blood pressure in children. In addition, VUR followed by renal fibrosis may result, gradually, in chronic renal failure in children. [12],[13],[14],[15],[16],[17]

VUS and RNC have been compared in previous studies in the literature. Meutzel et al reported that the sensitivity and specificity of VUS in comparison with RNC was 90% and 94.6%, respectively. [18] In a similar study, the specifity and sensitivity of VUS was reported as 100% and 88%, respectively. [1] In our study, all the patients with VUR diagnosed with VUS had grade I, and 40% of the cases assessed only with RNC suffering from grades I and II of VUR. [1] In our study, the NPV was 94%, being in the range of other previous studies. [8]

Accordingly, VUS at least has this capability to exclude high-grade VUR. In fact, some researchers recommend VUS as an initial test for evaluation and screening of VUR in females, for follow-up of cases and in high-risk patients, including the first degree relatives of the patients. [19]

In two studies, specifity and sensitivity of VUS as a comparison with RNC were reported as 86-100% and 88-100%, respectively, [1],[20],[21] which is in the range of our findings.

In contrast, sensitivity in VUS was lower in another study (67-79%), but specificity was 96%, similar to our study. [22]

In all these researches, there were some cases that reported the existence of VUR only with the RNC method. [20]

DMSA scan could be used to confirm the findings obtained by RNC. Two cases in our study were diagnosed only by VUS. DMSA has this ability to augment the transient VUR due to complete filling up of the urinary bladder. [1]

Although VCUG is considered a standard procedure for detecting VUR and contrast enhanced scentigraphy were introduced as a reliable imaging modality, which can be administrated in many cases. [24]

VUS and VCUG were compared. Interestingly, the range of disagreement between them was high (22%) in some studies. [25],[26] On the other hand, in some studies, the results were very close, but in case of disagreement, DMSA was performed to confirm the final result. RNC has less-invasive imaging than VCUG in the terms of exposure radiation. [26] The concordance between DMSA scan and VUS was reported to be around 85.3%. [23]

We conclude that VUS as a screening and diagnostic technique is highly useful, especially during follow-up of VUR with a low amount of exposure radiation and high accuracy.

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