Imaging and the first urinary infection in children. Respective role of each test during the initial evaluation apropos of 122 cases

122 pediatric patients with a first urinary tract infection underwent renal ultrasonography (US) and voiding cystourethrography (VCUG) to evaluate the usefulness of this association. The US was always the first examination undertaken, its sensitivity seems to be very good in detecting renal abnormalities. The major finding on the VCUG was the vesico-ureteral reflux: 25% of cases. When the sonogram and the VCUG are normal, 60% of cases, excretory urography is not considered necessary.     

Radiographic evaluation of children with urinary tract infections

Any child with urinary tract infection needs a radiologic work-up to determine his or her potential risk for sustaining renal damage. VCUG, either fluoroscopic or isotopic, should always be performed. If the infection responds to treatment and the VCUG is normal, ultrasonography should be performed. However, when the VCUG demonstrates reflux, radionuclide scan or, less preferably, excretory urography is indicated to assess renal parenchymal damage and function. When a urinary tract infection does not respond to treatment, ultrasonography or CT scan should be obtained to check for renal or perirenal abscess. If the findings are normal, medical treatment to control the infection is indicated. Further evaluation of the urinary tract may be temporarily delayed. In an infant with urinary tract infection and sepsis, renal ultrasonography is indicated. If the sonogram is normal, VCUG can be delayed until the infant responds to medical treatment. If ultrasonography is abnormal, VCUG and radionuclide scan such as 99mtechnetium DTPA with furosemide to evaluate gross morphology and function should be obtained. Complicated medical problems, such as urinary tract infection in combination with a history of intravenous drug abuse or with findings of fever and a mass, deserve immediate evaluation with ultrasonography or CT scan. A patient with fever of unknown origin and normal urine culture should have a radionuclide scan using gallium67 citrate or indium111-tagged leukocytes, both of which can demonstrate an extrarenal or unsuspected intrarenal site of infection. A variety of imaging modalities are available today for investigating urinary tract infections in the pediatric patient. Used intelligently, singly or in combination, these examinations provide information for the clinical evaluation as well as short-and long-term management of infections, their causes and complication, and their effect on renal function.     

Importance of echography in the study of urinary tract infections in childhood

One hundred and twenty-one children with a clinical diagnosis of urinary tract infection (UTI) were examined with sonography (US), ivp and voiding cystourethrography (VCUG). In 84 patients neither US nor radiographic findings were found of pathological significance; in 16 out of 37 patients with pathological findings both US and ivp were negative, whereas VCUG was decisive for a correct diagnosis. VCUG demonstrated vesicoureteric reflux in 10 patients, posterior urethral valves in 1 patient, and small diverticula of the urinary bladder in 5 patients. In 17 of the remaining 21 cases, there was agreement between US and urographic findings, whereas in 4 cases US provided us with false positives, with images of apparent renal scarring. The mistake was caused by an incorrect US detection of unilateral duplication of the collecting systems. The authors conclude by stressing the importance of ivp in the evaluation of urinary tract infections in children, even in case of negative VCUG and US results, and suggest comparing US measurements of renal length to the distance between three contiguous lumbar vertebrae in order to obtain measurements comparable to body growth.     

Diagnosis by imaging in renal and urinary tract malformations. Comparison of echography and traditional radiological studies

The diagnostic sensitivity of Ultrasound (US) was studied in 142 children with suspected kidney and urinary tract malformations. According to the clinical tests performed the patients underwent excretory urography (EU) and/or voiding cystouretrography (VCU); the results were compared to US findings. In the 75 patients with malformations, US proved to be extremely sensitive in abdominal renal ectopies, in "horseshoe" kidney, and in congenital obstructions of the ureteropelvic and vesico-ureteral junctions. US showed a higher sensitivity than EU in identifying multicystic kidney and in most cases of hypodysplasia. On the other hand, VCU was more accurate in vesico-ureteral reflux studies; US should thus be used in the follow-up of the patients undergoing medical therapy. EU must however be considered as the most important tool in the evaluation of early renal injuries and their possible development.     

Ureteral dilatation in children with febrile urinary tract infection or bacteriuria

Little information is available on the relationship between urinary infection in children and infants, with or without vesicoureteral reflux, and dilatation of the urinary tract. The purpose of this study was to determine the effects of infection and reflux on the diameter of the ureter at excretory urography in children with acute, febrile urinary tract infections and in infants with bacteriuria found at screening. Standardized measurements of ureteral diameter were obtained for 79 children (2 months to 6 years old) with urinary tract infections and for 45 infants with bacteriuria. Patients with urinary tract obstruction or malformations were excluded. Seventy-one children with febrile urinary tract infection had ureteral visualization that allowed measurements. Ureteral diameter in this group was significantly wider than in a reference group, and 42 children (59%) had ureteral diameters that were more than 2 standard deviations above the normal mean. Ureteral diameter at excretory urography increased with increasing grades of reflux, but dilatation occurred also in the absence of reflux. Twenty-two of the 45 infants in the group with bacteriuria had sufficient ureteral visualization for measurements. The ureters in this group were wider than in the reference group, and eight infants had ureteral diameters that were more than 2 standard deviations above the normal mean. We conclude that ureteral dilatation is a common effect of acute urinary tract infection and bacteriuria in children.     

Sonography as a substitute for excretory urography in children with urinary tract infection

The possibility was explored of substituting renal sonography for excretory urography in children with urinary tract infection. Seventy-one patients were studied prospectively with voiding cystourethrography, sonography, and excretory urography; each examination was reviewed independently and without knowledge of the results of the others. Compared with urography the sensitivity and specificity of sonography was 100% and 51%, respectively, provided sonograms were of good technical quality. In a few instances, however, focal renal parenchymal scars were clearly seen only on urography. The findings suggest that in the absence of vesicoureteral reflux children with urinary tract infection should be studied with sonography. No further study is needed if a good-quality sonogram is within normal limits. In the presence of vesicoureteral reflux, however, or a suspicious or abnormal sonogram, excretory urography appears to be still necessary, at least at the present level of knowledge and technical expertise.     

Vesicoureteral reflux grading in contrast-enhanced voiding urosonography

INTRODUCTION AND OBJECTIVE: The sonographic diagnosis of vesicoureteral reflux (VUR) with contrast-enhanced voiding urosonography (VUS) is gradually increasing. With the introduction of VUS as part of the routine diagnostic imaging modalities for reflux significant reduction in the number of voiding cystourethrographies (VCUG) was possible. Like in VCUG grading of reflux in VUS is becoming more and more relevant. The aim of this study was to find out if there are any sonomorphologic and sonomorphometric parameters that would correlate with reflux grading in VCUG. Furthermore, a reflux grading system for VUS is proposed and the correlation of this grading system tested with the one of VCUG. PATIENTS AND METHODS: In one examination session a total of 186 children underwent both VUS and VCUG of whom 89 had VUR in at least one and the same kidney-ureter-unit (KUU) in both diagnostic imagings. The VUS was conducted with intravesical administration of ultrasound (US) contrast medium (Levovist). Ureteral and pelvicalyceal dilatations before administration of US contrast medium and during reflux were documented. Renal pelvic diameter was measured. The density of microbubbles in the renal pelves was scored on a scale of 1-3 (low to high). A grading system for reflux in VUS was set up similar to the international reflux grading system for VCUG with the addition of one more differentiation parameter, namely whether the reflux was primarily in a dilated or non-dilated urinary tract. Reflux grades in VUS were compared with those in VCUG. RESULTS: None of the sonomorphologic and sonomorphometric parameters demonstrated any clear cut finding that would simplify reflux grading in VUS. In 59/95 (62%) KUUs the reflux grades were the same in both examinations. In 10/95 (11%) and 26/95 (27%) KUUs, the reflux was graded lower or higher, respectively, in VUS than in VCUG. Fifty-seven percent were in a primarily dilated system and the remaining 43% in a non-dilated one. Seventy percent of KUUs diagnosed as having grade I reflux in VCUG, showed as grade 2 on VUS. CONCLUSIONS: A reflux grading system similar to the one used in VCUG can be applied in VUS. Adding the parameter reflux into a primarily dilated or non-dilated ureter and/or pelvicalyceal system may bring in a further dimension to the reflux grading in VUS. Most of the refluxes labelled as grade I in VCUG are actually grade II or higher.     

Contrast-enhanced voiding US for grading of reflux in adult patients prior to antireflux ureteral implantation

PURPOSE: To prospectively assess contrast material-enhanced voiding ultrasonography (US) for grading of vesicoureteral reflux (VUR) and to compare results with those of voiding cystourethrography (VCUG) in adult patients undergoing antireflux ureteral implantation. MATERIALS AND METHODS: Thirty-seven consecutive adult patients who had undergone renal transplantation with Politano-Leadbetter (18 patients) or Lich-Gregoire (19 patients) technique were included on the basis of previous urinary tract infections (UTIs) and time elapsed after renal transplantation. Exclusion criterion was current UTI. US was performed by one of two sonologists with injection of saline and microbubble suspension and was recorded on videotape. Sonologists assigned VUR diagnosis in consensus after videotape review. VCUG was performed by one of two radiologists immediately after US. Radiologists were blinded to US findings and assigned VCUG diagnoses in consensus. Contingency table was used to compare US and VCUG. Agreement between US and VCUG was determined with kappa statistics. RESULTS: With VCUG, VUR was diagnosed in 15 patients and not diagnosed in 22 patients. US and VCUG results were in agreement in 14 patients with VUR and 21 patients without VUR. US sensitivity and specificity for detection of VUR were 93% (14 true-positive results in 15 abnormal cases) and 95% (21 true-negative results in 22 normal cases), respectively. Agreement between US and VCUG was 95% (kappa = 0.89, P <.001). In 11 of 14 patients, VUR grades were in agreement for US and VCUG. In three of 14 patients, US indicated a higher grade than did VCUG. VUR was diagnosed in seven of 18 Politano-Leadbetter cases and eight of 19 Lich-Gregoire cases. CONCLUSION: A high rate of agreement was seen between voiding US and VCUG.     

Vesicoureteral reflux in adults.

Vesicoureteral reflux was detected in 200 adults seen in a 4 year period. In group 1 (no history of urinary tract infection and negative urine cultures), all patients had abnormalities on excretory urograms that were suggestive of reflux. In patients with a history of recurrent urinary tract infection (groups 2 and 3), the excretory urograms showed an abnormality in 79 per cent of those with negative cultures and in 83 per cent of those with positive cultures. Thus, reflux should be suspected in patients with a history of recurrent urinary tract infection even if infection cannot be documented with urine culture. Urographic evidence of renal parenchymal scarring, ureteral dilatation, or mucosal striations should also suggest the possibility of vesicoureteral reflux even when the patient may have no urinary tract symptoms. Voiding cystourethrography should be performed in all adults with these findings to exclude the possibility of vesicoureteral reflux.     

The coexistence of ureteropelvic junction obstruction and reflux

Since ureteropelvic junction obstruction is the most common upper urinary tract problem in children, and vesicoureteral reflux the most common lower tract problem, it is not surprising that these entities sometimes coexist in the same child. Over a 10 year period this uncommon phenomenon has been noted 21 times (in about 2,800 children with reflux and 200 children with ureteropelvic junction obstruction). Significant ureteropelvic junction obstruction in association with mild reflux can mimic severe reflux, but the operation needed is not reimplantation but pyeloplasty. Conversely, when significant ureteropelvic junction obstruction coexists with significant reflux, both operations may be necessary, but the order in which they are done (pyeloplasty first) seems to be crucial. Voiding cystography with appropriate postvoid drainage films, excretory urography, often with a catheter draining the bladder to prevent reflux, and provocative diuretic excretory urography and/or renography can determine that ureteropelvic junction obstruction does coexist and quantitate the severity of each problem.     

Cyclic filling cystourethrography in the study of febrile urinary tract infection in children

PURPOSE: To assess the value of cyclic voiding cystourethrography (VCUG) for the detection of reflux in a large population of children with urinary tract infection. MATERIALS AND METHODS: 234 patients (67% less than 3 years of age) underwent VCUG with two fillings in 214 cases and three fillings in 139 cases. Appearance or increase in the grade of reflux compared with previous filling was expressed as "modification of the radiology report" (MRR). The amount of contrast material, the duration of fluoroscopy and the number of films were recorded. RESULTS: The rate of reflux was 18.4% at the first filling, 16% at the second filling with 9.8% MRR and 14.7% at the third filling with 10% MRR. These results were the same for children younger and older than 3 years. For children under three years, if one considered reflux grade higher than 1, the MRR was 9.6% at the second filling and 7.5% at the third while it was 5.8% and 3% for older children. On average, the use of contrast material increased 50% with a third filling, number of films was not modified and the time of fluoroscopy increased by 6 sec per filling. CONCLUSION: VCUG is recommended in all children. The detection of reflux higher than grade 1 is more frequent with multiple fillings in children under 3 years. The increase in radiation exposure and cost seems negligible.     

Comparison of direct radionuclide cystography and voiding direct cystography in the detection of vesicoureteral reflux

PURPOSE: The aim of this study is to compare the results of direct radionuclide cystography (DRNC) and voiding cystourethrography (VCUG) in a group of children with a high suspicion of vesicoureteral reflux (VUR). METHODS: For this purpose, 25 children were studied with both VCUG and DRNC. Among 50 ureter units able to be compared 39 ureter units did not show any VUR on either study. Eleven ureter units (10 children) had VUR either on one study or on both (VCUG and DRNC). In the children who had VUR on either study, a dimercaptosuccinic acid scintigraphy (DMSA) was performed to determine their cortical function. RESULTS: We identified the following four patterns: 1) Five ureter units (five children) read positive on DRNC who were negative on VCUG and four of these children had positive findings on DMSA; 2) Four ureter units (four children) read positive on VCUG who were negative on DRNC, and two of them had positive findings on DMSA; 3) Two ureters (one child) read positive in both studies and also had abnormal DMSA findings; 4) Thirty-nine ureter units read as negative on both studies. CONCLUSION: Although the results of these two methods did not show a significant difference, DRNC offers a high sensitivity in the younger age group whereas VCUG seems to be more sensitive in the older age group. DRNC also offers continuous recording during the study, ease of assessment and lower radiation dose to the gonads, which makes it a preferable method for the initial diagnosis and follow-up of VUR.     

Urinary tract infection in infants and children evaluated by ultrasound

Fifty-nine pediatric patients with urinary tract infection (UTI) underwent renal ultrasonography, excretory urography, and voiding cystourethrography. The imaging procedures were analyzed retrospectively to determine their relative effectiveness in detecting abnormalities that might predispose the patient to UTI. Voiding cystourethrography provided valuable information, particularly the presence or absence of vesicoureteral reflux, that could not be obtained from the other procedures. Excretory urography was less specific than ultrasonography in the majority of patients, with the exception of those who had renal scarring. The authors recommended ultrasonography as the initial imaging procedure in the evaluation of children with UTI. When the sonogram is normal, excretory urography is not considered necessary, but voiding cystourethrography is thought to be essential. If sonography is abnormal, excretory urography and/or other follow-up studies are indicated.     

Imaging of children with urinary tract infection: a tailored approach

We reviewed the initial imaging studies of 283 children with urinary tract infection in order to decide on the most effective approach. A voiding cystogram was performed in all, complemented by either urography (147 patients), ultrasonography (65), or both (71 patients). In the latter group there was good correlation between sonographic and urographic findings, except for a more accurate delineation of renal scars and anomalies on urography, all in children with vesicoureteral reflux and/or abnormal sonograms. From these data we derived two imaging sequences tailored to the clinical circumstances: cystography as the initial study in ambulatory patients after infection has subsided, and sonography followed by cystography in children hospitalised with severe infection. The upper tracts are studied by ultrasonography and/or urography in patients with significant vesicoureteral reflex or an abnormal sonogram. Both these sequences reduce radiation by omitting the urogram in roughly half of the patients.     

Imaging in acute renal infection in children

Infection is the most common disease of the urinary tract in children, and various imaging techniques have been used to verify its presence and location. On retrospective analysis, 50 consecutive children with documented upper urinary tract infection had abnormal findings on renal cortical scintigraphy with 99mTc-glucoheptonate. The infection involved the renal poles only in 38 and the poles plus other renal cortical areas in eight. Four had abnormalities that spared the poles. Renal sonograms were abnormal in 32 of 50 children. Excretory urograms were abnormal in six of 23 children in whom they were obtained. Vesicoureteral reflux was found in 34 of 40 children in whom voiding cystourethrography was performed. These data show the high sensitivity of renal cortical scintigraphy with 99mTc-glucoheptonate in documenting upper urinary tract infection. The location of the abnormalities detected suggests that renal infections spread via an ascending mode and implies that intrarenal reflux is a major contributing factor.     

Comparison of direct radionuclide cystography and voiding direct cystography in the detection of vesicoureteral reflux

Purpose: The aim of this study is to compare the results of direct radionuclide cystography (DRNC) and voiding cystourethrography (VCUG) in a group of children with a high suspicion of vesicoureteral reflux (VUR).Methods: For this purpose, 25 children were studied with both VCUG and DRNC. Among 50 ureter units able to be compared 39 ureter units did not show any VUR on either study. Eleven ureter units (10 children) had VUR either on one study or on both (VCUG and DRNC). In the children who had VUR on either study, a dimercaptosuccinic acid scintigraphy (DMSA) was performed to determine their cortical function.Results: We identified the following four patterns: 1) Five ureter units (five children) read positive on DRNC who were negative on VCUG and four of these children had positive findings on DMSA; 2) Four ureter units (four children) read positive on VCUG who were negative on DRNC, and two of them had positive findings on DMSA; 3) Two ureters (one child) read positive in both studies and also had abnormal DMSA findings; 4) Thirtynine ureter units read as negative on both studies.Conclusion: Although the results of these two methods did not show a significant difference, DRNC offers a high sensitivity in the younger age group whereas VCUG seems to be more sensitive in the older age group. DRNC also offers continuous recording during the study, ease of assessment and lower radiation dose to the gonads, which makes it a preferable method for the initial diagnosis and follow-up of VUR.     

Cyclic voiding cystouretrography without the use of fluoroscopic monitoring

PURPOSE: To determine whether cyclic voiding cystourethrography (VCUG) examinations can be performed without using real-time fluoroscopic monitoring. MATERIALS AND METHODS: VCUG examinations were performed in 209 children (133 girls and 76 boys). In each child, it was performed in a cyclic manner (three consecutive cycles) without using fluoroscopic monitoring and one radiograph was taken in each cycle of the examination. All patients were sedated by midazolam prior to examination. The degree of vesicoureteric reflux (VUR) was graded for each of the kidney ureter units (KUU) (total 418 KUU) separately. Statistical analysis included the comparison of the presence and absence of VUR and three ordinal-matched comparisons of each cycle. RESULTS: VCUG was detected in 37.3% of the children (78/209) and 28.7% (120/418) of the KUU. The absence of or same degree of VUR in three consecutive cycles were obtained in 345 KUU and the agreement was calculated as 82.5%. The same degree and presence of reflux were found in 85 and 89 refluxing KUU, the same negative findings (absence of VUR) in 306 and 298 KUU, and discordant findings in 27 and 31 KUU (between the first and second and between first and third cycles), respectively. Therefore, the agreement was 93.5 and 92.5% between the first and second cycles (p=0.70) and between the first and the third cycles (p=0.15), respectively. CONCLUSION: Both the cyclic nature of this study and the results indicated that VCUG without real-time fluoroscopic monitoring could be used where adequate fluoroscopic examination is not possible for children in whom VUR detection is necessary and impacts treatment. However, the responsibility of pediatric radiologist always must also include the task to provide proper equipment for imaging children with suspected VUR.     

Urinary tract infections in children: renal ultrasound evaluation

Ultrasound may replace urography in screening pediatric patients with uncomplicated urinary tract infections but without vesicoureteral reflux. A child undergoing a first radiographic evaluation for urinary tract infection is initially examined by voiding cystourethrography. If reflux is present, urography is performed. If no reflux is present, the kidneys are evaluated by real-time ultrasound; urography may also be performed if the ultrasound examination is abnormal, equivocal, or inadequate. A total of 192 patients was evaluated with this protocol; 146 (76%) had no reflux and therefore were examined with ultrasound. One patient was found to have hydronephrosis and underwent surgical correction. This group of patients was compared with a similar group of 223 patients without reflux who were evaluated by urography prior to the institution of the ultrasound protocol; there was no significant difference between the two groups in upper urinary tract findings that influenced patient management.     

The dilated urinary tract in children

Dilatation of the urinary tract is detected in a number of settings throughout childhood. Children may be asymptomatic or present with urinary tract infection, hematuria, or voiding symptoms. Evaluation of the affected urinary tract may require standard radiographic techniques (VCUG, EU) complemented by ultrasound and nuclear medicine studies. The goal of imaging is to differentiate hydronephrosis (HN) from hydroureteronephrosis (HUN) and to provide the correct diagnosis so that appropriate treatment can be given. This article reviews and demonstrates the findings in some common and uncommon causes of HN and HUN.     

Radiological imaging of urinary tract infection in Malaysian children--a private hospital experience.

The results of radiological investigations performed on 81 children with urinary tract infection (UTI) were reviewed. Investigations included 91 voiding cystourethrograms (VCU), 59 intravenous urograms (IVU) and 36 ultrasonograms (US). The aim was to study the local spectrum of renal tract abnormalities in childhood UTI and to compare the diagnostic yield of combining US and VCU against IVU and VCU. Renal tract abnormalities were detected in 37%. Vesico-ureteric reflux (VUR) was the commonest, detected in 26%, with renal scarring found in 9% of refluxing units. Ultrasound should replace IVU in the initial diagnostic work-up of these children.