Ureteral diameter in low-risk vesicoureteral reflux in infancy and childhood

In order to improve the accuracy of the grading of vesicoureteral reflux (VUR), reference values for ureteral diameter at micturition cystourethrography (MCUG) were established in infants and children with low-risk VUR. Low-risk VUR was defined as VUR not associated with infection, obstruction, calculi, duplication, malformations (except for hypospadia) or neurogenic bladder disturbances. Forty-six children (age 1 day-14 years) were selected by examining the records of 12000 MCUG:s performed 1960-1983. Ureteral diameter was measured at the widest point of the ureter on the films from MCUG:s and urographies. Ureteral diameter was slightly larger at MCUG than at urography in the same individuals but the difference was not significant. The ureteral diameter at MCUG also correlated closely to normal values at urography in a previous study. It is proposed that the reference values obtained at MCUG in the present investigation can be used for the differentiation between dilatation and no dilatation in the grading of VUR.     

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.     

Normal ureteral diameter in infancy and childhood

Ureteral diameters were estimated on films from intravenous urography in 194 children (100 boys and 94 girls) aged 0-16 years. Children with signs of urinary tract infection, calculi, obstruction, duplication or malformation were excluded. Films obtained without abdominal compression were used for measurements, including only ureters visualized over 50 per cent of their lengths. A good correlation was demonstrated between ureteral diameter and age (r = 0.69) and between ureteral diameter and the length of a segment of the lumbar spine (r = 0.73). The widest part of the ureter was most often located just above the crossing of the iliac vessels. The right ureter was slightly wider than the left one. No difference between boys and girls was noted. The results are in good agreement with those of others obtained at autopsy. Bearing in mind the possible physiologic variations, it would seem that measuring the ureteral diameter can be of value for a more objective differentiation between dilated and non-dilated ureters.     

Voiding cystourethrography: the initial radiologic study in children with urinary tract infection

The order in which children with urinary tract infection should undergo voiding cystourethrography (VCUG), excretory urography (EU), and/or renal ultrasonography (US) is not standardized. To determine a logical sequence of study, we performed VCUG and then either US or EU on 389 consecutive children with urinary tract infections. Thirty-seven percent (133/358) of the children were found to have reflux; of these, 22.5% (30/133) had an abnormal excretory urogram. No correlation was found between either the age of the child and the degree of reflux or the age of the child and the percentage of children with abnormal excretory urograms. Since normal EU or US results do not exclude significant reflux, VCUG is recommended as the preferred initial screening examination in children with urinary tract infection.     

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.     

Diminished radiopacity of contrast material: a urographic sign of ureteral calculus.

Eleven patients with unilateral ureteral calculus had excretory urography which showed the radiopacity of excreted contrast material to be diminished on the side of the calculus. This finding was of diagnostic importance in nine patients who demonstrated little or no dilatation of the urinary tract proximal to the calculus. Other forms of unilateral renal disease, such as acute pyelonephritis, can produce the same urographic finding.     

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.     

Prediction of vesico-ureteral reflux in children from intravenous urography films.

Intravenous urography and voiding urethrocystography were performed on 255 children with urinary tract infection. Eighty-six (34%) of these children had some kind of abnormality of the urinary tract. Vesico-ureteral reflux was observed to 96 ureters (19%) in 69 children (27%). The prediction of vesico-ureteral reflux by two radiologists from urography films only gave 46 (48%) and 51 (53%) false negative results respectively. In cases of clinically important reflux (III--V degrees), however, the rate of false negative predictions was 0/18 and 1/18 (6%) respectively. The rate for false positive predictions were 45/413 (11%) for both radiologists. In view of the number of pathological findings in this series i.v. urography is recommended as a routine in children undergoing urological work-up after their first urinary tract infection. As the clinically important vesico-ureteral reflux seems to be predictable from urography films alone, voiding urethrocystography seems not to be justified in children with negative i.v. urography, and can be postponed and carried out later if the urinary tract infection recurs.     

Radiologic investigation of renal colic: unenhanced helical CT compared with excretory urography.

OBJECTIVE: Our aim was to compare unenhanced helical CT and excretory urography in the assessment of patients with renal colic. SUBJECTS AND METHODS: Fifty-three of 70 consecutive patients with acute signs of renal colic were prospectively examined with unenhanced helical CT, which was followed immediately by excretory urography. Two radiologists who were unaware of the findings independently interpreted these examinations to determine the presence or absence of ureteral obstruction. On all CT scans that had positive findings for ureteral stones or obstruction, we looked for secondary signs of obstruction (perinephric or periureteral fat stranding, ureteral wall edema, ureteral dilatation, and blurring of renal sinus fat). RESULTS: A stone was recovered in 45 of the 53 patients, nine before and 36 after imaging. The latter 36 patients had their stones identified on CT, whereas only 24 patients had their stones identified on excretory urography. Eight patients without stone disease had normal ureters on both CT and excretory urography. Of the 45 patients who had stone disease, 26 had ureteral dilatation on both CT and excretory urography, and 36 patients who recovered a stone after CT had secondary signs of obstruction. Of the nine patients who recovered a stone before CT, three had secondary signs of obstruction. Two patients had periureteral fat stranding, ureteral wall edema, and renal sinus fat blurring. One patient had only ureteral wall edema. CONCLUSION: Compared with excretory urography, unenhanced helical CT is better for identifying ureteral stones in patients with acute ureterolithiasis. Secondary CT signs of obstruction, including renal sinus fat blurring, were frequently present even when the stone was eliminated before imaging.     

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.     

Ultrasound versus excretory urography in evaluating acute flank pain

To determine the role of ultrasound (US) in patients with acute flank pain and suspected acute urinary tract obstruction, a prospective study was performed on 20 patients comparing US with emergency excretory urography. US was not as sensitive as excretory urography for diagnosing hydronephrosis, for detecting ureteral or renal calcification, or for diagnosing forniceal rupture. Although US is an effective screening modality for hydronephrosis in patients with chronic renal obstruction, it is not useful for evaluating patients with acute flank pain in whom acute obstruction may be present. In this group of patients, excretory urography remains the examination of choice.     

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.     

MDCT urography of upper tract urothelial neoplasms

OBJECTIVE: The purpose of our study was to review the MDCT urography appearance of pathologically proven transitional cell carcinomas of the renal collecting system and ureter and to correlate the MDCT urography findings with pathology findings. MATERIALS AND METHODS: Of 370 MDCT urography examinations performed over an 18-month period, 18 patients were diagnosed with 27 renal collecting system or ureteral urothelial neoplasms at endoscopic biopsy (n = 8) or surgery (n = 19). Initial MDCT reports were reviewed to determine the sensitivity of original reviewers in detecting these neoplasms. Two radiologists also retrospectively reviewed these scans and characterized the CT appearance of the neoplasms on both axial CT and 3D reformatted images. Findings at retrospective review were correlated with pathology results to determine whether any CT features could be used to predict tumor grade. RESULTS: Eighteen of 27 neoplasms were prospectively identified on MDCT urography, and an additional six neoplasms were detected on retrospective review. Three ureteral neoplasms could not be visualized. The 24 retrospectively detected neoplasms had three distinct MDCT appearances: circumferential urothelial wall thickening (n = 14), small masses (> 5 mm in maximal diameter) (n = 5), and large masses (> 5 mm in maximal diameter) (n = 5). All detected lesions could be seen on axial excretory phase images provided wide window settings were reviewed; however, only six were detected on 3D reconstructions. MDCT urography appearance did not correlate with tumor grade. CONCLUSION: MDCT urography is a promising technique for detecting upper urinary tract neoplasms. The static 3D reconstructions used in this study are insufficient for visualization. Axial image review remains essential for tumor identification.     

Functional and morphologic evaluation of congenital urinary tract dilatation by using combined static-dynamic MR urography: findings in kidneys with a single collecting system

PURPOSE: To assess combined static-dynamic magnetic resonance (MR) urography in the evaluation of congenital urinary tract dilatation in infants and children. MATERIALS AND METHODS: Sixty-two patients with urinary tract dilatation underwent prospective examination with combined static-dynamic MR urography. A combination examination involved use of a static T2-weighted three-dimensional inversion-recovery fast spin-echo sequence and a dynamic T1-weighted two-dimensional fast field-echo sequence with gadopentetate dimeglumine-DTPA and furosemide application. Twelve additional patients underwent examination with only static MR urography. Thus, both image quality and morphologic features were assessed in 74 patients with the use of MR urography. The results were compared with those of ultrasonography and, when available, conventional urography or surgery. In 62 patients, the dynamic sequence was used to calculate split renal function from renograms generated from parenchymal regions of interest and to assess urinary excretion from whole-kidney renograms. Results were compared with those of diuretic renal scintigraphy (DRS) for split function (Spearman rank correlation coefficient) and urinary excretion (kappa coefficient). RESULTS: Stenoses at the ureteropelvic (n = 33) and ureterovesical (n = 31) junctions and within the ureter (n = 3) and nonstenotic dilatation (n = 23) were clearly depicted, while the normal urinary tract (n = 51) was depicted in its entirety in 47 of 51 examinations. Image quality was considered good or excellent in 95% of the kidney-ureter units. For split renal function, dynamic MR urography and DRS showed significant correlation (r = 0.92, P <.001). For urinary excretion, MR urography and DRS showed strong agreement (kappa = 0.67), with concordant classification of urinary excretion in 59 (81%) of 73 abnormal kidney-ureter units and in all 47 (100%) normal kidney-ureter units. CONCLUSION: Combined static-dynamic MR urography provides high-quality depiction of the urinary tract in infants and children, while allowing accurate determination of single-kidney function and reliable evaluation of urinary excretion.     

Comparative Study of Ureteral Stents Following Endoureterotomy in the Porcine Model: 3 vs 6 Weeks and 7F vs 14F

The aim of the study was to determine the optimal stent size and stenting duration following retrograde endoureterotomy of experimental ureteral strictures. Twenty healthy Large White female pigs were randomly divided into four groups, depending on stent size (7F vs 14F) and stenting duration (3 weeks vs 6 weeks). Three additional pigs were used as the control group. The internal ureteral diameter was measured 2 cm below the lower pole of the right kidney. Histopathological changes of the urinary tract, ultrasonographic and fluoroscopic studies, urine culture, and serum urea and creatine levels were analyzed during the different phases of the study. The study was divided into three phases. Phase I included premodel documentation of the normal urinary tract and laparoscopic ureteral stricture creation. During the second phase 1 month later, the diagnosis and endourologic treatment of strictures were performed. Phase III began 4 weeks after stent removal; follow-up imaging studies and postmortem evaluation of all animals were performed. Ureteral strictures developed in all animals 4 weeks after model creation. Results from ureteral diameter measurements and pathological studies revealed no statistically significant intergroup differences. However, prevalence of urinary infection proved to be directly related to stent size (14F) and permanence (6 weeks). The chi square results suggest a statistically significant relationship between the urinary tract infection and recurrent strictures (α = 0.046). We recommend the use of 7F stents for a period of 3 weeks or less, as these are more easily positioned and result in the reduction of secondary side effects (lower infection rate, less intramural ureteral lesions). A significant relationship between urinary tract infection and stricture recurrence was found in this experimental study.     

Reliability of the combination of ultrasonography-cystography in the study of urinary infection in children. Prospective study on 90 cases

The authors report a prospective study concerning 90 children with a urinary tract infection, investigated for the first time by radiological and ultrasonographic techniques. Amongst these 90 children, 50 (i.e. 55% of cases) had a normal retrograde cystography and ultrasonography. These children did not have any IVU and medical surveillance proved to be sufficient. Ten patients had a normal retrograde cystography and abnormal ultrasonography. Intravenous urography carried out in these 10 cases revealed in 8 instances an abnormality of the upper urinary tract. Finally 30 children had an abnormal retrograde cystography, with reflux in 29 cases, leading to intravenous urography which yielded a pathological result in only half of the cases studied. This series confirms the central role of retrograde cystography. When it is normal, intravenous urography may be legitimately substituted by ultrasonography.     

Urinary tract infection in children. A reappraisal of its radiologic investigation

In a prospective study, 100 children with either an acute or a previous history of urinary tract infection were investigated by intravenous urography, micturition cystourethrography, and ultrasonography. The results from the three diagnostic modalities were compared: The urinary tracts in 59 patients were normal, and revealed some abnormality in 41. Ultrasonography proved to be superior to intravenous urography in outlining renal contours and in detecting subtle cortical changes secondary to urinary tract infection (such as slight increases in cortical thickness and edema or cortical scarring). The mucosa of the renal pelvis and bladder was more easily assessed by ultrasound than by intravenous urography. Both modalities were "equally" accurate in detecting important congenital malformations of the urinary tract. Ultrasound failed to detect 24 of 28 ureters demonstrating reflux on voiding cystourethrography. We propose that carefully performed abdominal ultrasonography can replace intravenous urography in the initial investigation of urinary tract infection in children. It should be done in association with a radiographic or radionuclide voiding cystogram. Intravenous urography would then become a complementary examination for abnormal or problematic patients.     

Radiological findings of the urinary tract in hypospadias: a report of 110 cases.

One hundred and ten patients with hypospadias underwent excretory urography and micturating cysto-urethrography before surgical correction. Urographic studies revealed abnormalities in 50 patients (45%), mainly anomalies of ascent and rotation of the kidneys. None of these patients required corrective surgery. Voiding cysto-urethrography disclosed disease of the urinary tract in 65 of 110 patients (59%). Meatal stenosis was found in 38 patients and a rudimentary vagina or a prostatic utricle was revealed in 11 others. Vesico-ureteral reflux was present in 14 patients, seven of whom had meatal stenosis as well. Cystitis was found in eight and a stricture of the membraneous urethra in one patient. The voiding cysto-urethrogram is able to demonstrate functionally significant meatal stenosis, genital abnormalities and vesico-ureteral reflux. It can also serve as a useful baseline for comparison with postoperative studies. We therefore consider that it should be included in the preoperative work-up of every patient with hypospadias. Excretory urography, however, is perhaps indicated only in those with urinary tract infection, or in patients otherwise symptomatic.     

A protocol for the investigation of infants and children with urinary tract infection

An investigation protocol, designed to reduce invasive procedures to a minimum, is described for the detection of reflux nephropathy in infants and children. Intravenous urography and voiding cysto-urethrography is necessary in patients up to the age of 2 years presenting with urinary tract infection, but in children over 2 years of age the protocol limits the investigation to an intravenous urogram unless this is abnormal. A review of this policy after 5 years has indicated that it is appropriate provided that children who continue to have infections have further evaluation including a voiding cysto-urethrogram.     

排泄性磁共振尿路造影对小儿尿路畸形的评估

目的:探讨应用利尿剂的排泄性磁共振尿路造影(EMRU)诊断小儿尿路先天畸形的应用价值.材料和方法:对24例已知或高度怀疑尿路先天畸形的儿童进行磁共振水成像尿路造影及增强后排泄性尿路造影(MRU),患者都使用了利尿剂.由2位经验丰富医师在不知病史的情况下分别对两种MRU成像方法的图像进行质量评估并做出对比分析.结果:60.4%的水成像与85.4%排泄性MRU图像质量达到了诊断要求;58.3%排泄性MRU与相应的成像MRU相比,其图像质量和观察效果得到了提高或改善;其中20例(20/24,83%)患者做出定位定性诊断,2例(2/24,8.3%)排除了相关异常.结论:利尿剂排泄性磁共振尿路造影(EMRU)能比较准确的显示泌尿路先天畸形,可以替代传统方法用于大部分怀疑有先天畸形的患儿.