The influence of bladder fullness on upper urinary tract dimensions and renal excretory function

A new quantitative method for estimating glomerular filtration rate and its clinical value

BACKGROUND AND AIM

The estimation of the glomerular filtration rate (GFR) is essential for the renal function. However, all estimation methods for GFR have advantages and disadvantages. The aim of this study was to develop a new quantitative method for estimating GFR and evaluate its clinical value.

METHODS

The new GFR was estimated by quantifying the accumulation of Tc-99m DTPA in the dual kidneys and bladder during a gamma camera renogram study in 116 patients with chronic kidney disease. GFR was determined by this new method (nGFR), Gates' gamma camera technique (gGFR), a two-plasma sampling method (tGFR) and creatinine-based clearance as estimated by Cockcroft-Gault (cGFR) and abbreviated MDRD (aGFR) formulae. The correlation analysis, Bland-Altman analysis and receiver-operating characteristic (ROC) plots were carried out among above methods.

RESULTS

The nGFR value has significant correlation with tGRF (r = 0·827, P<0·01). The nGFR had the best overall performances with a lowest bias deviation (3·1 ml min(-1) /1·73 m(2) ), better precision (53·0 ml min(-1) /1·73 m(2) ), narrowest interquartile range (13·5 ml min(-1) /1·73 m(2) ) and best accuracy (68·1%) within 30% of the tGFR, compared with those of gGFR, cGFR and aGFR. The new method had the similar maximum accuracy with the Gates' method and creatinine clearance as estimated by Cockcroft-Gault and abbreviated modification of diet in renal disease (MDRD) method. The new method had better repeatability characteristic compared with the Gates' method.

CONCLUSIONS

The new method for estimating GFR had the better performances compared with the Gates' method and creatinine clearance as estimated by Cockcroft-Gault and MDRD method.

Dynamic ultrasound study on urinary bladder in infants with antenatally detected fetal hydronephrosis

To evaluate bladder function in infants with antenatally diagnosed hydronephrosis (ANH) using dynamic ultrasound protocol. Forty consecutive male infants (mean, 0.25 y) with ANH and 33 age-matched normal controls (mean, 0.49 y) were recruited. Anteroposterior (AP) diameter of renal pelvis (RP) and hydronephrosis index [HI = anteroposterior diameter of RP of kidney divided by urinary bladder volume (BV)] were calculated. Maximum BV (MaxBV) was determined just before voiding. Residual volume (RV) and bladder wall thickness (BWT) were measured after spontaneous voiding. Thirty-one infants (77.5%) showed persistently dilated RP postnatally in which 12 (39%) showed significantly high HI. In general, ANH infants had smaller MaxBV (30.71 versus 52.45 mL), larger residual volume (2.47 versus 1.93 mL), and larger BWT (4.4 versus 3.7 mm) than normal (p < 0.05, Mann-Whitney test). Infants with abnormally high HI had significantly more disturbed bladder parameters [smaller MaxBV (23.33 versus 33.49 mL) and larger BWT (4.67 versus 3.79 mm)] than the normal HI group (p < 0.05, Mann-Whitney test). Abnormal functional bladder parameters were evident in ANH infants. We postulated that immature function in the pelviureteric junction was associated with bladder dysfunction in these infants. Dynamic ultrasound protocol might help to understand the underlying pathophysiology of urinary system in ANH infants.

Hydronephrosis index: a better physiological reference in antenatal ultrasound for assessment of fetal hydronephrosis

OBJECTIVE

To establish a nomogram of fetal hydronephrosis index (HI) (anteroposterior diameter of renal pelvis divided by urinary bladder volume) at different gestational ages, to serve as a new reference for antenatal ultrasound examination, and to avoid overestimation of fetal hydronephrosis due to transient effect of a distended fetal bladder.

STUDY DESIGN

504 uncomplicated singleton pregnancies from 20 to 38 weeks' gestation were included. In each fetus, the maximum anteroposterior diameters of both renal pelves were measured on transverse view of fetal kidneys. Urinary bladder volume was calculated using the ovoid volume formula. HI was derived accordingly.

RESULTS

Values of HI vary significantly at different trimesters of pregnancy. HI was much higher (mean = 0.1543) from 20 to 27 weeks' gestation, and its value decreased significantly (mean = 0.0253) from 28 to 38 weeks' gestation (P < .05, independent-sample t test). As gestational age increased, HI decreased (R(2) = 0.5921).

CONCLUSIONS

HI is easy to be measured and can be used as a new physiological reference for assessment of fetal hydronephrosis by eliminating the confounding effect of a full fetal bladder. The change in values of HI throughout gestation supports the clinical importance of a nomogram for this new index.

International Scientific Committee of Radionuclides in Nephrourology (ISCORN) consensus on renal transit time measurements

This report is the conclusion of the international consensus committee on renal transit time (subcommittee of the International Scientific Committee of Radionuclides in Nephrourology) and provides recommendations on measurement, normal values, and analysis of clinical utility. Transit time is the time that a tracer remains within the kidney or within a part of the kidney (eg, parenchymal transit time). It can be obtained from a dynamic renogram and a vascular input acquired in standardized conditions by a deconvolution process. Alternatively to transit time measurement, simpler indices were proposed, such as time of maximum, normalized residual activity or renal output efficiency. Transit time has been mainly used in urinary obstruction, renal artery stenosis, or renovascular hypertension and renal transplant. Despite a large amount of published data on obstruction, only the value of normal transit is established. The value of delayed transit remains controversial, probably due to lack of a gold standard for obstruction. Transit time measurements are useful to diagnose renovascular hypertension, as are some of the simpler indices. The committee recommends further collaborative trials.

Effect of hydration and continuous urinary drainage on urine production in children

OBJECTIVE

Although urine production depends on numerous physiological variables there are no quantitative data regarding the effect of bladder decompression, by means of continuous catheter drainage, on urine production. The aim of this study was to investigate this effect.

MATERIAL AND METHODS

The study was carried out in two stages, each consisting of two phases. The effect of two distinct orally administered amounts of water was recorded in relation to continuous bladder decompression on the changes with time of urine volume and the urine production rate. In the first stage, 35 children were randomly divided into two groups and two different hydration schemes (290 and 580 ml of water/m2) were used. After the second urination of Phase 1, continuous drainage was employed in the phase that followed (Phase 2). In the second stage, a group of 10 children participated and Phase 2 was carried out 1 day after the completion of Phase 1.

RESULTS

It was shown that the amount of urine produced increased in accordance with the degree of hydration and doubled or tripled with continual urine drainage by catheter for the same degree of hydration and within the same time interval. This was also true for Stage 2, in which Phase 2 was performed 24 h after Phase 1, indicating that diuresis during Phase 2 (as a result of Phase 1) was negligible.

CONCLUSION

It was shown that during continuous drainage of urine with bladder catheterization there is an increased need for fluids, which should be administered early.

Doppler waveform of the ureteric jet in pregnancy

We have shown that the function of the bladder vesicoureteric junction (VUJ) can be studied by the Doppler waveform of the ureteric jet, and this reflects the active sphincteric mechanism of the VUJ. We wished to investigate if the hormonal changes of pregnancy cause any alteration of VUJ function. A total of 107 pregnant women and 375 nonpregnant women were recruited. Three scans, 20 and 32 weeks of gestational age and 3 months postpartum, were done. The occurrence of a monophasic waveform in the nonpregnant group was 1.9%. In the pregnancy group, this was 18.7%, 41.1% and 1.6% at 20, 32 weeks of gestational age and 3 months postpartum, respectively. The difference in occurrence of the monophasic waveforms was statistically significant (both p = 0.0005 at 20 and 32 weeks). This suggests an adverse hormonal effect on the vesicoureteric junction during pregnancy, and may be a factor in the increased risk of UTI in pregnancy.

Low dose effect of in utero exposure to bisphenol A and diethylstilbestrol on female mouse reproduction

In utero exposure to bisphenol-A (BPA) at doses relevant to human consumption has been reported to accelerate weight gain and puberty in female mice, but the effect of low dose BPA on female reproduction has not been described. In this study, we investigated low dose effects of BPA on sexual maturation and reproduction in female ICR/Jcl mice. Pregnant ICR mice (F0) were injected (s.c.) with BPA (2 and 20 microg/kg), diethylstilbestrol (DES; 0.02, 0.2, and 2 microg/kg) or oil vehicle once per day from gestational days 11-17. For both female and male offspring (F1), body weights were measured on postnatal day (PND) 0 (the day of birth), 11, 22, and 60, and anogenital distance (AGD) was measured on PNDs 22 and 60. Pups were weaned at PND 22 and males were caged separately from females. Vaginal smears were taken daily beginning the day of vaginal opening for 30 days. The age at vaginal opening was significantly earlier in all exposed females except for 2 microg/kg BPA females compared to oil controls. Body weight at vaginal opening was lower than controls in all exposed females. The first vaginal estrus was earlier in all exposed females except for the 2 microg/kg BPA group females compared to controls. From PND 90 to 120, gestationally exposed F1 female mice were mated with unexposed males. Total numbers of pups and sex ratio in F1 mice exposed to BPA or DES, and those of their offspring (F2) were not different from controls in any treatment group. The present results indicate that prenatal exposure to low doses of BPA and DES induces early vaginal opening, but does not affect reproductive functioning at the first breeding.

Sonographic diagnosis of hydronephrosis in patients with spinal cord injury: influence of bladder fullness

OBJECTIVE

To investigate and compare the diagnostic accuracy of prevoid and postvoid renal sonography in detecting hydronephrosis in patients with spinal cord injury.

STUDY DESIGN

A prospective, blind comparison of renal sonography and excretory urography in 67 spinal cord injury patients who underwent periodic urologic examinations. Renal sonography was performed twice, once when the patient's bladder was physiologically full (prevoid) and again when it was just emptied (postvoid).

RESULTS

Of 140 kidneys, 24 from 16 patients were found to have hydronephrosis by excretory urography; 116 kidneys had normal urogram findings. Prevoid sonography missed the diagnosis of hydronephrosis in one kidney and showed hydronephrosis in 18 kidneys that had normal results on excretory urography (sensitivity, 95.8%; specificity, 84.5%; negative predictive value, 99.0%). The postvoid sonograms did not detect hydronephrosis in four kidneys and showed hydronephrosis in six kidneys that had normal results on excretory urography (sensitivity, 83.3%; specificity, 94.8%; negative predictive value, 96.5%). Compared to excretory urography, renal sonography detected eight more upper urinary tract abnormalities, which were confirmed by cystograms or radioisotopic renograms.

CONCLUSION

Performing renal sonography while the bladder is full can increase the sensitivity in detecting hydronephrosis in asymptomatic spinal cord injured patients.

The relevance of parity to ureteric dilatation

OBJECTIVE

To assess whether the mild dilatation of the right ureter in women that is sometimes seen on intravenous urography (IVU) represents persistent dilatation after a previous pregnancy.

PATIENTS AND METHODS

The intravenous urograms of 71 men, 63 parous and 27 nulliparous women were evaluated prospectively. The two groups of women were divided into those with and without a confirmed history of urinary tract infection (UTI) as the indication for IVU. producing five groups in all. Measurements were taken on both the 5-min and the compressed or release films on each side.

RESULTS

There were no significant differences in ureteric diameters among the five groups for the uncompressed right ureter (P=0.23), the left ureter uncompressed (P=0.32) or compressed (P=0.87). For the compressed right ureter, the difference was significant, with the diameters in the parous women with proven UTIs being larger than in the other groups (P=0.043).

CONCLUSION

There is a significant increase in the diameter of the compressed right ureter in the group of parous women with a history of proven UTI. Infection or parity alone do not produce this effect: the combination of the two factors is required.

Hydronephrosis accidentally detected by gastrointestinal sonography

A retrospective study was carried out on patients with gastrointestinal complaints, who were accidentally found to have varying degrees of hydronephrosis between October 1989 and April 1991. The criteria for hydronephrosis given by Ellenbogen et al were used for ultrasonographic diagnosis. Grade 0 and 1 were classified as mild degree and grade 2 and 3 as moderate and severe, respectively. The causes of hydronephrosis were determined by intravenous pyelography, retrograde pyelography, and/or computed tomography. Of 44 patients with hydronephrosis who had complete studies, 20 had a mild degree of hydronephrosis, 18 had a moderate degree, and 6 had a severe degree. All 24 patients with moderate and severe degrees of hydronephrosis had obstruction as the etiology, but only 50% of the cases with mild hydronephrosis were found to have pathological lesions. Urolithiasis (79.4%) was the most common cause of hydronephrosis in this study. Benign prostate hypertrophy, carcinomas, external compression, and tuberculosis followed. Hydronephrosis found accidentally by sonography in the patients with gastrointestinal complaints is significant.

A review of the literature on the use of ultrasonography in schistosomiasis with special reference to its use in field studies

This review presents an outline of the pathology resulting from Schistosoma haematobium infections, and the ways in which the lesions can be investigated. The use of ultrasonography is covered in detail. Ultrasonography can provide direct information about lesions in internal organs, and thus provide information about patterns of morbidity and about the regression of pathological changes after treatment. The method has the advantages that it is non-invasive, and is also relatively inexpensive and can be used under field conditions. Ultrasonography has already been used in a number of epidemiological studies in areas where S. haematobium is endemic. The method has proved to be feasible and useful. However, the methodology used for ultrasound studies has varied considerably, so that it is difficult to make valid comparisons between results obtained in different places or at different times. A standardized methodology for making observations and recording the results is needed if the full potential benefit of using ultrasound in the monitoring of schistosomiasis control projects is to be realised. The correlation of results obtained using ultrasound with the results of clinical, parasitological and other observations has been investigated in a number of studies, but many questions remain to be answered.

Renal pelvicalyceal dilation in antepartum pyelonephritis: ultrasonographic findings

The purpose of the present study was to determine whether pregnant women with pyelonephritis have differences of pelvicalyceal systems, compared with normal pregnant control subjects, that might predispose to upper urinary tract infection. Ultrasonographic examination of both kidneys in coronal and axial planes of 24 women with clinical pyelonephritis and positive urine cultures was compared with results in control subjects matched for gestational age, parity, and race. Women with right or bilateral pyelonephritis had increased dilation of the right calyceal system, compared with controls (1.7 cm vs 0.8 cm, p less than 0.001). Renal pelvis volume was increased as well (29.3 vs 5.5 cm3, p less than 0.001). Renal pelvicalyceal dilation in antepartum pyelonephritis was significantly increased compared with normal physiologic dilation of pregnancy. Follow-up nephrosonography in a small number of women (N = 10) after treatment of pyelonephritis did not reveal a consistent decrease in renal dilation, suggesting that dilation of the renal pelvis may antedate pyelonephritis. Further study of this phenomenon is warranted.

The effect of urinary flow and bladder fullness on renal pelvic pressure in a rat model

We describe an in vivo animal model used to study the interactions of urinary flow, and bladder pressure and fullness on renal pelvic pressure. These parameters were examined in 17 nonrefluxing Sprague-Dawley rats. At urinary flow rates less than 14 cc/kg. per hour and bladders less than 60% full, renal pelvic pressures were below 9 cm. water but at urinary flow rates more than 30 cc/kg. per hour renal pelvic pressure increased above 10 cm. water when the bladder was only 20% full. At all urinary flow rates examined renal pelvic pressure increased to more than 20 cm. water as the bladder approached 100% fullness. To quantitate the combined effects of these changes in renal pelvic pressure and urinary flow on the renal pelvis a renal pelvic work index (renal pelvic pressure times urinary flow rate) was defined. Using this index the magnitude of the change between low urinary flows with an empty bladder and high urinary flows with a full bladder can be observed. The results of these studies in this model might be applicable to high urinary flow states or bladders that fail to empty completely.

Acute nondilated anuric obstructive nephropathy on echography: difficult diagnosis in the intensive care unit

Renal echography (RE) is a well recognized, accurate, non-invasive imaging procedure for detecting urinary tract (UT) obstruction in Intensive Care Unit (ICU) patients: a dilated collecting system is usually present but a few cases of nondilated obstructive nephropathy have been previously described. We report the clinical, biological, imaging procedure data and outcome of 6 additional cases of anuric obstructive nephropathy without dilatation on one or more RE. All patients had previous and/or actual history suggestive of UT obstruction. Retrograde ureteropyelography (RUP) was performed in all of them: it provided the diagnosis of obstruction in 4 and was immediately followed by dramatic improvement of renal function in all, including the 2 patients with septic shock from proven or suspected UT origin. The cause of obstruction was a neoplastic retroperitoneal process in 4. We conclude that anuric nondilated obstructive renal failure is not uncommon and should be considered in anuric patients when UT obstruction is likely to occur. The sole visualization of a non-dilated collecting system on RE should lead to repeat RE, especially in hypovolemic anuric patients. RUP provided immediate diagnostic and therapeutic benefits in comparison with other imaging procedures in our series.

Detubularisation in cystoplasty: clinical review

Cystoplasty using a detubularised bowel segment is preferable to using a tubularised length of intestine. This has been shown experimentally to result in a reduction in the contractility of the neobladder, although contractions are not completely abolished. Incontinence, especially nocturnal, may still be a problem. Assessment of renal function has shown a marked incidence of upper tract dysfunction despite detubularisation. All patients remain at risk of upper tract obstruction following cystoplasty. Because bowel contraction waves are brought on by distension, it may be possible either to postpone or to prevent the onset of contractions by avoiding an excessive build-up of bladder volume. Clean intermittent self-catheterisation is an efficient means of emptying the bladder, although sphincter rebalancing may also be required.

Hydronephrosis Secondary to Bladder Distension

This study was undertaken to evaluate if distension of the urinary bladder can cause reversible distension of the pelvicalyceal system of the kidneys. Ultrasound examinations on 72 healthy individuals with distended bladders showed a 13.9% incidence of mild (Grade 1) and a 2.8% incidence of moderate (Grade 2) hydronephrosis which disappeared when the bladder was emptied. Altered ureteral peristaltic patterns resulting from elevated intravesicular pressure and anatomic changes at the ureterovesical junction may provide a physiologic explanation for the transient hydronephrosis observed. A finding of moderate or severe hydronephrosis irrespective of the degree of bladder distension should alert the sonographer to the likely presence of obstructive uropathy.

The impact of unilateral ureteral obstruction on pelvic and parenchymal transit times in the pig kidney

In 10 female pigs a partial unilateral ureteral obstruction was investigated for 3 weeks. The pigs were monitored with 131I-iodo-hippuran scintigraphies before obstruction and once a week during the course of obstruction. Parenchymal and pelvic mean transit times were calculated by deconvolution analysis. Before the pigs were killed, pelvic pressure and volume were measured. During the course of obstruction there was a slight, but significant (P less than or equal to 0.05) difference in renographical split function between the 2 sides. Parenchymal transit times increased moderately ipsilaterally during the 1st and 2nd week after obstruction and a significant difference (P less than 0.02) appeared in the 2nd week compared to the contralateral side, which was unchanged during the course of obstruction. Pelvic transit times increased steadily ipsilaterally during the course of obstruction and the opposite took place contralaterally. A fair correlation (r = 0.65) was found between parenchymal transit time and pelvic baseline pressure. Pelvic transit times were prolonged at any time after obstruction and significantly correlated to the presence of obstruction. The study suggests that interpretation of the obstructed renogram will encounter analysis of both parenchymal and pelvic transit times in cases where renal function is moderately reduced.

Obstructive uropathy in patients with benign prostatic hyperplasia

In an attempt to determine the role of obstructive prostatic hyperplasia as a cause of irreversible renal function the records of 32 men with a diagnosis of benign prostatic hyperplasia and renal failure were reviewed. Patients were classified as either having a serum creatinine of more than or less than 4 mg.per 100 ml. when they were discharged from the hospital. Admission serum creatinine levels were comparable in both groups. Characteristics of the group with permanently impaired renal function included a longer mean duration of symptoms, higher incidence of urinary tract infection, lower average volume of residual urine and greater incidence of small kidneys with increased parenchymal echogenicity. These data assist in the objective prediction of patients who will have irreversible renal dysfunction when presenting with obstructive benign prostatic hyperplasia.

Medical Concerns Among Wheelchair Road Racers

In brief: Before participating in the 1987 Peachtree Road Race in Atlanta, 43 wheelchair athletes completed a questionnaire about their training methods, injuries, and medical concerns. The injuries reported most frequently were abrasions and musculoskeletal syndromes of the upper extremities. Of particular interest in the study were the types of residual neurologic deficits and autonomic dysfunction among athletes with spinal cord injury. These deficits included altered temperature regulatory mechanisms, neurogenic bladder and bowel, spasticity, and autonomic dysreflexia. Athletes also reported the medications they used; several medications used frequently by this group of athletes may have an adverse effect on performance.

Long-term monitoring of bladder pressure in chronic retention of urine: the relationship between detrusor activity and upper tract dilatation

We investigated 41 men with chronic retention of urine owing to bladder outflow obstruction by long-term monitoring of bladder pressure and conventional cystometry to determine the relationship between detrusor pressure and upper tract dilatation. We confirmed that high pressures during conventional filling cystometry were common in men with upper tract dilatation. However, important differences were demonstrated between long-term monitoring and conventional cystometry. The pressure increase during the natural filling phase of long-term monitoring was significantly smaller than that during conventional cystometry. Detrusor instability was found in 88 per cent of the men during long-term monitoring but in only 51 per cent during conventional cystometry (p less than 0.001). High frequency unstable detrusor contractions during long-term bladder pressure monitoring were associated significantly with upper tract dilatation (p less than 0.0001) and correlated significantly with impairment of glomerular filtration rate (rs equals -0.7339, p less than 0.001).

Iatrogenic dilatation of the upper urinary tract during radiographic evaluation of patients with spinal cord injury

Patients with upper and lower motor neuron spinal cord injuries were observed to determine whether cystography immediately before excretory urography induced iatrogenic dilatation of the upper urinary tract that was indistinguishable from true pathological dilatation. Evidence is given that such dilatation occurs. This iatrogenic dilatation is not seen in patients with normally innervated urinary tracts and appears to be caused by exaggerated bladder reflexes in patients with upper motor neuron lesions. Bladder spasms precipitated by cystographic contrast material also may create vesicoureteral obstruction and lead to dilatation of the upper urinary tract. Consequently, it is suggested that cystography should not immediately precede excretory urography. When such a sequence is necessary, room or body temperature contrast medium should be used for the cystogram, the bladder should be emptied before the excretory urogram is started and a 1-hour interval should be allowed between the 2 procedures. The findings also suggest that any factors that induce repeated or continuing bladder spasms may contribute to progressive dilatation of the upper urinary tract.

Sonographic biometry in obstructive uropathy of children: preoperative diagnosis and postoperative monitoring

Renal sonography was performed in 92 children with obstructive uropathy or vesicoureteral reflux preoperatively and at follow-up. Renal volume and the anteroposterior diameter of the renal pelvis proved to be the most reliable morphometric criteria for objective sonographic staging and follow-up of urinary tract obstruction. If transient obstruction occurred after uncomplicated antireflux ureterovesico-plasties (n = 41), it lasted at most 4 weeks. Kidneys with transient postoperative ureterovesical junction obstruction (n = 21) reverted to normal sonographic pattern within 4 weeks following ureteral reimplantation. In cases of ureteropelvic junction obstruction (n = 30), it took up to 6 months for the majority of kidneys to present almost normal sonographic findings. Sonographic biometry and the knowledge about the uncomplicated postoperative course render postsurgical monitoring easier and more reliable.

Noncompliant bladder resulting from posterior urethral valves

We report on 4 boys with abnormally functioning, poorly compliant bladders and residual urine associated with posterior urethral valves. All 4 boys have been managed with clean intermittent self-catheterization and have shown stabilization or improvement in renal function, and improvement in upper tract drainage and urinary continence. The pathophysiological findings of this type of bladder dysfunction are discussed.

The value of post-void radiographs in excretory urography

For years, urologists and radiologists have had differing opinions on the value of post-void radiographs in excretory urography. This report is based on a questionnaire sent to the members of the Association of University Urologists and the Society of Uroradiologists. Satisfactory evaluation of bladder function by the use of post-void radiographs is not always possible. Nevertheless, such radiographs have value in selected cases and often play a major role in determining future therapy.

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.

The ureterovesical junction

The ureterovesical junction was studied by dissection and serial sections in 50 post mortem specimens. Three points are considered in this paper: the structure of the terminal ureter, the anatomical arrangement of the ureteral hiatus and the ureteral sheath. Study of the structure of the intramural segment of the ureter demonstrated on one hand, the perfect continuity of the terminal ureter with the trigone and on the other hand, the abundance of the fibroelastic connective fibers which like the muscle fibers run longitudinally. The compliance of the intravesical ureter is dependent on the balance between these two components. The modification of this balance can lead to the creation of a functional obstacle. The anatomical arrangement of the ureteral hiatus is described. The inner muscle layer of the detrusor extends almost to the ureteral orifice, the truly submucosal part of the ureter thus being very small. The constitution of the ureteral orifice and its relations to the ureter account for the different positions of juxtaureteral diverticula and transhiatal herniae of the bladder mucosa. The many descriptions of the ureteral sheath appearing in the literature are reviewed in light of the findings from the present study. The juxtavesical segment of the ureter is surrounded by a fibroconjunctive sheath which fixes the ureter to the bladder wall. The transparietal segment of the ureter is ensheathed in its adventitia, whereas a fibromuscular sheath cannot be truly individualized over this ureteral segment.

Acute effects of full urinary bladder and full caecal urinary reservoir on regional renal function. A study with scintillation camera renography

Scintillation camera renograms were recorded in six patients without a history of bladder function disturbances and in eight patients with caecal urinary reservoir. Each patient was studied once with empty bladder/reservoir and once with full bladder/reservoir. Renograms were obtained from parenchyma, pelvis and whole kidney. Time was measured from injection of isotope to peak of the renogram curve (Tmax) and to the point corresponding to the centre of gravity of the area under the curve (Tg). A full reservoir gave longer Tmax and Tg for both parenchyma and pelvis than an empty reservoir. With full bladder the only significant change was Tg increase for renal pelvis. In the patients with full caecal reservoir, the elimination of radioisotope from the renal pelvis was significantly slower, reflected as longer Tmax and Tg, than in the subjects with full bladder. In comparisons between empty and full bladder/reservoir, Tg permitted clearer separation between the groups than did Tmax. The higher Tmax and Tg values for full than for empty reservoir indicated obstruction to urinary flow and could be ascribed to the high intrareservoir pressure. Regularly occurring pressure waves with amplitudes of 30-65 cm H2O were recorded in the reservoirs, sometimes reflected as transient increases in radioisotope activity in the renograms. In some patients the two kidneys differed considerably in their response to a full urinary bladder or reservoir. The cause may have been difference in the dynamics of the two ureterovesical junctions or of the ureterointestinal anastomoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonography in the diagnosis of hydronephrosis in patients with normal renal function

In order to define the sensitivity and specificity of ultrasonography (US) in the diagnosis of hydronephrosis, 125 patients with normal renal function were examined after urography using high-resolution real-time scanning. The overall diagnostic accuracy of US in detecting hydronephrosis was 85.2%, with a specificity of 84.4% and a sensitivity of 89.9%. It is concluded that US may be considered the screening test of choice for the diagnosis of hydronephrosis. However, urography is still required for the evaluation of renal function, site, and nature of the obstruction when US shows a dilated collecting system and in the patient with a normal US but renal colic.

Clinical experience with upper tract urodynamics

Of 25 upper tract urodynamic studies performed in 22 patients 9 positive results were obtained. The diagnosis of intrinsic ureterovesical junction obstruction was suspected in 11 children but only confirmed in 2. However, in 6 other children changes in bladder volume markedly affected upper tract function. While diuretic renography may confirm obstruction in many doubtful cases, when function is poor and the system is dilated massively a urodynamic study often will be the only definitive diagnostic procedure.

The clinical significance of dilatation of the collecting system in the transplanted kidney

The significance of dilatation of the collecting system of the transplanted kidney and its relationship to bladder distention was reviewed in 39 renal recipients examined by sonography (94 studies). The degree of pelvicaliceal (PCS), ureteral, and bladder distention was graded and correlated with the 24-h urine output, nuclear renal scan, and clinical follow-up. marked PCS distention can indicate obstruction (33%), especially when there is no associated bladder distention (60%) and a fluid collection lies along the path of the ureter. The 24-hr urine output did not influence the degree of PCS distention.

Misleading appearances in pediatric uroradiology

Certain misleading appearances are peculiar to pediatric uroradiology. The most frequently encountered pitfalls are related to the bladder, to vesicoureteral reflux, and to the duplicated collecting system. The bi-chambered nature of the child's bladder, and the rapid settling of contrast material to the most dependent portion causes many pitfalls in diagnosis. When the child is prone, normal ureters may seem to be ectopic, and ureteroceles may become invisible. When the child is supine, the volume of urine in the bladder may be grossly under-estimated. Reflux can mimic function at urography. The dynamic nature of reflux leads to under-estimation of its presence and degree on the IVP and static cystogram. Reflux into an already dilated system can lead to over-estimation of its degree. Aberrant micturition with rapid refilling of the bladder can simulate incomplete emptying. The diagnosis of "ectopic ureterocele" is based on indirect evidence. Any condition that affects the urinary apparatus in the same way will have a similar appearance. A hugh ureterocele may have a small ureter, and massive reflux into a lower pole ureter may make the diagnosis of duplication difficult. Ureteroicele "look-alikes", and effacement or intussusception of the ureterocele are cystographic pitfalls. Lower pole ureteropelvic junction obstruction and Wilms tumor in the lower portion of a kidney can have surprisingly similar appearances.

The effect of bladder function on the dynamics of the ureterovesical junction

Upper tract perfusion studies in suspected ureterovesical junction obstruction should always be performed with measurement of intravesical pressure and with variation in bladder volume. Obstruction observed with increasing bladder volumes may be related to a non-compliant bladder wall, mechanical obstruction at or near the junction itself or a combination of both factors.