Quantitative analysis of infantile ureteropelvic junction obstruction by diuretic renography

Infantile hydronephrosis detected by ultrasonography poses a clinical dilemma on how to treat the condition. This article reports a retrospective study to evaluate infantile hydronephrosis due to suspected ureteropelvic junction (UPJ) obstruction by means of standardized diuretic renography and to speculate its usefulness for quantitative assessment and management of this condition. Between November 1992 and July 1999, 43 patients who had the disease detected in their fetal or infantile period were submitted to this study. Standardized diuretic renograms were obtained with 99mTc-labeled diethylene-triaminepenta-acetate (Tc-99m-DTPA) or 99mTc-labeled mercaptoacetyl triglycine (Tc-99m-MAG3) as radiopharmaceuticals. Drainage half-time clearance (T 1/2) of the activity at each region of interest set to encompass the entire kidney and the dilated pelvis was used as an index of quantitative analysis of UPJ obstruction. Initial T 1/2s of 32 kidneys with suspected UPJ obstruction were significantly longer than those of 37 without obstruction. T 1/2s of kidneys which had undergone pyeloplasty decreased promptly after surgery whereas those of units followed up without surgery decreased more sluggishly. These findings demonstrate that a standardized diuretic renographic analysis with T 1/2 can reliably assess infantile hydronephrosis with UPJ obstruction and be helpful in making a decision on surgical intervention.     

^99Tc^m—DTPA肾皮质通过时间延迟预测肾盂输尿管连接部狭窄术后肾功能改善的价值

目的探讨^99Tc^m-DTPA利尿肾动态显像皮质通过时间（PTT）作为预测肾盂输尿管连接部狭窄（UPJO）离断式肾盂成形术后肾功能改善指标的可行性。方法回顾性分析47例[男37例,女10例,年龄（29．7±10．8）岁]单侧UPJO患者临床情况及手术前后^99Tc^m-DTPA利尿。肾动态显像,记录患者的年龄、性别、患肾位置、梗阻类型、手术方式、相对肾功能[RRF（患肾放射性摄取占总肾的百分比）]以及PTT,评价不同因素或指标对术后患肾RRF改善率（术后与术前RRF差值）的影响。符合以下情况之一即为PTT延迟：（1）在第2—7帧慢动态影像上,积水肾盂内未见放射性;（2）在第2～9帧慢动态影像上,肾皮质放射性无变化,肾大小、形态变化不明显;（3）肾皮质放射性持续增加;（4）自慢动态第2帧影像始,肾皮质放射性清除较对侧正常肾慢。采用配对t检验、KruskM—Wallis及Mann—Whitney秩和检验和Pearson相关分析对数据进行统计学分析。结果术后患肾RRF高于术前,分别为（40．70±13．30）％、（44．96±12．60）％,t=4．19,P〈0．01。PTT延迟组（16例）RRF改善率显著高于PTT正常组（27例）,分别为（11．69±6．52）％、（0．48±2．98）％,z=-5．13,P〈0．01;4例患肾PTT不能明确判断延迟或正常。术前不同RRF（〈40％与40％）、梗阻类型（机械性与非机械性）、患肾位置（左与右）、手术方式（开放手术与腹腔镜手术）以及性别（男与女）组间的患肾RRF改善率差异均无统计学意义（z=-1．93～1．25,均P〉0．05）。患肾RRF改善率与患者年龄之间未见有统计学意义的相关性（r=0．01,P〉0．05）。结论^99Tc^m-DTPA利尿肾动态显像PTT延迟是预测UPJO患者术后肾功能改善的唯一有效指标。     

Diuretic radionuclide renography in assessing Anderson-Hynes pyeloplasty in unilateral pelviureteric junction obstruction

The topic of whether improvement can be expected after pyeloplasty in patients with pelvi-ureteric junction obstruction (PUJO) continues to generate debate. The aim of this study was to analyse the functional outcome of unilateral Anderson-Hynes (A-H) pyeloplasty using differential renal function (DRF) and drainage patterns determined by diuretic radionuclide renography (DRR). A retrospective study was carried out by evaluation of the records of patients who underwent A-H pyeloplasty for unilateral PUJO and reported for a follow up renal dynamic scan between the years 2000 and 2003. A total of 126 patients (93 males and 33 females) aged three months to 40 years had undergone pre-operative and post-operative DRR and were followed for at least six months after operation. For comparison, the renal function prior to and after pyeloplasty was classified into three Groups based on the DRF: Group A: > or = 40% DRF 52 patients, Group B: 20%-39% DRF 65 patients and Group C: < 20% DRF 9 patients. The difference between pre-operative and post-operative DRF in the last follow up study, which ranged from six months to 144 months after operation, was calculated for each patient. To account for an accepted error of measurement, an absolute difference in DRF of more than 5% was considered significant. Improvement in drainage was assessed by the time Tmax 1/2 of the renographic curve. Unpaired t test was applied between Group A and Group B patients. Chi square analysis was applied to estimate the proportion of improvement between Groups A and B. Post-pyeloplasty scans revealed stable renal function in 102 (81%) subjects, while improvement was noticed in 14 (11%) subjects. The remaining 10 (8%) subjects had deterioration in renal function. No improvement in renal function was seen in Group C patients. Our results have shown that in the majority of cases studied, after A-H pyeloplasty renal function remains stable. A-H pyeloplasty applied in patients with preserved DRF and obstruction will result in long term preservation of renal function.     

Volume expansion diuretic renal scan in urinary tract obstruction

The diuretic renal scan is used to differentiate the obstructed dilated urinary system from the nonobstructed dilated system. The technique, however, has a false-positive and indeterminate rate of 10%-15%. This usually is due to variables such as the degree of dilatation of the pelvicalyceal system or ureter, the degree of bladder distention, the diuretic dose, and the state of hydration. We developed the volume expansion diuretic renal scan (VEDRS) to overcome these variables and to improve the accuracy of the technique. Twelve patients who had obstructive patterns on the diuretic renal scan were evaluated. Ten patients were shown to be dilated but not obstructed. Two patients were confirmed as obstructed. This technique improves the accuracy of the diuretic renal scan.     

Volume related configurational changes in the aetiology of pelvi-ureteric junction obstruction

The aetiology of pelivi-ureteric junction (PUJ) obstruction is controversial. We present four patients who had normal or equivocal intravenous pyelograms and non-obstructive Whitaker tests in whom complete pelvi-ureteric obstruction was precipitated by more rapid distension of the renal pelvis. We speculate that in vivo physiological urine flow rates and temporary kinking of PUJ produces a critical increase in pelvic volume and subsequent valvular kinking of the upper ureter, which cannot be usually achieved by maximal urine flow rates alone. Co-existence of vesico-ureteric reflux (VUR) may be a contributory factor to critical pelvic distension and tortuous PUJ. Volume related configurational changes of this type are probably a more frequent cause of PUJ obstruction than is generally recognised.     

Utility of diuretic renography in the detection of an enteroureteral fistula

After a 2-year-old male with left impairment underwent surgery for a left vesicoureteral stenosis, his renal function was followed up by means of dynamic renal scintigraphy with 99mTc-DTPA. Incidental radiotracer accumulation was observed in left hemiabdomen tracing the descending and sigmoid colon. A vesico-colonic fistula was suspected. However, ultrasonography and cystography studies showed no presence of a vesico-enteric fistula. Because the patient persisted without symptoms, an expectant approach was adopted. One year later, he began to suffer watery diarrhoea episodes. 99mTc-DTPA renography was again performed to re-evaluated renal function and explore presence of urinary-enteric fistula. Diuretic renography demonstrated the presence of a vesical leak to sigmoid gut, which was confirmed by recovery of fecal matter from the patient. Both isotopic renograms evidenced the presence of uretero-sigmoid fistula, an uncommon postsurgical that was not detected by cystography, ultrasonography or RMN. The patient subsequently underwent surgery for fistula repair.     

Multidetector computed tomography arteriography in the preoperative assessment of patients with ureteropelvic junction obstruction

BACKGROUND: Nowadays, endoscopic management of ureteropelvic junction (UPJ) obstruction is the treatment of choice. However, in the presence of crossing vessels, the success rate of endoscopic management decreases and the risk of hemorrhagic and vascular complications rises. The purpose of this study is to evaluate patients with UPJ obstruction using contrast enhanced multidetector computed tomography (CT) angiography to aid in surgical planning and management. PATIENTS AND METHODS: Between 2001 and 2005, 27 patients (mean age: 43 years; age range: 17-75 years) with UPJ obstruction were studied with multidetector CT angiography. Identification and characterization of crossing vessels was performed with multidirectional images and three-directional reconstructions. RESULTS: 12 patients (44%) were found to have 16 crossing vessels (vessels in contact with the UPJ or within a vicinity of less than 2 mm). Nine of these vessels were arteries and seven were veins. Nine vessels crossed anteriorly, two posteriorly, and one anteromedially. Endopyelotomy was contraindicated in these 12 patients due to the presence of crossing vessels. Eleven out of the 12 patients underwent a pyeloplasty by open surgery or laparoscopy, where the presence of crossing vessels was confirmed. One of the 12 patients did not undergo surgery. CONCLUSION: Multidetector CT angiography permits an adequate preoperative assessment of patients with UPJ obstruction as it is able to identify the presence and location of crossing vessels. Furthermore, it allows to study in detail the anatomy of the renal area and its vascular variants.     

Use of helical CT in assessment of crossing vessels in pelviureteric junction obstruction

AIM: The purpose of this study is to confirm the accuracy of non-invasive helical computed tomography (CT) with multiplanar reformatting in the diagnosis of crossing vessels in patients with pelviureteric junction (PUJ) obstruction. MATERIALS AND METHODS: Nineteen patients with confirmed PUJ obstruction underwent CT of the renal area with intravenous contrast medium. Patients shown to have crossing vessels had to undergo a pyeloplasty by open surgery or laparoscopy. Patients with no vessels could have their PUJ obstruction safely treated with less invasive techniques such as balloon dilatation. RESULTS: Fourteen patients were shown to have crossing vessels. Of these, 10 had their relationship to the PUJ confirmed at a subsequent laparotomy. Of the remaining four patients, one was lost to follow-up and two were unwell due to unrelated disease. The other patient had already had a vessel moved at a previous laparotomy. Of the five patients without obstructing vessels, two were confirmed not to have a related vessel at laparotomy, one has undergone balloon dilatation and the other two were lost to follow-up. CONCLUSION: Helical CT is an accurate and non-invasive method of demonstrating crossing vessels in PUJ obstruction. Diagnosis of these vessels has a major role in the choice of therapeutic treatment.     

利尿肾动态显像在小儿先天性泌尿系统畸形中的应用

目的 探讨利尿肾动态显像（DR）在小儿先天性泌尿系统畸形诊断及随访评价中的应用价值.方法 163例确诊为先天性泌尿系统畸形的患儿均行DR检查,其中97例术后复查DR.观察泌尿系统各部位的形态特征,并根据DR结果对肾积水进行分度;对随访结果进行定性和定量评估.结果 泌尿系统畸形各有其DR影像改变特征.术后随访见肾功能明显提高;肾重复与输尿管畸形预后较好,尿道瓣膜预后较差.结论 DR可显示先天性泌尿系统畸形的特征性改变;用于定性或定量评估随访结果,简便可靠.     

Role of MR renography in the evaluation of acute upper urinary tract obstruction

Purpose

To present the role of MR renography in diagnosis of upper urinary tract obstruction (UTO) with evaluation of diagnostic criteria for acute obstruction.

Material and methods

Thirty consecutive patients with obstructive anuria were included in our study. For identification of the cause of obstruction, all patients were subjected to plain abdominal X-ray (KUB), gray scale ultrasonography, non-contrast CT for the abdomen and pelvis (NCCT). There were five patients with bilateral obstruction and 25 with obstructed solitary functioning kidney, so the study included 35 units. All patients were subjected to radioisotope diuretic renography and magnetic resonance renography (MRR) before relief of obstruction and 3 days after drainage. Of the 30 patients included, 20 were men and 10 women.

Results

Among our patients the mean serum creatinine at time of presentation was 7 ± 4.5 mg/dl (range 2.4–12) and GFR ranged from 33 to 48 ml/min (mean ± SD; 38 ± 4.2). All the renal units have hydronephrosis. The mean pre drainage SI values 133 ± 22 (range 120–180). The mean time to peak (TP) for each unit was 171.6 ± 78 s and at isotope renography it was 320 ± 66 s. There was good corticomedullary differentiation (CMD) in 31 units and the remaining 4 showed loss of CMD differentiation. The CMD crossing time was 163.6 ± 70.4 s. Post kidney drainage the parenchymal SI was increased in 30 units, in 3 units there was drop and no change in 2 (r = 0.29). There is relative reduction in the time to peak, it becomes 67 ± 79 s after drainage (r = 0.76).

Conclusion

MR renography is a clinically valuable technique that provides diagnostic criteria to diagnose the acute urinary obstruction and allows follow up of renal function.     

^99Tc^m-双半胱氨酸利尿肾动态显像评价小儿先天性肾盂积水手术前后肾功能

目的探讨^99Tc^m-双半胱氨酸（EC）利尿。肾动态显像（DR）在小儿先天性肾盂积水手术前肾功能评价和术后随访中的临床价值。方法回顾性分析40例肾盂积水患儿的DR（常规方法中第15分钟注射呋塞米）,对患肾血流灌注率（BPR）及有效肾血浆流量（ERPF）、肾盂积水分度、肾图曲线和动态显像图进行手术前后的比较。符合正态分布数据间比较采用t检验,等级资料数据间比较采用非参数检验。结果（1）40只患肾的BPR术前为（34．05±11．07）％,术后为（40．04±8．56）％,平均提高5．99％（t=-5．13,P〈0．01）。患肾的ERPF术前为（57．81±34．32）ml／min,术后为（70．29±5．37）ml／min,平均提高12．48ml／min（t=-4．35,P〈0．01）。（2）40只患肾的。肾盂积水分度的平均秩和术前为47．21,术后为33．79（Z=-2．64,P〈0．01）。（3）随着积水程度的加重,患肾形态增大,肾实质变薄,肾内放射性缺损范围增大,对利尿试验的反应明显减弱直至无反应。（4）术前DR诊断肾盂输尿管连接处梗阻（UPJO）37例,输尿管膀胱入口处梗阻（UVJO）3例,术前梗阻的定位均为手术证实。结论DR是评价小儿先天性肾盂积水的一种可靠方法,能够准确反映病情、指导治疗,并监测手术疗效。     

Aspirin renography and captopril renography in the diagnosis of renal artery stenosis.

Preliminary data suggest that aspirin renography is more sensitive than captopril renography for indicating renal artery stenosis (RAS). Considering that aspirin, compared with captopril, reduces renal blood flow and, thus, tubular tracer delivery in poststenotic kidneys, aspirin renography is expected to be more useful, particularly if tubular tracers are used. METHODS: We prospectively compared aspirin renography (20 mg/kg orally) and captopril renography (25 mg orally) with 99mTc-mercaptoacetyltriglycine in 75 consecutive patients suspected of having RAS. RESULTS: RAS, diagnosed as stenosis of more than 50% on angiography, was found unilaterally in 34 patients and bilaterally in 17 patients. RAS was absent in 24 patients. The sensitivities for unilateral RAS or bilateral RAS (i.e., stenosis that was at least unilateral) were, respectively, 88% and 88% for captopril renography and 82% and 94% for aspirin renography (not significant). The overall specificity was 75% for captopril renography and 83% for aspirin renography (not significant). Tracer uptake ratios, time to peak activity, and percentage of 20-min tracer retention were also not significantly different for captopril and aspirin renography. Subgroup analysis of modest (50-75%) and severe (> or =75%) RAS, or of plasma creatinine greater than 120 micromol/L, also showed no difference between captopril and aspirin renography. CONCLUSION: We conclude that for identification of RAS, the usefulness of aspirin renography equals, but does not surpass, that of captopril renography.     

Lower-pole ureteropelvic junction obstruction with abnormal rotation in duplicated system.

The association of lower pole ureteropelvic junction obstruction and duplicated system is rare. We present a unique case of duplex system with lower pole ureteropelvic junction obstruction and reverse rotation anomaly of this moiety.     

The F + 0 protocol for diuretic renography results in fewer interrupted studies due to voiding than the F - 15 protocol.

Timing of diuretic administration is not universally standardized in renography. Over the past year, our practice has changed from F-15 administration of furosemide to an F + 0 protocol. Therefore, we have retrospectively compared these 2 cohorts to assess if the shorter interval between diuretic administration and study completion in the F + 0 study results in a greater frequency of patients able to complete the subsequent 30-min dynamic acquisition without disruption due to voiding. METHODS: We identified 108 diuretic (99m)Tc-mercaptoacetyltriglycine renograms performed in the previous 18-mo period. Three patients were given furosemide at 30 min after the radiopharmaceutical and were excluded. Twenty studies in children under 3 y of age were excluded from consideration because voiding is neither restricted in this age group nor does voiding into a diaper cause disruption. Forty milligrams of furosemide were administered to adults, whereas 0.5 mg/kg was given to children. In the first cohort of 56 studies, radiopharmaceutical was administered 15 min after furosemide (F-15), whereas, in the second cohort of 29 patients, it was administered immediately thereafter (F + 0). In all cases, patients were asked to void proximal to radiopharmaceutical injection. Dynamic images and renogram curves were inspected for evidence of interruption or voiding midstudy. Statistical significance was determined by a 1-tailed Fisher exact test for proportions, with P < 0.05. RESULTS: The F-15 and F+0 groups of patients were comparable in terms of age, sex, and diuretic amount. In 17 of the F-15 patients, renography was interrupted because of voiding (30%), whereas this occurred in only 3 of the F + 0 patients (10%). This difference was significant at the P = 0.033 level. The mean time of voiding was 18.3 min (range, 12-25 min) for F-15 patients and 16 min (range, 12-19 min) for the F + 0 group. CONCLUSION: The F + 0 renal diuretic protocol is associated with a significantly lower rate of disruption because of voiding than the F-15 protocol, likely due to the shorter period between diuretic administration and study termination, which results in less bladder distention and discomfort. On the basis of these data, the F + 0 protocol appears to be a more tolerable procedure.     

Sonographic analysis of the fetus with ureteropelvic junction obstruction

Twenty-five fetuses with ureteropelvic junction obstruction were evaluated to determine the likelihood of progression of hydronephrosis in utero, and the outcome for the neonate. Such information may alter prenatal as well as perinatal management. These observations showed that the degree of dilatation in utero is likely to be greater than that observed postnatally; the degree of dilatation does not necessarily correlate with renal functional impairment measured postnatally; significant progression of dilatation in utero is relatively uncommon, especially in unilateral cases; and uretero-pelvic junction obstruction, even when bilateral, is unlikely to be fatal. Of 21 live newborn infants with follow-up, 14 required surgery and seven were placed under observation.     

The use of prone films for suspected bowel obstruction in infants and children.

Prone frontal and cross-table lateral views of the abdomen are recommended as most helpful in radiographic evaluation of infants and children suspected of having obstructive of nonobstructive ileus. A series of films in multiple projections is recommended to evaluate the gas in the large bowel, particularly the rectum. When studies must be limited, prone and left lateral decubitus views are recommended. In obstructive ileus, the collapsed rectum contains little or no air. Utilization of the prone view will often obviate the use of fluoroscopic contrast studies. The level of obstruction, as well as the cause, can often be determined by this plain film approach. Six cases are presented to illustrate these points.