Diagnostic accuracy of color Doppler sonographic study of the ureteric jets in evaluation of hydronephrosis

Color Doppler Ultrasound's Utility in Detecting Vesicoureteral Reflux Using the Ureteral Jet Angle

OBJECTIVES

This study hypothesizes using color Doppler ultrasound to measure ureteral jet angles (UJA) as a diagnostic screening tool for reflux.

METHODS

The present prospective cohort study included 122 patients and 238 renal unit pediatric patients suspected of VUR who presented to our hospital between 2019 and 2021. All patients underwent ultrasonography and VCUG, and the UJA was measured color Doppler evaluation of the ureteral jet. The UJA was compared with the VCUG findings in patients with and without reflux. SPSS 26 was used to analyze the data.

RESULTS

A total of 96 patients and 139 renal units exhibited reflux. The mean ureteral jet angle in refluxing units was 60.47 + 16.66 degrees, whereas, it was 42.59 + 13.26 degrees in non-refluxing units, a significant difference between the two groups (P < .001). The mean ureteral jet angle was 42.59, 45.89, 60.32, 68.23, and 56.16, for reflux grading from 0 to 5 (except grade 1), respectively. The angle value in each reflux grade increased significantly except for grade 5. For reflux detection (grade I-V), a cut-off angle of 50 degrees was associated with sensitivity and specificity of 70 and 79, respectively. Grade IV/V reflux can be diagnosed with a sensitivity of 70% and specificity of 84% using a cut-off angle of 68 degrees or greater.

CONCLUSIONS

UJA detection via color Doppler ultrasound demonstrates high accuracy, is non-invasive method can be utilized as an alternative primary diagnostic tool or in follow-up cases of VUR in children.

Urinary tract obstruction: Ultrasound-guided intervention

Introduction

Urinary tract obstruction (UTO) is a common clinical problem of which there are many potential causes. The aim of this feature article is to explore the role of ultrasound in diagnosing UTO, during guided interventional procedures and the potential procedural complications.Topic description and discussion: Ultrasound is an integral imaging modality throughout the management pathway of a patient with UTO and is often utilised as a first-line test in diagnosis and treatment. Percutaneous nephrostomy is an interventional technique, usually performed by radiologists or interventional sonographers, as either a short- or long-term management strategy. It can either be used in isolation or to gain access to the renal collecting system prior to more complex interventional or surgical techniques. Ultrasound-guided interventional techniques to relieve UTO can be employed in a number of clinical scenarios each with their own indications, contraindications and complications.

Conclusion

Ultrasound plays a unique role in the planning and active stages of intervention with the provision of dynamic imaging which is crucial for providing safe and effective patient management.

Role of pretreatment Doppler ultrasound in the prediction of factors affecting stone-clearance post-shockwave lithotripsy for ureteral stones: a prospective study

PURPOSE

To identify the role of Doppler US (DUS) in the prediction of factors affecting stone-clearance post-SWL for ureteral stones in addition to its role in prediction of pretreatment stone impaction.

METHODS

We prospectively included patients with ureteric stone for SWL between October 2018 and September 2019. Patient's demographics were collected. Using DUS, resistive index (RI), Δ RI, and ureteric jets were evaluated in both kidneys. Also, stone site, volume, density, skin to stone distance, degree of hydronephrosis, ureteral wall thickness (UWT) were evaluated by NCCT. Univariate and multivariate logistic regression analyses were performed to identify factors that contribute to treatment success. Correlation between ipsilateral RI with other radiological findings predicting stone impaction was done.

RESULTS

A total of 93 patients were finally included (61 males and 32 females). The mean age was 31.4 ± 7.7 years. The success rate (absence of significant residuals post 1 month by NCCT) was 51.6%. In multivariate analysis, the presence of ureteric jet, ipsilateral lower RI, and ipsilateral lower UWT were independent factors for treatment success (P = 0.0001, 0.002, and 0.03, respectively). Also, ipsilateral absence of ureteric jet, increased hydronephrosis, and increased UWT were correlated with higher ipsilateral RI in prediction of stone impaction. Ipsilateral higher RI was found to achieve higher accuracy in stone impaction prediction (PPV of 94.8%).

CONCLUSION

Pretreatment DUS is a useful, non-invasive with a less irradiative tool for prediction of stone impaction and stone-free rate post-SWL for ureteric stones.

Urinary Ultrasound and Other Imaging for Ureteropelvic Junction Type Hydronephrosis (UPJHN)

Ultrasound is the main imaging study used to diagnose ureteropelvic junction (UPJ) obstruction. On ultrasound, abnormal dilatation of the pelvicalyceal system of varying degrees is seen, whereas the ureter is normal in caliber. A properly performed study provides essential information regarding laterality, renal size, thickness, and architecture of the renal cortex and degree of dilatation of the pelvicalyceal system. Doppler ultrasound may identify a crossing vessel, when present. This imaging method also has been used differentiating obstructive from non-obstructive hydronephrosis by renal arterial resistive index measurements. Abdominal radiographs may show soft tissue fullness, bulging of the flank, and displacement of bowel loops from the affected side. The voiding/micturating cystourethrogram helps exclude other causes of upper tract dilatation, including vesicoureteral reflux, urethral valves, and ureteroceles. Computerized Tomography angiography with multiplanar reformation and three-dimensional images may be used to depict suspected crossing vessels as a cause of UPJ obstruction in older children and adults. Magnetic Resonance Urography has progressed significantly in recent years due to the development of both hardware and software that are used to generate high-resolution images. This imaging technique currently allows for the detailed assessment of urinary tract anatomy, while also providing information regarding renal function, including differential renal function, and the presence or absence of obstructive uropathy.

Ultrasound and color Doppler applications in chronic kidney disease

Chronic kidney disease (CKD) includes all clinical features and complications during the progression of various kidney conditions towards end-stage renal disease (ESRD). These conditions include immune and inflammatory disease such as: primary and hepatitis C virus (HCV)-related glomerulonephritis; infectious disease such as pyelonephritis with or without reflux and tuberculosis; vascular disease such as chronic ischemic nephropathy; hereditary and congenital disease such as polycystic disease and congenital cystic dysplasia; metabolic disease including diabetes and hyperuricemia; and systemic disease (collagen disease, vasculitis, myeloma). During the progression of CKD, ultrasound imaging and color Doppler imaging (US-CDI) can differentiate the etiology of the renal damage in only 50-70% of cases. Indeed, the end-stage kidney appears shrunken, reduced in volume (Ø < 9 cm), unstructured, amorphous, and with acquired cystic degeneration (small and multiple cysts involving the cortex and medulla) or nephrocalcinosis, but there are rare exceptions, such as polycystic kidney disease, diabetic nephropathy, and secondary inflammatory nephropathies. The main difficulties in the differential diagnosis are encountered in multifactorial CKD, which is commonly presented to the nephrologist at stage 4-5, when the kidney is shrunken, unstructured and amorphous. As in acute renal injury and despite the lack of sensitivity, US-CDI is essential for assessing the progression of renal damage and related complications, and for evaluating all conditions that increase the risk of CKD, such as lithiasis, recurrent urinary tract infections, vesicoureteral reflux, polycystic kidney disease and obstructive nephropathy. The timing and frequency of ultrasound scans in CKD patients should be evaluated case by case. In this review, we will consider the morpho-functional features of the kidney in all nephropathies that may lead to progressive CKD.

How may Doppler indices help in the differentiation of obstructive from nonobstructive hydronephrosis?

Background:

We assess the potency of different Doppler indices in the differentiation of obstructive and nonobstructive hydronephrosis.

Materials and Methods:

In this study, infants and children who were referred for the evaluation of unilateral hydronephrosis were enrolled. Ultrasonography for the assessment of the degree of hydronephrosis and a voiding cystourethrogram for the exclusion of vesicoureteral reflux was performed. Then, Doppler ultrasonography was done for both kidneys of each patient using four classic Doppler indices as well as the difference (delta) of each index between to kidneys. Diuretic renography with 99 mTc-ethylene dicysteine (99 mTc-EC) was performed for each patient.

Results:

Thirty-nine patients met the inclusion criteria. After diuretic renography, 29 (74.35%) patients had shown a nonobstructive pattern, and ten (25.65%) patients had a partial (intermediate) or complete obstruction. Using receiver operating characteristic (ROC) curve, none of the classic indices of Doppler duplex (i.e., resistive index [RI], resistance index, end diastolic velocity, and peak systolic velocity) had the ability to make a difference between obstructive and nonobstructive hydronephrosis. However, by calculating the difference (delta) of these indices between two kidneys of each patient, delta RI could differentiate the nonobstructive condition, significantly (P = 0.006). A cutoff value of 0.055 has 60% sensitivity and 82.8% specificity. The area under the ROC curve for delta RI is 0.795 (standard error: 0.086, 95% confidence interval [CI]: 0.626, 0.964). Furthermore, RI ratio between two kidneys of each patient could differentiate the nonobstructive condition, significantly (P = 0.012). A cutoff point of 1.075 has 70% sensitivity and 82.8% specificity. The area under the ROC curve for RI ratio was 0.769 (standard error: 0.104, 95% CI: 0.565, 0.973).

Conclusion:

This study shows that RI ratio and delta RI with a high specificity could differentiate nonobstructive hydronephrosis and therefore it is a promising way to use especially in the follow-up of children with hydronephrosis.

Diagnostic accuracy of Onen's Alternative Grading System combined with Doppler evaluation of ureteral jets as an alternative in the diagnosis of obstructive hydronephrosis in children

Introduction

Ureteropelvic junction obstruction (UPJO) is a common congenital anomaly leading to varying degrees of hydronephrosis (HN), ranging from no apparent effect on the renal function to atrophy. Evaluation of these children is based on Diuretic Renal Scintigraphy (DRS) and Ultrasonography (US). Recent studies have suggested that new parameters of conventional and color Doppler ultrasonography (CDUS) may be useful in discriminating which kidneys are obstructed. The present study aims to assess the diagnostic accuracy of such parameters in the diagnosis of obstruction in children with UPJO.

Methods

We evaluated 44 patients (33 boys) with a mean age of 6.53 ± 4.39 years diagnosed with unilateral high-grade hydronephrosis (SFU grades 3 and 4). All underwent DRS and index tests (conventional US and CDUS to evaluate ureteral jets frequency) within a maximum interval of two weeks. Hydronephrotic units were reclassified according to the alternative grading system (AGS) proposed by Onen et al. Obstruction in the DRS was defined as a differential renal function <40% on the affected side and/or features indicating poor drainage function like T1/2 >20 minutes after the administration of furosemide, and a plateau or ascending pattern of the excretion curve.

Results

Nineteen hydronephrotic units (43.1%) were obstructed. Some degree of cortical atrophy—grades 3 (segmental) or 4 (diffuse)—was present in those obstructed units. AGS grades had 100% sensitivity, 76% of specificity and 86.4% of accuracy. The absence of ureteral jets had a sensitivity of 73.68%, a specificity of 100% with an accuracy of 88.6%. When we analyzed the two aspects together and considered obstructed the renal units classified as AGS grade 3 or 4 with no jets, sensitivity increased to 78.9%, accuracy to 92%, remaining with a maximum specificity of 100%. These features combined would allow us to avoid performing DRS in 61% of our patients, leaving more invasive tests to inconclusive cases.

Conclusions

Although DRS remains the mainstay to distinguishing obstructive from non-obstructive kidneys, grade of hydronephrosis and frequency of ureteral jets, independently or in combination may be a reliable alternative in the mostly cases.This alternative approach has high accuracy, it is less invasive, easily reproducible and may play a role in the diagnosis of obstruction in pediatric population.

Evaluation of ureteral jet dynamics in pediatric kidney stone formers: A cross-sectional study

INTRODUCTION

The risk of kidney stone formation increases with urinary stasis, which is associated with decreased peristaltism. The relationship between nonobstructive kidney stone formation and ureteral jet dynamics, which can be measured with Doppler ultrasonography (US) and provide information about ureteral peristaltism, has been demonstrated in adults.

OBJECTIVE

To investigate the relationship between ureteral jet dynamics, which provide information about ureteral peristaltism, and stone formation in children.

STUDY DESIGN

Children admitted to Dokuz Eylul University Hospital with flank pain, and asymptomatic age-matched children for the control group, were prospectively enrolled and underwent Doppler US for diagnostic reasons and bilateral ureteral jet flow measurements. Children diagnosed with unilateral nonobstructive lower pole kidney stones formed Group 1, and the control group, without any evidence of stone disease, formed Group 2. Ureteral jet dynamics were compared between the affected renal units in Group 1, and healthy renal units in Group 1 and Group 2.

RESULTS

A total of 32 children were included for each group. The mean average jet flow-rate (JETave (cm/second)) in affected renal units in Group 1 was found to be significantly lower than in the healthy renal units in Group 1 and left and right healthy renal units in Group 2 (P < 0.05). The continuous JETpattern rate in affected renal units in Group 1 was found to be significantly higher compared with healthy renal units in Groups 1 and 2 (P = 0.012) (Table). The odds ratio for kidney stone formation was 5.6 for renal units with JETave <9.5 cm/s when compared with renal units with JETave ≥9.5 cm/s.

DISCUSSION

In a recent study, it was demonstrated in adults that low ureteral jet flow-rate and continuous JETpattern were significantly higher in affected renal units. The findings in children were also similar to adults: the mean JETave was significantly lower and determination rate of continuous flow pattern was significantly higher in affected renal units.

CONCLUSIONS

Children with low JETave and continuous JETpattern as a sign of decreased ureteral peristaltism are at an increased risk of kidney stone formation. However, it is vital that further studies are conducted to elaborate on this topic.

Ultrasonography of hydronephrosis in the newborn: a practical review

Widespread use of fetal ultrasonography is accompanied by more frequent detection of antenatal hydronephrosis. Therefore, sonographic evaluation of neonates with a history of antenatal hydronephrosis is becoming more widespread. As an initial postnatal non-invasive imaging modality, ultrasonography is used to screen for persistence of hydronephrosis, determine the level and severity of obstruction, and contribute to appropriate diagnosis and treatment. This review aims to provide a practical overview of the sonographic evaluation of neonatal hydronephrosis and to describe the sonographic findings of conditions associated with hydronephrosis in the newborn.

Drainage-related ultrasonography (DRUS): a novel technique for discriminating obstructive and nonobstructive hydroureters in children

BACKGROUND

Despite advances in urologic imaging, the paucity of an optimal technique that accurately clarifies obstructive and nonobstructive hydroureter exists.

OBJECTIVE

This study was conducted to introduce a novel and modified ultrasonographic technique, known as drainage-related ultrasonography (DRUS), discriminating obstructive and nonobstructive, nonrefluxing hydroureter.

MATERIALS AND METHODS

A total of 358 children (mean age, 3.7 years) with 418 nonrefluxing hydroureter were included. These children were composed of two groups of obstructive nonrefluxing (141 children with 157 dilated ureters) and nonobstructive, nonrefluxing (217 children with 261 hydroureter). The definite diagnosis regarding the subtype of hydroureter was derived from appropriate investigation. The maximum diameter of the dilated ureter, which was observed on ultrasonography, was recorded before and after 3 h of catheterization, as D1 and D2, respectively. To assess the D ratio, a formula was developed, that is, [(|D1 - D2|)/D1] × 100. Values were recorded and cutoff points were set to discriminate between subtypes.

RESULTS

Obstructive versus nonobstructive subtypes of nonrefluxing hydroureter were clarified with 78.5 % sensitivity and 83.4 % specificity, by setting a cutoff point of 22 % for the D ratio. Regardless of the cutoff point assigned to the reduction in D (D2 compared with D1), DRUS revealed 93.9 % sensitivity, 80.6 % specificity, 63.2 % positive predictive value, and 97.4 % negative predictive value in discriminating upper from lower obstruction.

CONCLUSION

DRUS affords favorable results in terms of differentiating between obstructive and nonobstructive, nonrefluxing hydroureter, as well as between upper and lower obstruction in obstructive cases. It has the potential to become an efficient imaging modality in the diagnostic algorithm of hydroureter.