Helical CT and CT angiography for the identification of crossing vessels at the ureteropelvic junction

Ureteropelvic junction obstruction in children by polar vessels: histological examination result

In children, ureteropelvic junction obstruction (UPJO) is mostly caused by intrinsic factors (IUPJO) such as abnormal amounts of muscle and collagen deposition; extrinsic UPJO are rare and often due to crossing vessels (CVs). What is not clear is whether there is also intrinsic UPJ pathology in patients with CV. The aim of our study was to compare the histology of the two types of obstruction and to determine whether these histologic features are distinguishable enough to enable to identify the cause of obstruction based on histologic appearance alone. We retrospectively reviewed pathology reports of 38 children with UPJO that underwent surgery in our hospital from 2008 to 2022. The intrinsic and extrinsic groups consisted of 18 and 20 patients, respectively. After ematoxylin-eosin and Gomori's trichrome staining the specimens were scored for fibrosis and muscular hypertrophy in histhopatology, and CD117 antibody were used to detect interstitial Cajal-like cells. In our study, histological analyses revealed no differences between the CV and IUPJO specimens in terms of presence and degree of fibrosis and muscular hypertrophy; likewise, for presence of interstitial Cajal-like cells.

Intraoperative inspection of the ureteropelvic junction during pyeloplasty is not sufficient to distinguish between extrinsic and intrinsic causes of obstruction: Correlation with histological analysis

INTRODUCTION

Based on current knowledge, it is possible to have an initial diagnosis of intrinsic or extrinsic ureteropelvic junction obstruction (UPJO) based solely on clinical and imaging findings. However, it may not be possible to strictly discriminate an intrinsic case with an additional extrinsic component from a primarily intrinsic stenosis because of lower pole aberrant vessels. These two disorders may coexist or trigger each other. Herein, we aimed to compare the histological changes observed in intrinsic and extrinsic types of UPJO. Our hypothesis is that inspecting the UPJ during pyeloplasty may not be a sufficient way to delineate the underlying cause of obstruction in every individual.

MATERIAL AND METHODS

We retrospectively reviewed the data of 56 patients who had dismembered pyeloplasty. The intrinsic and extrinsic groups consisted of 38 and 18 patients, respectively. Masson's trichrome stain, CD117, and connexin 43 (Cx43) antibody were used in histopathology and immunochemistry. Statistical calculations were done with chi-square and Mann-Whitney U tests.

DISCUSSION

Connexin 43 staining pattern, CD117 positive cell count, and the extent of fibrosis did not differ significantly between extrinsic and intrinsic cases. However, the difference with regard to the degree of muscular hypertrophy was close to statistical significance. The exact pathophysiological mechanism underlying UPJO has yet to be elucidated. A study directly comparing both groups histologically is indeed rare. Our study showed that there are no significant differences between the intrinsic and extrinsic groups in terms of the pacemaker activity, gap junctional communication, and extent of fibrosis. Muscular hypertrophy, which was marginally higher in our extrinsic group, may persist despite successful relocation of the obstructing vessel. The main drawbacks of our study are; the absence of a control group and the retrospective study design with its inherent selection biases.

CONCLUSIONS

Immunohistochemical profiles of intrinsic and extrinsic UPJOs resemble each other. Intraoperative inspection of the UPJ may not be enough for accurate discrimination for a surgical procedure that can correct only the extrinsic cause.

Multidetector CT Angiography of the Abdomen

Multidetector CT angiography (MDCTA) is redefining traditional imaging strategies of the vascular structures of the abdomen. Angiographic depiction of normal and variant anatomy is becoming the standard for evaluation and has a significant impact in transplant and oncologic surgery. MDCTA is increasingly being used for assessing diseases affecting the vasculature of the abdominal organs, including the abdominal aorta for treatment planning and post therapy follow-up.

Adult Ureteropelvic Junction Obstruction: Insights with Three-dimensional Multi–Detector Row CT

Ureteropelvic junction obstruction (UPJO) is a benign, congenital condition that remains an enigma in terms of both diagnosis and therapy. On the basis of a series of cases that were referred to the authors in their clinical practice, they found that the unprecedented quality and novel perspectives of multi-detector row computed tomography (CT) with two- and three-dimensional postprocessing allow a comprehensive, single-study assessment of the ureterovascular relationships in UPJO. This topic is important because the causative role of crossing vessels may be questioned on the basis of such studies, and the therapeutic approach may be altered by using precise anatomic images customized to the pathologic features of the individual patient. Although CT images can provide only circumstantial or supportive evidence of the pathophysiology of UPJO, they greatly facilitate therapeutic intervention when it is clinically indicated and may eliminate the need for it in select cases. Careful attention to the postprocessing of CT images may show that the crossing vasculature has no direct relationship to the transition point of the UPJO in many cases.

MDCT angiography of pediatric vascular diseases of the abdomen, pelvis, and extremities

Multi-detector-row computed tomography (MDCT) enables rapid, noninvasive, high-resolution, and three-dimensional imaging of pediatric vascular diseases. In this paper, we explore the adaptation of the MDCT angiographic principles to pediatric patients for vascular diseases of the abdomen, pelvis, and extremities. Special emphasis is placed on the practical aspects of how to perform these studies. Optimizations of scan parameters, contrast medium usage, radiation dose, and three-dimensional image processing are discussed in detail. We provide practical guidance on how to choose between MR angiography and CT angiography. Finally, we review important pediatric vascular diseases, categorized into traumatic injuries, inherited vascular diseases, congenital vascular diseases, vasculitides, and surgical planning and assessment. In each category, we discuss how CT angiography can be tailored to maximize its clinical benefits.

Detection of crossing vessels as the cause of ureteropelvic junction obstruction: the role of antegrade pyelography prior to endopyelotomy

PURPOSE

To review the utility of antegrade pyelography in detecting crossing vessels as the cause of uretero-pelvic junction (UPJ) obstruction prior to planned endopyelotomy.

MATERIALS AND METHODS

A retrospective review of the medical records, surgical reports, and medical images was performed in 109 consecutive adult patients in our practice who underwent antegrade pyelography just prior to planned endopyelotomy for symptomatic UPJ obstruction between January 1996 and December 2002.

RESULTS

Fourteen patients were identified in whom a specific antegrade pyelographic appearance was detected in the diagnosis UPJ obstruction caused by crossing vessels. Surgical plans were changed in all 14 patients from antegrade endopyelotomy to open surgical pyeloplasty, during which the anterior (ventral) crossing vessels causing obstruction were confirmed. An additional three patients in the reviewed endopyelotomy group clinically failed their initial endopyelotomy procedure and were shown at the time of subsequent open or laparoscopic reconstructive surgery to have UPJ obstruction caused by anterior crossing vessels, but that diagnosis was missed at the time of the initial antegrade pyelogram.

CONCLUSION

A specific antegrade pyelographic appearance was identified to diagnose UPJ obstruction caused by anterior crossing vessels with a sensitivity of 82.4% and a specificity of 100%. The direct obstructing effect of the vessels on the ureter is defined with pyelography as an acute posteriorly angulated ureteral deformity just below a patent UPJ. Recognition of this specific antegrade pyelographic appearance permits use of an appropriate surgical technique for UPJ obstruction repair.

The value of colour Doppler ultrasonography for identification of crossing vessels in children with pelvi-ureteric junction obstruction

BACKGROUND

Pelvi-ureteric junction (PUJ) obstruction is caused by the presence of an aperistaltic dysplastic segment at the PUJ. Besides this intrinsic aetiology, extrinsic abnormalities, mainly crossing vessels, may be an associated factor.

OBJECTIVE

To determine the reliability of colour Doppler US in the detection of crossing vessels in children with surgically proven PUJ obstruction.

MATERIALS AND METHODS

Forty-eight patients (50 kidneys) with PUJ obstruction, surgically treated from 1998 to 2001, were prospectively studied by colour Doppler US prior to open pyeloplasty. There were 33 boys and 15 girls (age 2 months-12 years; median 3.5 years). There were 24 right kidneys and 26 left kidneys. The indication for surgery was according to the usual criteria. The crossing vessel was considered as present when depicted on colour Doppler US at the PUJ.

RESULTS

Colour Doppler assessment of the crossing vessels was correct in all but two patients. At surgery, a crossing vessel was found in 14 kidneys (i.e. 28%). Colour Doppler US results were correlated with intra-operative findings in 50 renal units. Surgically proven vessels in 14 kidneys were identified by colour Doppler US in 13, and not shown in 1. In PUJ obstruction without a crossing vessel ( n=36), US findings were concordant in 26, discordant in 8 and inconclusive in 2 (with kidney malrotation) cases. Colour Doppler US had a sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy of 92.8%, 76.5%, 62%, 96.3% and 78%, respectively. The reliability of colour Doppler US was greatly improved with the increasing experience of the sonographer, as shown by the results of the last 2 years (26 kidneys):Se=100%, Sp=87.5%, PPV=81.8%, NPV=100%, accuracy=88.5%.

CONCLUSIONS

Colour Doppler US is reliable in the detection of crossing vessels at the PUJ.

Novel Technique for Diagnosis and Management of Fraley's Syndrome: Helical CT with Three-Dimensional Volume Rendering

We report on the diagnosis and minimally invasive management of Fraley's syndrome using helical CT with volume-rendering techniques in an 18-year-old patient. Three-dimensional images were generated rapidly and allowed safe planning and execution of a laser infundibulotomy of the upper-pole calix. After 24 months of follow-up, the patient remains pain free.

Ureteropelvic Junction Obstruction: Some new Acquisitions about Etiology, Pathophysiology and Diagnostics

The etiopathogenesis of uretero-pelvic junction obstruction (UPJO) has been the subject of many speculations and it remains, in some ways, a debatable matter. Some recently reported thorough research refer to neuro-mediated pathogenetic mechanisms rather than (or together with) myogenic ones.

Advances in US, radioisotopic functional imaging, CT and RM contribute to differentiate the obstructive conditions from the non-obstructive ones and to afford today a better assessment of renal functional damage. Particularly, diuretic renography is a non-invasive test for characterization of the renal functional abnormalities resulting from UPJO. Helical CT with angiography is a useful technique for identification of crossing vessels (pyelo-vascular tangle) which can be used for the pre-surgical planning of endopyelotomy. Endoluminal ultrasonography can be used to guide the position of the incision for endopyelotomy (US-guided endopyelotomy).

Laboratory examinations are important to determine the overall renal function (serum creatinine, acid-base balance, serum electrolytes, etc.), urinary MCP-1 and NAG (markers of tubular damage), and to rule out urinary tract infections.

The management of UPJO (watchful waiting; either open or laparoscopic dismembered pyeloplasty; endoluminal procedures) is greatly influenced by the diagnostic evaluation.

The paper aims to outline the advances in both physiopathology and diagnostics of UPJO on the basis of a review of the literature.

Results of selective management of ureteropelvic junction obstruction

BACKGROUND AND PURPOSE

Controversy continues over the need to image the ureteropelvic junction (UPJ) before endopyelotomy to detect crossing vessels. We evaluated a selective management model for UPJ obstruction.

PATIENTS AND METHODS

Intraoperative ultrasonography was performed before endopyelotomy in 19 men and 16 women. Patients with large (>4-mm) crossing vessels underwent open or laparoscopic pyeloplasty; the others had ureteroscopic or percutaneous endopyelotomy with electrocautery or the holmium laser.

RESULTS

Crossing vessels were found in 25 of the 35 patients and a high-inserting ureter in 4. The vessels were >4 mm in nine patients, seven of whom had successful pyeloplasty and two of whom were managed expectantly with good results. Endopyelotomy was successful in 94% without a crossing vessel and 70% of those with a crossing vessel. The overall success rate (absence of symptom and resolution of obstruction on renal scintigraphy) was 89%.

CONCLUSION

Selective management of UPJ obstruction, avoiding endopyelotomy in the presence of a large crossing vessel, appears to improve the success rate.

The role of endourology in ureteropelvic junction obstruction

Endopyelotomy has benefited from abundant confirmatory investigations, and significant progress in different technical modalities has occurred. Retrograde techniques, including the Acucise (Applied Medical, Laguna Hills, CA) cutting balloon and the ureteroscopic Holmium laser incision, are becoming preferred approaches while the other modalities retain their specific indications. Long-term results and potential complications have been carefully studied and reported. Better identification of risk factors has prompted precise preoperative investigations and allowed for careful patient selection, leading to improved results. These results approach those of open pyeloplasty, but with minimal morbidity.

Evaluation of crossing vessels in patients with ureteropelvic junction obstruction by means of helical CT

Helical computed tomography (CT) was used to demonstrate the distribution of crossing vessels in patients with ureteropelvic junction (UPJ) obstruction for planning surgical management. Twenty patients with symptomatic UPJ obstruction were evaluated with dual-phase contrast material-enhanced helical CT. In addition to axial images, coronal, sagittal, and curved paracoronal images along the crossing vessels or the UPJ were obtained by means of multiplanar reconstruction. Crossing vessels were evaluated according to type, position, and association with UPJ obstruction. Fifteen vessels in 12 of the 20 patients were found to cross the UPJ at helical CT. Nine vessels were arteries and six were veins; seven vessels crossed anteriorly and eight crossed posteriorly. In 11 patients, crossing vessels were thought to be associated with UPJ obstruction at helical CT; retroperitoneoscopic repair was performed, and the diagnosis was found to have been accurate in all except one. In the eight patients in whom no significant vessels were seen and the one patient in whom the crossing vessel was not associated with UPJ obstruction at helical CT, endopyelotomy was performed and UPJ obstruction was relieved, with no complications. Helical CT is useful for evaluation of vessels crossing the UPJ and for planning surgical management.

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.