MAGNETIC RESONANCE UROGRAPHY: A NEW GOLD STANDARD FOR THE EVALUATION OF SOLITARY KIDNEYS AND RENAL BUDS?

Proposal of the 3O (Obstruction, Ureteric Orifice, and Outcome) Subclassification System Associated with Obstructed Hemivagina and Ipsilateral Renal Anomaly (OHVIRA)

STUDY OBJECTIVE

To propose a "3O" (obstruction, ureteric orifice, and outcome) subclassification system associated with obstructed hemivagina and ipsilateral renal anomaly (OHVIRA).

DESIGN

Retrospective case series.

SETTING

Xiangya Hospital, Central South University, Changsha, Hunan, China.

PARTICIPANTS

A total of 26 women with obstructed hemivagina and ipsilateral renal anomaly (OHVIRA) over a 9-year period.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

In all cases, the obstruction, ureteric orifice, outcome and surgical strategy were reviewed.

RESULTS

In our study, the "obstruction" category included 14 cases of blind hemivagina, 8 cases of buttonhole septum, 3 cases of cervical fistula, and 1 case of cervical atresia. A total of 25 patients with vaginal obstruction underwent resection of the vaginal septum. The patient with cervical atresia underwent a failed cervicoplasty, followed by hemi-hysterectomy. The "ureteric orifice" category included 24 cases of absent ureter with no orifice, as well as 2 cases of ureteric orifice emptying into the obstructed hemivagina. The 2 patients were treated with laparoscopic extirpation of the ectopic ureter and renal moiety. Regarding the "outcome" category, 5 patients with severe recurrent hematometra, hematosalpinx, and ovarian endometrioma underwent hemi-hysterectomy, salpingectomy, and cystectomy of the ovarian endometrioma. Both patients (1 with a septate uterus and 1 with a bicornuate uterus) who experienced recurrent abortion accepted uterine correction.

CONCLUSION

We provide new insights into the anatomical variants of this rare syndrome with the relevant surgical implications. Magnetic resonance imaging is the most useful tool in 3O diagnosis.

Morphologic and functional evaluation of duplicated renal collecting systems with MR urography: A descriptive analysis

PURPOSE

To describe the morphology and function of duplicated collecting systems in pediatric patients undergoing functional MR urography (fMRU).

METHODS

This is a HIPAA compliant IRB approved retrospective study of all patients with duplicated renal collecting systems undergoing fMRU at our institution between 2010 and 2017. Two pediatric radiologists evaluated the studies to determine the presence, morphology and function of duplicated collecting systems using both T2-weighted and dynamic post-contrast fat saturated T1-weighted images. Assessed morphologic features included pelvic and calyceal dilation, partial or complete ureteral duplication, ureteral dilation, ectopic ureteral insertion and ureteroceles. Functional analysis was carried out per moiety.

RESULTS

A total of 86 examinations (63 girls; 23 boys), median age 2.6 years (Standard Deviation 6.4 years, interquartile range: 0.4-10.3 years) and 107 kidneys (39 right; 30 left and 19 bilateral), which yielded 214 evaluable moieties, were included in the final sample. One hundred and sixty-three (76.1%) of the moieties had normal morphological features and normal functional results (average calyceal transit time and renal transit time of 2 min 28 s and 3 min 16 s, respectively). The remaining 51 moieties (23.8%) were hypoplastic or dysplastic. Seventy-seven (35.9%) had pelvic and calyceal dilation. Slightly more than half of the kidneys had complete ureteral duplication (60/107; 56%); 50 (50/107, 46.7%) had ectopic ureters (23 intra- and 27 extravesical) and 9 (9/107, 8.4%) had ureteroceles.

CONCLUSION

fMRU provides comprehensive information regarding the morphology and function of duplicated renal collecting systems in children. In particular, fMRU is useful for assessing barely or non-functioning renal poles and ectopic ureters.

Seminoma Arising from Intra-abdominal Cryptorchidism with Ipsilateral Renal Agenesis: A Rare Association

Unilateral renal agenesis is usually asymptomatic and may be found incidentally during examination for other causes. The incidence of testicular tumors arising from cryptorchidism is well established, but if it is coexistent with ipsilateral renal agenesis, the diagnosis and management becomes a challenge. Only three cases of such association have been reported in literature so far. This association has to be kept in mind when dealing with a case of testicular tumor arising from abdominal cryptorchidism, so that the function of the other kidney can be assessed before surgery, and protection given to it in the event of using radiotherapy in an adjuvant setting.

A 12-year-old boy with an infected ectopic ureter presenting with acute appendicitis-like symptoms and acute scrotum

An ectopic ureter draining into the seminal vesicle or vas deferens in males is a very rare anomaly and is usually associated with renal dysplasia or agenesis. An ectopic ureter associated with a dysplastic kidney is not usually a suspected cause during clinical evaluation of children with abdominal pain. This report presents a rare case of an ectopic ureter associated with a dysplastic kidney with an acute infection in a previously healthy 12-year-old boy, demonstrated by magnetic resonance imaging. He presented with abdominal pain that mimicked acute appendicitis-like symptoms which was subsequently complicated by epididymitis manifesting as an acute scrotum. Clinicians should consider including an ectopic ureter in the differential diagnosis of children presenting with acute abdomen.

MR urography: technique and results for the evaluation of urinary obstruction in the pediatric population

MR urography has the potential to revolutionize imaging of the urinary tract in both adults and children, because of its ability to provide an unprecedented level of anatomic information and quantitative functional evaluation of each kidney. MR urography can now provide useful assessment of obstructive uropathy and may provide predictive information about which children will benefit from surgery. It has the potential to identify parameters that indicate a significant obstruction as opposed to self-limited hydronephrosis. Further technical developments in the field will produce greater insights into the pathophysiology of not only urologic disorders but also disorders of the kidney itself.

Potential of MR-imaging in the paediatric abdomen

OBJECTIVE

To describe the potential and relevant applications of MR-imaging (MRI) in typical paediatric abdominal conditions and diseases.

METHOD

The commonly used indications, applications, and sequences as well as typical imaging findings of paediatric abdominal MRI are presented and discussed, with emphasis on specific paediatric needs and queries. Only applications as used in routine clinical work are listed, other more sophisticated and advanced techniques will only briefly be mentioned. Furthermore, some aspects of paediatric MR Urography are presented and discussed.

CONCLUSION

Though conventional imaging methods (ultrasound and plain film) are valuable and - particularly in the paediatric abdomen - form the mainstay of routine imaging in paediatric abdominal radiology, some conditions require sectional imaging. MRI is increasingly applied to these queries in neonates, infants and children as an alternative method to CT without any radiation burden, and - when performed adequately and skilfully - can answer most treatment relevant questions. MR will increasingly be applied with new applications and broader availability also with functional information deriving from new equipment and research offering an ideal one stop imaging approach to many conditions also in children.

The role of dynamic magnetic resonance urography in complex neonatal hydrometrocolpos

Urinary hydrometrocolpos is rarely diagnosed and is most often attributed to a persistent urogenital sinus or a cloaca. We report the case of a neonate in which the use of dynamic MRI allowed accurate preoperative diagnosis of urinary hydrometrocolpos secondary to ectopic drainage of a small left pelvic kidney, associated with a bicornuate uterus.

Magnetic resonance urography in pediatric urology

PURPOSE OF REVIEW

Magnetic resonance urography (MRU) has emerged as a powerful diagnostic tool in the evaluation of the pediatric genitourinary tract. The purpose of this review is to familiarize the reader with the basic techniques, strengths and limitations, as well as the current and potential future applications of MRU in pediatric urology.

RECENT FINDINGS

MRU can provide detailed anatomical information and assess renal function and drainage in a single study. MRU does not employ ionizing radiation and may be utilized in patients with iodine-based contrast allergy or impaired renal function. MRU has been most often applied to the evaluation of hydronephrosis and provides valuable insight into a wide range of obstructive uropathies. MRU was shown to be superior to renal scintigraphy for the diagnosis of pyelonephritis and renal scarring. The use of MRU for the assessment of urolithiasis and vesicoureteral reflux is limited and technical refinements are required. Potential future applications include fetal MRU, virtual endoscopy, and MRU-guided procedures. The development of new contrast agents and new image-processing software will further enhance the diagnostic potential of MRU in pediatric urology.

SUMMARY

MRU is currently thought of as a problem-solving tool to define anatomy and function when conventional methods fall short. This technique is likely to emerge as the imaging modality of choice for children with complex genitourinary pathology.

Dystopic dysplastic kidney with ectopic ureter: improved localization by fusion of MR urography and (99m)Tc-DMSA SPECT datasets

We report a 12-year-old girl with a long history of constant urinary dribbling and apparently only a left kidney. Using a multimodality approach involving the fusion of MR urography and (99m)Tc-dimercaptosuccinic acid (DMSA) SPECT datasets, it was finally possible to exactly localize the very small dystopic, dysplastic right kidney and its ectopic ureter draining into the vagina.

Renal dysplasia and MRI: a clinician's perspective

Renal dysplasia is a common abnormality in children. The role of MRI in evaluating children with renal dysplasia is evolving. More information is clearly necessary before MRI replaces conventional imaging modalities. In order to appropriately use MRI, the radiologist must have an understanding of the clinical questions that are important in the management of children with renal dysplasia. This review provides background information on renal dysplasia for the pediatric radiologist. The focus is on unilateral disease, especially multicystic dysplastic kidneys, and bilateral dysplasia, which is the most common cause of kidney failure in children. The emphasis is on the important clinical issues, and the potential of MRI as a methodology for providing clinically useful information not otherwise available from other imaging modalities.

Ureterektopie mit Harnträufeln im Kindesalter — eine diagnostische Herausforderung

Based on the observations in four girls suffering from constant urinary dribbling we analyzed the special features and difficulties in making the diagnosis of an ectopic ureter. In all patients there was marked diagnostic delay. In one symptomatic case the abnormality was not detected before the age of 18 years. Failure to recognize the characteristic signs and symptoms played a crucial role in delaying the diagnosis. Moreover, imaging of ureteral ectopia represents a diagnostic challenge. The ectopic ureters were associated with dysplastic, poorly functioning renal moieties. Common diagnostic imaging procedures, such as ultrasound, intravenous pyelography, or voiding cystourethrography yielded incomplete diagnostic information and often failed to provide a definitive diagnosis. The latter could only be obtained with MR urography. We assessed the diagnostic value of the different examinations and compared our findings with those reported in the literature.

[Magnetic resonance urography in the diagnosis of the ectopic ureters]

INTRODUCTION

Ectopic ureters are often very difficult to diagnose with conventional diagnostic modalities (physical examination, ultrasound, intravenous urography, cystography, urethro-cystoscopy, isotop examinations) in children.

AIM OF THE STUDY

The authors report their experience with a relatively new method, the magnetic resonance urography (MRU) diagnosing ectopic ureters in childhood.

METHOD

MRU was used in 7 girls to detect an ectopic ureter in the last 3 years. On the basis of typical clinical signs, an ectopic ureter was suspected in all patients, but it could not be demonstrated by conventional diagnostic methods. Thus, MRU was done to confirm the suspected diagnosis.

RESULTS

In all of the 7 patients, the examinations demonstrated ectopic ureters with the intraoperative findings further confirming the pre-operative diagnosis. In 2 patients, the intraoperative findings of the upper urinary tract anomalies were slightly different from the MRU report.

CONCLUSION

The MRU is a reliable diagnostic method to diagnose ectopic ureters which are not easily detectable with conventional diagnostic modalities.

The role of magnetic resonance imaging in pediatric urology

PURPOSE OF REVIEW

Magnetic resonance imaging has emerged as a powerful diagnostic tool for the imaging of the pediatric genitourinary tract. The aim of this review is to familiarize the reader with the current applications and basic techniques utilizing magnetic resonance imaging in pediatric uroradiology.

RECENT FINDINGS

Magnetic resonance imaging can provide both a detailed anatomic and functional assessment of the pediatric genitourinary tract in a single study without the use of ionizing radiation. Magnetic resonance urography combines static and dynamic evaluation of the urinary tract following contrast administration and has been most often applied to the evaluation of hydronephrosis. In addition to unparalleled anatomic assessment, it allows for the evaluation of glomerular filtration rate, renal transit time, and differential renal function. It also provides unique insights into a wide range of obstructive uropathies and has been demonstrated to be useful in the evaluation of complex genitourinary anomalies. Magnetic resonance voiding cystourethrography has been used to rule out vesicoureteral reflux. Magnetic resonance imaging has also been demonstrated to be superior to nuclear scintigraphy for the diagnosis of pyelonephritis and renal scarring.

SUMMARY

Magnetic resonance imaging has emerged as a powerful tool for the diagnosis of pediatric genitourinary anomalies. It provides functional and anatomic assessment with a single procedure that in most cases is superior to conventional procedures. Magnetic resonance imaging will probably become the modality of choice for the imaging of pediatric genitourinary tract anomalies.

MR urography in children

MR urography represents the next step in the evolution of uroradiology in children by combining superb anatomic imaging with quantitative functional evaluation in a single examination that does not use ionizing radiation. MR imaging has inherently greater soft-tissue contrast than other imaging techniques. When used in conjunction with dynamic scanning after administration of a contrast agent, it provides non-invasive analysis of the perfusion, concentration and excretion of each kidney. The purpose of this review is to outline our experience with more than 500 MR urograms in children. We outline our technique in detail, showing how we calculate differential renal function and how we assess concentration and excretion in the different regions of the kidney. We show that the dynamic contrast-enhanced data can be processed to yield quantitative measures of individual kidney GFR. In the clinical section we show how MR urography adds unique aspects to the anatomic evaluation of the urinary tract, and by combining the anatomic information with functional information, how we assess hydronephrosis and obstructive uropathy, congenital malformations, pyelonephritis and renal scarring.

Magnetic resonance urography in the evaluation of prenatally diagnosed hydronephrosis and renal dysgenesis

PURPOSE

We present our experience with dynamic contrast enhanced magnetic resonance urography for evaluation and treatment in infants born with prenatally recognized hydronephrosis. We determined the characteristics of renal dysgenesis in this population.

MATERIALS AND METHODS

We reviewed magnetic resonance urography images done within the first 6 months of life in 67 infants born with prenatally recognized hydronephrosis. High resolution imaging was used to establish a morphological diagnosis. Functional evaluation was used to assess obstruction and individual renal function. Voiding cystourethrography was performed in 62 patients.

RESULTS

Our study included 67 infants (87 renal units). There were 54 boys and 13 girls with a mean age of 2.8 months (range 0.9 to 4.6). Of these 87 renal units 30 (35%) had ureteropelvic junction obstruction, 18 (21%) had primary megaureters, 10 (11%) had nondilating vesicoureteral reflux, 10 (11%) had fetal folds, 8 (9%) had posterior urethral valves, 6 (7%) had ectopic ureters, 4 (5%) had multicystic dysplastic kidneys and 1 (1%) had a normal study. Magnetic resonance urography revealed renal dysgenesis in 24 renal units (28%), consisting of loss of corticomedullary differentiation, renal cystic changes distinct from multicystic dysplastic kidneys, solid renal dysplasia, hypoplasia and dysmorphic calyces.

CONCLUSIONS

Magnetic resonance urography is an excellent addition to our armamentarium for evaluating neonatal hydronephrosis and renal dysgenesis. Due to its comprehensiveness magnetic resonance urography has the potential to become the study of choice for evaluating infants with significant prenatally recognized hydronephrosis. However, further prospective, comparative studies in larger patient populations are needed to justify the cost and the need for sedation in infants.

Imaging of the neonatal genito-urinary tract

OBJECTIVE

To describe imaging of typical conditions and diseases in the neonatal genito-urinary (GU) tract.

METHOD

The use, the applications, and typical findings using standard imaging techniques (e.g., ultrasound, US, voiding cystourethrography, VCUG) are described, with emphasis on technical aspects, indications, and restrictions in neonatal queries. Only basic applications as used in routine clinical work are included, other more sophisticated and advanced imaging techniques such as scintigraphy, MR-urography, genitography or image-guided interventional procedures will only briefly be mentioned.

SUMMARY AND CONCLUSION

Conventional imaging methods are valuable and - particularly in the neonatal GU tract - sometimes irreplaceable. Skillfully used basic imaging techniques, particularly of US (including modern methods such as Doppler sonography, Harmonic imaging or contrast enhanced US), supplemented by fluoroscopy for VCUG can answer most acutely treatment relevant queries. Rarely early scintigraphic studies, genitography, or MRI may become indicated, usually not for establishing the diagnosis, but to collect additional (functional or anatomical) information necessary for deciding on further treatment, or even image guided interventional procedures may become necessary.