The duplicated collecting system of the urinary tract: embryology, imaging appearances and clinical considerations.

Duplication anomalies of the urinary collecting system are common and can be discovered and characterized with multiple imaging modalities. The embryology, imaging manifestations and clinical ramifications of duplicated ureters and renal collecting systems vary from a normal anatomical variant to urological pathology and are discussed and illustrated in this review.

Pediatric MR Urography: Indications, Techniques, and Approach to Review.

Magnetic resonance (MR) urography is a valuable imaging modality for assessing disorders of the pediatric urinary tract. It allows comprehensive evaluation of the kidneys and urinary tract in children by providing both morphologic and functional information without exposing the child to ionizing radiation. Pediatric MR urography can be used to thoroughly evaluate renal and urinary tract abnormalities that are difficult to identify or fully characterize with other imaging techniques, and it has the potential to allow earlier diagnosis while decreasing the number of imaging studies performed. Common indications for pediatric MR urography include evaluation of complex renal and urinary tract anatomy, suspected urinary tract obstruction, operative planning, and postoperative assessment. MR hydrography (T2-weighted imaging of urine) excellently depicts dilated or obstructed urinary systems, whereas postcontrast imaging (gadolinium-enhanced T1-weighted imaging of the kidneys and urinary system) excellently depicts nondilated or nonobstructed urinary systems. Postcontrast MR urography also allows a functional evaluation of the kidneys and urinary tract that includes estimation of differential renal function. The authors review common indications for pediatric MR urography, detail MR urography techniques, compare the strengths and weaknesses of MR urography with those of alternative imaging strategies for children, and describe numerous common and uncommon abnormalities of the pediatric kidneys and urinary tract.

Radiology trainees' comfort with difficult conversations and attitudes about error disclosure: effect of a communication skills workshop.

PURPOSE: The aim of this study was to assess the effect of communication skills training on radiology trainees' (1) comfort with communicating directly with patients and family members about unexpected or difficult diagnoses ("bad news"), radiologic errors, and radiation risks and (2) attitudes about disclosing radiologic errors directly to patients and their families. METHODS: One hundred nine radiology trainees from 16 US programs were asked to complete questionnaires immediately before and after attending an institutional review board-exempted, full-day communication workshop. Questionnaires assessed (1) comfort communicating with patients and their families generally and about bad news, radiologic errors, and radiation risks specifically; (2) attitudes and behavioral intent regarding a hypothetical vignette involving a radiologic error; and (3) desire for additional communication training. RESULTS: All trainees completed the questionnaires. After completing the workshop, more trainees reported comfort communicating with patients about bad news, errors, and radiation risks (pre vs post, 44% vs 73%, 25% vs 44%, and 34% vs 58%, respectively, P < .001 for all). More also agreed that the radiologist in the error vignette should discuss the error with the patient (pre vs post, 84% vs 95%; P = .002) and apologize (pre vs post, 78% vs 94%; P < .001). After participation, fewer trainees reported unwillingness to disclose the error despite medicolegal concerns (pre vs post, 39 vs 15%; P < .001). Despite high baseline comfort (92%) and low stress (14%) talking with patients in general, most respondents after participation desired additional communication training on error disclosure (83%), general communication (56%), and radiation risks (80%). CONCLUSIONS: This program provides effective communication training for radiology trainees. Many trainees desire more such programs.

Pediatric radiation exposure and effective dose reduction during voiding cystourethrography.

PURPOSE: To compare radiation exposure and effective dose in children who underwent voiding cystourethrography (VCUG) performed with grid-controlled variable-rate pulsed fluoroscopy (GCPFL) with radiation exposure and effective dose in children who underwent VCUG performed with continuous fluoroscopy (CFL) and to compare these effective doses with those estimated with radionuclide cystography (RNC). MATERIALS AND METHODS: Institutional review board approval was obtained, and the informed consent requirement was waived for this HIPAA-compliant retrospective study. Radiation exposure and fluoroscopy time during VCUG were reviewed in 145 children (75 girls, 70 boys; age range, 3 days to 8 years) who underwent GCPFL or CFL between 2001 and 2002. Children were grouped on the basis of the fluoroscopy unit used and their supine anteroposterior abdominal diameter (group 1, 8.0-8.5-cm diameter; group 2, 10-11-cm diameter; group 3, 12-13-cm diameter). Analysis of variance was used to compare radiation exposure and fluoroscopy time between fluoroscopy units and patient diameter groups. Effective doses were calculated and compared for both fluoroscopes and for estimated RNC dose values. RESULTS: GCPFL resulted in a significant reduction in total radiation exposure, which was at least eight times lower than that with CFL in all three groups (P < .001 for all). There was no significant difference in fluoroscopy time (P > .50). Effective radiation doses from GCPFL were approximately one order of magnitude lower than those from CFL but one order of magnitude higher than those from RNC. CONCLUSION: In children, VCUG can be performed with a GCPFL unit that delivers radiation exposures that are at least eight times lower than those delivered by a conventional CFL unit. SUPPLEMENTAL MATERIAL: http://radiology.rsnajnls.org/cgi/content/full/2492062066/DC1.

Imaging of hypospadias: pre- and postoperative appearances.

Hypospadias is a common condition that is typically diagnosed and repaired in early life. Boys with hypospadias can present with complications from their surgery months to years later. Imaging in patients with hypospadias is usually accomplished by retrograde urethrography (RUG) and less commonly by voiding cystourethrography (VCUG). This pictorial essay demonstrates the fluoroscopic appearances of hypospadias preoperatively as well as the normal postoperative appearance and a variety of complications that can occur.

Pre- and postnatal imaging of a girl with a cloacal variant.

We describe the prenatal MR findings in a 29-week fetus with a cloacal variant (urogenital sinus and anterior placed anus) in combination with an enlarged clitoris and urethral duplication and correlate them with postnatal imaging. Fetal MR imaging permits the diagnosis and characterization of cloacal and urogenital sinus malformations in utero. This information may guide pre-, peri- and postnatal management.

Radiation exposure reduction during voiding cystourethrography in a pediatric porcine model of vesicoureteral reflux.

PURPOSE: To compare grid-controlled variable-rate pulsed fluoroscopy (GCPFL) and continuous fluoroscopy (CFL) for the reduction of radiation exposure during voiding cystourethrography (VCUG) in a pediatric porcine model of vesicoureteral reflux. MATERIALS AND METHODS: Institutional animal care and use committee approval was obtained. Vesicoureteral reflux was simulated in four pigs, and 48 VCUG studies were performed (24 with GCPFL, 24 with CFL). VCUG was performed at abdominal girths of 8-10 cm (group 1, simulates human newborn to 6-month-old infant), 12-13 cm (group 2, simulates 2-3-year-old child), and 15-17 cm (group 3, simulates 10-year-old child). An electronic device calculated total radiation exposure during fluoroscopy and image recording. With five-point ordinal scales, VCUG images were scored independently for anatomic conspicuity and overall diagnostic quality by two radiologists (radiologists A and B). An analysis of variance was used to compare radiation exposures and fluoroscopy times between GCPFL and CFL and to determine whether radiation exposure and fluoroscopy time were dependent on the pig's abdominal girth. The Pearson product-moment correlation coefficient was used to assess whether fluoroscopy time was correlated with radiation exposure. Anatomic conspicuity and diagnostic quality scores were compared by means of the Wilcoxon signed rank test. RESULTS: Results of analysis of variance revealed that GCPFL resulted in a significant reduction in total radiation exposure compared with CFL for each of the three groups (P < .05 for each comparison), and this reduction was most marked in the larger animals. There were no significant differences in diagnostic quality of the recorded VCUG images (P > .05). Anatomic conspicuity was not significantly different for groups 2 and 3, but there was a significantly higher score for GCPFL in group 1 for radiologist A (P = .04). CONCLUSION: By using GCPFL in the performance of VCUG in a pediatric porcine model of vesicoureteral reflux, total radiation exposure can be reduced by a factor of 4.6-7.5 lower than with CFL, and diagnostic-quality images can be obtained.

The clinical significance of an empty renal fossa on prenatal sonography.

OBJECTIVE: The purpose of this study was to characterize the significance of an empty renal fossa on prenatal sonography. METHODS: A hospital database was reviewed retrospectively to find all fetuses with an empty renal fossa diagnosed on prenatal sonography between 1989 and 2003. For each case, prenatal and postnatal data were recorded. RESULTS: Ninety-three fetuses had an empty renal fossa: 49 on the left, 41 on the right, and 3 unspecified. Forty-four fetuses were male and 29 were female. For 20, the sex was not recorded. The average gestational age at diagnosis was 29.5 weeks. Final diagnoses were made on the basis of prenatal and postnatal imaging. The missing kidney was ectopic in 39 cases (42%): 34 in the pelvis, 4 fused to the contralateral kidney, and 1 in the thorax due to a congenital diaphragmatic hernia. The absent kidney was never located in 44 cases (47%) and presumed to be congenitally absent. Ten kidneys (11%) originally thought absent were normally located, 7 of which were dysplastic, 2 normal, and 1 infiltrated by a tumor. In 39 patients (42%), other anomalies were identified, sometimes involving multiple systems, most commonly genitourinary (29) and cardiovascular (13). Of the 77 cases with the number of umbilical cord vessels recorded, 68 (88%) were normal and 9 (12%) had only 2 vessels. CONCLUSIONS: If a kidney is not found in the renal fossa, most are either ectopic (42%) or congenitally absent (47%). An empty renal fossa is often (42%) associated with other congenital anomalies.

Anterior urethral valves and diverticula in children: a result of ruptured Cowper's duct cyst?

OBJECTIVE: To review a series of children with anterior urethral valves and diverticula, to elucidate the pathophysiology and optimal management of this entity. PATIENTS AND METHODS: Nine cases (all boys; 1963 to 2003) were reviewed retrospectively. RESULTS: Seven of nine boys had bulbar diverticula. Continuity between Cowper's duct and the diverticulum was noted endoscopically in two and confirmed radiographically in one. Initially, open surgery was curative but more recently endoscopic management has been the procedure of choice. CONCLUSION: This series indicates that the distal lip of a ruptured syringocele may function as a flap-valve, leading to anterior urethral obstruction. Advances in imaging and endoscopic instruments have altered the mode of presentation and management of this entity.

Fibroepithelial polyps causing ureteropelvic junction obstruction in children.

PURPOSE: Fibroepithelial polyps are benign mucosal projections that can be found throughout the urinary system. We review our experience with fibroepithelial polyps of the ureteropelvic junction in children to define more clearly this entity and its outcome following treatment. METHODS: We reviewed the records of all children with fibroepithelial polyps causing ureteropelvic junction obstruction treated at our institution between December 1967 and February 2002. RESULTS: Nine patients 6 weeks to 9 years old had 11 ureteropelvic junction obstructions secondary to fibroepithelial polyps, representing a 0.5% incidence of all ureteropelvic junction obstructions seen during that period. The majority of the patients were male (89%) and had obstruction on the left side (78%). Only 22% of the patients had a diagnosis of obstructing polyps suggested preoperatively. All patients underwent dismembered pyeloplasty but 1 required subsequent nephrectomy due to progressive loss of renal function. All lesions were characterized microscopically by polypoid projections of fibrous tissue covered by epithelium and demonstrating varying degrees of inflammation. No recurrences were seen during a mean followup of 44 months. CONCLUSIONS: Fibroepithelial polyps are rare lesions that cause ureteropelvic junction obstruction in children, primarily in males and on the left side. Filling defects were diagnosed preoperatively in 22% of the patients in this series. Excision and dismembered pyeloplasty were curative, and recurrences were not observed. The etiology of this disease remains obscure.

Rate and predictors of spontaneous resolution of prenatally diagnosed primary nonrefluxing megaureter.

PURPOSE: We assessed clinical and ultrasound predictors of the spontaneous resolution of prenatally diagnosed, primary nonrefluxing megaureter. MATERIALS AND METHODS: Primary nonrefluxing megaureter was prenatally diagnosed in 54 neonates from 1993 to 1998, including 15 in whom it was bilateral (69 megaureters). Median followup period from birth to the last radiology examination was 25.8 months (range 2.3 to 72). RESULTS: Of the patients 10 underwent surgical repair for severe hydroureteronephrosis, including decreasing renal function on diuretic renography in 1, and an episode of bilateral obstruction and acute renal failure in 1. Hydroureteronephrosis resolved in 39 cases (72%) and persisted in 5 at 30 to 72 months of followup. Laterality, gender and retrovesical ureteral diameter had no significant effect on the resolution rate (p >0.05). Mean initial ureteral diameter in patients with resolution was less than in those without resolution and in those who underwent surgery (0.8 versus 1.15 and 1.32 cm., respectively). Presenting hydronephrosis grade was a significant predictor of the resolution rate (p = 0.03). Grades 1 to 3 hydronephrosis resolved at a median age of 12.9, 23.9 and 34.6 months, respectively (range 4.1 to 66). In patients in whom grades 4 and 5 hydronephrosis resolved the median age at resolution was 48.5 months. CONCLUSIONS: Most cases of prenatally diagnosed, primary nonrefluxing megaureter resolve spontaneously. Grades 1 to 3 hydronephrosis tend to resolve between ages 12 and 36 months. For these grades followup intervals may be progressively elongated after a pattern of improving hydronephrosis has been established. In children with grade 4 or 5 hydronephrosis, or a retrovesical ureteral diameter of greater than 1 cm. the condition may resolve slowly and require surgery.