Megaureter

Fig. 1.2.11a,b. A 3-month-old boy with non-obstructive megaureter and simple ureteroceles, a Volume-rendered image showing bilateral hydroureteronephrosis. The renal transit time was normal bilaterally, b Detailed imaging of the ureterovesical junction showing simple ureteroceles... 

Fig. 5.5. MR imaging of bilateral infundibulo-pelvic stenosis. T2-weighted sequence. The anomaly is associated with a right megaureter and with a segmental ureteral cystic dilatation to the left ureter...

Fig. 5.7a-c. Megacalycosis and megaureter, a US sagittal scan ofthe left kidney. Unusual cystic dilatation of all the calyces. A lithiasis is visible at the lower pole, b US of the pelvis showing an associated dilated ureter (1.8 cm between crosses), c MR urography typical megacalycosis of the left kidney... 

Ureteral dilatation, or hydroureter, is a frequent cause of a dilatation of the fetal urinary tract. Under normal conditions, on fetal or postnatal US, the normal ureter is not visualized. Once it is visible (Fig. 5.20), a urinary tract dilatation is present and must be investigated (Keller and Weiss 1993). The presence of a dilated ureter may correspond to primary megaureter (MU), to refluxing MU (see Chap. 11), to nonobstructive nonrefluxing hydro-ureter, or to secondary hydroureter. The various imaging techniques will be necessary in order to differentiate between these entities. 

Fig. 5. 22. Primary left megaureter on MR urography (courtesy of JN Dacher, MD)...

Fig. 5.28a,b. Crural hernia of a left megaureter. MR imaging T2-weighted sequence, a Upright AP view, b Lateral view showing the anterior course of the ureter... 

Baskin LS, Zderic SA, Snyder HM et al (1994) Primary dilated megaureter long-term follow-up. J Urol 152 618-621... 

Liu AHY, Dhillon HK, Diamond DA et al (1994) Clinical outcome and management of prenatally diagnosed primary megaureters. J Urol 152 614-617 Lucaya J, Enriquez G, Delgado R et al (1984) Infundibulopel-vic stenosis in children. AJR 142 471-474 Maizels M, Stephens FD (1980) Valves of the ureter as a cause of primary obstruction of the ureter. J Urol 123 742-746 Maizels M, Reisman ME, Flom LS et al (1992) Grading nephro-ureteral dilatation detected in the first year of life. JUrol 148 609-614... 

Mandell GA, Snyder HM, Heyman S et al (1986) Association of congenital megacalycosis and ipsilateral segmental megaureter. Pediatr Radiol 17 28-33... 

Peters CA, Mandell J, Lebowitz RL et al (1989) Congenital obstructed megaureters in early infancy. J Urol 142 641-... 

Pinter AB, Szabo L, Szever ZS et al (1997) Bilateral congenital segmental megaureter. J Urol 158 570-571 Ransley PG, Dhillon HK, Gordon I et al (1990) The postnatal management of hydronephrosis diagnosed by antenatal US. JUrol 144 584-587... 

Megacystis-megaureter association (high-grade reflux)... 

The main differential diagnosis is the megacys-tis-megaureter association (Willi and Lebowitz 1979 Reuter and Lebowitz 1985), which is due to massive reflux and the phenomenon of aberrant micturition (Fig. 6.5). Prenatal diagnosis is relatively straightforward in female fetuses, but more subtle in males (absence of a dilated posterior urethra). 

Fig. 6.5. VCU in a neonate with prenatal diagnosis of megacystis and bilateral ureterohydronephrosis. Absence of posterior urethral valves. Megacystis megaureter association by aberrant micturition phenomenon...

Willi UV, Lebowitz RL (1979) The so-called megaureter-megacystis syndrome. AJR 133 409-416... 

Fig. 8.3. IVU. Bilateral duplicated dysplastic kidney systems with megaureters and ureter dysmotility. Note dysplastic sacrum...

Fig. 11.20a,b. VUR and primary megaureter, a VCU left grade II VUR the right VUR is very subtle (arrowheads) because of the dilatation and obstruction of the ureter, b IVU typical right megaureter... 

In the megacystis-megaureter association, massive bilateral grade IV or V VUR is present. During micturition, the bladder empties normally through the urethra, but also through reflux into the ureters (Fig. 11.23a-d). At the end of micturition, the bladder is completely empty, but only for a very short time. It refills immediately with the refluxed urine ... 

Blane CE, Zerin MJ, Bloom DA (1994) Bladder diverticula in children. Radiology 190 695-697 Blickman JG, Lehowitz RL (1984) The coexistence of primary megaureter and reflux. AJR 143 1053-1057 Blickman J, Taylor G, Lehowitz R (1985) VCU the initial study in children with UTL Radiology 156 659-662 Blyth B, Passerini-Glazel G, Camuffo C et al (1993) Endoscopic incision of ureteroceles intravesical versus ectopic. J Urol 149 556-559... 

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