Antegrade MDCT Pyelography for the Evaluation of Patients with Obstructed Urinary Tract

Magnetic resonance urography and X-ray urography findings of congenital megaureter

OBJECTIVE

To observe the imaging findings of congenital megaureter in order to enhance the understanding of this disease.

METHODS

Image data of 5 patients with congenital megaureter and 2 misdiagnosed patients were analyzed, and image findings of congenital megaureter were summarized.Elscint Prestig 2.0T superconductive magnetic resonance urography (MRU) with conventional sequence (spin-echo, T1WI560 ms/16 ms; fast spin-echo, T2WI 9600 ms/96 ms ) was performed. Raw data were acquired with fastspin-echo sequence from heavy T2-weighted image (9600 ms/120 ms). Post-processing method of MRU was the maximum intensity projection with three-dimensional reconstruction in the workstation. Intravenous pyelography (IVP) was conducted, in which X-rayfilms were taken 7 minutes, 15 minutes, and 30 minutes after injecting contrast agent, exceptthat in 2 patients the films were taken delayed at 60 and 90 minutes .X-ray retrograde pyelography was performed on 2 patients, successful in one butfailed in the other.

RESULTS

The dilated ureter showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images in conventional MRI. The mass wall was intact, uniform in thickness, and showing hypointensity on T1-weighted and T2-weighted images. The MRU images showed a retroperitoneal mass appearing as an elongated tubular cystic structure spreading from kidney to bladder. MRU also revealed dilated calices and renal pelvis, pelviureteric obstruction, and renal duplication. The main signs of congenital megaureter in X-urography was significant dilatation of ureter, or normal renal pelvis with ureter dilatation, hydronephrosis, deformity, and displacement.

CONCLUSIONS

MRU with X-urography could visualizethe characteristics of congenital megaureter, including the dilation of renal pelvis and ureter, calculi, urinary tract duplication, and stenosis location. The two techniques can complement each other in disease diagnosis and provide more detailed information for preoperative treatment.

Congenital urological anomalies diagnosed in adulthood - management considerations

OBJECTIVE

Despite worldwide availability of prenatal ultrasound, many patients are diagnosed in adult life with congenital anomalies such as ureteropelvic junction obstruction (UPJO), undescended testicle (UDT), ureterocele, hypospadias, vesicoureteral reflux (VUR) and primary obstructing megaureter (POM). The aim of this review was to describe these clinical conditions and their suggested management based on the available medical literature.

REVIEW

Adult UPJO is not a rare condition; symptomatic patients should be treated rather than observed. Treatment options are nephrectomy for non-functioning kidneys and reconstructive surgery for functioning renal units. The adult UDT has low fertility potential and increased cancer risk; hence most of the data in the literature indicate performing an orchiectomy. Adult ureteroceles are usually related to single systems and they are intravesical and less obstructive. For symptomatic patients endoscopic incision showed high efficacy for symptom elimination with minimal side effects. Primary hypospadias correction in the adult patient is feasible, but success rates are low compared to the pediatric age group. Secondary correction, whether primary correction was performed in childhood or adulthood, is a challenging task with a high complication rate. Treatment decisions regarding adult patients with VUR are difficult to make as the available data are inconsistent; there is no strict evidence that reflux in an adult is directly related to renal growth impairment, ascending pyelonephritis, and/or embryo loss in a pregnant woman. In contrast to the pediatric age group, adult POM is usually a symptomatic condition and related to a high complication rate including infections, stone formation and renal failure. Spontaneous resolution is rare and hence active surgical management is advocated.

CONCLUSION

Congenital urological anomalies identified in adulthood are not rare and pose a management challenge to the urologist. For most of the reviewed diseases, evidence-based management direction is difficult due to a lack of randomized trials and long-term follow up.

Imaging and intervention of retroperitoneal fibrosis

Retroperitoneal fibrosis is a rare condition characterized by the development of fibrous plaques in the retroperitoneal space. The fibrous plaques characteristically arise distal to the bifurcation of the abdominal aorta and progress to encase the iliac vessels distally and are defined by the associated encasement of one or both ureters. Imaging plays an important role in not only establishing the diagnosis, but also in monitoring disease progression. Historically, the radiological diagnosis was made predominantly by intravenous urography and retrograde pyelography. More recently, advances in cross-sectional imaging with ultrasound and contrast-enhanced CT have allowed for a more precise diagnosis as well as helping to accurately define the extent of the disease. At our institution, we have found ultra-fast MRI to also play a useful role in establishing the diagnosis. In particular, magnetic resonance urography using HASTE (half Fourier-acquired single shot turbo spin-echo) sequences allow a safe alternative to intravenous urography, particularly in patients with poor renal function. The purpose of this article is to describe the role of the various imaging methods available to the radiologist and to emphasize the important role that the interventional radiologist now plays, not only in obtaining tissue for diagnosis, but also in providing treatment of the disease by percutaneous nephrostomy drainage and subsequent stent placement in select cases.