British Journal of Radiology 75 (2002),177-179 © 2002 The British Institute of Radiology
Retrocaval ureter: MR appearances
M C Uthappa, MBBS, FRCS, FRCR
D Anthony, DCR
and
C Allen, MBBS, MRCR, FRCR
Department of Radiology, Central Middlesex Hospital, Acton Lane, Park Royal, London NW10 7NS, UK
Correspondence: Dr M C Uthappa, SpR in Radiology, 336 Carr Road, Northolt, Middlesex UB5 4RW
 |
Abstract
|
|---|
We present a case of retrocaval ureter and its MR appearances. This is the first case in reported literature. The findings on iv urography are correlated with the MRI findings. So far CT has been the procedure of choice to confirm the diagnosis of retrocaval ureter. However, we believe MRI is likely to replace CT in the diagnosis of retrocaval ureter.
|
Introduction
|
|---|
Retrocaval (circumcaval) ureter is an uncommon venous anomaly in which the right ureter courses posterior to the inferior vena cava and partially encircles it. Since its first description by Hochstetter in 1893 [1], approximately 200 cases have been reported worldwide. Retrocaval ureter results from persistence of the posterior cardinal venous system that anomalously forms the inferior vena cava, and subsequently courses anterior to the ureter for a variable distance. This can cause varying degrees of ureteral obstruction, and surgical intervention is often necessary.
|
Case report
|
|---|
A 24-year-old male presented with a right testicle that had been painful for 6 months. Urine analysis showed microscopic haematuria. There was no previous history of renal stones. Physical examination was unremarkable. Ultrasound examination of the scrotum and urinary tract showed pelvicalyceal dilatation in the right kidney with no apparent cause and normal appearances of the scrotal structures. An iv urogram (Figure 1
), performed two weeks later, showed marked dilatation of the right pelvicalyceal system and proximal ureter to the level of the transverse process of L3 vertebra. In addition there was medial deviation of the ureter at the point of transition. The distal few centimetres of the right ureter were of normal calibre. No renal tract calcification was seen on the control radiograph. The findings were consistent with that of a retrocaval ureter.
View larger version (110K):
[in this window]
[in a new window]
|
Figure 1. 30 min prone iv urogram showingright-sided hydronephrosis and dilatation of the proximal ureter up to the level of the transverse process of L3. In addition there is medial deviation of the ureter at this level.
|
|
MRI was performed to confirm the diagnosis of retrocaval ureter in view of the patient's age and lack of symptoms of right-sided renal colic. The following sequences were obtained on a 1.5 tesla Phillips Gyroscan ACS NT scanner (Phillips, Eindhoven, The Netherlands); standard spin echo axial T2 weighted (TR 2552, TE 60), coronal T1 weighted (TR 352, TE 11) and gradient echo coronal T1 weighted (TR 73, TE 1.7, flip angle 80) supplemented by post iv gadolinium (10 ml injected 5 min after iv frusemide 10 mg) volume acquisition in axial and coronal planes (TR 38, TE 3.8, flip angle 80, slice thickness 6.0/0.6). The entire procedure took approximately 30 min. This was followed by multiplanar reconstruction and maximum intensity projection (MIP) to show the renal tracts. The full course of the right-sided retrocaval ureter was traced on the workstation and the most relevant slices selected for imaging (Figure 2, 3). The MIP image shows a magnetic resonance urogram.
View larger version (139K):
[in this window]
[in a new window]
|
Figure 2. Axial T2 weighted image through the midpole of the right kidney showing hydronephrosis of the right kidney and dilated proximal ureter as high signal (consistent with fluid) area. The flow void in the inferior vena cava and aorta is of low signal.
|
|
View larger version (93K):
[in this window]
[in a new window]
|
Figure 3. Magnetic resonance urogram clearly showing right-sided hydronephrosis and the full course of the right ureter. The left renal tract has a normal appearance.
|
|
|
Discussion
|
|---|
A retrocaval ureter is a rare congenital anomaly. It occurs in about 1 in 1000 people with a two to three-fold male predominance. The embryological significance of the retrocaval ureter is, strictly speaking, an anomaly affecting the inferior vena cava and not the ureter. In the majority of patients, symptoms are due to ureteral obstruction and resulting hydronephrosis. Pain can be intermittent, dull and aching. Haematuria in varying degrees is also present in many cases. Bateson and Atkinson (cited in [2]) analysed 92 cases and found that they could classify 79 cases into one of two types on the basis of radiographic criteria. Type 1, the more common form, has severe or moderate hydronephrosis with extreme medial deviation of the middle ureteral segment, usually medial to the pedicle or across the midline at the L3 level. An "S" or "fish hook" deformity is present at the point of obstruction. In type 2 there is mild hydronephrosis and less medial deviation of the ureter. The ureter is noted to be sickle shaped at the level of obstruction.
Other entities that may produce medial deviation of the ureter include retroperitoneal fibrosis and a retroperitoneal mass. In the past it was thought that CT was the most efficacious and least invasive method of confirming diagnosis of retrocaval ureter [3] owing to the inherent ability of CT to define the three-dimensional relationships of retroperitoneal structures. This case clearly shows that MRI is equally good and has the benefit of no radiation risk. Also, there is no need for the use of iodinated contrast medium.
There have been reports of various complications and associations with retrocaval ureters and most of these have implications regarding its possible medical, radiological and surgical management [4–11]. Treatment of retrocaval ureters has been open surgery [12], is usually successful but requires a large skin incision and causes significant post-operative pain with a prolonged convalescence. Recently, reconstructive laparoscopic techniques have been reported, including the use of an automatic suture device [13]. Further reports have suggested that minimally invasive laparoscopic treatment is useful for the treatment of retrocaval ureter with minimal post-operative pain and short convalescence [14].
Our case has clearly demonstrated that using MRI in the diagnostic confirmation of a retrocaval ureter has distinct advantages, although the limitation of this case report is the lack of a comparative CT study. The advantages of MRI are an accurate multiplanar analysis of the retroperitoneal structures and a lack of radiation.
Received for publication July 31, 2001.
Revision received September 20, 2001.
Accepted for publication September 24, 2001.
|
References
|
|---|
-
Zhang XD, Hou SK, Zhu JH, Wang XF, Meng GD, Qu XK. Diagnosis and treatment of retrocaval ureter. Eur Urol 1990;18:207–10.[Medline]
-
Carrion H, Gatewood J, Politano V, Morillo G, Lynne C. Retrocaval ureter: report of 8 cases and the surgical management. J Urol 1978.
-
Murphy BJ, Casillas J, Becerra JL. Retrocaval ureter: computed tomography and ultrasound appearance. J Comput Tomogr 1987;11:89–93.[Medline]
-
Reese L, Hanna MK. The retrocaval ureter: an intrinsic abnormality. Can J Surg 1980;23:485–7.[Medline]
-
Costea F, Pontin AR, Botha JF, Halkett JA, Kahn D. Renal transplantation from a living related donor with a retrocaval ureter—a note of caution. Transpl Int 1999;12:229–30.[Medline]
-
Shigeta M, Nakamoto T, Nakahara M, Hiromoto N, Usui T. Horseshoe kidney with retrocaval ureter and ureteropelvic junction obstruction: a case report. Int J Urol 1997;4:206–8.[Medline]
-
Hidai H, Kohdaira T, Terashima K, Takahashi G. Retrocaval ureter in children: report of two cases. Eur Urol 1978;4:127–31.[Medline]
-
Varma KT. Transitional cell carcinoma associated with retrocaval ureter. J Okla State Med Assoc 1989;82:463–5.[Medline]
-
Kokubo T, Okada Y, Yashiro N, Itai Y, Iio M. CT diagnosis of retrocaval ureter associated with double inferior vena cava: report of a case. Radiat Med 1990;8:96–8.[Medline]
-
Fukuoka H, Fukushima N, Uekane K, Higurashi M. Retrocaval ureter with recurrent pyelonephritis. Gynecol Obstet Invest 1992;34:57–60.[Medline]
-
Bhatia V, Biyani CS. ESWL for stone in a retrocaval ureter: a case report. Int Urol Nephrol 1994;26:263–8.[Medline]
-
Stojkovic J, Zvara V. Treatment of retrocaval ureter. Czech Med 1986;9:15–22.[Medline]
-
Mugiya S, Suzuki K, Ohhira T, Un-No T, Takayama T, Fujita K. Retroperitoneoscopic treatment of a retrocaval ureter: case report. Int J Urol 1999;6:419–22.[Medline]
-
Matsuda T, Yasumoto R, Tsujino T. Laparoscopic treatment of a retrocaval ureter: case report. Eur Urol 1996;29:111–4.[Medline]
Top
Abstract
Introduction
