All 21 MRU examinations were successfully completed. MR urography images were diagnostically sufficient in all patients. A total of 42 kidneys, 42 collecting systems and 21 bladders in 21 patients were examined. The results of MR urography are presented in .
In this study the most common indication for MRU was hydronephrosis of unclear aetiology: 66.7% (n=14) of all our patients were admitted with this diagnosis. In the case of 4 patients where it was challenging to establish the cause of hydronephrosis via classical methods, MRU solved a diagnostic dilemma and established that hydronephrosis was caused by intraluminal ureteropelvic junction (UPJ) stenosis.
MRU was performed on 19% (n=4) of patients with a hydronephrotic collecting system as a part of the postoperative evaluation after pyeloplasty. MRU identified the postoperative presence of functional UPJ stenosis as a cause of hydronephrosis in 1 patient with the additional finding of UPJ stenosis on the contralateral side which wasn’t identified with other methods, while in the remaining 3 patients MRU demonstrated that hydronephrosis was the continuation of previously treated stenosis and in one case the additional finding was caliceal lithiasis.
In one case of unclear hydronephrosis the cause was both UPJ and vesico-ureteric junction (VUJ) stenosis with hydromegaureter and the additional finding was UPJ stenosis on the contralateral side.
In two cases of hydronephrosis MRU established not only the cause – fetal ureter, but gave additional findings: UPJ stenosis on the contralateral side in one case and VUJ stenosis on the contralateral side in the second case.
With two patients, where based on previously conducted methodologies (intravenous urography and voiding cystouretrography), hydronephrosis was proved to be connected to VUR, MRU not only identified established insufficient broad ureter orifice but also provided further information. In one case, MRU established the occurrence of neurogenic bladder and hypotonic ureter with further signs of the urinary infection. In the case of the other patient MRU established the condition of urine retention with UPJ stenosis and fetal ureter on the contralateral side.
With one patient where renal hypoplasia and hydronephrosis of the kidney caused by VUR were diagnosed via classical methodology, this diagnosis was corroborated by MRU results which further established the condition of duplication of pelvis and ureter on the contralateral side.
contains the MRU identified pathological conditions that caused hydronephrosis.
MRU identified 6 stenosis at the level of UPJ associated with the hydronephrosis: 5 of this were intraluminal and 1 was functional.
In two patients where cysts were identified via ultrasound, MRU not only enabled the diagnosis of cyst type but also the analysis of cyst influence on the collecting system: in one of these two patients a caliceal cyst was identified establishing no repercussion on the collecting system, while in the other patient a simple cortical cyst with a subtle compressive effect on the upper and middle region calices was diagnosed.
MRU conducted on 3 patients, where previously polycystic disease of the kidney - cystic dysplasia was diagnosed via ultrasound, enabled the morphological analysis of cysts, renal parenchyma and collecting system and the analysis of functional capabilities of kidney which were normal in all three cases.
With one patient who previously had normal ultrasound results but had repeated urinary infection MRU revealed long, hypotonic and twisted ureters.
Before performing MRU, 100% (n=21) of our patients were examined with one or more other diagnostic modalities (US, intravenous urography, voiding cystouretrography). MRU findings gave additional information about existing pathological conditions in 100% (n=21) of patients, which have not been identified with other mentioned modalities. In additionally acquired information after performing MR urography is presented.
Additional MR urography findings.
As a part of MRU examination we evaluated the renal function of 100% (n=21) of our patients. In 19% (n=4) of patients we identified the decreased renal function. We performed MRU due to the suspicion of malign tumour only in 4.8% (n=1) of patients. MRU finding denied the malign diagnosis: we identified the benign condition – hypertrophied column of Bertini (–).
Intraluminal UPJ stenosis on the right causing hydronephrosis. Hydronephrosis on the left side is continuation of previously treated stenosis.
Caliceal cyst of left kidney. Vascular impression on the proximal ureter on the right side.