Bilateral congenital midureteric strictures associated with multicystic dysplastic kidney and hydronephrosis: evaluation with MR urography.

We report a case of bilateral congenital midureteric strictures diagnosed using MR urography. The severity of obstruction differed in the two ureters, resulting in a multicystic dysplastic kidney (MCDK) with an atretic ureter on one side and hydronephrosis that worsened over time due to progressive stenosis on the other. Although midureteric strictures are usually misdiagnosed as ureteropelvic junction (UPJ) or ureterovesical junction (UVJ) obstruction on conventional imaging, MR urography was able to clearly demonstrate both the anatomical and functional abnormalities. Additionally, because of the excellent anatomical resolution, similarities in the underlying pathological lesions could be contrasted with the severity of the pathophysiological impact upon each kidney.