Retroperitoneal lymphatics on CT and MR.

We report the CT and MRI appearances of dilated retroperitoneal lymphatic channels in six patients. In two patients, these dilated channels resembled a mass of confluent low-density lymph nodes on CT. On MR urography the lymphatic channels in all six patients were seen as a meshwork of multiple tubular, tortuous, fluid-filled structures in the retroperitoneum of the abdomen and pelvis. On axial T1W images, these channels were seen as numerous, interconnected small, nodular and streaky intensities and as a cloak of diffuse homogenous hyperintensity on T2W axial images. The lymphatic nature of these abnormalities was confirmed at surgery in one patient. In another patient, the calibre and number of the dilated retroperitoneal channels reduced following anti-filarial therapy. The remaining four patients presented with chyluria.