Adrenal hemorrhage and renal vein thrombosis in the newborn: MR imaging.

Three newborn infants with flank masses underwent magnetic resonance (MR) imaging after ultrasound (US) indicated adrenal hemorrhage and/or renal vein and inferior vena cava thrombosis. MR imaging was valuable in defining the hemorrhagic nature of echogenic and hypoechoic suprarenal masses and in delineating thrombi within the renal veins and inferior vena cava. Two infants with renal parenchymal damage had abnormal radionuclide scans and abnormal corticomedullary distinction on MR images. The major role of MR imaging may be in the early course of these conditions, when added diagnostic specificity is likely to affect patient management. In most instances, size of hemorrhage and intravenous clots, as well as renal size, may be accurately followed with US, while radionuclide scanning remains necessary for evaluation of renal functional impairment.