Diagnosis and imaging of the fetal and neonatal abdominal mass: an integrated approach.

Almost all of the renal causes of NAM and adrenal neuroblastoma, the most common nonrenal cause, can be categorized as cystic or solid by sonography. Evaluation with CT is usually the most appropriate next step for assessment of solid renal tumors lacking clinical features of RVT. Renal scintigraphy and diuretic renal scintigraphy offer valuable information about relative individual kidney GFR and excretory function, whether normal, partially, or completely obstructed. Many dilated urinary tracts, especially those diagnosed in utero, are found to resolve spontaneously when serial studies are performed. The informed pediatrician should play a major role in the selection of diagnostic procedures and determination of management strategy. Only he or she has the detailed clinical knowledge of the patient that can give appropriate direction to the consultants. A tentative algorithm for imaging studies in the evaluation of NAM is presented in Figure 1 and emphasizes the functionally more informative radionuclide studies 15,25,26 over the traditional radiocontrast studies.