CONSIDERABLE PROGRESS has been made in unraveling the problems involved in the diagnosis of various disorders of the cardiovascular system, and much of the credit for this progress can be attributed to the development of safe contrast media for use in radiological procedures. However, the use of intra-arterial contrast media involves a degree of risk, and even the more recently developed media have not been free from at least some unpleasant side effects. Although publications on this subject indicate that cases of mortality and morbidity associated with diatrizoate sodium (Hypaque) are decidedly fewer than with some other commonly used media, there is still a potential danger, especially from renal toxicity. Harvard1 reported in 1953 his experience with more than 100 translumbar aortographic procedures, using mostly 75% iodomethamate (Neo-Iopax) 75%. A patient who received the entire injection in the right renal artery had gross hematur[ill]a for 18 hr afterward and