To the Editor.—
The recent series of four cases of acute renal failure as a complication of cerebral angiography reported by Adornato and Winestock (Arch Neurol 33:687, 1976) necessitates critical (and hopefully constructive) comments. The reported volumes of contrast material used in angiography, particularly in patients with known preexisting renal disease, are excessive. Certainly, technical difficulties will arise in older persons with extreme vessel tortuosity, and catheterization via the femoral route may be difficult if not impossible. The utilization of 106 ml of diatrizoate meglumine for right common carotid angiography is almost ten times the amount needed for any single injection. It has been the custom of many neuroradiologists for years to limit the amount of contrast agent used in direct carotid angiography to a maximum of 50 ml (total of right and left injections) at any one examination. Further, if possible, the total amount of contrast material should be