In Reply.—
We agree with Dr. Colley's view that excessive amounts of contrast medium are implicated in the toxicity we report, and we concur that in selected cases, in the hands of an experienced operator, that direct carotid or brachial artery studies may be preferable to prolonged femoral catheterizations.However, he may be oversimplifying the clinical situation. The precise dosage at which one should abandon the femoral approach and attempt a more direct route is not as clear as suggested by Dr Colley. Many neuroradiologists in present practice recommend the femoral route initially, especially in elderly patients with suggested vascular disease1 to avoid the complications of direct carotid puncture.2.3 To study angiographically both common carotid arteries, a vertebral artery, and the aortic arch in two projections requires at least 160 ml of contrast material for the filming sequences alone, an amount exceeding that used in one of our reported cases.