EDITORLAL Blood flow measurement with nuclear magnetic resonance technology: A clinically apJicable technique?

An exciting aspect of nuclear magnetic resonance (NMR) technology is its potential ability to measure blood flow transcutaneously. In an article appearing in this issue of the JOURNAL OF VASCULAR SURGERY, Kerr et al. report the results of a careful study of a commercially available NMR instrument designed specifically for evaluating arterial blood flow in human limbs.’ Like other work from this innovative group, the investigation was objective, meticulous, and thorough, and the results were interpreted cautiously-allowing the reader to formulate his or her own conclusions. In this era of ever-expanding technology, new devices and diagnostic tests encroach on limited medical resources. Before a new device or test is incorporated into the standard diagnostic armamentarium, it should either (1) provide “new” information that can be obtained in no other way or (2) provide “old” information more accurately, cheaply, expeditiously, simply, or safely than existing devices. The information derived from a new test should represent a significant improvement over that derived from established tests in terms of clinical diagnosis, selection of therapy, formulating a prognosis, or follow-up studies; or it should offer a better understanding of the natural history or pathophysiology of the disease process. Does the NMR instrument in its current state of development fulfill these criteria? The equipment is capable of performing only one function: measurement of blood flow. Even in this area, it is restricted to the measurement ofpulsatib bloodJEav. It does not