Nuclear magnetic resonance (NMR) principles have been used for industrial measurement of steady flow in pipes. Research has been performed by others since 1958 to apply NMR techniques to the measurement of blood flow. An NMR device has been constructed at the Medical College of Wisconsin for the non-invasive detection and measurement of blood flow in arteries and veins of limbs. The design is based on several criteria which were developed by computer modelling. Detector coils are mounted on a 5 cm. I. D. form which can be slipped over the limbs of monkeys and dogs and over the arms of small children. Steady and pulsatile flows similar to those observed in vivo have been measured with signal averaging techniques using tubing of various sizes from 1. 6 mm to 6. 4 mm I. D. A tag-detect method is used for steady flow or venous flow, whereas the velocity sensitivity of magnetization causes a ″self-tagging″ effect for pulsatile flow or arterial flow. Peak pulsatile flow rates down to 20 ml/min were reliably measured in 1. 6 mm I. D. tubing. There is no significant difference between signals obtained in tests with or without saline solution which surrounded the flow tube to simulate body fluids and tissue. In vivo experiments with monkeys and dogs were conducted to prove the feasibility of this method of blood flow measurement.
|Original language||English (US)|
|Number of pages||9|
|Journal||[No source information available]|
|State||Published - Jan 1 1974|
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