Phase-contrast single-point imaging with synchronized encoding: a more reliable technique for in vitro flow quantification.

Abstract

The purpose of this study is to provide a standard method for flow velocity measurements with phase-contrast (PC) MRI. This method can be used for in vitro studies that place high demands on measurement accuracy. Clinically relevant PC MRI techniques can be validated using this method before being applied in vivo. Many motion-related errors in PC MRI, particularly flow misregistration, depend on the timing of the encoding gradients in the pulse sequence. By synchronizing all encoding gradients and shortening the overall encoding interval, these errors can be significantly reduced. Based on this concept, a single-point PC MRI method is proposed. Flow experiments were conducted in vitro. No considerable errors were found in the velocity data of the proposed method. For comparison, a conventional PC MRI technique showed up to 100% local velocity deviation and up to 35% flow rate deviation in the same experiments. With the proposed method, the overall measurement accuracy is significantly increased compared to conventional PC MRI techniques. Due to long acquisition times and high specific absorption rates, this method can only be applied in vitro.