In vitro validation of phase‐contrast flow measurements at 3 T in comparison to 1.5 T: Precision, accuracy, and signal‐to‐noise ratios

Abstract

Purpose:To evaluate the signal-to-noise ratio (SNR), precision, and accuracy of phase-contrast flow measurements at 3 T with the help of an in vitro model and to compare the results with data from two 1.5-T scanners. Materials and Methods:Using an identical setup of a laminar flow model and sequence parameters, measurements were done at one 3-T and at two 1.5-T systems. Precision, accuracy, and SNR were obtained for velocity encodings ranging from 55 up to 550 cm -1 . SNRs were calculated from the magnitude as well as the flow encoded images.Results: Precision and accuracy for the in vitro flow model were similarly high in all scanners with no significant difference. For velocity encodings from 55 cm -1 up to 550 cm -1 , the SNR in magnitude as well as phase encoded images of the 3-T measurements was approximately 2.5 times higher than the SNR obtained from the two 1.5-T systems. Conclusion:Even without optimization for the 3-T environment, flow measurements show the same high accuracy and precision as is known from clinical 1.5-T scanners. The superior SNR at 3 T will allow further improvements in temporal and spatial resolution. This will be of interest for small-size vessels like coronary arteries or for slow diastolic flow patterns.

4D phase contrast MRI at 3 T: Effect of standard and blood‐pool contrast agents on SNR, PC‐MRA, and blood flow visualization

“…Based on results from a previous study comparing PC-MRI at 1.5 T and 3 T, the 3-T system used on our study was expected to provide the same accuracy and precision compared to 1.5 T (27) and to show reduced noise levels in magnitude and velocity data relative to 1.5 T (27).…”

“…Furthermore, as PC-MRA is sensitive to the available signal-to-noise ratio (SNR), contrast agents may help to enhance vessel surface extraction and 3D flow visualization (26)(27)(28).…”

Visualization of iliac and proximal femoral artery hemodynamics using time‐resolved 3D phase contrast MRI at 3T

“…Imaging at 3T as performed in this study is associated with a gain of SNR (23), which is directly translated in reduced noise of the flow images. Yet, this generally accepted hypothesis will have to be evaluated in a setting where contrast-enhanced phase-contrast imaging in peripheral arteries is performed in larger numbers at 1.5 and 3T.…”

The emerging clinical role of cardiovascular magnetic resonance imaging

“…Several methods are available for this purpose -phase-contrast sequences quantify anterograde and retrograde flow volumes and velocities in any desired imaging plane, within a vessel or a valvular plane (89,90). The accuracy of phase-contrast measurements as assessed with in vitro models is excellent (91,92) and good correlations have been documented between CMR flow measurements and Doppler echocardiography (93), as well as cardiac catheterization (94,95). Cine imaging is applied to quantify the orifice of a stenotic valve (96).…”