MRI phase contrast flow measurement of portal vein. Influence and compensation of respiratory motion and propriety of phase correction using background

The purposes of this study were to determine which condition, breath holding (BH) or quiet breathing (QB), is better for phase contrast (PC) measurement of the portal flow (PF); assess the usefulness of respiratory compensation (RC), a technique that diminishes motion artifacts due to breathing, on PC flow measurement; and evaluate the propriety of phase correction (PhC) using background for PC flow measurement. Respiratory simulation phantom (RSP) was measured, and PF measurements were performed in 6 healthy subjects (HS) and 53 patients. Thirty of the patients had liver cirrhosis (LC) and 23 did not. Flow measurements were carried out in the phantom and 6 HS. In 6 HS, intra-subjective coefficients of variation (CV) were smaller under QB than under BH (p<0.05). And PF in patients with LC was less than in those not under QB (p<0.01). This difference was not statistically significant under BH. In the RSP study PC flow measurement with high sort RC showed good reliability. Intraobserver variation was smaller without PhC than with PhC (p<0.05) in the HS study. It may be more useful to perform portal flow measurements under QB with RC and without PhC than with PhC or under BH. (author)