  Clinically significant portal hypertension (CSPH) is a severe complication of
chronic liver disease associated with cirrhosis, which is diagnosed by the
measurement of hepatic venous pressure gradient (HVPG). However, HVPG
measurement is invasive and therefore difficult to be widely applied in
clinical routines. There is no currently available technique to measure HVPG
noninvasively. Computational fluid dynamics (CFD) has been used for noninvasive
measurement of vascular pressure gradient in the intracranial and coronary
arteries. However, it has been scarcely employed in the hepatic vessel system
due to the difficulties in reconstructing precise vascular anatomies and
setting appropriate boundary conditions. Several computer tomography and
ultrasound based studies have verified the effectiveness of virtual HVPG
(vHVPG) by directly connecting the portal veins and hepatic veins before CFD
simulations. We apply the latest techniques of phase-contrast magnetic
resonance imaging (PC-MRI) and DIXON to obtain the velocity and vessel
anatomies at the same time. Besides, we improve the CFD pipeline in regards to
the construction of vessel connections and reduction of calculation time. The
proposed method shows high accuracy in the CSPH diagnosis in a study containing
ten healthy volunteers and five patients. The MRI-based noninvasive HVPG
measurement is promising in the clinical application of CSPH diagnosis.
