Estimation of venous sinus pressure drop in patients with idiopathic intracranial hypertension using 4D-flow MRI

Objective We aimed to explore a non-invasive estimate of pressure drop in patients who undergo venous sinus stenting to treat idiopathic intracranial hypertension (IIH). Methods This prospective study included 28 IIH patients scheduled for venous stenting. 4D-flow MRI was acquired 24–48 h before venous manometry. Manometry-obtained pressure drop (Mp) was dichotomized into low (Lp: 0–8 mmHg) and high (Hp: 8–30 mmHg) groups. Hemodynamic indices were compared between Lp and Hp. Trans-stenotic pressure drop was estimated by work–energy equation, simplified Bernoulli equation, vorticity magnitude, and velocity difference between inlet and outlet and was compared with Mp. Measurement agreement, correlation, and accuracy were evaluated using the κ coefficient, Pearson’s r , and confusion matrix-derived accuracy. Results Among 28 patients (mean age 38.8 ± 12.7), 19 (67.9%) were female. Work–energy equation-estimated pressure drop (WEp) had strong correlation ( r = 0.91, 95% confidence interval [CI]: 0.81–0.96, p < 0.001) and high agreement (intraclass correlation coefficient = 0.90, 95% CI: 0.78–0.95, p < 0.001) with Mp. WEp classified Lp and Hp with an accuracy of 0.96. The κ value between WEp and Mp was 0.92 (95% CI: 0.78–1.00). In the work–energy equation, the viscosity energy term ( V e ) had the largest weights, and the ratio of V e to the summation of the three energy terms was 0.93 ± 0.07. V e had strong correlation with mVort ( r = 0.93, 95% CI: 0.85–0.97, p < 0.001), and mean vorticity magnitude was significantly elevated in Hp compared to that in Lp (259.8 vs. 174.9 mL/s, p < 0.001). Conclusion Trans-stenotic pressure drop in IIH can be estimated using the work–energy equation with favorable accuracy. Key Points • Trans-stenotic pressure drop in patients with idiopathic intracranial hypertension can be estimated accurately with the work – energy equation using the 4D-flow MRI full velocity field. • Compared with traditional venous sinus manometry, the 4D-flow MRI-derived pressure drop is totally non-invasive and cost-saving. • 4D-flow MRI may help neurointerventionalist to select IIH patients suitable for venous sinus stenting.