Evaluation of sigmoid sinus hemodynamics through four-dimensional flow magnetic resonance imaging in pulsatile tinnitus patients caused by sigmoid sinus wall dehiscence coexisting with idiopathic intracranial hypertension.

PURPOSE: To evaluate hemodynamics in the sigmoid sinus of sigmoid sinus wall dehiscence (SSWD)-pulsatile tinnitus (PT) patients with idiopathic intracranial hypertension using four-dimensional (4D) flow MRI.

METHODS

Thirty-five SSWD-PT patients with idiopathic intracranial hypertension were prospectively enrolled, together with 35 age-, sex-matched healthy controls and underwent MRI. Hemodynamics in the sigmoid sinus were evaluated by 4D flow MRI. Receiver operating characteristic curves and logistic regression analysis evaluated the ability of the hemodynamic indicators to differentiate SSWD-PT patients from healthy controls.

RESULTS

PT patients presented significantly increased maximum velocity [86.77 ± 7.92 cm/s vs. 46.32 (38.89, 53.96) cm/s], maximum through-plane velocity (Vtp_max) (63.83 ± 16.89 cm/s vs. 45.65 ± 10.92 cm/s), backward flow volume [0.27 (0.06, 0.84) mL vs. 0.04 (0.01, 0.06) mL], regurgitant fraction [10.73 (2.11, 24.30) % vs. 0.47 (0.17, 1.31) %], and average wall shear stress (WSSavg) [0.27 (0.24, 0.33) N/m2 vs. 0.14 (0.11, 0.19) N/m2] (all p < 0.001). Average velocity (18.47 ± 2.69 cm/s vs. 21.97 ± 6.66 cm/s), average through-plane velocity [5.06 (3.25, 7.74) cm/s vs. 20.30 ± 6.44 cm/s], forward flow volume [3.70 (2.40, 5.44) mL vs. 6.90 ± 3.50 mL], and average blood flow (4.16 ± 2.03 mL/s vs. 7.42 ± 3.67 mL/s) were significantly decreased in PT group (all p < 0.05). Abnormal vortex or turbulent flow occurred in 88.6% of patients, none in controls (p < 0.001). The combination of Vtp_max and WSSavg showed the highest ability to differentiate SSWD-PT patients from healthy controls (AUC = 0.956).

CONCLUSION

SSWD-PT patients have hemodynamic changes in the sigmoid sinus. The combination of Vtp_max and WSSavg may serve as a valuable noninvasive indicator for differentiating SSWD-PT patients from healthy controls.