Combined hemodynamic and cerebrospinal fluid alterations contribute to the occurrence of sigmoid sinus diverticulum-pulsatile tinnitus.

PURPOSE: To evaluate sigmoid sinus hemodynamics and cerebrospinal fluid (CSF) dynamics in patients with pulsatile tinnitus (PT) induced by sigmoid sinus diverticulum (SSD), and to explore potential correlations between the two systems.

METHODS

Forty-five SSD-PT patients and 35 matched healthy controls were prospectively enrolled. Hemodynamics were assessed using Four-dimensional flow MRI. Cardiac-driven CSF flow dynamics were quantified by phase-contrast MRI, and CSF volume was measured using ITK-SNAP.

RESULTS

Compared with controls, PT patients demonstrated higher body mass index (P = 0.018). In sigmoid sinus hemodynamics, PT patients showed higher maximum velocity, maximum through-plane velocity (Vtp_max), backward flow volume, regurgitant fraction (RF), and average wall shear stress (all P < 0.001), while lower average through-plane velocity, forward flow volume, and average blood flow (all P < 0.001). In CSF dynamics, PT patients exhibited decreased mean flux (P = 0.005), mean velocity (P = 0.030), and peak velocity (PV) (P = 0.016), along with increased RF (P = 0.002) and CSF volume (P = 0.027). The PV of CSF correlated negatively with sigmoid sinus Vtp_max (ρ=-0.416, P = 0.004) and sigmoid sinus RF (ρ=-0.319, P = 0.033). The Combined model of hemodynamics and CSF achieved the highest diagnostic efficacy (AUC = 0.942), significantly outperforming the Hemodynamic Model (AUC = 0.919) and the CSF model (AUC = 0.770).

CONCLUSION

SSD-PT patients exhibit concurrent abnormalities in sigmoid sinus hemodynamics and CSF dynamics, with significant correlations between them. Combined hemodynamics and CSF dynamics may provide a valuable noninvasive biomarker for aiding etiological diagnosis and potentially guiding treatment.