Cerebrospinal fluid changes may be related to sigmoid sinus wall dehiscence-pulsatile tinnitus coexisting with normal intracranial pressure.

BackgroundIntracranial pressure is closely associated with pulsatile tinnitus (PT) caused by sigmoid sinus wall dehiscence (SSWD). Cerebrospinal fluid (CSF) plays a key role in regulating intracranial pressure; however, CSF alterations have not been reported in SSWD-PT patients.PurposeTo evaluate cardiac-driven CSF flow dynamics and volume changes in SSWD-PT patients with normal intracranial pressure.Material and MethodsSSWD-PT patients with normal intracranial pressure and age-, sex-, and handedness-matched healthy controls were prospectively enrolled and underwent MRI. Intracranial pressure was assessed using the index of transverse sinus stenosis and morphological changes. Cardiac-driven CSF flow dynamics were quantified by phase-contrast magnetic resonance imaging (MRI), and CSF volume was measured using ITK-SNAP segmentation software.ResultsThe study included 20 SSWD-PT patients and 35 controls. Compared with controls, the PT group showed a significant decrease in mean flux (MF) and a significant increase in regurgitant fraction (RF) (P = 0.043 and 0.008, respectively). No significant differences were observed in other parameters. The area under the curve (AUC), sensitivity, and specificity for MF and RF were 0.643, 100.0%, 31.4%, and 0.716, 50.0%, 88.6%, respectively. The combined diagnostic efficacy of MF and RF (AUC = 0.764) was higher than RF alone, though the difference was not significant (P = 0.390). The combined model and RF demonstrated significantly better diagnostic efficacy than MF (P = 0.025 and 0.045, respectively).ConclusionSSWD-PT patients exhibited altered cardiac-driven CSF flow dynamics, which may contribute to PT. The combination of MF and RF may serve as a complementary index for identifying the underlying etiology of SSWD-PT.