Reduced Jet Velocity in Venous Flow after CSF Drainage: Assessing Hemodynamic Causes of Pulsatile Tinnitus

Abstract

Background and Purpose Idiopathic intracranial hypertension (IIH) is commonly associated with transverse sinus stenosis - a venous cause of pulsatile tinnitus (PT). In IIH patients, CSF drainage via lumbar puncture (LP) decreases intracranial pressure, which relieves the stenosis, and may provide at least temporary cessation of PT. The objective of this study is to evaluate changes in venous blood flow caused by lowered intracranial pressure in PT patients to help identify the cause of PT. Materials and methods 10 patients with suspected transverse sinus stenosis as a venous etiology for PT symptoms underwent MRI before and after LP in the same session. The protocol included flow assessment and rating of PT intensity before and after LP, and MRV before LP. Post-LP MRV was performed in one subject. Results There was an LP induced reduction in venous peak velocity that correlated with the opening pressure (r=−0.72, p=0.019) without a concomitant reduction in flow rate. Patients with flow jets had their peak velocity reduced by 0.30±0.18m/s (p=0.002), correlating with reduction in CSF pressure (r=0.82, p=0.024) and the reduction in subjectively scored PT intensity (r=0.78, p=0.023). The post-LP MRV demonstrated alleviation of the stenosis. Conclusion Our results show a LP induced reduction in venous peak velocity without a concomitant reduction in flow rate. We hypothesize the reduction is caused by the expansion of the stenosis after LP. Our results further show a correlation between the peak velocity and PT intensity, suggesting the flow jet to be instrumental in the development of sound.

Correlation Between Trans-Stenotic Blood Flow Velocity Differences and the Cerebral Venous Pressure Gradient in Transverse Sinus Stenosis: A Prospective 4-Dimensional Flow Magnetic Resonance Imaging Study

“…A flow jet in the poststenotic region, which indicates a high velocity, has been reported by some previous studies, 8 , 20 and the results were consistent with ours. Haraldsson et al 21 found that the flow jet velocity was reduced after cerebrospinal fluid drainage, which may be caused by the expansion of the stenosis after lumbar puncture. Because the flow jet is directly related to the pressure gradient, the color of the poststenotic flow jet according to the color scale can reflect CVPG, with red coloration in the venous sinus potentially indicating a high CVPG.…”

Evidence of air‐conduction transmission pathway and strategized transtemporal operative techniques for venous pulsatile tinnitus: Combining water occlusion test and operative sensing applications

“…Although some authors have suspected a need to decompress the sigmoid sinus, 27 other studies have reported that eradicating flow pathologies at the prominent sinus junction reduces flow amplitude. 5,17,18 Furthermore, the operative change in jugular outflow volume is insignificant based on current Doppler outcomes. This may be due to the regulation of flow dynamics via the external jugular and vertebral pathways.…”

Anatomical Variations of the Jugular Foramen Region in Patients with Pulsatile Tinnitus

“…It may imply that the dominance of the JF may potentially predispose to the development of PT to some extent, which might be associated with alterations of hemodynamics around the JF region. 22,23 However, this potential mechanism is still undefined and deserves further investigation.…”