Prediction of the Jugular Venous Waveform using a Model of Cerebrospinal Fluid Dynamics

Background and Purpose: We have previously reported a model of cerebral hydrodynamics in the form of an equivalent electrical circuit. The aim of this work was to demonstrate that the model could predict venous flow patterns seen in the superior sagittal sinus, straight sinus and jugular vein in normal volunteers. Methods: An electrical equivalence model of cerebro-spinal fluid (CSF) and cerebral blood flow was fitted to measured arterial and CSF data from 16 normal volunteers. Predictions of the venous outflow waveform derived from the model were compared to measured venous flows in the superior sagittal sinus (SSS), straight sinus (STS) and jugular vein (JV). Results: The model accurately predicted the measured jugular waveform. The measured waveforms from SSS and STS showed a less pronounced and delayed systolic peak compared to the predicted outflow. The fitted bulk model parameters provided relative values that correspond approximately to the impedance of arterial capillaries (1.0), cerebral aqueduct (≈ 0), venous capillaries (≈ 0), and arteries (0.01) and for the elastic capacitance of the ventricles (4.11), capillaries (≈ 0), and veins (271). The elastic capacitance of the major cerebral arteries was large and could not be accurately determined. Conclusions: We have confirmed the ability of the model to predict the venous waveforms in normal individuals. The absence of any statistically significant component of the venous waveform not described by the model implies that measurements of venous flow could be used to constrain further the model fitting process.