Cerebral Sinus Hemodynamics in Adults Revealed by 4D Flow MRI

Quantification of the Dynamics of the Vascular Flows in the Cerebral Arterial and Venous Trees

Objective: Cerebral vascularization is made of the symmetrical arterial system, with muscular walls, and the venous system, more variable and dominated by sinuses and jugular veins. Factors like age and posture influence this network, complicating its study. Phase-contrast MRI is the gold standard for quantifying cerebral circulation. This study aimed to quantify the dynamics of the cerebral blood system using PC-MRI. Materials and Methods: Thirty-six healthy adults participated. Imaging was performed on a 3T MRI (Philips Achieva) in a supine position. Two slices were acquired: intracranial and extracranial. In-house software analyzed flow curves over a cardiac cycle. Each vessel's contribution was evaluated. Results: Extracranial venous drainage was categorized as jugular-dominant, equivalent, or peripheral-dominant. A similar classification applied intracranially. Intracranial flows showed low variability (5-9%), while extracranial venous flows, especially in the internal jugular veins, had higher variability (17-21%). Some extracranial veins were absent. Conclusions: There is significant venous heterogeneity in the extracranial region. PC-MRI enables the quantification of cerebral dynamics.

Angulation of the dural venous sinuses in the posterior cranial fossa: an anatomical study and its implications for venous circulation

The purpose of the current study was to determine the angulation of the dural venous sinuses in soft tissue, to evaluate differences between types of tissue, and to discuss the potential influence of these angulations on intracranial venous hemodynamics and related pathologies. Angulations formed in different segments of the transverse, sigmoid, and superior sagittal sinuses were measured in 13 adult human cadaveric heads (26 sides). After the soft tissues were removed, measurements were also taken from the underlying bone. The overall angulation of the transverse sinus was assessed using two reference points, while the lengths and widths of the dural venous sinuses were measured using microcalipers. Statistical analyses were performed considereing sides, sex, and types of tissue. The mean angulation of the superior sagittal sinuses - transverse sinus junction was 116 degrees. The mean angulations of the transverse sinus - sigmoid sinus junction in medial and superior views were 108 degrees and 114 degrees, respectively. The mean angulations of the entire transverse sinus at two different points were 45 degrees and 44 degrees, respectively. There were statistically significant differences in angulation in some variables when they were adjusted for sides and sex, but not types of tissue. Angulation is a paramount factor in venous hemodynamics. Certain angulations of the dural venous sinuses differed significantly between sides and sexes, but not between types of tissue. Future research should investigate the effects of these angulations on intracranial venous circulation and their relevance to related pathologies.