EXTRACRANIAL VENOUS ABNORMALITIES
The extra-cranial venous system is complex and variable. In the last decade, it has been repeatedly shown that the presence and severity of jugular vein reflux is associated with a number of central nervous system (CNS) disorders. A newly proposed vascular condition, named extracranial venous abnormalities, has triggered intense interest in better understanding the role of extra-cranial venous anomalies and developmental variants. Their association to intra-cranial CNS pathology, especially in patients with multiple sclerosis (MS), is poorly understood at this time. The use of noninvasive diagnostic imaging techniques for the diagnosis of extracranial venous abnormalities such as Doppler sonography remains controversial; however, consensus guidelines and standardized protocols are emerging. The use of magnetic resonance venography and phase-contrast imaging is gaining an increasing interest as an alternative noninvasive diagnostic approach for the investigation of the extra-cranial venous system.
There is no established invasive diagnostic imaging modality that can serve as a “gold standard” for the detection of these venous anomalies/developmental variants at this time. The use of catheter venography and intravascular ultrasound are becoming important diagnostic tools for confirming the presence and severity of these venous anomalies/developmental variants in the internal jugular and azygous veins. Each of these noninvasive and invasive imaging modalities has it’s own advantages and disadvantages. Most likely, a multimodal imaging approach will ultimately be the most comprehensive means for screening, diagnostic as well as monitoring purposes. Further research is needed to determine the spectrum of these extra-cranial venous anomalies/developmental variants and to compare the imaging findings with pathological examinations. The ability to define and reliably detect noninvasively extra-cranial venous anomalies/developmental variants is an essential step toward establishing their incidence and prevalence. The proposed role for these anomalies in causing significant hemodynamic consequences for the intra-cranial venous drainage remains unproven. That being said, hemodynamic effects of these lesions on the extra-cranial venous system, need to be rigorously investigated, particularly in regards to their potential role in aging and CNS disorders.
The goal of the Buffalo Neuroimaging Analysis Center (BNAC) is to determine the role of extracranial venous abnormalities in neurologic disorders, with particular emphasis to MS, and to firmly establish its clinical, MRI and genetic correlates.