The concept of a Medullary Venous Malformation, or DVA, as a vein collecting more than its physiologic share of medullary territory now emerges. The esthetic beauty is intrinsically valuable In this specimen roentgenograph, some veins are medial hemispheric, others (particularly parieto-occipital) are transmedullary The high density of transmedullary vein is appreciated on this slide Some of those deep tree-like collectors look almost like DVAs already Notice the taller, denser, and larger deep veins, reflecting the increased vascularity of the germinal matrix compared with the developing cortex in this embryo. Imagine what might one of these look like of the adjacent ones were absent – the remaining vein vertically-oriented vein would likely collect a larger territory o longitudinally-oriented tributaries - isn’t that what a DVA looks like.Ī really spectacular image of both deep and superficial systems. Huang’s collection - beautiful depiction of the superficial venous collectors. The venous resolution is incredible - in vivoīack to Dr. Now here comes flat panel imaging - DYNA CT in this case. We get the info, fellow keeps the brain - everyone wins. All veins - pial, superficial medullary, deep medullary (arrow), subependymal, ependymal, transmedullary - are seen here.
Notice how a few veins traverse the entire white distance between the pial and ependymal surface – the transmedullary veins.Īnother really gorgeous specimen of superficial veinsĪ momentary jump into the present - look at his amazing 7T MRI image of one of our own NYU very bright neurointerventional fellow, made by Dr. SC probably refers to surface cortical.Īn x-ray of injected coronal section specimen exquisitely shows this venous apparatusĪ beautiful stereo image. In this picture, DM = deep medullary veins, SM = superficial medullary veins. In the following image, the numbers correspond to those of the preceding slide. This subdivision, in my view, has clear anatomical validity it is however not presently taught and has been effectively forgotten The deep draining veins (deep medullary veins in slide below) were further subdivided into for “Zones of convergence”. Venous drainage of cerebral mantle consists of superficial and deep veins This intriguing hypothesis has not been proven. The term Developmental Venous Anomaly presumes existence of some form of intrauterine event, resulting in anomalous development – one proposition was microthrombosis of either deep or superficial venous apparatus, requiring the other one to assume control of the at-risk territory. Huang, with its name reflecting the nature and location of the malformation. This venous collector is the Medullary Venous Malformation of Y.P. When the balance of drainage is shifted towards either one, the vein or veins collecting the larger than “normal” territory is enlarged. The superficial and deep medullary territories represent, if you will, the watershed zone between the pial and ependymal collectors. They appear to be more common in the embryonic stages, and their density seems to decrease with increasing thickness of the hemispheric parenchyma.
Some anastomotic venous channels, known as transmedullary veins, traverse the entire distance between pial and ependymal veins. The deep system includes subependymal veins and deep medullary veins which drain the bulk of white matter. The superficial drainage apparatus consists of the extraparenchymal pial veins, cortical (subpial) veins, and superficial medullary veins located just underneath the cortex. Fundamentally, they seem to be aberrations in the “normal” balance between superficial and deep venous drainage systems, particularly involving the territory of the deep white matter. There is no consensus on how exactly DVAs form. It is a purely venous structure which drains normal brain parenchyma, and an incidental finding in vast majority of cases, with some rare exceptions. The Medullary venous Malformation, now better known as the Developmental Venous Anomaly, or DVA, is seen in as many as 15% of brains on current generation MR scanners. Our current understanding of the DVA is a result of these insights. The microarchitecture of the venous drainage was one such area credit for advancing knowledge here goes to very large extent to Dr. Consequently many conditions which affect the venous system remained, and continue to be, less well understood than those of the arteries. The venous system has historically taken a back seat to its arterial complement. Toshio Okudera carried out seminal research on the topic of cerebral venous architecture.
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