 Hello, everyone, myself, Dr. Mitusha Verma, I'm a Consultant Theologist at Nanamity Mac Super Speciality Hospital, Mumbai. And the topic which we are going to discuss in next 15, 20 minutes is Anatomy of CSF Spaces and Systems. So this is something which all of us already know, but it's going to be a quick revision with few important highlights. So before we begin, I would like to thank all the organizers of this 21st MRI teaching course for their efforts. And especially, I would like to thank Dr. Deepak Patkarsar for all the ideology knowledge which I have gained. So these are the headings under which we are going to discuss this topic today. So first of all, we would like to revise the CSF physiology, then CSF flow pathway, then CSF spaces and systems, important ones, and their clinical applications. So as we all know, CSF is a clear water flow that fills the ventricle of the brain and the subredacted spaces. So the normal CSF pressure is around 5 to 15 millimeters of mercury in adults, which is 65 to 195 millimeters of water. This is important to know because sometimes we get the reports of CSF pressure to understand whether it is a high-pressure state or a low-pressure state by the measurements. Sight of CSF origin is the coral plexus. Even the brain, panorama, and spinal cord, as well as the ependymine lining of the ventricles. See, we all know the CSF flow pathway, but just a revision. So from the lateral ventricles after the production of the CSF mainly through the coral plexus, the CSF flows into the third ventricle. And the passage is the foramen of moon row. So this is a few monex which they have mentioned in the bracket. So moon row is the first foramen after which she's on the third ventricle via the aqueduct of civilians. The CSF flows into the fourth ventricle, as we see on the mid-sagittal. This is the site where we are planning our CSF velocity analysis studies, so that we see with few slides. And then afterwards, from the fourth ventricle, the CSF flows via the foramen of McKinney, which is a median aperture. And also through the two lateral apertures, these are the foramen of Nushkas. And then a part of the CSF also flows through the central canal into the Sparrow Cod region. After this flow, it is the portion of CSF absorption, which takes place. And there are three recognized routes through which the CSF absorption occurs. One is through the adenoid granulations via the sub-adenoid spaces, which ultimately brings the CSF into the cerebral venous system. Second is through my new channel, so that passes through the triple-form plate of the etymol pool. And the third is the glymphatic system. So something important is that these sub-adenoid granulations or space adenoid granulations, they are connecting the sub-adenoid space with the sinuses via the dura matter. So these are actually piercing the dura matter. And then they are communicating with the dura venous sinuses, where they're ultimately training the CSF. So this red line is the pion matter, which is just covering the cortex. Above this, the green band is the sub-adenoid space, which is lined by the adenoid membrane. This sub-adenoid space is incontinutive via these piercing channels. The blue thing is the dura, and then they are continuing into the venous sinuses. So CSF is constantly being getting produced at a definition rate of 0.2 to 0.7 ml per minute. These values are sometimes important to know. So this is like a quick revision. And so in our day, around 600 to 700 ml of newly produced CSF is there in the system. And since the total volume of CSF averages 150 to 270 ml at a time, this means that the entire volume of CSF is replaced around four times per day. There is no functional communication between the ventricles and the sub-adenoid spaces in any region, except from the fourth ventricle. And there are two theories, or there are two components through which the CSF circulation may be explained. One is the bulk flow, and the second is the pulse-style flow. So bulk flow is consistent of the CSF flow through the fourth ventricle, and finally into the spinal canal, whereas the pulse-style flow consists of the theory where we consider that during the cardiac phases of systole and diastole, the CSF also moves back and forth. And this forms the basis of what we call the CSF flow or CSF velocity analysis using MR, where we use phase contrast MR imaging and try to quantify the CSF velocity, the stroke volumes, and the peak systolic as well as the diastolic velocities. So the pulse-style flow, thing to remember is that during the cardiac systole, the CSF flows in the cordal direction, and in the diastole, the CSF flows in the cranial direction. So it is in the opposite direction. This is in terms of the Moldow-Kaley doctrine, and that is because in the systole, the blood flow into the cranial cavity is more, and therefore, the CSF moves in the cordal direction. So that is something to remember, and this is based upon the bi-directional oscillatory movement of the CSF through the aqueduct. So we are not getting into the details of CSF flow studies here, but we can calculate the peak diastolic as well as the systolic velocities and the stroke volumes, and there are studies where you have to compare and the control group for your own machine and double that value is now considered as a cut-off for the patients for the shunt-responsive normal-pressure hydrotrophilus. So there are various situations where the CSF flow studies are important. One is normal-pressure hydrotrophilus, very commonly done. Second are areas of hydrotrophilus like aqueductal stenosis or where the ventricleostomy has been performed where they want to know whether it is patent or not, then intracranial hypotensions with asymmetric age-inappropriate brain atrophy and also in carry malformations. Now coming to the part of subarachnoid systems or basal systems and their anatomy. So these are the compartment within the subarachnoid space where the biomatter and the arachnoid membrane are not in close approximation and the CSF pools in this area. So as they are interconnected, their potency is essential for CSF circulation. So blockage anywhere may hamper the normal CSF circulations and what they normally consist of beyond the CSF are vessels and cranial nodes. So if we see this mid-sagittal graphical image, even on this, at least 11 to 12 of the important cisternal spaces we can identify. So we are going to revise these multiple times in the frequent slides and then we are going to discuss about some relevant clinical aspects. So if these are the central circuits, here is the pericalosal cistern which is along the corpus callosum and this is the space where we get those pericalosan type umas, interpotential cistern which is somewhere here, it's in the midline subatocinone axioles, supracellar cisterns which is around the cellar, pre-pontine cistern which is again midline and in front of the bonds, ventrally to the bonds, pre-medulary system. Then here we have the parito-oxypetal cells, focal spaces, systems of the vellum interpositum, superior cellular system, quadrigeminal systems which we are also going to see on the actual plates. So this is how a mid-sagittal section of MRT1 weighted image would look like where you can identify all these cisternal spaces as well as the different CSF recesses. So third ventricle going into the acnyrduct, fourth ventricle, quadrigeminal systems, pre-pontine system, pre-medulary system, interpedacular system, supracellar system, all these can be identified clearly on a mid-sagittal image as well. So same thing revised you see here, this mentioned as a system of the lamina terminalis, isometric system, here is the interpedacular system. Then we come here which is marked as E that is the quadrigeminal system, pre-pontine system, lateral cerebellum, medulary system. So as it is a lateral system, it will be better seen on axioms or coronals and cisternal magma. So there are multiple images which clearly depict these cisternal spaces on mid-sagittal as well as actual and different planes. And here again the same thing which has been described on MR mid-sagittal P2 weighted image. So you see this is the pericalosal system where you can see the pericalosal lipooma lining up along the same plane, quadrigeminal system. This is the lamina terminalis, the thin line, hypotensile, isometric system, liquid membrane, interpedacular system, pre-pontine, pre-medulary system and these spaces consists of vessels and cranial nerves. So that also we are going to discuss. So if we try to remember them as dividing them into supra-tentorial, infratentorial and lateral system, the supra-tentorial ones, the important ones are supra-cellar system, superior to the pituitary clamp, interpedantular system, ambient system, then quadrigeminal system which is under the corpus callus and spleenium behind the pineal clamp, tectum and continues anteriorly with the vellum interpositive and system of the vellum interpositive. So same thing supra-cellar system we saw on the mid-sagittal images. Interpedantular system is this one which you can see clearly in between ventral portion of the mid-brain and this is an unpaired system. Quadrigeminal system on axial and sagittal and this is where we commonly also find out these quadrigeminal rate lipomas, ambient system. So we are going to see this particular perimes in catalytic systems once again. So interpedantular system, crura system, ambient system and quadrigeminal systems. So these are the contents of these supra-tendolian systems. Supra-cellar is infundibular optic nerve and circular phyllis. Interpedantular is oculomotor nerve, basilar artery bifurcation and posterior thalamus perforating arteries. Ambient is trochlear nerve and P2 segments of PCA. So we get sagittal artery. Quadrigeminal is pineal gland, trochlear nerve and P3 segment of PCA, vein of gallin and tributaries and system of filamentopositam is internal cerebral vein. So these are the important contents and because of this particular location, if aneurysm is there involving these segments of the arteries and the rupture happened, the bulk of samarangmar hemorrhage is going to be located in these particular systems. So that helps us in localizing the site of aneurysm rupture. In front end, totally the important ones and these are midline unpaired single systems, pre-pontine, pre-medulary, as the names are, so they are easy to locate, cisterna magna and superior cerebellar system. These are their contents. So pre-pontine is the main content is basilar artery, cranial nerve 5 and cranial nerve 6. Pre-medulary is vertebral arteries and t-just spinal arteries, picas and cranial nerve 12. Superior cerebellar systems, SCA branches, cisterna magna and cerebellar tonsils themselves, cerebellopontine systems, that is cranial nerve 5th and 7th and 8th, CP angle system, that is an cerebellum medullary system. So with this 9, 10, 10, 11th, then the paired system. So CP angle, the very famous CP angle system. So commonly seen regions, they are asked even for the preliminary examinations. So CP angle systems between the enterorator points and the cerebellum. Then you have cerebellum medullary system as well, fissures-wise inter-anesthetic fissure and salient fissures, which are separating the phantral and temporal lobes anteriorly. So this is the salient system. So these are all the important cisternal spaces, supra-tentorial, inter-tentorial and in the later ones. Now discussing few important points. So CP angle system is the area where we see the 7th and 8th nerve complexes. If we perform the dedicated sequences, having the divided sequences for the cranial nerve, status, ph, star, or cis. And there are multiple lesions which can occur in this particular location. The commonest being the vestibular sonomas, next being the meningiomas or the arachnoid cysts as well. But all of these lesions, including lymphoma, glioma, metastasis, they can happen at this particular site. And including the non-enhancing ones like denoids, lipomas, et cetera, cholesterol, ganyloma, also can happen close to this area. So this is one of the important cisternal space. Then we have the perinbase endophelic system which consists of the inter-predensular system, the crural systems here, then the ambient systems and the cordage and vinyl plate system. So the inter-predensular and the cordage and vinyl systems are the midline unpaired systems, whereas the crural and ambient are the ones which are paired cisternal spaces. So when you have the subarachnoid space hemorrhage, you're going to see something like this on a CT, axial image, and where these are the sylvian systems somewhere here, then the crural, inter-predensular, ambient, cordage and vinyl, and in total becoming the perinbase endophelic systems. So there is something called as perinbase endophelic subarachnoid hemorrhage, which is most commonly of non-annuosomal etiology. So the incidence is about 0.5 per one lakh and it's 5% of all subarachnoid hemorrhages. And most commonly, it is venous in origin rather than arterial. So we are not able to get the aneurysms at the side. So we have to be careful looking, not only for the aneurysms, but also for the venous etiology, for these perinbase endophelic subarachnoid hemorrhages. So to conclude this talk, the knowledge of physiology of CSF dynamics and anatomy of CSF spaces, helping understanding various pathologies as well as the exact radiological description also becomes very easy. So thank you for your patient listening. And with this, I would like to end my talk. Thank you.