An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. Arterioles are the primary site of vascular resistance; the greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries. In a healthy vascular system the endothelium lines all blood-contacting surfaces, including arteries, veins, venules and heart chambers; this healthy condition is promoted by the ample production of nitric oxide by the endothelium, which requires a biochemical reaction regulated by a complex balance of polyphenols, various nitric oxide synthase enzymes and L-arginine. In addition there is direct electrical and chemical communication via gap junctions between the endothelial cells and the vascular smooth muscle. Blood pressure in the arteries supplying the body is a result of the work needed to pump the cardiac output through the vascular resistance termed total peripheral resistance by physicians and researchers.
An increase in the media to lumenal diameter ratio has been observed in hypertensive arterioles as the vascular wall thickens and/or lumenal diameter decreases. The up and down fluctuation of the arterial blood pressure is due to the pulsatile nature of the cardiac output and determined by the interaction of the stroke volume versus the volume and elasticity of the major arteries; the decreased velocity of flow in the capillaries increases the blood pressure, due to Bernoulli's principle. This induces gas and nutrients to move from the blood to the cells, due to the lower osmotic pressure outside the capillary; the opposite process occurs when the blood leaves the capillaries and enters the venules, where the blood pressure drops due to an increase in flow rate. Arterioles receive autonomic nervous system innervation and respond to various circulating hormones in order to regulate their diameter. Retinal vessels lack a functional sympathetic innervation. Further local responses to stretch, carbon dioxide, pH, oxygen influence arteriolar tone.
Norepinephrine and epinephrine are vasoconstrictive acting on alpha 1-adrenergic receptors. However, the arterioles of skeletal muscle, cardiac muscle, pulmonary circulation vasodilate in response to these hormones when they act on beta-adrenergic receptors. Stretch and high oxygen tension increase tone, carbon dioxide and low pH promote vasodilation. Pulmonary arterioles are a noteworthy exception. Brain arterioles are sensitive to pH with reduced pH promoting vasodilation. A number of hormones influence arteriole tone such as angiotensin II, bradykinin, atrial natruretic peptide, prostacyclin. Arteriole diameters decrease with exposure to air pollution. Any pathology which constricts blood flow, such as stenosis, will increase total peripheral resistance and lead to hypertension. Arteriolosclerosis is the term used for the hardening of arteriole walls; this can be due to decreased elastic production from fibrinogen, associated with ageing, or hypertension or pathological conditions such as atherosclerosis.
The muscular contraction of arterioles is targeted by drugs that lower blood pressure, for example the dihydropyridines, which block the calcium conductance in the muscular layer of the arterioles, causing relaxation. This decreases the resistance to flow into peripheral vascular beds, lowering overall systemic pressure. A "metarteriole" is an arteriole. Surface chemistry of microvasculature Venule
A capillary is a small blood vessel from 5 to 10 micrometres in diameter, having a wall one endothelial cell thick. They are the smallest blood vessels in the body: they convey blood between the arterioles and venules; these microvessels are the site of exchange of many substances with the interstitial fluid surrounding them. Substances which exit include water and glucose. Lymph capillaries connect with larger lymph vessels to drain lymphatic fluid collected in the microcirculation. During early embryonic development new capillaries are formed through vasculogenesis, the process of blood vessel formation that occurs through a de novo production of endothelial cells which form vascular tubes; the term angiogenesis denotes the formation of new capillaries from pre-existing blood vessels and present endothelium which divides. Blood flows from the heart through arteries, which branch and narrow into arterioles, branch further into capillaries where nutrients and wastes are exchanged; the capillaries join and widen to become venules, which in turn widen and converge to become veins, which return blood back to the heart through the venae cavae.
Individual capillaries are part of the capillary bed, an interweaving network of capillaries supplying tissues and organs. The more metabolically active a tissue is, the more capillaries are required to supply nutrients and carry away waste products. There are two types of capillaries: true capillaries, which branch from arterioles and provide exchange between tissue and the capillary blood, metarterioles, found only in the mesenteric circulation, they are short vessels that directly connect the arterioles and venules at opposite ends of the beds. Metarterioles are found in the mesenteric microcirculation; the physiological mechanisms underlying precapillary resistance is no longer considered to be a result of precapillary sphincters outside of the mesentery organ. Lymphatic capillaries are larger in diameter than blood capillaries, have closed ends; this structure permits interstitial fluid to flow into them but not out. Lymph capillaries have a greater internal oncotic pressure than blood capillaries, due to the greater concentration of plasma proteins in the lymph.
There are three types of blood capillaries: Continuous capillaries are continuous in the sense that the endothelial cells provide an uninterrupted lining, they only allow smaller molecules, such as water and ions to pass through their intercellular clefts. Lipid-soluble molecules can passively diffuse through the endothelial cell membranes along concentration gradients. Continuous capillaries can be further divided into two subtypes: Those with numerous transport vesicles, which are found in skeletal muscles, fingers and skin; those with few vesicles, which are found in the central nervous system. These capillaries are a constituent of the blood–brain barrier. Fenestrated capillaries have pores in the endothelial cells that are spanned by a diaphragm of radially oriented fibrils and allow small molecules and limited amounts of protein to diffuse. In the renal glomerulus there are cells with no diaphragms, called podocyte foot processes or pedicels, which have slit pores with a function analogous to the diaphragm of the capillaries.
Both of these types of blood vessels have continuous basal laminae and are located in the endocrine glands, intestines and the glomeruli of the kidney. Sinusoid capillaries are a special type of open-pore capillary, that have larger openings in the endothelium; these types of blood vessels allow red and white blood cells and various serum proteins to pass, aided by a discontinuous basal lamina. These capillaries lack pinocytotic vesicles, therefore utilize gaps present in cell junctions to permit transfer between endothelial cells, hence across the membrane. Sinusoid blood vessels are located in the bone marrow, lymph nodes, adrenal glands; some sinusoids are distinctive in. They are called discontinuous sinusoidal capillaries, are present in the liver and spleen, where greater movement of cells and materials is necessary. A capillary wall is simple squamous epithelium; the capillary wall performs an important function by allowing nutrients and waste substances to pass across it. Molecules larger than 3 nm such as albumin and other large proteins pass through transcellular transport carried inside vesicles, a process which requires them to go through the cells that form the wall.
Molecules smaller than 3 nm such as water and gases cross the capillary wall through the space between cells in a process known as paracellular transport. These transport mechanisms allow bidirectional exchange of substances depending on osmotic gradients and can be further quantified by the Starling equation. Capillaries that form part of the blood–brain barrier however only allow for transcellular transport as tight junctions between endothelial cells seal the paracellular space. Capillary beds may control their blood flow via autoregulation; this allows an organ to maintain constant flow despite a change in central blood pressure. This is achieved by myogenic response, in the kidney by tubuloglomerular feedback; when blood pressure increases, arterioles are stretched and subsequently constrict to counteract the
Cerebrospinal fluid is a clear, colorless body fluid found in the brain and spinal cord. It is produced by the specialised ependymal cells in the choroid plexuses of the ventricles of the brain, absorbed in the arachnoid granulations. There is about 125mL of CSF at any one time, about 500 mL is generated every day. CSF acts as a cushion or buffer for the brain, providing basic mechanical and immunological protection to the brain inside the skull. CSF serves a vital function in cerebral autoregulation of cerebral blood flow. CSF occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord, it fills the ventricles of the brain and sulci, as well as the central canal of the spinal cord. There is a connection from the subarachnoid space to the bony labyrinth of the inner ear via the perilymphatic duct where the perilymph is continuous with the cerebrospinal fluid. A sample of CSF can be taken via lumbar puncture; this can reveal the intracranial pressure, as well as indicate diseases including infections of the brain or its surrounding meninges.
Although noted by Hippocrates, it was only in the 18th century that Emanuel Swedenborg is credited with its rediscovery, as late as 1914 that Harvey W. Cushing demonstrated CSF was secreted by the choroid plexus. There is about 125–150 mL of CSF at any one time; this CSF circulates within the ventricular system of the brain. The ventricles are a series of cavities filled with CSF; the majority of CSF is produced from within the two lateral ventricles. From here, CSF passes through the interventricular foramina to the third ventricle the cerebral aqueduct to the fourth ventricle. From the fourth ventricle, the fluid passes into the subarachnoid space through four openings – the central canal of the spinal cord, the median aperture, the two lateral apertures. CSF is present within the subarachnoid space, which covers the brain, spinal cord, stretches below the end of the spinal cord to the sacrum. There is a connection from the subarachnoid space to the bony labyrinth of the inner ear making the cerebrospinal fluid continuous with the perilymph in 93% of people.
CSF moves in a single outward direction from the ventricles, but multidirectionally in the subarachnoid space. Fluid movement is pulsatile, matching the pressure waves generated in blood vessels by the beating of the heart; some authors dispute this, posing that there is no unidirectional CSF circulation, but cardiac cycle-dependent bi-directional systolic-diastolic to-and-fro cranio-spinal CSF movements. CSF is derived from blood plasma and is similar to it, except that CSF is nearly protein-free compared with plasma and has some different electrolyte levels. Due to the way it is produced, CSF has a higher chloride level than plasma, an equivalent sodium level. CSF contains 0.3% plasma proteins, or 15 to 40 mg/dL, depending on sampling site. In general, globular proteins and albumin are in lower concentration in ventricular CSF compared to lumbar or cisternal fluid; this continuous flow into the venous system dilutes the concentration of larger, lipid-insoluble molecules penetrating the brain and CSF.
CSF is free of red blood cells, at most contains only a few white blood cells. Any white blood cell count higher. At around the third week of development, the embryo is a three-layered disc, covered with ectoderm and endoderm. A tube-like formation develops in the midline, called the notochord; the notochord releases extracellular molecules that affect the transformation of the overlying ectoderm into nervous tissue. The neural tube, forming from the ectoderm, contains CSF prior to the development of the choroid plexuses; the open neuropores of the neural tube close after the first month of development, CSF pressure increases. As the brain develops, by the fourth week of embryological development three swellings have formed within the embryo around the canal, near where the head will develop; these swellings represent different components of the central nervous system: the prosencephalon and rhombencephalon. Subarachnoid spaces are first evident around the 32nd day of development near the rhombencephalon.
At this time, the first choroid plexus can be seen, found in the fourth ventricle, although the time at which they first secrete CSF is not yet known. The developing forebrain surrounds the neural cord; as the forebrain develops, the neural cord within it becomes a ventricle forming the lateral ventricles. Along the inner surface of both ventricles, the ventricular wall remains thin, a choroid plexus develops and releasing CSF. CSF fills the neural canal. Arachnoid villi are formed around the 35th week of development, with aracnhoid granulations noted around the 39th, continuing developing until 18 months of age; the subcommissural organ secretes SCO-spondin, which forms Reissner's fiber within CSF assisting movement through the cerebral aqueduct. It disappears during early development. CSF serves several purposes: Buoyancy: The actual mass of the human brain is about 1400–1500 grams; the brain therefore exists in neutral buoyancy, which allows the brain to maintain its density without being impaired by its own weight, which would cut off blood supply and kill neurons in the lower sections without CSF.
Protection: CSF protects the brain tissue from injury when jolted or hit, by providing a fluid buffer that acts as a shock absorber from some forms of mechanical injury. Prevention of brain ischemia: The prevention of brai
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table, a reactive nonmetal, an oxidizing agent that forms oxides with most elements as well as with other compounds. By mass, oxygen is the third-most abundant element in the universe, after helium. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. Diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. As compounds including oxides, the element makes up half of the Earth's crust. Dioxygen is used in cellular respiration and many major classes of organic molecules in living organisms contain oxygen, such as proteins, nucleic acids and fats, as do the major constituent inorganic compounds of animal shells and bone. Most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. Oxygen is continuously replenished in Earth's atmosphere by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide.
Oxygen is too chemically reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone absorbs ultraviolet UVB radiation and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. However, ozone present at the surface is a byproduct of thus a pollutant. Oxygen was isolated by Michael Sendivogius before 1604, but it is believed that the element was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, Joseph Priestley in Wiltshire, in 1774. Priority is given for Priestley because his work was published first. Priestley, called oxygen "dephlogisticated air", did not recognize it as a chemical element; the name oxygen was coined in 1777 by Antoine Lavoisier, who first recognized oxygen as a chemical element and characterized the role it plays in combustion. Common uses of oxygen include production of steel and textiles, brazing and cutting of steels and other metals, rocket propellant, oxygen therapy, life support systems in aircraft, submarines and diving.
One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle and surrounding the vessel's neck with water resulted in some water rising into the neck. Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries Leonardo da Vinci built on Philo's work by observing that a portion of air is consumed during combustion and respiration. In the late 17th century, Robert Boyle proved. English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. In one experiment, he found that placing either a mouse or a lit candle in a closed container over water caused the water to rise and replace one-fourteenth of the air's volume before extinguishing the subjects.
From this he surmised that nitroaereus is consumed in both combustion. Mayow observed that antimony increased in weight when heated, inferred that the nitroaereus must have combined with it, he thought that the lungs separate nitroaereus from air and pass it into the blood and that animal heat and muscle movement result from the reaction of nitroaereus with certain substances in the body. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract "De respiratione". Robert Hooke, Ole Borch, Mikhail Lomonosov, Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element; this may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, modified by the chemist Georg Ernst Stahl by 1731, phlogiston theory stated that all combustible materials were made of two parts.
One part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. Combustible materials that leave little residue, such as wood or coal, were thought to be made of phlogiston. Air did not play a role in phlogiston theory, nor were any initial quantitative experiments conducted to test the idea. Polish alchemist and physician Michael Sendivogius in his work De Lapide Philosophorum Tractatus duodecim e naturae fonte et manuali experientia depromti described a substance contained in air, referring to it as'cibus vitae', this substance is identical with oxygen. Sendivogius, during his experiments performed between 1598 and 1604, properly recognized that the substance is equivalent to the gaseous byproduct released by the thermal decomposition of potassium nitrate. In Bugaj’s view, the isolation of oxygen and the proper association of the substance to that part of air, required for life, lends sufficient weight to the discovery of oxygen by Sendivogius.
Neurosurgery, or neurological surgery, is the medical specialty concerned with the prevention, surgical treatment, rehabilitation of disorders which affect any portion of the nervous system including the brain, spinal cord, peripheral nerves, extra-cranial cerebrovascular system. In different countries, there are different requirements for an individual to practice neurosurgery, there are varying methods through which they must be educated. In most countries, neurosurgeon training requires a minimum period of seven years after graduating from medical school. In the United States, a neurosurgeon must complete four years of undergraduate education, four years of medical school, seven years of residency. Most, but not all, residency programs have some component of clinical research. Neurosurgeons may pursue additional training in the form of a fellowship, after residency or in some cases, as a senior resident; these fellowships include pediatric neurosurgery, trauma/neurocritical care and stereotactic surgery, surgical neuro-oncology, neurovascular surgery, skull-base surgery, peripheral nerve and spine surgery.
In the U. S. neurosurgery is considered a competitive specialty composed of 0.6% of all practicing physicians. In the United Kingdom, students must gain entry into medical school. MBBS qualification takes four to six years depending on the student's route; the newly qualified physician must complete foundation training lasting two years. Junior doctors apply to enter the neurosurgical pathway. Unlike most other surgical specialties, it has its own independent training pathway which takes around eight years. Neurosurgery remains amongst the most competitive medical specialties in which to obtain entry. Neurosurgery, or the premeditated incision into the head for pain relief, has been around for thousands of years, but notable advancements in neurosurgery have only come within the last hundred years; the Incas appear to have practiced a procedure known as trepanation since the late Stone age. During the Middle Ages in Arabia from 936 to 1013 AD, Al-Zahrawi performed surgical treatments of head injuries, skull fractures, spinal injuries, subdural effusions and headache.
There was not much advancement in neurosurgery until late 19th early 20th century, when electrodes were placed on the brain and superficial tumors were removed. History of electrodes in the brain: In 1878 Richard Canton discovered that electrical signals transmitted through an animal's brain. In 1950 Dr. Jose Delgado invented the first electrode, implanted in an animal's brain, using it to make it run and change direction. In 1972 the cochlear implant, a neurological prosthetic that allowed deaf people to hear was marketed for commercial use. In 1998 researcher Philip Kennedy implanted the first Brain Computer Interface into a human subject. History of tumor removal: In 1879 after locating it via neurological signs alone, Scottish surgeon William Macewen performed the first successful brain tumor removal. On November 25, 1884 after English physician Alexander Hughes Bennett used Macewen's technique to locate it, English surgeon Rickman Godlee performed the first primary brain tumor removal, which differs from Macewen's operation in that Bennett operated on the exposed brain, whereas Macewen operated outside of the "brain proper" via trepanation.
On March 16, 1907 Austrian surgeon Hermann Schloffer became the first to remove a pituitary tumor. The main advancements in neurosurgery came about as a result of crafted tools. Modern neurosurgical tools, or instruments, include chisels, dissectors, elevators, hooks, probes, suction tubes, power tools, robots. Most of these modern tools, like chisels, forcepts, hooks and probes, have been in medical practice for a long time; the main difference of these tools and post advancement in neurosurgery, were the precision in which they were crafted. These tools are crafted with edges. Other tools such as hand held power saws and robots have only been used inside of a neurological operating room; as an example, the University of Utah developed a device for computer-aided design / computer-aided manufacturing which uses an image-guided system to define a cutting tool path for a robotic cranial drill. General neurosurgery involves most neurosurgical conditions including neuro-trauma and other neuro-emergencies such as intracranial hemorrhage.
Most level 1 hospitals have this kind of practice. Specialized branches have developed to cater to difficult conditions; these specialized branches co-exist with general neurosurgery in more sophisticated hospitals. To practice advanced specialization within neurosurgery, additional higher fellowship training of one to two years is expected from the neurosurgeon; some of these divisions of neurosurgery are: Vascular neurosurgery includes clipping of aneurysms and performing carotid endarterectomy. Stereotactic neurosurgery, functional neurosurgery, epilepsy surgery (the latter includes partial or total corpus callosotomy – severing part or all of the corpus callosum to stop or lessen seizure spread and activity, the surgical removal of functional, physiological and/or anatomical pieces or divisions of the brain, called epileptic foci, that are operable and th
Cyanoacrylates are a family of strong fast-acting adhesives with industrial and household uses. They are various esters of cyanoacrylic acid; the acryl groups in the resin polymerises in the presence of water to form long, strong chains. They have some minor toxicity. Specific cyanoacrylates include methyl 2-cyanoacrylate, ethyl 2-cyanoacrylate, n-butyl cyanoacrylate, octyl cyanoacrylate and 2-octyl cyanoacrylate. Octyl cyanoacrylate was developed to address toxicity concerns and to reduce skin irritation and allergic response. Cyanoacrylate adhesives are sometimes known generically as power glues or superglues; the abbreviation "CA" is used for industrial grade cyanoacrylate. The original patent for cyanoacrylate was filed in 1942 by Goodrich Company as an outgrowth of a search for materials suitable for clear plastic gun sights for the war effort. In 1942, a team of scientists headed by Harry Coover Jr. stumbled upon a formulation that stuck to everything with which it came in contact. The team rejected the substance for the wartime application, but in 1951, while working as researchers for Eastman Kodak, Coover and a colleague, Fred Joyner, rediscovered cyanoacrylates.
The two realized the true commercial potential, a form of the adhesive was first sold in 1958 under the title "Eastman #910". During the 1960s, Eastman Kodak sold cyanoacrylate to Loctite, which in turn repackaged and distributed it under a different brand name "Loctite Quick Set 404". In 1971, Loctite developed its own manufacturing technology and introduced its own line of cyanoacrylate, called "Super Bonder". Loctite gained market share, by the late 1970s it was believed to have exceeded Eastman Kodak's share in the North American industrial cyanoacrylate market. National Starch and Chemical Company purchased Eastman Kodak’s cyanoacrylate business and combined it with several acquisitions made throughout the 1970s forming Permabond. Other manufacturers of cyanoacrylate include LePage, the Permabond Division of National Starch and Chemical, a subsidiary of Unilever. Together, Loctite and Permabond accounted for 75% of the industrial cyanoacrylate market; as of 2013 Permabond continued to manufacture the original 910 formula.
In its liquid form, cyanoacrylate consists of monomers of cyanoacrylate ester molecules. Methyl 2-cyanoacrylate has a molecular weight of 111.1 g/mol, a flashpoint of 79 °C, a density of 1.1 g/mL. Ethyl 2-cyanoacrylate has a molecular weight of 125 g/mol and a flashpoint of more than 75 °C. To facilitate easy handling, a cyanoacrylate adhesive is formulated with an ingredient such as fumed silica to make it more viscous or gel-like. More formulations are available with additives to increase shear strength, creating a more impact resistant bond; such additives may include rubber, as in Loctite's "Ultra Gel", or others. In general, the acryl groups undergo chain-growth polymerisation in the presence of water, forming long, strong chains, joining the bonded surfaces together; because the presence of moisture causes the glue to set, exposure to normal levels of humidity in the air causes a thin skin to start to form within seconds, which greatly slows the reaction. Cyanoacrylate adhesives have a short shelf life—about one year from manufacture if unopened, one month once opened.
The reaction with moisture can cause a container of glue, opened and resealed to become unusable more than if never opened. To minimise this reduction in shelf life, once opened, should be stored in an airtight container with a package of silica gel desiccant. Another technique is to insert a hypodermic needle into the opening of a tube. After using the glue, residual glue soon clogs the needle; the clog is removed by heating the needle before use. The polymerisation is temperature-dependent: storage below freezing point of water, 0 °C, stops the reaction, so keeping it in the freezer is effective. Cyanoacrylates are used as adhesives, they require some care and knowledge for effective use: they do not bond some materials. They have an exothermic reaction to natural fibres: cotton, leather, see reaction with cotton below. Cyanoacrylate glue has a low shearing strength, which has led to its use as a temporary adhesive in cases where the piece needs to be sheared off later. Common examples include mounting a workpiece to a sacrificial glue block on a lathe, tightening pins and bolts.
It is used in conjunction with another, but more resilient adhesive as a way of forming a joint, which holds the pieces in the appropriate configuration until the second adhesive has set. Cyanoacrylate-based glue has a weak bond with smooth surfaces and as such gives to friction. Cyanoacrylates are used to assemble prototype electronics, fl
Interventional Neuroradiology or Endovascular Surgical Neuroradiology is a medical subspecialty specializing in minimally invasive image-based technologies and procedures used in diagnosis and treatment of diseases of the head and spine. Diagnostic angiography The first experience with cerebral angiography was developed by Portuguese doctor Egas Moniz at the University of Lisbon, in order to identify central nervous system diseases such as tumors or arteriovenous malformations, he performed the first brain angiography in Lisbon in 1927 by injecting iodinated contrast medium into a carotid and using the rays discovered 30 years earlier by Roentgen to visualize the cerebral vessels. In pre-TC and pre-RM, it was the only tool to observe the structures within the skull and was used to diagnose extravascular pathologies. Subsequently, European radiologists further developed the angiographic technique by replacing the traumatic direct puncture with catheterization: in 1953, Swedish physician Sven Seldinger introduced the technique of arterial and venous catheterisation still in practice.
In 1964, the Norwegian radiologist Per Amudsen was the first to perform a complete brain angiography with a transfemoral approach, as it is performed today. These two stages, at the basis of modern invasive vascular diagnostics, prepared the way for therapeutic developments; the first treatments: balloon occlusion The first to carry out a true endovascular treatment was Charles Dotter, the father of the angioplasty and considered by many as the father of all interventional radiology as well as the first to have performed endovascular treatment. On January 16, 1964, he performed a therapeutic angioplasty of a superficial femoral artery in an 82-year-old woman with an ischemic leg refusing amputation; the artery remained open for the next 2 and a half years after. In the 1970s Fedor Serbinenko developed a technique for closing aneurysms with balloons that were released into the internal carotid artery by occluding the light; the first treatment was performed in 1970 in Moscow, with the occlusion of an internal carotid to treat a carotid-cavernous fistula.
He can be considered, the first interventional neuroradiologist. This technique was subsequently refined by neuroradiologists all over the world and in France, where interventional neuroradiology developed and flourished. Parallel to the development of catheters, in the radiology and neuroradiology units, image technology improved: Charles Mistretta in 1979 invented digital subtraction angiography, the technique in use, it consists of performing skull radiography under basic conditions, "subtracted" to the image after contrast media injection, to provide an image where only brain vessels are displayed, with great improvement in the diagnostic potential. The coils replace the balloons Between the end of the'80s and the beginning of the'90s, INR was revolutioned after the work of two Italian physicians: Cesare Gianturco and Guido Guglielmi; the first combined a deep knowledge of diagnostic radiology with a great ability to solve technical and manual problems. He invented Gianturco's coils, which he used to make the first attempts to embolize arteries and aneurysms.
Gianturco patented the first endovascular stent approved by the American FDA. In the second half of the 1980s, Hilal was the first in Columbia University to use coils to treat brain aneurysms; the coil embolization was revolutionized by the work of Guido Guglielmi in UCLA, who realized that electricity could function as a controlled release mechanism for coils. The treatment of aneurysms was thus made more safe. New techniques: flow diversion stents Since the early'2000s, it was observed that intracranial stents positioned to keep the coils in the aneurysmal sac favored the redirection of blood flow, helping to exclude aneurysm from the circus. Flow diversion devices were developed, with the function of reconstructing the vessel's normal anatomy without directly closing the aneurysm neck and therefore preserving side branches. Not just hemorrhages: the treatment of ischemic stroke Between January and June 2015, 5 major randomized trials were published on the New England Journal of Medicine with the collaboration of interventional neuroradiologists and stroke neurologists regarding the role of mechanical thrombectomy in the treatment of ischemic stroke, demonstrating that if it is performed in centers with proven experience, intra-arterial mechanical thrombectomy is more effective than traditional treatment.
Thrombectomy is today recommended by the guidelines written by the main American and European societies of stroke neurologists and interventional neuroradiologists. The following is a list of diseases and conditions treated by neurointerventionalists. Cerebral aneurysm Brain arteriovenous malformation Carotid-cavernous fistula Dural arteriovenous fistula Extracranial atherosclerosis Extracranial and paraspinal vascular malformations Head and neck tumors Intracranial atherosclerosis Juvenile nasopharyngeal tum