Angiography is a method of studying the vascular system of the brain and spinal cord by injecting a contrast agent into the arteries that supply blood to the brain. First proposed by Monica in 1927, but widespread use in clinical practice began only in the 1940s.
Improvement of X-ray equipment, creation of intravascular catheter systems, the appearance of X-ray and new radiopaque preparations made it possible to pass to isolated contrasting of basins of first trunk and then intracranial arteries. It became possible to perform selective angiography, a method in which a catheter after puncture and catheterization of a large artery (usually femur) is carried out under fluoroscopic X-ray control in a certain vascular pool of the brain (selective angiography) or a separate vessel (super selective angiography), after which the contrast is intraarterially administered substance with a serial shooting of the skull in the appropriate projection. Modern angiographic installations are television systems in which the registration of an X-ray beam is performed using an electron-optical converter and a television camera or position-charge system. The recorded video signals are digitized at high resolution, and the computer performs the mathematical processing of the entire series of digital images, consisting in subtracting from each serial image the so-called mask - the first image in the series obtained before the introduction of the contrast preparation. After subtracting the "mask" in the images, only the contours of the vessels filled with contrast medium remain as it passes through the vascular system. Bone structures are practically not visible. This method was called "digital subtraction angiography."
Currently, cerebral angiography is used mainly in cases of suspected arterial or arteriovenous cerebral aneurysms, as a method of preoperative diagnosis and postoperative control, as well as in determining thrombosis or stenosis of the main vessels on the neck. It is still important to use cerebral angiography in determining blood supply sources and relationships with large arteries of various brain tumors, primarily located basally on the base of the skull, which allows planning for surgical access and removal volume (meningiomas, pituitary adenomas, etc.). In a number of indications to digital subtraction angiography, there remains the planning of radiation therapy for small arteriovenous malformations.
New opportunities in visualization of the vascular pathology of the central nervous system opened with the introduction of clinical methods of ZD reconstruction. It became possible to combine high resolution angiography and the construction of three-dimensional models of cerebral vessels.
The method of digital subtraction angiography underlies interventional endovasal methods of treatment of vascular diseases of the brain and spinal cord, which in neurosurgery is considered to be minimally invasive. This direction is currently allocated in a separate specialty - interventional neuroendology.
Spinal angiography is used to study blood vessels that supply blood to the spinal cord. The procedure for the study is similar to cerebral angiography. Through the catheter in the femoral artery catheterization of the artery is performed, in the basin of which the vascular pathology is assumed (usually, these are intercostal arteries). Selective spinal angiography is the main method of diagnosing arteriovenous malformations of the spinal cord that allows to identify both afferent and efferent vessels of malformations. Less often it is used to determine the blood supply of some types of tumors of the spine and spinal cord, for example, hemangiomas and hemangioblast. The catheterization of vessels feeding the spinal cord and spine allows not only to detect vascular pathology, but simultaneously to perform embolization of arteriovenous malformations and large vessels involved in the blood supply of the tumor.
In modern neuroendgenological practice, methods with positive contrast between subarachnoid spaces and the ventricular system of the brain still persist. Currently, contrasting of cerebrospinal fluid is used with radiopaque preparations based on iodine. Since the appearance of the first contrast preparation in 1925, work has continued to reduce the toxicity of such substances.
Ventriculography with non-ionic radiopaque substances is an invasive method of diagnosis, it is now used very rarely and according to strict clinical indications. The method consists in introducing a contrast medium into the cavity of the lateral ventricles by puncturing, as a rule, one of the anterior horns. Indications for the study include determining the patency of interventricular orifices, the state of the brain waterway, III and IV ventricles, mainly in complex congenital malformations of cerebrospinal fluid and the brain itself. As a modification of the method, cystography is distinguished (the introduction of contrast agents into the cavity of the intracranial cyst, less often in the cyst of craniopharyngioma, to determine its relationship with the cerebrospinal fluid spaces). In the conditions of a modern neurosurgical hospital equipped with CT, a combination of puncture of the lateral ventricle with the introduction of a contrast preparation and the possibilities of CT-CT-ventriculography are most often used.
Myelography is a method of investigation of the cerebrospinal fluid system. Carried out by puncture the subarachnoid space of the spinal cord and the introduction of a water-soluble contrast drug into it. The method is classified as invasive and is not used on an outpatient basis. Allocate a descending myelography when puncture of the subcoach spaces is performed at the level of the large occipital cistern (currently practically not used), and ascending myelography-puncture is performed at the level of the lower lumbar region. This method has been widely used before, but with the advent of MRI, it is almost superseded from everyday practice. In modern conditions it is used mainly to determine the degree of compression of subarachnoid spaces of the spinal cord in complex herniated intervertebral discs, in the diagnosis of inflammatory changes in the membranes of the spinal cord (arachnoiditis), in the postoperative period in order to solve the problem of patency of subarachnoid spaces with recurrent hernia disk or tumor, postoperative cicatricial-adhesive process. Indication for myelography remains a suspicion of the developmental defect of the spinal cord (meningocele). In the presence of CT, myelography, as a rule, is only the primary stage for the further conduct of CT-myelography or its variety - CT-cisternography (for visualization of cerebrospinal fistulas in the cranial cavity).
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