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Pneumoencephalography
Pneumoencephalography (sometimes abbreviated PEG; also referred to as an "air study") was a common medical procedure in which most of the cerebrospinal fluid (CSF) was drained from around the brain by means of a lumbar puncture and replaced with air, oxygen, or helium to allow the structure of the brain to show up more clearly on an X-ray image. It was derived from ventriculography, an earlier and more primitive method where the air is injected through holes drilled in the skull. The procedure was introduced in 1919 by the American neurosurgeon Walter Dandy and was performed extensively until the late 1970s, when it was replaced by more-sophisticated and less-invasive modern neuroimaging techniques. Procedure Though pneumoencephalography was the single most important way of localizing brain lesions of its time, it was, nevertheless, extremely painful and generally not well tolerated by conscious patients. Pneumoencephalography was associated with a wide range of side-effects, inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walter Dandy
Walter Edward Dandy (April 6, 1886 – April 19, 1946) was an American neurosurgeon and scientist. He is considered one of the founding fathers of neurosurgery, along with Victor Horsley (1857–1916) and Harvey Cushing (1869–1939). Dandy is credited with numerous neurosurgical discoveries and innovations, including the description of the circulation of cerebrospinal fluid in the brain, surgical treatment of hydrocephalus, the invention of air ventriculography and pneumoencephalography, the description of brain endoscopy, the establishment of the first intensive care unit ( Fox 1984, p. 82), and the first clipping of an intracranial aneurysm, which marked the birth of cerebrovascular neurosurgery. During his 40-year medical career, Dandy published five books and more than 160 peer-reviewed articles while conducting a full-time, ground-breaking neurosurgical practice in which he performed during his peak years about 1000 operations per year ( Sherman et al. 2006). He was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Neuroimaging
The first neuroimaging technique ever is the so-called 'human circulation balance' invented by Angelo Mosso in the 1880s and able to non-invasively measure the redistribution of blood during emotional and intellectual activity. Then, in the early 1900s, a technique called pneumoencephalography was set. This process involved draining the cerebrospinal fluid from around the brain and replacing it with air, altering the relative density of the brain and its surroundings, to cause it to show up better on an x-ray, and it was considered to be incredibly unsafe for patients (Beaumont 8). A form of magnetic resonance imaging (MRI) and computed tomography (CT) were developed in the 1970s and 1980s. The new MRI and CT technologies were considerably less harmful and are explained in greater detail below. Next came SPECT and PET scans, which allowed scientists to map brain function because, unlike MRI and CT, these scans could create more than just static images of the brain's structure. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroimaging
Neuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Increasingly it is also being used for quantitative studies of brain disease and psychiatric illness. Neuroimaging is a highly multidisciplinary research field and is not a medical specialty. Neuroimaging differs from neuroradiology which is a medical specialty and uses brain imaging in a clinical setting. Neuroradiology is practiced by radiologists who are medical practitioners. Neuroradiology primarily focuses on identifying brain lesions, such as vascular disease, strokes, tumors and inflammatory disease. In contrast to neuroimaging, neuroradiology is qualitative (based on subjective impressions and extensive clinical training) but sometimes uses basic quantitative methods. Functional brain imaging techniques, such as functional magn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumbar Puncture
Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to help diagnose diseases of the central nervous system, including the brain and spine. Examples of these conditions include meningitis and subarachnoid hemorrhage. It may also be used therapeutically in some conditions. Increased intracranial pressure (pressure in the skull) is a contraindication, due to risk of brain matter being compressed and pushed toward the spine. Sometimes, lumbar puncture cannot be performed safely (for example due to a severe bleeding tendency). It is regarded as a safe procedure, but post-dural-puncture headache is a common side effect if a small atraumatic needle is not used. The procedure is typically performed under local anesthesia using a sterile technique. A hypodermic needle is used to access the suba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroimaging
Neuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Increasingly it is also being used for quantitative studies of brain disease and psychiatric illness. Neuroimaging is a highly multidisciplinary research field and is not a medical specialty. Neuroimaging differs from neuroradiology which is a medical specialty and uses brain imaging in a clinical setting. Neuroradiology is practiced by radiologists who are medical practitioners. Neuroradiology primarily focuses on identifying brain lesions, such as vascular disease, strokes, tumors and inflammatory disease. In contrast to neuroimaging, neuroradiology is qualitative (based on subjective impressions and extensive clinical training) but sometimes uses basic quantitative methods. Functional brain imaging techniques, such as functional magn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Effect (medicine)
In medicine, a mass effect is the effect of a growing mass that results in secondary pathological effects by pushing on or displacing surrounding tissue. In oncology, the mass typically refers to a tumor. For example, cancer of the thyroid gland may cause symptoms due to compressions of certain structures of the head and neck; pressure on the laryngeal nerves may cause voice changes, narrowing of the windpipe may cause stridor, pressure on the gullet may cause dysphagia and so on. Surgical removal or debulking is sometimes used to palliate symptoms of the mass effect even if the underlying pathology is not curable. In neurology, a mass effect is the effect exerted by any mass, including, for example, hydrocephalus (cerebrospinal fluid buildup) or an evolving intracranial hemorrhage (bleeding within the skull) presenting with a clinically significant hematoma. The hematoma can exert a mass effect on the brain, increasing intracranial pressure and potentially causing midline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiocontrast Agent
Radiocontrast agents are substances used to enhance the visibility of internal structures in X-ray-based imaging techniques such as computed tomography ( contrast CT), projectional radiography, and fluoroscopy. Radiocontrast agents are typically iodine, or more rarely barium sulfate. The contrast agents absorb external X-rays, resulting in decreased exposure on the X-ray detector. This is different from radiopharmaceuticals used in nuclear medicine which emit radiation. Magnetic resonance imaging (MRI) functions through different principles and thus MRI contrast agents have a different mode of action. These compounds work by altering the magnetic properties of nearby hydrogen nuclei. Types and uses Radiocontrast agents used in X-ray examinations can be grouped in positive (iodinated agents, barium sulfate), and negative agents (air, carbon dioxide, methylcellulose). Iodine (circulatory system) Iodinated contrast contains iodine. It is the main type of radiocontrast used for in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Procedure
A medical procedure is a course of action intended to achieve a result in the delivery of healthcare. A medical procedure with the intention of determining, measuring, or diagnosing a patient condition or parameter is also called a medical test. Other common kinds of procedures are therapeutic (i.e., intended to treat, cure, or restore function or structure), such as surgical and physical rehabilitation procedures. Definition *"An activity directed at or performed on an individual with the object of improving health, treating disease or injury, or making a diagnosis."''International Dictionary of Medicine and Biology'', Page 2297. *"The act or conduct of diagnosis, treatment, or operation."''Stedman's Medical Dictionary'', 27th ed. Page 1446. *"A series of steps by which a desired result is accomplished."''Dorland's Illustrated Medical Dictionary'', 28th ed. Page 1353. *"The sequence of steps to be followed in establishing some course of action."''Mosby's Medical, Nursing, & ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tomography
Tomography is imaging by sections or sectioning that uses any kind of penetrating wave. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, astrophysics, quantum information, and other areas of science. The word ''tomography'' is derived from Ancient Greek τόμος ''tomos'', "slice, section" and γράφω ''graphō'', "to write" or, in this context as well, "to describe." A device used in tomography is called a tomograph, while the image produced is a tomogram. In many cases, the production of these images is based on the mathematical procedure tomographic reconstruction, such as X-ray computed tomography technically being produced from multiple projectional radiographs. Many different reconstruction algorithms exist. Most algorithms fall into one of two categories: filtered back projection (FBP) and iterative reconstruction (IR). These procedures give inexact results: they repres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiology (journal)
''Radiology'' is a monthly, peer reviewed, medical journal, owned and published by the Radiological Society of North America. The editor is David A Bluemke, MD, PhD. The focus of ''Radiology'' is imaging research articles in radiology and medical imaging. Publishing formats Publishing formats are original research articles (3000 words), research letters (600 words), technical developments (2000), invited perspectives (2500) review articles (6500), special report, invited editorial, invited controversies, diagnoses with brief description of the case, solicited science to practice (commentary on a novel basic science investigation or technical development), letter to the editor, and book review. Abstracting and indexing According to the ''Journal Citation Reports'', ''Radiology'' has a 2021 impact factor of 29.146. In addition, the journal is indexed in the following databases: * ''Science Citation Index'' * '' SciSearch'' * ''Chemical Abstracts'' * ''Current Contents/C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Computed Tomography
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz ( to ) and energies in the range 145 eV to 124 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it on November 8, 1895. He named it ''X-radiation'' to signify an unknown type of radiation.Novelline, Robert (1997). ''Squire's Fundamentals of Radiology''. Harvard University Press. 5th edition. . Spellings of ''X-ray(s)'' in English include the variants ''x-ray(s)'', ''xray(s)'', and ''X ray(s)''. The most familiar use of X-rays is checking for fractures (broken bones), but X-rays are also used in other ways. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. MRI does not involve X-rays or the use of ionizing radiation, which distinguishes it from CT and PET scans. MRI is a medical application of nuclear magnetic resonance (NMR) which can also be used for imaging in other NMR applications, such as NMR spectroscopy. MRI is widely used in hospitals and clinics for medical diagnosis, staging and follow-up of disease. Compared to CT, MRI provides better contrast in images of soft-tissues, e.g. in the brain or abdomen. However, it may be perceived as less comfortable by patients, due to the usually longer and louder measurements with the subject in a long, confining tube, though "Open" MRI designs mostly relieve this. Additionally, implants and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
