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 computed tomography (CT) and positron emission tomography (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.
Cystoscopy is endoscopy of the urinary bladder via the urethra. It is carried out with a cystoscope.
Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical and industrial radiography. Similar techniques are used in airport security,. To create an image in conventional radiography, a beam of X-rays is produced by an X-ray generator and it is projected towards the object. A certain amount of the X-rays or other radiation are absorbed by the object, dependent on the object's density and structural composition. The X-rays that pass through the object are captured behind the object by a detector. The generation of flat two-dimensional images by this technique is called projectional radiography. In computed tomography, an X-ray source and its associated detectors rotate around the subject, which itself moves through the conical X-ray beam produced. Any given point within the subject is crossed from many directions by many different beams at different times. Information regarding the attenuation of these beams is collated and subjected to computation to generate two-dimensional images on three planes which can be further processed to produce a three-dimensional image.
Radiology is the medical specialty that uses medical imaging to diagnose diseases and guide their treatment, within the bodies of humans and other animals. It began with radiography, but today it includes all imaging modalities, including those that use no electromagnetic radiation, as well as others that do, such as computed tomography (CT), fluoroscopy, and nuclear medicine including positron emission tomography (PET). Interventional radiology is the performance of usually minimally invasive medical procedures with the guidance of imaging technologies such as those mentioned above.
Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
Pneumoencephalography 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.
Vertebral augmentation, including vertebroplasty and kyphoplasty, refers to similar percutaneous spinal procedures in which bone cement is injected through a small hole in the skin into a fractured vertebra in order to relieve back pain caused by a vertebral compression fracture. After decades of medical research into the efficacy and safety of vertebral augmentation, there is still a lack of consensus regarding certain aspects of vertebroplasty and kyphoplasty.
Radiocontrast agents are substances used to enhance the visibility of internal structures in X-ray-based imaging techniques such as computed tomography, 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.
Cerebral angiography is a form of angiography which provides images of blood vessels in and around the brain, thereby allowing detection of abnormalities such as arteriovenous malformations and aneurysms. It was pioneered in 1927 by the Portuguese neurologist Egas Moniz at the University of Lisbon, who also helped develop thorotrast for use in the procedure.
The study of neurology and neurosurgery dates back to prehistoric times, but the academic disciplines did not begin until the 16th century. From an observational science they developed a systematic way of approaching the nervous system and possible interventions in neurological disease.
An arthrogram is a series of images of a joint after injection of a contrast medium, usually done by fluoroscopy or MRI. The injection is normally done under a local anesthetic such as Novocain or lidocaine. The radiologist or radiographer performs the study using fluoroscopy or x-ray to guide the placement of the needle into the joint and then injects around 10 ml of contrast based on age. There is some burning pain from the anesthetic and a painful bubbling feeling in the joint after the contrast is injected. This only lasts 20 – 30 hours until the Contrast is absorbed. During this time, while it is allowed, it is painful to use the limb for around 10 hours. After that the radiologist can more clearly see what is going on under your skin and can get results out within 24 to 48 hours.
Myelography is a type of radiographic examination that uses a contrast medium to detect pathology of the spinal cord, including the location of a spinal cord injury, cysts, and tumors. Historically the procedure involved the injection of a radiocontrast agent into the cervical or lumbar spine, followed by several X-ray projections. Today, myelography has largely been replaced by the use of MRI scans, although the technique is still sometimes used under certain circumstances – though now usually in conjunction with CT rather than X-ray projections.
Lipiodol, also known as ethiodized oil, is a poppyseed oil used by injection as a radio-opaque contrast agent that is used to outline structures in radiological investigations. It is used in chemoembolization applications as a contrast agent in follow-up imaging. Lipiodol is also used in lymphangiography, the imaging of the lymphatic system. It has an additional use in gastric variceal obliteration as a dilutant that does not affect polymerization of cyanoacrylate.
Jean-Athanase Sicard was a French neurologist and radiologist born in Marseille.
Methiodal is a pharmaceutical drug that was used as an iodinated contrast medium for X-ray imaging. Its uses included myelography ; for this use, cases of adhesive arachnoiditis have been reported, similar to those seen under the contrast medium iofendylate.
Metrizamide is a non-ionic iodine-based radiocontrast agent. It is also a density gradient medium for the centrifugation of biological particles.
A cerebrospinal fluid leak is a medical condition where the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord leaks out of one or more holes or tears in the dura mater. A CSF leak is classed as either nonspontaneous (primary), having a known cause, or spontaneous (secondary) where the cause is not readily evident. Causes of a primary CSF leak are those of trauma including from an accident or intentional injury, or arising from a medical intervention known as iatrogenic. A basilar skull fracture as a cause can give the sign of CSF leakage from the ear nose or mouth. A lumbar puncture can give the symptom of a post-dural-puncture headache.
Computed tomography of the head uses a series of X-rays in a CT scan of the head taken from many different directions; the resulting data is transformed into a series of cross sections of the brain using a computer program. CT images of the head are used to investigate and diagnose brain injuries and other neurological conditions, as well as other conditions involving the skull or sinuses; it used to guide some brain surgery procedures as well. CT scans expose the person getting them to ionizing radiation which has a risk of eventually causing cancer; some people have allergic reactions to contrast agents that are used in some CT procedures.
Mihran Krikor Kassabian was an Armenian-American physician, one of the early investigators into the medical uses of X-rays, and a faculty member at the Medico-Chirurgical College of Philadelphia. He became director of the Roentgen Ray Laboratory at Philadelphia General Hospital and vice president of both the American Roentgen Ray Society (ARRS) and the American Electro-Therapeutic Association.
Magnetic resonance myelography is a noninvasive medical imaging technique that can provide anatomic information about the subarachnoid space. It is a type of MRI examination that uses a contrast medium and magnetic resonance imaging scanner to detect pathology of the spinal cord, including the location of a spinal cord injury, cysts, tumors and other abnormalities. The procedure involves the injection of a gadolinium based contrast media into the cervical or lumbar spine, followed by the MRI scan.
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