query: what does barium do in a ct scan

pos: Barium sulfate suspension of the ease of the actual test, the paced two-hour consumption of the barium sulfate suspension is often considered the worst part of a CT scan. Barium sulfate suspension Barium sulfate suspension, often simply called barium, is a contrast agent used during X-rays. Specifically it is used to improve visualization of the gastrointestinal tract (esophagus, stomach, intestines) on plain X-ray or computed tomography. It is taken by mouth or used rectally. Side effects include constipation, diarrhea, appendicitis, and if inhaled inflammation of the lungs. It is not recommended in people with intestinal perforation or bowel obstruction. Allergic reactions are rare.

neg: Gastrointestinal stromal tumor can be visible on plain films. Barium fluoroscopic examinations and CT are commonly used to evaluate the patient with abdominal complaints. Barium swallow images show abnormalities in 80% of GIST cases. However, some GISTs may be located entirely outside the lumen of the bowel and will not be appreciated with a barium swallow. Even in cases when the barium swallow is abnormal, an MRI or CT scan must follow since it is impossible to evaluate abdominal cavities and other abdominal organs with a barium swallow alone. In a CT scan, abnormalities may be seen in 87% of patients and it

neg: CT scan oral alternatives to iodinated contrast exist, such as very dilute (0.5–1% w/v) barium sulfate suspensions. Dilute barium sulfate has the advantage that it does not cause allergic-type reactions or kidney failure, but cannot be used in patients with suspected bowel perforation or suspected bowel injury, as leakage of barium sulfate from damaged bowel can cause fatal peritonitis. Computed tomography operates by using an X-ray generator that rotates around the object; X-ray detectors are positioned on the opposite side of the circle from the X-ray source. A visual representation of the raw data obtained is called a sinogram, yet it is

neg: Barium sulfate suspension meal, along with abstaining from all liquids, clear or otherwise, during this time. Consumption of the barium sulfate suspension begins 90 minutes to two hours prior to the CT/Fluoroscopic scan, as instructed in the patient education provided. For a Barium Swallow or Dysphagiagram the barium is consumed after the study begins to discern if the patient has difficulties swallowing or masticating. Consumption is paced, beginning two hours before the scan is to occur, with levels marked on the provided container indicating how much is to be consumed between each of the two hours prior to the test. A small portion

neg: Gastric volvulus the fundus. The diagnosis of gastric volvulus is usually based on barium studies; however, some authors recommend computed tomography (CT) scanning as the imaging modality of choice. Upper gastrointestinal (GI) contrast radiographic studies (using barium or Gastrografin) are sensitive and specific if performed with the stomach in the "twisted" state and may show an upside-down stomach. Contrast studies have been reported to have a diagnostic yield in 81–84% of patients. Often performed for an evaluation of acute abdominal pain, a computed tomography (CT) scan can offer immediate diagnosis by showing two bubbles with a transition line. Proponents of CT scanning

neg: Barium sulfate suspension advance of, or during a CT scan or fluoroscopic study to allow for better visualization of the gastrointestinal tract, such as in upper or lower gastrointestinal series. In upper gastrointestinal series, the patient is instructed to take nothing by mouth, which means to abstain from eating and drinking (fasting), with the exception of drinking the barium sulfate suspension. The amount of time for this fast may vary, depending on the instructions given by the imaging facility and the area of the body to be scanned, but generally lasts for several hours prior to the scan. The patient generally skips one

neg: CT scan on the diagnostic task. This is referred to as multiplanar reformatted imaging. CT is regarded as a moderate- to high-radiation diagnostic technique. The improved resolution of CT has permitted the development of new investigations, which may have advantages; compared to conventional radiography, for example, CT angiography avoids the invasive insertion of a catheter. CT colonography (also known as "virtual colonoscopy" or VC for short) is far more accurate than a barium enema for detection of tumors, and uses a lower radiation dose. CT VC is increasingly being used in the UK and US as a screening test for colon polyps

neg: Etonogestrel birth control implant Nexplanon can be located using traditional X-ray or CT-scan because of the inclusion of barium sulphate. There have been rare reports of Nexplanon implants having reached the lung via the pulmonary artery. Correct subdermal insertion reduces the risk of these events. Possible weight gain: Some women may experience slight weight gain when using the implant. However, current studies are not conclusive because they do not compare the weight of women using Implanon/Nexplanon with a control group of women not using the implant. The average increase in body weight in studies was less than 5 pounds (2,25 kg) over 2 years.

neg: Spondylolysis this test is positive, a CT scan is usually ordered to confirm spondylolysis. Commonly known as a CT Scan or CAT scan, this form of imaging is very similar to x-ray technology but produces many more images than an x-ray does. The multiple images produce cross-sectional views not possible with an x-ray. This allows a physician or radiologist to examine the images from many more angles than an x-ray allows. For this reason the CT scan is much more accurate in detecting spondylolysis than an x-ray. Bone scintigraphy combined with CT scan is considered the gold standard which means that

neg: Carcinoid syndrome about 80%. Gallium-68 labelled somatostatin analogues such as Ga-DOTA-Octreotate (DOTATATE), performed on a PET/CT scanner is superior to conventional Octreoscan. Usually, on a CT scan, a spider-like/crab-like change is visible in the mesentery due to the fibrosis from the release of serotonin. F-FDG PET/CT, which evaluate for increased metabolism of glucose, may also aid in localizing the carcinoid lesion or evaluating for metastases. Chromogranin A and platelets serotonin are increased. Tumour localization may be extremely difficult. Barium swallow and follow-up examination of the intestine may occasionally show the tumor. Capsule video endoscopy has recently been used to localize the tumor.

neg: Abdominal x-ray enema through the rectum. The term "barium enema" usually refers to a lower gastrointestinal series, although enteroclysis (an upper gastrointestinal series) is often called a small bowel barium enema. Abdominal x-ray An abdominal x-ray is an x-ray of the abdomen. It is sometimes abbreviated to AXR, or KUB (for kidneys, ureters, and urinary bladder). In children, abdominal x-ray is indicated in the acute setting: Yet, CT scan is the best alternative for diagnosing intra-abdominal injury. For acute abdominal pain in adults, an abdominal x-ray has a low sensitivity and accuracy in general, as well as for specific conditions such as

neg: Stroke into the space between the brain's membranes. Bleeding may occur due to a ruptured brain aneurysm. Diagnosis is typically based on a physical exam and supported by medical imaging such as a CT scan or MRI scan. A CT scan can rule out bleeding, but may not necessarily rule out ischemia, which early on typically does not show up on a CT scan. Other tests such as an electrocardiogram (ECG) and blood tests are done to determine risk factors and rule out other possible causes. Low blood sugar may cause similar symptoms. Prevention includes decreasing risk factors, as well as

neg: Full-body CT scan early identification can improve the success of curative efforts. Controversy arises from the use of full-body scans in the screening of patients who have no signs or symptoms suggestive of a disease. As with any test that screens for disease, the risks of full-body CT scans need to be weighed against the benefit of identifying a treatable disease at an early stage. An alternative to a full-body CT scan may be Magnetic resonance imaging (MRI) scans. MRI scans are generally more expensive than CT but do not expose the patient to ionizing radiation and are being evaluated for their potential

neg: Lung cancer staging scheme has two stages. Limited-stage disease is confined to an area that is tolerably treated by one radiotherapy area ("port"), but excludes cancers with pleural and pericardial effusions. All other small-cell lung cancers are extensive-stage in this scheme. There has been some drift over time in what this definition means. The mainstay of non-invasive staging is a CT scan of the chest followed by metabolic imaging with a PET scan. The CT scan shows abnormalities such as a lung nodule or enlarged lymph nodes whereas the PET scan reveals increased metabolism such as occurs in structures which contain rapidly growing

neg: CT scan agents. PCDs have only recently become feasible in CT scanners due to improvements in detector technologies that can cope with the volume and rate of data required. As of February 2016 photon counting CT is in use at three sites. Some early research has found the dose reduction potential of photon counting CT for breast imaging to be very promising. CT scan A CT scan, also known as computed tomography scan, and formerly known as a computerized axial tomography scan or CAT scan, makes use of computer-processed combinations of many X-ray measurements taken from different angles to produce cross-sectional (tomographic)

neg: Full-body CT scan Full-body CT scan A full-body scan is a scan of the patient's entire body as part of the diagnosis or treatment of illnesses. If computed tomography (CAT) scan technology is used, it is known as a full-body CT scan, though many medical imaging technologies can perform full-body scans. Full-body CT scans allow a transparent view of the body. For polytrauma patients, aggressive use of full-body CT scanning improves early diagnosis of injury and improves survival rates, with widespread adoption of the technique seen worldwide. Full-body CT scans are not indicated in patients with minor or single system trauma, and should

neg: Baryte carbonate associated sulfates (CAS) to determine past seawater sulfur concentrations which can help identify specific depositonal periods such as anoxic or oxic conditions. The use of sulfur isotope reconstruction is often paired with oxygen when a molecule contains both elements. Baryte is used in added-value applications which include filler in paint and plastics, sound reduction in engine compartments, coat of automobile finishes for smoothness and corrosion resistance, friction products for automobiles and trucks, radiation-shielding cement, glass ceramics, and medical applications (for example, a barium meal before a contrast CT scan). Baryte is supplied in a variety of forms and the

neg: Volvulus term constipation and a high fiber diet may also increase the risk. The most commonly affected part of the intestines in adults is the sigmoid colon with the cecum being second most affected. In children the small intestine is more often involved. The stomach can also be affected. Diagnosis is typically with medical imaging such as plain X-rays, a GI series, or CT scan. Initial treatment for sigmoid volvulus may occasionally occur via sigmoidoscopy or with a barium enema. Due to the high risk of recurrence, a bowel resection within the next two days is generally recommended. If the bowel

neg: Barium sulfate suspension their radiologist, but most patients find the common side effects more of an annoyance than a serious problem. Among the possible side effects, listed on MedlinePlus are nausea and diarrhea, which may begin as soon as 15 minutes after consumption begins and may persist through the day after the test is completed. Other side effects may include a feeling of weakness, pale skin, ringing in the ears, constipation, and vomiting. Patients may be strongly encouraged to avoid vomiting, as expelling a substantial quantity of the suspension may void its effect on the CT scan and produce unusable results, requiring a

neg: Dysphagia of distal esophagus, this is also described as a "rat's tail" appearance. In esophageal strictures, liquid barium may remain above the stricture and then gradually trickles down. Strictures can sometimes be seen on a VFSS if the clinician suspects stricture or esophageal dysmotility. The clinician can scan down the esophagus after giving solid foods like cookie or bread. It is helpful to scan the esophagus on the VFSS as this is the exam that can test a full array of solids. The barium swallow/esophagram typically only tests barium liquids and a barium tablet. All causes of dysphagia are considered as

neg: Necrotizing fasciitis which is strongly suggestive of necrotizing changes, but it is not sensitive enough to detect all the cases, because necrotizing skin infections caused by the bacteria other than clostridial infections usually do not show subcutaneous emphysema. If the diagnosis is still in doubt, computed tomography (CT) scans and magnetic resonance imaging (MRI) are more sensitive modalities than plain radiography. However, both the CT scan and MRI are not sensitive enough rule out necrotizing changes completely. CT scan may show fascial thickening, edema, subcutaneous gas, and abscess formation. In MRI, when fluid collection with deep fascia involvement occurs, thickening or enhancement

neg: CT scan is indicated and MRI is not available, or in emergency settings when hemorrhage, stroke, or traumatic brain injury are suspected. Even in emergency situations, when a head injury is minor as determined by a physician's evaluation and based on established guidelines, CT of the head should be avoided for adults and delayed pending clinical observation in the emergency department for children. CT scan can be used for detecting both acute and chronic changes in the lung parenchyma, that is, the internals of the lungs. It is particularly relevant here because normal two-dimensional X-rays do not show such defects. A variety

neg: Nausea neurological deficits are red flag signs for elevated intracranial pressure. When a history and physical exam are not enough to determine the cause of nausea and vomiting, certain diagnostic tests may prove useful. A chemistry panel would be useful for electrolyte and metabolic abnormalities. Liver function tests and lipase would identify pancreaticobiliary diseases. Abdominal X-rays showing air-fluid levels indicate bowel obstruction, while an X-ray showing air-filled bowel loops are more indicative of ileus. More advanced imaging and procedures may be necessary, such as a CT scan, upper endoscopy, colonoscopy, barium enema, or MRI. Abnormal GI motility can be assessed using

neg: Ear pain In addition, swimming is the most significant risk factor for otitis externae, though other risk factors include high humidity in the ear canal, eczema and/or ear trauma. If red flags are present it may be necessary to do additional workup such as a CT scan or biopsy to rule out a more dangerous diagnosis. Such diagnoses include malignant (or necrotizing) otitis externa, mastoiditis, temporal arteritis, and cancer. It is important to note that while the presence of a red flag does raise suspicion for one of these four disease, it does not guarantee a diagnosis as any one symptom can

neg: Coronary CT calcium scan Coronary CT calcium scan A coronary CT calcium scan is a computed tomography (CT) scan of the heart for the assessment of severity of coronary artery disease. Specifically, it looks for calcium deposits in the coronary arteries that can narrow arteries and increase the risk of heart attack. This severity can be presented as Agatston score or coronary artery calcium (CAC) score. The CAC score is an independent marker of risk for cardiac events, cardiac mortality, and all-cause mortality. In addition, it provides additional prognostic information to other cardiovascular risk markers. A typical coronary CT calcium scan is done without

neg: Photon-counting computed tomography reduce the amount of X-ray dose from a contrast scan by removing the need for a reference scan before contrast injection. Although spectral CT is already clinically available in the form of dual-energy scanners, photon-counting CT offers a number of advantages. A PCD can implement more than two energy thresholds with a higher degree of separation than what is possible to achieve in dual-energy CT. This improvement in energy resolution translates to higher contrast-to-noise ratio in the image, in particular in contrast-enhanced and material-selective images. Also, it can be shown that at least three energies are necessary to simultaneously decompose

neg: Full-body CT scan to $3000, full-body scans are expensive, and are rarely covered by insurance. However, in December 2007, the IRS stated that full-body scans qualify as deductible medical expenses, without a doctor's referral. This will likely lead employer-sponsored, flexible-spending plans to make the cost of the scans eligible for reimbursement. Full-body CT scan A full-body scan is a scan of the patient's entire body as part of the diagnosis or treatment of illnesses. If computed tomography (CAT) scan technology is used, it is known as a full-body CT scan, though many medical imaging technologies can perform full-body scans. Full-body CT scans allow

neg: Out of the Chute the plate in his skull to do a CT scan, and finally forcing his aortic valve to rupture during surgery to identify a weak spot in the valve in time to repair it. When the patient wakes up after surgery, Masters asks him out, having been attracted to him for most of the diagnostic process. The patient is embarrassed and does not respond. At the end of the episode, House takes more Vicodin and then jumps from the balcony of his hotel room into the pool to do a cannonball while Wilson watches in shock. Television Without Pity gave the

neg: Upper gastrointestinal series tract in addition to barium, and this procedure is called double-contrast imaging. In this case the gas is referred to as the negative contrast medium. Traditionally the images produced with barium contrast are made with plain-film radiography, but computed tomography is also used in combination with barium contrast, in which case the procedure is called CT enterography. Various types of barium X-ray examinations are used to examine different parts of the gastrointestinal tract. These include barium swallow, barium meal, barium follow-through, and barium enema. The barium swallow, barium meal, and barium follow-through are together also called an upper gastrointestinal series

neg: Kidney stone disease made on the basis of the location and severity of the pain, which is typically colicky in nature (comes and goes in spasmodic waves). Pain in the back occurs when calculi produce an obstruction in the kidney. Physical examination may reveal fever and tenderness at the costovertebral angle on the affected side. In people with a history of stones, those who are less than 50 years of age and are presenting with the symptoms of stones without any concerning signs do not require helical CT scan imaging. A CT scan is also not typically recommended in children. Otherwise a noncontrast

neg: CT scan involving stroke or head trauma. CT scanning of the head is also used in CT-guided stereotactic surgery and radiosurgery for treatment of intracranial tumors, arteriovenous malformations and other surgically treatable conditions using a device known as the N-localizer. Magnetic resonance imaging (MRI) of the head provides superior information as compared to CT scans when seeking information about headache to confirm a diagnosis of neoplasm, vascular disease, posterior cranial fossa lesions, cervicomedullary lesions, or intracranial pressure disorders. It also does not carry the risks of exposing the patient to ionizing radiation. CT scans may be used to diagnose headache when neuroimaging

neg: Dementia problems that commonly cause confusion or disorientation in the elderly. A CT scan or magnetic resonance imaging (MRI scan) is commonly performed, although these tests do not pick up diffuse metabolic changes associated with dementia in a person that shows no gross neurological problems (such as paralysis or weakness) on neurological exam. CT or MRI may suggest normal pressure hydrocephalus, a potentially reversible cause of dementia, and can yield information relevant to other types of dementia, such as infarction (stroke) that would point at a vascular type of dementia. The functional neuroimaging modalities of SPECT and PET are more useful

neg: MR Enterography features. CT scan instead provides cross sectional and multiplanar images of intraluminal and extra-mucosal, extra-luminal or even extra-enteric features, but costing higher radiation dose. The spread of MR technique has revolutionized the diagnostic imaging of the small bowel loop, restricting CT scan to particular situations, such as emergency or MR contraindications like patients with pacemaker implant, recently implanted vascular/bilious stent or other ferromagnetic prosthesis/devices. It is a safe, multi-planar imaging modality with high soft tissue contrast resolution that does not expose to ionizing radiation, so it is feasible for young patients or when several follow up are required. Cathartic preparation

neg: Nuclear medicine generally more organ-, tissue- or disease-specific (e.g.: lungs scan, heart scan, bone scan, brain scan, tumor, infection, Parkinson etc.) than those in conventional radiology imaging, which focus on a particular section of the body (e.g.: chest X-ray, abdomen/pelvis CT scan, head CT scan, etc.). In addition, there are nuclear medicine studies that allow imaging of the whole body based on certain cellular receptors or functions. Examples are whole body PET scans or PET/CT scans, gallium scans, indium white blood cell scans, MIBG and octreotide scans. While the ability of nuclear metabolism to image disease processes from differences in metabolism is

neg: CT scan CT scan A CT scan, also known as computed tomography scan, and formerly known as a computerized axial tomography scan or CAT scan, makes use of computer-processed combinations of many X-ray measurements taken from different angles to produce cross-sectional (tomographic) images (virtual "slices") of specific areas of a scanned object, allowing the user to see inside the object without cutting. Digital geometry processing is used to further generate a three-dimensional volume of the inside of the object from a large series of two-dimensional radiographic images taken around a single axis of rotation. Medical imaging is the most common application of

neg: Coronary CT calcium scan been described, including mass-based calcium scoring, volume-based calcium scoring, or lesion-specific calcium-scoring have been developed. A lesion-specific calcium score has been developed. Each individual calcified lesion is characterized and measured using parameters including the width, length, density, and distance from the entrance of the major coronary arteries. Research has shown that the lesion-specific calcium scoring method is superior to the traditional Agatston score for the prediction of significant blockages in the heart. A patent application protecting this method has been filed. Coronary CT calcium scan A coronary CT calcium scan is a computed tomography (CT) scan of the heart for

neg: Computed tomography of the thyroid RAI therapy, and has a poorer prognosis. There is not yet consensus in the research literature on whether cross-sectional imaging (CT or MRI) or an 18FDG-PET/CT scan should be performed as the first-line imaging modality for such patients. Enhanced CT scan was thought to be more sensitive for detection of lymph node metastases. Nonetheless, scans using modern PET/CT equipment are as reliable as a proper routine staging CT scan. Many lesions can be found on 18FDG-PET/CT scanning despite the lack of IV contrast injection. However, differentiation between local recurrence versus lymph node metastases and detection of direct involvement of the

neg: CT scan CT of 8 mSv is estimated to be 0.05%, or 1 one in 2,000. Because of increased susceptibility of fetuses to radiation exposure, the radiation dosage of a CT scan is an important consideration in the choice of medical imaging in pregnancy. In October, 2009, the US Food and Drug Administration (FDA) initiated an investigation of brain perfusion CT (PCT) scans, based on radiation burns caused by incorrect settings at one particular facility for this particular type of CT scan. Over 256 patients over an 18-month period were exposed, over 40% lost patches of hair, and prompted the editorial to

neg: CT scan number of artifacts, such as the following: An important issue within radiology today is how to reduce the radiation dose during CT examinations without compromising the image quality. In general, higher radiation doses result in higher-resolution images, while lower doses lead to increased image noise and unsharp images. However, increased dosage raises the adverse side effects, including the risk of radiation-induced cancer – a four-phase abdominal CT gives the same radiation dose as 300 chest X-rays (See the Scan dose section). Several methods that can reduce the exposure to ionizing radiation during a CT scan exist. Industrial CT Scanning (industrial

neg: Pneumonia to treatments. However, CT scan is more expensive, has a higher dose of radiation, and cannot be done at bedside. Lung ultrasound may also be useful in helping to make the diagnosis. Ultrasound is radiation free and can be done at bedside. However, ultrasound requires specific skills to operate the machine and interpret the findings. It may be more accurate than chest X-ray. In patients managed in the community, determining the causative agent is not cost-effective and typically does not alter management. For people who do not respond to treatment, sputum culture should be considered, and culture for "Mycobacterium tuberculosis"

neg: Spinal cord injury an X-ray, CT scan, or MRI can determine if there is damage to the spinal column and where it is located. X-rays are commonly available and can detect instability or misalignment of the spinal column, but do not give very detailed images and can miss injuries to the spinal cord or displacement of ligaments or disks that do not have accompanying spinal column damage. Thus when X-ray findings are normal but SCI is still suspected due to pain or SCI symptoms, CT or MRI scans are used. CT gives greater detail than X-rays, but exposes the patient to more radiation,

neg: CT scan and colon cancer and can negate the need for a colonoscopy in some cases. The radiation dose for a particular study depends on multiple factors: volume scanned, patient build, number and type of scan sequences, and desired resolution and image quality. In addition, two helical CT scanning parameters that can be adjusted easily and that have a profound effect on radiation dose are tube current and pitch. Computed tomography (CT) scan has been shown to be more accurate than radiographs in evaluating anterior interbody fusion but may still over-read the extent of fusion. The radiation used in CT scans can

neg: Astrocytoma computed tomography (CT) or magnetic resonance imaging (MRI) scan is necessary to characterize the extent of these tumors (size, location, consistency). CT will usually show distortion of third and lateral ventricles with displacement of anterior and middle cerebral arteries. Histologic analysis is necessary for grading diagnosis. In the first stage of diagnosis the doctor will take a history of symptoms and perform a basic neurological exam, including an eye exam and tests of vision, balance, coordination and mental status. The doctor will then require a CT scan and MRI of the patient's brain. During a CT scan, X-rays of the

neg: Major trauma agent, but not oral administration. There are concerns that intravenous contrast administration in trauma situations without confirming adequate renal function may cause damage to kidneys, but this does not appear to be significant. In the U.S., CT or MRI scans are performed on 15% of those with trauma in emergency departments. Where blood pressure is low or the heart rate is increasedlikely from bleeding in the abdomenimmediate surgery bypassing a CT scan is recommended. Modern 64-slice CT scans are able to rule out with a high degree of accuracy, significant injuries to the neck following blunt trauma. Surgical techniques, using

neg: CT scan computed tomography is a CT technique currently under development. Typical CT scanners use energy integrating detectors; photons are measured as a voltage on a capacitor which is proportional to the x-rays detected. However, this technique is susceptible to noise and other factors which can affect the linearity of the voltage to x-ray intensity relationship. Photon counting detectors (PCDs) are still affected by noise but it does not change the measured counts of photons. PCDs have several potential advantages including improving signal (and contrast) to noise ratios, reducing doses, improving spatial resolution and, through use of several energies, distinguishing multiple contrast

neg: Magdalenian Girl order to do this, they used a high quality x-ray scanning machine to produce a CT scan, which recorded images of the skull from multiple angles. The digital reconstruction took place at Alloyweld Inspection Company. Unfortunately, when these remains were originally found, the archaeologists had accidentally shattered the skull with a pickaxe and had to piece it back together. Before the scanning process, the skull was in at least six pieces and was inexpertly put back together. This makes it difficult for anthropologists to understand what Magdalenian Girl looked like and to answer important questions about the remains. The new

neg: CT scan surveillance gives better outcomes, and because of risks associated with having CT scans, patients should not receive CT screening in excess of those recommended by established guidelines. "Computed tomography angiography" (CTA) is contrast CT to visualize arterial and venous vessels throughout the body. This ranges from arteries serving the brain to those bringing blood to the lungs, kidneys, arms and legs. An example of this type of exam is CT pulmonary angiogram (CTPA) used to diagnose pulmonary embolism (PE). It employs computed tomography and an iodine based contrast agent to obtain an image of the pulmonary arteries. A CT scan

neg: CT scan modern Dual-energy CT scanners, new areas of use have been established, such as aiding in the diagnosis of gout. There are several advantages that CT has over traditional 2D medical radiography. First, CT completely eliminates the superimposition of images of structures outside the area of interest. Second, because of the inherent high-contrast resolution of CT, differences between tissues that differ in physical density by less than 1% can be distinguished. Finally, data from a single CT imaging procedure consisting of either multiple contiguous or one helical scan can be viewed as images in the axial, coronal, or sagittal planes, depending

neg: Intraparenchymal hemorrhage autoregulatory dysfunction with excessive cerebral blood flow e.g.: - reperfusion injury - hemorrhagic transformation - cold exposure - rupture of an aneurysm or arteriovenous malformation (AVM) - arteriopathy (e.g. cerebral amyloid angiopathy, moyamoya) - altered hemostasis (e.g. thrombolysis, anticoagulation, bleeding diathesis) - hemorrhagic necrosis (e.g. tumor, infection) - venous outflow obstruction (e.g. cerebral venous sinus thrombosis). Nonpenetrating and penetrating cranial trauma can also be common causes of intracerebral hemorrhage. Computed tomography (CT scan): A CT scan may be normal if it is done soon after the onset of symptoms. A CT scan is the best test to look for bleeding

neg: Marginal zone B-cell lymphoma types of lymphoma. In order to determine the correct type of lymphoma and stage it accurately, the physician will also need to do a physical exam, blood tests to determine blood cell counts, a CT scan, and/or a PET scan. A PET scan is the most important in planning a course of treatment. A bone marrow biopsy and aspiration test may also be ordered to test for bone marrow involvement, which is found in 30-50% of cases. In order to diagnose MALT, a biopsy is needed from the affected tissue. If the abnormal tissue is suspected to be in the

neg: Marginal zone B-cell lymphoma stomach or bowel, an endoscopy is done in order to get the biopsy. This requires either a gastroscopy or colonoscopy. If the lymphoma is thought to have spread to other areas in this region, an ultrasound scan is often done at the same time. If the abnormal tissue is thought to be in the lungs, a bronchoscopy is ordered. In order to determine the correct type of lymphoma and stage it accurately, the physician will also need to do a physical exam, blood tests to determine blood cell counts, a CT scan, an MRI and/or a PET scan. A PET

neg: Appendicitis than 20 WBC per high-power field in the urine is more suggestive of a urinary tract disorder. In children the clinical examination is important to determine which children with abdominal pain should receive immediate surgical consultation and which should receive diagnostic imaging. Because of the health risks of exposing children to radiation, ultrasound is the preferred first choice with CT scan being a legitimate follow-up if the ultrasound is inconclusive. CT scan is more accurate than ultrasound for the diagnosis of appendicitis in adults and adolescents. CT scan has a sensitivity of 94%, specificity of 95%. Ultrasonography had an overall

neg: Aneurysm and turkeys Diagnosis of a ruptured cerebral aneurysm is commonly made by finding signs of subarachnoid hemorrhage on a computed tomography (CT) scan. If the CT scan is negative but a ruptured aneurysm is still suspected based on clinical findings, a lumbar puncture can be performed to detect blood in the cerebrospinal fluid. Computed tomography angiography (CTA) is an alternative to traditional angiography and can be performed without the need for arterial catheterization. This test combines a regular CT scan with a contrast dye injected into a vein. Once the dye is injected into a vein, it travels to the

neg: Laminotomy as well as facet hypertrophy, which are some of the main pathophysiological changes indicative of lumbar spinal stenosis. Even though a CT scan can reveal these pertinent signs of lumbar spinal stenosis, it can sometimes give a cloudy image due to the shadowing of the tissue contrast. When this occurs, an intrathecal myelography contrast is conducted with the CT scan to fix the abnormal contrast. A CT scan can also reveal an increase in the cross sectional area of the L3 vertebrae, which ultimately decreases the cross sectional area of the spinal canal. As an increase in the size of

neg: Lumbar disc disease material. Pain is in the distribution of the nerve compressed, usually down the back of the leg, side of the calf and inside of the foot (sciatica). Most commonly, the nerve root between the fourth and fifth lumbar vertebrae or between the fifth lumbar vertebra and first sacral segment are impinged. In symptomatic cases the diagnosis should be confirmed by an MRI scan. However, in cases with slight symptoms, a faster and cheaper CT scan (although it is inferior to MRI scan) may be recommended. While a CT scan can show the bony structures in more detail, an MRI scan

neg: CT scan 1980. Similar increases have been seen in Europe and Asia. In Calgary, Canada 12.1% of people who present to the emergency with an urgent complaint received a CT scan, most commonly either of the head or of the abdomen. The percentage who received CT, however, varied markedly by the emergency physician who saw them from 1.8% to 25%. In the emergency department in the United States, CT or MRI imaging is done in 15% of people who present with injuries as of 2007 (up from 6% in 1998). The increased use of CT scans has been the greatest in two

neg: Shunichi Yamashita of CT scan one time. But CT scan is necessary for medication, so CT scan itself is not bad”. On March 19, 2011, Yamashita visited the prefectural government's disaster headquarters and said, "Information about radiation risks has not been correctly communicated. Under the current levels, administering iodine pills is unnecessary." Meanwhile, as the president of the Japan Thyroid Association, Yamashita wrote a letter dated March 24, 2011 to its members that thyroid blockage was not necessary, citing the opinion of the Japanese Society of Nuclear Medicine. However, in the affected areas like Iitate, Soma and Minami-Soma, high radiation doses required

neg: Cardiac imaging anesthesia and in a non-invasive way. A coronary CT calcium scan is a computed tomography (CT) scan of the heart for the assessment of severity of coronary artery disease. Specifically, it looks for calcium deposits in the coronary arteries that can narrow arteries and increase the risk of heart attack. This severity can be presented as Agatston score or Coronary Artery Calcium (CAC) score. The CAC score is an independent marker of risk for cardiac events, cardiac mortality, and all-cause mortality. In addition, it provides additional prognostic information to other cardiovascular risk markers. A typical coronary CT calcium scan is

neg: Computed tomography of the thyroid have variable CT scan findings, such as calcifications, single or multiple nodules, cysts, or diffuse enlargement. Thyroid calcifications on a CT scan can be seen in both benign and malignant thyroid lesions. Sonographic examination of the thyroid can differentiate between micro-calcifications, which are highly associated with papillary thyroid carcinoma, and eggshell calcifications, which favour a benign process such as colloid cysts (Figs. 1 and and2)2). In a retrospective review of preoperative CT scan, 35 % (135 of 383) of the patients had detectable intra-thyroidal calcifications. Among them, 48 % had a histopathologically proven thyroid cancer. Calcified nodules had a significantly

neg: What Would We Do Without You? violent with Tom. In a moment of anger, Tom seizes Lynette and asks why she's mad at him, and she reveals it's because he had lunch with Rick and because she had to fire him. Lynette then shoves Tom back onto the bed, hurting his back. Tom's back spasms and he moves suddenly causing Lynette to fall off the bed, banging her head on the side table. She goes to hospital for her injury and Tom finds out Lynette fell for Rick and misses him. The doctor performs a CT scan on Lynette and finds swollen lymph nodes and suggests

neg: Hodgkin's lymphoma chest X-ray radiographs, computed tomography (CT)/Positron emission tomography (PET)/magnetic resonance imaging (MRI) scans of the chest, abdomen and pelvis, and usually a bone marrow biopsy. Positron emission tomography (PET) scan is now used instead of the gallium scan for staging. On the PET scan, sites involved with lymphoma light up very brightly enabling accurate and reproducible imaging. In the past, a lymphangiogram or surgical laparotomy (which involves opening the abdominal cavity and visually inspecting for tumors) were performed. Lymphangiograms or laparotomies are very rarely performed, having been supplanted by improvements in imaging with the CT scan and PET scan. On

neg: Angiography be clearly determined. Coronary angiography can visualize coronary artery stenosis, or narrowing of the blood vessel. The degree of stenosis can be determined by comparing the width of the lumen of narrowed segments of blood vessel with wider segments of adjacent vessel. To detect coronary artery disease, a CT scan is more satisfactory than an MRI scan. The sensitivity and specificity between CT and MRI were (97.2 percent and 87.4 percent) and (87.1 percent and 70.3 percent), respectively. Therefore, CT (mainly multislice CT) is more accepted, more widely available, more favored by patients, and more economic. Moreover, CT requires shorter

neg: Electroceramics information storage; solid electrolytes - energy storage and conversion; piezoelectrics - sonar; semiconducting oxides - environmental monitoring. Recent advances in these areas are described in the Journal of Electroceramics. Dielectric materials used for construction of ceramic capacitors include: zirconium barium titanate, strontium titanate (ST), calcium titanate (CT), magnesium titanate (MT), calcium magnesium titanate (CMT), zinc titanate (ZT), lanthanum titanate (TLT), and neodymium titanate (TNT), barium zirconate (BZ), calcium zirconate (CZ), lead magnesium niobate (PMN), lead zinc niobate (PZN), lithium niobate (LN), barium stannate (BS), calcium stannate (CS), magnesium aluminium silicate, magnesium silicate, barium tantalate, titanium dioxide, niobium oxide, zirconia, silica,

neg: Pachycephalosaurus CT scan comparisons of the skulls of "Stegoceras validum", "Prenocephale prenes", and several head-striking artiodactyls have also supported pachycephalosaurids as being well-equipped for head-butting. Scientists do not yet know what these dinosaurs ate. Having very small, ridged teeth they could not have chewed tough, fibrous plants as effectively as other dinosaurs of the same period. It is assumed that pachycephalosaurs lived on a mixed diet of leaves, seeds, and fruits. The sharp, serrated teeth would have been very effective for shredding plants. Nearly all "Pachycephalosaurus" fossils have been recovered from the Lance Formation and Hell Creek Formation of the western

neg: National Lung Screening Trial of interest related to the tobacco company, although this time on the contra-CT scan side: on October 8, 2007, the "Wall Street Journal" reported that at least two lead investigators of the study had conflicts of interest arising from their serving as paid, expert defense witnesses for the tobacco industry – one of them had given testimony asserting that promoting CT screening was "reckless or irresponsible", and another had provided an expert report warning that CT screening "may do more harm than good." Deaths in either group were then logged for up to five years. As of October 2010, 354

neg: Neuroimaging use, increases in CT scan use, especially in asymptomatic patients, is a topic of concern since patients are exposed to significantly high levels of radiation. In PET scans, imaging does not rely on intrinsic biological processes, but relies on a foreign substance injected into the bloodstream traveling to the brain. Patients are injected with radioisotopes that are metabolized in the brain and emit positrons to produce a visualization of brain activity. The amount of radiation a patient is exposed to in a PET scan is relatively small, comparable to the amount of environmental radiation an individual is exposed to across

neg: Mantle cell lymphoma scans are routinely performed. Since mantle cell lymphoma may present a lymphomatous polyposis coli and colon involvement is common, colonoscopy is now considered a routine part of the evaluation. Upper endoscopy and neck CT scan may be helpful in selected cases. In some patients with the blastic variant, lumbar puncture is done to evaluate the spinal fluid for involvement. CT scan - Computerized tomography scan yields images of part or whole body. Gives a large number of slices on X-ray image. PET scan - Generally of the whole body, shows a three-dimensional image of where previously injected radioactive glucose is

neg: Vestibular schwannoma to 5 millimeters in diameter (the scan spacing). When an MRI is not available or cannot be performed, a computerized tomography scan (CT scan) with contrast is suggested for patients in whom an acoustic neuroma is suspected. The combination of CT scan and audiogram approach the reliability of MRI in making the diagnosis of acoustic neuroma. There are three treatment options available to a patient. These options are observation, microsurgical removal and radiation (radiosurgery or radiotherapy). Determining which treatment to choose involves consideration of many factors including the size of the tumor, its location, the patient's age, physical health and

neg: Neuroimaging became one of the most widely used methods of imaging. A CT scan can be performed in under a second and produce rapid results for clinicians, with its ease of use leading to an increase in CT scans performed in the United States from 3 million in 1980 to 62 million in 2007. Clinicians oftentimes take multiple scans, with 30% of individuals undergoing at least 3 scans in one study of CT scan usage. CT scans can expose patients to levels of radiation 100-500 times higher than traditional x-rays, with higher radiation doses producing better resolution imaging. While easy to

neg: CT scan Surface rendering is limited in that it will display only surfaces that meet a threshold density, and will display only the surface that is closest to the imaginary viewer. In volume rendering, transparency, colors and shading are used to allow a better representation of the volume to be shown in a single image. For example, the bones of the pelvis could be displayed as semi-transparent, so that, even at an oblique angle, one part of the image does not conceal another. Although images produced by CT are generally faithful representations of the scanned volume, the technique is susceptible to a

neg: Transmediastinal gunshot wound 22 stable patients who were screened with CT, chest x ray and abdominal ultrasound; seven patients showed a positive CT scan and required additional evaluation, and of these seven patients, three required surgical management. Additionally the work of Burack et al., whose evaluation of stable patients with penetrating injuries to the mediastinum — this time including stab wounds — relied mostly on CT and ultrasound, showed similar results. The work of Ibirogba et al. did so as well. Recent data suggests that the use of CT scan with some additional noninvasive techniques, such as ultrasound and chest roentgenogram are reliable

neg: Holotomography reconstructed from these multiple 2D holographic images by inversely solving light scattering in the sample. The principle of HT is very similar to X-ray computed tomography (CT) or CT scan. CT scan measures multiple 2-D X-ray images of a human body at various illumination angles, and a 3-D tomogram (X-ray absorptivity) is then retrieved via the inverse scattering theory. Both the X-ray CT and laser HT shares the same governing equation – Helmholtz equation, the wave equation for a monochromatic wavelength. HT is also known as optical diffraction tomography. The applications of HT includes HT provides 3D dynamic images of

neg: Gallium scan acquired. In some imaging centers, SPECT images may be combined with computed tomography scan using either fusion software or SPECT/CT hybrid cameras to superimpose both physiological image-information from the gallium scan, and anatomical information from the CT scan. A common injection doses is around 150 megabecquerels. Imaging should not usually be sooner than 24 hours - high background at this time produces false negatives. Forty-eight-hour whole body images are appropriate. Delayed imaging can be obtained even 1 week or longer after injection if bowel is confounding. SPECT can be performed as needed. Oral laxatives or enemas can be given before

neg: Deep vein thrombosis prior to proximal vein ultrasound. For a suspected first leg DVT in a moderate-probability scenario, a high-sensitivity D-dimer is suggested as a recommended option over ultrasound imaging, with both whole-leg and compression ultrasound possible. The NICE guideline uses a two-point Wells score and does not refer to a moderate probability group. Imaging tests of the veins are used in the diagnosis of DVT, most commonly either proximal compression ultrasound or whole-leg ultrasound. Each technique has drawbacks: a single proximal scan may miss a distal DVT, while whole-leg scanning can lead to distal DVT overtreatment. Doppler ultrasound, CT scan venography, MRI

neg: Epiploic appendagitis diagnose, for inflammation of the appendices epiploicae may be resultant to other inflammatory conditions in the colonic wall and surrounding mesocolon. Ultrasound and CT scans are the normal means of positive diagnosis of Epiploic Appendagitis. Ultrasound scans show "an oval, non-compressible hyperechoic mass with a subtle hypoechoic rim directly under the site of maximum tenderness". Normally, epiploic appendages cannot be seen on CT scan. After cross-sectional imaging and the increased use of abdominal CT for evaluating lower abdominal pain, EA is increasingly diagnosed. Pathognomonic CT scan data represent EA as 2–4 cm, oval shaped, fat density lesions, surrounded by inflammation.

neg: Computed tomography of the abdomen and pelvis patients in an attempt to prospectively characterize potential lesions detected during the scan. However, unindicated multiphase CT examinations are an important source of medical radiation that does not contribute to the care of patients. Adherence to published standards such as the ACR Appropriateness Criteria can both decrease medical radiation and optimize imaging for the specific clinical indication. Computed tomography of the abdomen and pelvis Computed tomography (CT) is a sensitive method for diagnosis of abdominal diseases. It is used frequently to determine stage of cancer and to follow progress. It is also a useful test to investigate acute abdominal pain

neg: National Lung Screening Trial people in the CT scan group had died from lung cancer, versus 442 people in the X-ray group; in other words, deaths in the CT scan group of patients were 20.3% lower than in the X-ray group. The study's review board concluded that this difference was statistically significant and recommended terminating the study. The director of the National Cancer Institute's director, Harold Varmus, said that early analysis results appeared to indicate that CT scans detected more lung cancers, at an earlier and more treatable stage, and that CT scans could therefore reduce the number of deaths in patients at high

neg: CT scan mSv a year and 100 mSv every 5 years. Lead is the main material used by radiography personnel for shielding against scattered X-rays. The radiation dose reported in the gray or mGy unit is proportional to the amount of energy that the irradiated body part is expected to absorb, and the physical effect (such as DNA double strand breaks) on the cells' chemical bonds by X-ray radiation is proportional to that energy. The sievert unit is used in the report of the effective dose. The sievert unit, in the context of CT scans, does not correspond to the actual radiation

neg: Computed tomography of the thyroid ,88 and and9).9). CT scans are also the most sensitive diagnostic tool for the detection of pulmonary micro-metastases. Many of the neck US features that are considered as suggestive signs of disease recurrence are also applicable to CT examination. These signs might include sizable rounded nodules in the thyroid bed, fine calcifications, or cystic change. In cases of elevated thyroglobulin with negative neck US and iodine whole body scintigraphy (WBS), fluorodeoxyglucose (FDG) positron emission tomography (PET) is the next modality of choice. Dedifferentiated thyroid carcinoma usually has avid FDG-PET uptake and a negative radioiodine scan, typically does not respond to

neg: Blunt kidney trauma gross or microscopic hematuria. The imaging modality of choice is contrast-enhanced, computed tomography (CT) which is readily available in most emergency departments of moderate or above size. Scan times have become shorter with each generation of scanners and current scans are quick and accurately demonstrate renal injuries together with associated injuries to other abdominal or retroperitoneal organs. Unlike ultrasound examination (FAST), CT provides anatomic and functional information that allows for accurate grading of the injury which is partly responsible for a growing trend toward conservative management (intravenous fluids, close monitoring, watchful waiting) of renal trauma. Conservative management does not apply

neg: Hodgkin's lymphoma infections) and from other types of cancer. Definitive diagnosis is by lymph node biopsy (usually excisional biopsy with microscopic examination). Blood tests are also performed to assess function of major organs and to assess safety for chemotherapy. Positron emission tomography (PET) is used to detect small deposits that do not show on CT scanning. PET scans are also useful in functional imaging (by using a radiolabeled glucose to image tissues of high metabolism). In some cases a Gallium scan may be used instead of a PET scan. Classical Hodgkin lymphoma (excluding nodular lymphocyte predominant Hodgkin's lymphoma) can be subclassified into

neg: Scaphoid fracture box" ) are often splinted in a thumb spica for 7–10 days at which point a second set of X-rays is taken. If there was a hairline fracture, healing will now be apparent. Even then a fracture may not be apparent. A CT Scan can then be used to evaluate the scaphoid with greater resolution. The use of MRI, if available, is preferred over CT and can give one an immediate diagnosis. Bone scintigraphy is also an effective method for diagnosis fracture which do not appear on Xray. Treatment of scaphoid fractures is guided by the location in the bone

neg: Barium sulfate suspension of the suspension is reserved for the minutes just before the test, to ensure that as much of the gastrointestinal tract as possible is coated. After the scan is complete, the patient is encouraged to eat and drink normally, with special attention to plenty of fluids. The barium sulfate is excreted through defecation, so extra fluid intake helps prevent constipation, which is a possible side effect (see Johns Hopkins Medicine Health Library for an example of a possible patient education instruction sheet). Some patients with allergies or sensitive stomachs may choose to discuss alternatives to the barium sulfate suspension with

neg: Tracheobronchomalacia the lives of at least 3 infants. Initially symptoms asymptomatic or some patients do not experience symptoms at all. In a progressive TBM case symptoms include: Symptoms may become worse if the patient is stressed, sick, lying down, or forcing a cough. Diagnosis is conducted according to the severity of the symptoms. Initially pulmonary function tests are administered. These tests include the lungs' capability of air intake and outtake, and gas flow of oxygen and carbon dioxide between the body and environment. Following these function tests a CT scan or bronchoscopy will be ordered. The results to the scan and

neg: CT scan absence of symptoms (sometimes referred to as an incidentaloma) may raise concerns that it might represent a tumor, either benign or malignant. Perhaps persuaded by fear, patients and doctors sometimes agree to an intensive schedule of CT scans, sometimes up to every three months and beyond the recommended guidelines, in an attempt to do surveillance on the nodules. However, established guidelines advise that patients without a prior history of cancer and whose solid nodules have not grown over a two-year period are unlikely to have any malignant cancer. For this reason, and because no research provides supporting evidence that intensive

neg: Pseudocyst cystic neoplasm. Also, the intravenous contrast given at the time of the CT scan may worsen kidney dysfunction. MRI and MRCP are effective methods of detecting pseudocysts, but are not regularly used because CT scans offer most of the needed information. These scans do, however, provide better contrast, which allows for better characterization of fluid collections, depicting debris within the collections, and detection of bleeding. Endoscopic ultrasound is generally used as a secondary test to further evaluate the cysts found in other tests, and is used when determining if a cyst is a pseudocyst or not. Adrenal pseudocysts are found

neg: Prostate cancer a CT scan evaluates spread within the pelvis, a bone scan look for spread to the bones, and endorectal coil magnetic resonance imaging to closely evaluate the prostatic capsule and the seminal vesicles. Bone scans should reveal osteoblastic appearance due to "increased" bone density in the areas of bone metastasis—opposite to what is found in many other cancers that metastasize. After a prostate biopsy, a pathologist looks at the samples under a microscope. If cancer is present, the pathologist reports the grade of the tumor. The grade tells how much the tumor tissue differs from normal prostate tissue and suggests

neg: Enlarged vestibular aqueduct likely. Enlarged vestibular aqueducts are commonly picked up after newborn hearing screen when a child is identified as having a hearing loss. The hearing loss is commonly mixed and can be of any degree when first identified. The conductive component is due to a third window effect caused by the widened vestibular aqueduct. Identification of the enlarged vestibular aqueduct in a child is usually by MRI scan which identifies the fluid within the endolymphatic duct and sac. CT scan may be needed to see the vestibular aqueduct clearly. In adults CT scan may be the first investigation. In order to

neg: Pseudocyst Transabdominal ultrasound can be used to identify pseudocysts, which appear on the scan as echoic structures associated with distal acoustic enhancement. They tend to be round and enclosed in a smooth wall. Pseudocysts may appear more complex when young, hemorrhaged, or when complicated due to infection. The transabdominal ultrasound has a sensitivity rate in detection of pancreatic pseusocysts of 75%-90%, making it inferior to a CT scan, which has a rate of 90%-100%. CT scans are more accurate, and provide more detail regarding the pseudocyst and its surroundings. The CT scan’s weakness is its lack of differentiation between pseudocysts and

neg: Sinusitis more than 10 days or get worse in that time, then the infection is considered bacterial sinusitis. Imaging by either X-ray, CT or MRI is generally not recommended unless complications develop. Pain caused by sinusitis is sometimes confused for pain caused by pulpitis (toothache) of the maxillary teeth, and vice versa. Classically, the increased pain when tilting the head forwards separates sinusitis from pulpitis. For sinusitis lasting more than 12 weeks a CT scan is recommended. On a CT scan, acute sinus secretions have a radiodensity of 10 to 25 Hounsfield units (HU), but in a more chronic state they

neg: CT scan the Greek "tome" (slice) and "graphein" (to write). Computed tomography was originally known as the "EMI scan" as it was developed in the early 1970s at a research branch of EMI, a company best known today for its music and recording business. It was later known as "computed axial tomography" ("CAT" or "CT scan") and "body section röntgenography". Although the term "computed tomography" could be used to describe positron emission tomography or single photon emission computed tomography (SPECT), in practice it usually refers to the computation of tomography from X-ray images, especially in older medical literature and smaller medical facilities.

neg: CT scan dose that the scanned body part absorbs but to another radiation dose of another scenario, the whole body absorbing the other radiation dose and the other radiation dose being of a magnitude, estimated to have the same probability to induce cancer as the CT scan. Thus, as is shown in the table above, the actual radiation that is absorbed by a scanned body part is often much larger than the effective dose suggests. A specific measure, termed the computed tomography dose index (CTDI), is commonly used as an estimate of the radiation absorbed dose for tissue within the scan region,

neg: Polymicrogyria whereas the effect of PMG is the formation of multiple small gyri. Underneath a computerized tomography (CT scan) scan, these both appear similar in that the cerebral cortex appears thickened. However, MRI with a T1 weighted inversion recovery will illustrate the gray-white junction that is characterized by patients with PMG. An MRI is also usually preferred over the CT scan because it has sub-millimeter resolution. The resolution displays the multiple folds within the cortical area, which is continuous with the neuropathology of an infected patient. Gross examination exposes a pattern of many small gyri clumped together, which causes an irregularity

neg: Dental implant positioning of the implant. Increasingly, dentists opt to get a CT scan of the jaws and any existing dentures, then plan the surgery on CAD/CAM software. The stent can then be made using stereolithography following computerized planning of a case from the CT scan. The use of CT scanning in complex cases also helps the surgeon identify and avoid vital structures such as the inferior alveolar nerve and the sinus. Most implant systems have five basic steps for placement of each implant: There are different approaches to placement dental implants after tooth extraction. The approaches are: There are also various

neg: Hepatocellular carcinoma by CT or MRI scans. Optimally, these scans are performed with intravenous contrast in multiple phases of hepatic perfusion to improve detection and accurate classification of any liver lesions by the interpreting radiologist. Due to the characteristic blood flow pattern of HCC tumors, a specific perfusion pattern of any detected liver lesion may conclusively detect an HCC tumor. Alternatively, the scan may detect an indeterminate lesion and further evaluation may be performed by obtaining a physical sample of the lesion. Ultrasound, CT scan, and MRI may be used to evaluate the liver for HCC. On CT and MRI, HCC can

neg: CT scan reformatting the volume, it becomes much easier to visualise the position of one vertebral body in relation to the others. Modern software allows reconstruction in non-orthogonal (oblique) planes so that the optimal plane can be chosen to display an anatomical structure. This may be particularly useful for visualising the structure of the bronchi as these do not lie orthogonal to the direction of the scan. For vascular imaging, curved-plane reconstruction can be performed. This allows bends in a vessel to be "straightened" so that the entire length can be visualised on one image, or a short series of images. Once

neg: Appendicitis tomography (CT scan). CT scan has been shown to be more accurate than ultrasound in detecting acute appendicitis. However, ultrasound may be preferred as the first imaging test in children and pregnant women because of the risks associated with radiation exposure from CT scans. The standard treatment for acute appendicitis is surgical removal of the appendix. This may be done by an open incision in the abdomen (laparotomy) or through a few smaller incisions with the help of cameras (laparoscopy). Surgery decreases the risk of side effects or death associated with rupture of the appendix. Antibiotics may be equally effective

neg: CT scan call for increased CT quality assurance programs, while also noting that "while unnecessary radiation exposure should be avoided, a medically needed CT scan obtained with appropriate acquisition parameter has benefits that outweigh the radiation risks." Similar problems have been reported at other centers. These incidents are believed to be due to human error. In response to increased concern by the public and the ongoing progress of best practices, The Alliance for Radiation Safety in Pediatric Imaging was formed within the Society for Pediatric Radiology. In concert with The American Society of Radiologic Technologists, The American College of Radiology and The

neg: Dosimetry is kept below unacceptable levels and that tissue reactions are avoided. It is difficult to compare the stochastic risk from localised exposures of different parts of the body (e.g. a chest x-ray compared to a CT scan of the head), or to compare exposures of the same body part but with different exposure patterns (e.g. a cardiac CT scan with a cardiac nuclear medicine scan). One way to avoid this problem is to simply average out a localised dose over the whole body. The problem of this approach is that the stochastic risk of cancer induction varies from one tissue

neg: Midline shift an indication for neurosurgeons to take measures to monitor and control ICP. Immediate surgery may be indicated when there is a midline shift of over 5 mm. The sign can be caused by conditions including traumatic brain injury,stroke, hematoma, or birth deformity that leads to a raised intracranial pressure. Doctors detect midline shift using a variety of methods. The most prominent measurement is done by a computed tomography (CT) scan and the CT Gold Standard is the standardized operating procedure for detecting MLS. Since the midline shift is often easily visible with a CT scan, the high precision of Magnetic