Items in AFP with MESH term: Tomography, X-Ray Computed
ABSTRACT: Risks of diagnostic imaging include cancer from radiation exposure and nephrogenic systemic fibrosis. The increase in volume of imaging between 1980 and 2006 has led to a sixfold increase in annual per capita radiation exposure. It is predicted that 2 percent of future cancers will be caused by radiation from computed tomography (CT) exposure. Gadolinium contrast media should be avoided in patients with stage 4 or 5 chronic kidney disease because of the risk of nephrogenic systemic fibrosis. Appropriate use of imaging based on guidelines for specific clinical conditions can reduce these risks. Although noncontrast CT of the head is needed to rule out bleeding in patients with suspected stroke within the first three hours of symptom onset, diffusion-weighted imaging with magnetic resonance of the head and neck is superior to CT within three to 24 hours of symptom onset. Headache merits neuroimaging in special circumstances only. Sestamibi radioisotope has less radiation than thallium for myocardial perfusion imaging. Use of intravenous contrast media with abdominopelvic CT significantly increases the diagnostic accuracy for appendicitis. Cholescintigraphy has better discrimination to diagnose acute cholecystitis than CT in patients with equivocal ultrasonography results. Limited three-view intravenous urography is recommended in pregnancy to evaluate urolithiasis if initial ultrasonography findings are negative or equivocal. Given that many asymptomatic adults have abnormal findings on lumbar spine magnetic resonance imaging, this modality generally should not be performed for nonspecific chronic low back pain in the absence of red flags. Whole body scanning is not supported by current evidence.
Gastric Ulcer and Abnormal Findings on CT - Photo Quiz
Evaluation of First Nonfebrile Seizures - Article
ABSTRACT: Nonfebrile seizures may indicate underlying disease or epilepsy. The patient history can often distinguish epileptic seizures from nonepileptic disorders by identifying the events directly preceding the convulsion, associated conditions, and details of the seizure, including triggers, length, and type of movements. Laboratory testing, lumbar puncture, and neuroimaging may be indicated depending on the presentation, suspected etiology, and patient’s age. Electroencephalography should be performed 24 to 48 hours after a first seizure because of its substantial yield and ability to predict recurrence. Neuroimaging is recommended for adults, infants, and children who have cognitive or motor developmental delay or a focal seizure. Neuroimaging may be scheduled on an outpatient basis for patients with stable vital signs who are awake and have returned to neurologic baseline. Emergent neuroimaging should be performed in patients with persistent decreased mental status or a new focal neurologic abnormality. Although magnetic resonance imaging is generally preferred to head computed tomography because of its greater sensitivity for intracranial pathology, computed tomography should be performed if intracranial bleeding is suspected because of recent head trauma, coagulopathy, or severe headache. Treatment with an antiepileptic drug after a first seizure does not prevent epilepsy in the long term, but it decreases the short-term likelihood of a second seizure. Adults with an unremarkable neurologic examination, no comorbidities, and no known structural brain disease who have returned to neurologic baseline do not need to be started on antiepileptic therapy. Treatment decisions should weigh the benefit of decreased short-term risk of recurrence against the potential adverse effects of antiepileptic drugs.
ABSTRACT: Patients with wrist pain commonly present with an acute injury or spontaneous onset of pain without a definite traumatic event. A fall onto an outstretched hand can lead to a scaphoid fracture, which is the most commonly fractured carpal bone. Conventional radiography alone can miss up to 30 percent of scaphoid fractures. Specialized views (e.g., posteroanterior in ulnar deviation, pronated oblique) and repeat radiography in 10 to 14 days can improve sensitivity for scaphoid fractures. If a suspected scaphoid fracture cannot be confirmed with plain radiography, a bone scan or magnetic resonance imaging can be used. Subacute or chronic wrist pain usually develops gradually with or without a prior traumatic event. In these cases, the differential diagnosis is wide and includes tendinopathy and nerve entrapment. Overuse of the muscles of the forearm and wrist may lead to tendinopathy. Radial pain involving mostly the first extensor compartment is commonly de Quervain tenosynovitis. The diagnosis is based on history and examination findings of a positive Finkelstein test and a negative grind test. Nerve entrapment at the wrist presents with pain and also with sensory and sometimes motor symptoms. In ulnar neuropathies of the wrist, the typical presentation is wrist discomfort with sensory changes in the fourth and fifth digits. Activities that involve repetitive or prolonged wrist extension, such as cycling, karate, and baseball (specifically catchers), may increase the risk of ulnar neuropathy. Electrodiagnostic tests identify the area of nerve entrapment and the extent of the pathology.
Evaluation of Hip Pain in Older Adults - FPIN's Clinical Inquiries
ABSTRACT: Transient ischemic attack is defined as transient neurologic symptoms without evidence of acute infarction. It is a common and important risk factor for future stroke, but is greatly underreported. Common symptoms are sudden and transient, and include unilateral paresis, speech disturbance, and monocular blindness. Correct and early diagnosis of transient ischemic attack versus mimicking conditions is important because early interventions can significantly reduce risk of future stroke. Nonspecific symptoms and gradual onset are more likely with mimics than with true transient ischemic attacks. Transient ischemic attacks are more likely with sudden onset, focal neurologic deficit, or speech disturbance. Urgent evaluation is necessary in patients with symptoms of transient ischemic attack and includes neuroimaging, cervicocephalic vasculature imaging, cardiac evaluation, blood pressure assessment, and routine laboratory testing. The ABCD2 (age, blood pressure, clinical presentation, diabetes mellitus, duration of symptoms) score should be determined during the initial evaluation and can help assess the immediate risk of repeat ischemia and stroke. Patients with higher ABCD2 scores should be treated as inpatients, whereas those with lower scores are at lower risk of future stroke and can be treated as outpatients.
When to Order Contrast-Enhanced CT - Article
ABSTRACT: Family physicians often must determine the most appropriate diagnostic tests to order for their patients. It is essential to know the types of contrast agents, their risks, contraindications, and common clinical scenarios in which contrast-enhanced computed tomography is appropriate. Many types of contrast agents can be used in computed tomography: oral, intravenous, rectal, and intrathecal. The choice of contrast agent depends on route of administration, desired tissue differentiation, and suspected diagnosis. Possible contraindications for using intravenous contrast agents during computed tomography include a history of reactions to contrast agents, pregnancy, radioactive iodine treatment for thyroid disease, metformin use, and chronic or acutely worsening renal disease. The American College of Radiology Appropriateness Criteria is a useful online resource. Clear communication between the physician and radiologist is essential for obtaining the most appropriate study at the lowest cost and risk to the patient.
ABSTRACT: Swift diagnosis and treatment are critical for good outcomes in patients with nontraumatic subarachnoid hemorrhage, which is usually caused by a ruptured aneurysm. This type of stroke often results in death or disability. Rates of misdiagnosis and treatment delays for subarachnoid hemorrhage have improved over the years, but these are still common occurrences. Subarachnoid hemorrhage can be more easily diagnosed in patients who present with severe symptoms, unconsciousness, or with thunderclap headache, which is often accompanied by vomiting. The diagnosis is more elusive in patients who present in good condition, yet these patients have the best chance for good outcome if they are correctly diagnosed at the time of presentation. Physicians should be alert for warning headaches, which are often severe, and headaches that feel different to the patient. Other symptoms may include nausea, vomiting, impaired consciousness, nuchal rigidity, orbital pain, focal neurologic deficits, dysphasia, lightheadedness, and dizziness. The most important risk factors for subarachnoid hemorrhage include cigarette smoking, hypertension, heavy alcohol use, and personal or family history of aneurysm or hemorrhagic stroke. The first step in the diagnostic workup is noncontrast computed tomography of the head. If computed tomography is negative or equivocal, a lumbar puncture should be performed. Subsequent imaging may include computed tomographic angiography, catheter angiography, and magnetic resonance angiography.