CJEM Articles: computed tomography

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  • An international study of emergency physicians’ practice for acute headache management and the need for a clinical decision rule
    November 2009 11 6
    Anne-Maree Kelly, Catherine M. Clement, Debra Eagles, Ian G. Stiell, Jamie Brehaut, Jeffrey J. Perry, Suzanne Mason

    Objective: Patients with acute headache often undergo com puted tomography (CT) followed by a lumbar puncture to rule out subarachnoid hemorrhage. Our international study exam ined current practice, the perceived need for a clinical deci sion rule for acute headache and the required sensitivity for such a rule.

    Methods: We approached 2100 emergency physicians from 4 countries (Australia, Canada, the United Kingdom and the United States) to participate in our survey by sampling the membership of their emergency associations. We used a modified Dillman technique with 3-5 notifications and a prenotification letter employing a combination of electronic mail and postal mail. Physicians were questioned about neu rologically intact patients who presented with headache. Analysis included both descriptive statistics for the entire sample and stratification by country.

    Results: The total response rate was 54.7% (1149/2100). Respondents were primarily male (75.5%), with a mean age of 42.5 years and a mean 12.3 years of emergency depart ment (ED) experience. Of the physicians who responded, 49.5% thought all acute headache patients should be investi gated with CT and 57.4% felt CT should always be followed by lumbar puncture. Of the respondents, 95.7% reported they would consider using a clinical decision rule for patients with acute headache to rule out subarachnoid hemorrhage. Respondents deemed the median sensitivity required by such a rule to be 99% (interquartile range 98%-99%). Approxi mately 1 in 5 physicians suggested that 100% sensitivity was required.

    Conclusion: Emergency physicians report that they would welcome a clinical decision rule for headache that would determine which patients require costly or invasive tests to rule out subarachnoid hemorrhage. The required sensitivity of such a rule was realistic. These results will inform and inspire the development of clinical decision rules for acute headache in the ED.

  • The utility of multiple imaging modalities to diagnose acute aortic dissection
    January 2008 10 1
    James Ducharme, Katrina F. Hurley

    A 21-year-old man with Marfan syndrome and known aortic root aneurysm presented to our emergency department with symptoms suggestive of acute aortic dissection. The patient was hemodynamically stable and bilateral upper extremity blood pressures were similar. There was no mediastinal widening on portable chest radiograph. Both contrast CT and retrograde angiography of the aorta failed to identify dissection. Subsequent transesophageal echocardiography demonstrated a Stanford classification type A dissection. This case demonstrates the utility of multiple imaging modalities for identifying aortic dissection in high-risk patients.

  • Pediatric appendicitis: pathophysiology and appropriate use of diagnostic imaging
    November 2006 8 6
    Gerald D.G. Brennan

    Evaluating children for appendicitis can be extremely difficult, and various strategies have been developed to improve the precision of preoperative diagnosis. Among these, ultrasound and computed tomography (CT) are now widely used but remain controversial. Although CT scanning is superior to ultrasound in terms of diagnostic accuracy for appendicitis, the large dose of ionizing radiation from CT and the risk of subsequent radiation-induced malignancy (RIM) are of particular concern in pediatric patients. This article reviews the literature on the pathophysiology, morbidity and mortality of appendicitis, summarizes the data regarding pediatric imaging in appendicitis, provides a practical approach to imaging for clinicians who evaluate pediatric patients, and makes recommendations for reducing the risk of RIM in pediatric patients.

  • The role of lumbar puncture in the diagnosis of subarachnoid hemorrhage when computed tomography is unavailable
    March 2002 4 2
    David Mann

    Subarachnoid hemorrhage (SAH) is an important but uncommon condition in the differential diagnosis of acute headache. Most authorities recommend that patients with suspected SAH undergo noncontrast computed tomography (CT) as a first diagnostic intervention. If the results of the CT scan are negative, a lumbar puncture should be performed. Many nonurban Canadian hospitals do not have CT scanners and must either transfer patients or consider performing lumbar puncture prior to CT. In selected patients, performing lumbar puncture first may be an option, but timing of the procedure and the interpretation of results is important.