Everything you need to know about Computed Tomography (CT) & CT Scanning

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Colon: Acute Abdomen Imaging Pearls - Learning Modules | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Colon ❯ Acute Abdomen
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  • The routine use of contrast (both oral and IV, and certainly rectal) is unnecessary for the majority of abdominal CT scans performed in the ED.  At least that is what the literature says over and over. Unfortunately, many radiologists disagree.  Is their objection based on a sound analysis of the literature?  Hardly.  In most cases it is a matter of personal preference.  They have been using contrast since their residency, or at least since CTs came on the scene, and just feel more comfortable with it. Have they made an honest effort to compare results with and without contrast ?  Probably not.  Do they care that oral contrast will add about two hours to an ED stay and, even when given, frequently doesn’t get to the cecum?  Probably not.
  •  “In the care of elderly patients, CT is accurate for diagnosing the cause of acute abdominal pain, particularly when it is of surgical origin, regardless of the availability of clinical and biologic findings. Thus CT interpretation should not be delayed until complete clinicobiologic data are available, and the images should be quickly transmitted to the emergency physician so that appropriate therapy can be begun.”
    Acute abdominal pain in elderly patients: effect of radiologist awareness of clinicobiologic information on CT accuracy
    Millet I et al.
    AJR Am J Roentgenol. 2013 Dec;201(6):1171-8
  •  “In both the entire cohort (87.4% vs. 85.3%, p = 0.07) and the surgical group (94% vs. 91%, p = 0.15), there was no significant difference in CT accuracy between diagnoses made when the radiologist was aware and those made when the radiologist was not aware of the clinicobiologic findings. Agreement between the CT diagnosis and the final diagnosis was excellent whether or not the radiologist was aware of the clinicobiologic findings.”
    Acute abdominal pain in elderly patients: effect of radiologist awareness of clinicobiologic information on CT accuracy
    Millet I et al.
    AJR Am J Roentgenol. 2013 Dec;201(6):1171-8
  •  “The cases of 333 consecutively registered patients 75 years old or older presenting to the emergency department with acute abdominal pain and who underwent CT were retrospectively reviewed by two radiologists blinded or not to the patient's clinicobiologic results. Diagnostic accuracy was calculated according to the level of correctly classified cases in both the entire cohort and a surgical subgroup and was compared between readings performed with and without knowledge of the clinicobiologic findings. Agreement between each reading and the reference diagnosis and interobserver agreement were assessed with kappa statistics.”
    Acute abdominal pain in elderly patients: effect of radiologist awareness of clinicobiologic information on CT accuracy
    Millet I et al.
    AJR Am J Roentgenol. 2013 Dec;201(6):1171-8
  • “Axial and coronal reformations of 64-section multidetector row CT have equal sensitivity and specificity for the diagnosis of acute abdominal pathology. However, coronal reformations improved the diagnostic confidence for all readers but most significantly for the least experienced. Therefore, radiology departments with residents should consider routinely generating coronal images in patients with acute abdominal pain.”
    Acute abdomen: Added diagnostic value of coronal reformations with 64-slice multidetector row computed tomography.
    Zangos S et al.
    Acad Radiol. 2007 Jan;14(1):19-27.
  • “For the most inexperienced reader, the coronal reformations were helpful in 95% of cases, while for the most experienced reader, the coronal reformations were helpful in 35% of the cases. The coronal images were deemed helpful in an average of 62.3% of the cases for the four readers. However, diagnosing subtle pathology in the abdominal wall was difficult on coronal reformations alone. Overall, coronal reformations improved diagnostic confidence and interobserver agreement over axial images alone for visualization of normal abdominal structures and in the diagnosis of abdominal pathology.”
    Acute abdomen: Added diagnostic value of coronal reformations with 64-slice multidetector row computed tomography.
    Zangos S et al.
    Acad Radiol. 2007 Jan;14(1):19-27.
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