• CT Angiography Delivers High Diagnostic Accuracy but Also High Radiation Dose in Patients with Atrial Fibrillation
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  CT angiography delivers high diagnostic accuracy in patients with atrial fibrillation but is associated with significantly higher effective radiation dose (13 mSv) than in patients with sinus rhythm. In a study of 247 patients, Vorre and Abdulla found that CT coronary angiography is useful for excluding coronary artery disease in patients with atrial fibrillation (94% sensitivity), but heart rate reduction and use of prospective imaging protocols are important to reduce the radiation dose. The older age of patients with atrial fibrillation may make accumulated cancer risk less of a concern, but in patients who are younger and/or female, the issue may be of greater concern, the researchers concluded
  

  Intracranial Aneurysms: CT Angiography

  
  
  

   

  
  

    (a) Cranial anteroposterior 15° intraarterial DSA image shows a 2-mm aneurysm (arrow) of the right intracavernous carotid artery. (b) On the targeted maximum intensity projection CT angiogram, obtained in the same patient, at an angle comparable to that in a, the site of the 2-mm aneurysm of the right intracavernous carotid artery is indicated (arrow), but the aneurysm cannot be readily appreciated. (c) On the collapsed maximum intensity projection MR angiogram in the coronal plane (three-dimensional time-of-flight, 43/8, 20° flip angle, 20-cm field of view, one signal acquired, 256 × 512 matrix, acquisition time of 11 minutes 48 seconds), similar to findings in b, the site of the 2-mm aneurysm of the right intracavernous carotid artery is indicated (arrow), but the aneurysm cannot be readily appreciated.