Accuracy of Spiral Computed Tomographic Angiography in the Evaluation of Aortic Dissection Among Patients with Aortic Disease: a Prospective Study

Background --- Aortic dissection is the most common acute illness of the aorta. It is a life-threatening medical condition associated with high mortality and morbidity rates. Traditionally, aortography is used to evaluate the presence of this disease entity. However, computed tomographic angiography is now preferred because it is less invasive and its ability to detect associated findings that could lead to the diagnosis of aortic dissection. This study aims to determine the accuracy of spiral computed tomography in the diagnosis of aortic dissection in patients with aortic disease. Methods --- This is a validation study of patients who were referred to the CT/MRI section of the Philippine Heart Center for the evaluation of aortic disease. Population includes all patients who underwent Computed Tomographic Angiography (CTA) and subsequent aneurysmal repair. CTA were reviewed to evaluate the following: site and extent of aortic dissection, size of aortic aneurysm, aortic wall calcification, presence of luminal thrombus, and aortic branch involvement in relation to aortic dissection. The accuracy of CTA was determined using surgery/ histopathology or angiography as gold standard. Results --- We enrolled 64 patients who had aortic dissection and fulfilled the eligibility criteria for the study. The predominant CTA finding is the presence of aneurysm followed by the presence of intimal calcification and thrombus formation. Most of these aneurysms are fusiform type and are commonly seen in the infrarenal segment. Among the 64 patients, dissection was correctly diagnosed by CTA in 18 patients, with 1 false positive finding. The most commonly encountered type of dissection is DeBakey1. We observed aortic branch extension of dissection in 4 patients and hemopericardium in 3 patients. The sensitivity of CTA is 100%, specificity is 97.8% positive predictive value is 94.7% and negative predicitive value is 100%. Conclusion --- With high sensitivity, specificity, positive predictive value, and negative predictive value, CTA is a useful primary and maybe the only imaging modality needed in the evaluation of aortic dissection. Phil Heart Center J 2012; 16(2):55-64