Abstract
Background & Purpose: Despite advances in diagnostic imaging and surgical therapy, the mortality of acute aortic dissection remains high. Early stage diagnosis and intervention can improve prognosis. While enhanced computed tomography (CT) is an effective diagnostic tool, characteristic imaging findings such as inward displacement of intimal calcifications and a hematoma-filled false lumen as a crescentic, high attenuation region following the aorta wall (crescentic high-attenuation hematoma) can also be observed on unenhanced CT. However, the incidence of such findings and the diagnostic accuracy of unenhanced CT have not been reported to date. The present study investigated the possibility of diagnosing aortic dissection using unenhanced CT.
Methods: A retrospective investigation was conducted using unenhanced CT images taken on admission to hospital of 44 patients diagnosed with acute aortic dissection between January 2008 and December 2009 after excluding from a total of 54 patients two patients who had not undergone enhanced CT, five patients who had cardiopulmonary arrest on arrival, and three patients who had been transferred to our hospital after being diagnosed with dissection at another hospital. Any of the following unenhanced CT findings was considered indicative of acute aortic dissection: inward displacement of intimal calcifications, crescentic high-attenuation hematoma, a visible flap, or pericardial hemorrhage. The findings were also compared with those of 37 non-dissection patients.
Results: Inward displacement of intimal calcifications and a crescentic high-attenuation hematoma were present in 29 (65.9%) and 33 (75.0%) patients, respectively, significantly more than in the non-dissection patients (p<0.01). A visible flap and pericardial hemorrhage were present in 4 (9.1%) and 5 (11.4%) patients, respectively, but no significant difference with respect to the non-dissection patients was observed due to the low incidence. Unenhanced CT diagnosis of aortic dissection was possible in 40 of 44 (90.9%) patients.
Conclusions: Unenhanced CT is useful for the diagnosis of aortic dissection.
