Imaging the thoracic aorta

Comparison of feasibility and accuracy of transthoracic echocardiography versus computed tomography in patients with known ascending aortic aneurysm

Aortic valve diseases, hypertension, and connective tissue disorders may be causes of ascending aortic aneurysms. Aortic enlargement monitoring is essential for surgical timing and for operative design. In this regard, several imaging techniques may have limitations: magnetic resonance is not widespread and is expensive, computed tomography uses radiation, and transesophageal echocardiography is a semi-invasive method. The aim of this study was to analyze the feasibility of transthoracic echocardiography in the evaluation of aortic dimensions and its accuracy in comparison with multidetector computed tomography. In 44 patients with known ascending aortic aneurysms, transthoracic echocardiographic and computed tomographic measurements were obtained and compared at different levels: the annulus, sinuses of Valsalva, sinotubular junction, ascending aorta, and aortic arch. Transthoracic echocardiographic diameters were obtained in all patients, apart from the aortic arch, which was measured in 40 cases. Transthoracic echocardiographic and computed tomographic diameters correlated significantly (p <0.001), with very small SEEs: for the annulus, r = 0.846 (SEE 0.37); for the sinuses of Valsalva, r = 0.967 (SEE 0.35); for the sinotubular junction, r = 0.965 (SEE 0.33); for the ascending aorta, r = 0.976 (SEE 0.41); and for the aortic arch, r = 0.87 (SEE 0.50). In conclusion, transthoracic echocardiography is a feasible and accurate technique for the assessment and follow-up of thoracic aortic diameters in patients with ascending aortic aneurysms.

Spiral CT in acute non-cardiac chest pain

AIM

Spiral CT in acute non-cardiac chest pain is usually requested to diagnose aortic dissection but a spectrum of other cardiovascular diseases may simulate this. The purpose of this study was to assess the impact of spiral computed tomography (CT) in patients with suspected aortic dissection and to determine the nature and frequency of other disorders simulating it.

METHODS

Over a 26-month period, all patients undergoing CT for suspected acute aortic dissection were recruited. CT was performed using a standard protocol. The CT examinations and reports were reviewed along with other relevant imaging, clinical data, surgical findings and post-mortem results. The pattern of diagnoses and their associations were evaluated.

RESULTS

Seventy-six CT examinations were performed on 70 patients of whom 47 were male. The age of the patients ranged from 24 to 84. Seven patients had previously undergone cardiothoracic surgery. Twenty-four patients had normal CT findings; 46 patients (66%) had abnormal findings. Seventy-three significant pathologies were identified including thoracic aortic aneurysm (16 cases), aortic dissection (14 cases), acute intramural aortic haematoma (nine cases), aortic rupture (eight cases), atherosclerosis (four cases) and penetrating atheromatous ulcer (two cases), pulmonary embolus (four cases), pericardial disease (12 cases) and complications following surgery (three cases). The majority of patients had a life-threatening disease. Five patients without dissection had CT findings that explained clinical pulse deficits.

CONCLUSION

Sudden onset non-cardiac, non-pleuritic chest pain is common to several acute cardiovascular disorders. Patients have a high incidence of life-threatening disease. Of this group, classic aortic dissection is the most common diagnosis but comprises a minority of cases. Spiral CT is a reliable diagnostic test but requires conscientious technique for optimum sensitivity and accuracy. Most patients will have abnormal CT findings.