The authors compared prospective (n = 20) and retrospective (n = 20) electrocardiography (ECG)-assisted multi-detector row computed tomography (CT) with non-ECG-assisted multi-detector row CT (n = 20) of the thoracic aorta with regard to reduction of motion-related artifacts. Image quality was rated for transverse source and sagittal oblique images of the thoracic aorta, including the aortic valve. ECG-assisted multi-detector row CT compared with non-ECG-assisted multi-detector row CT showed a significant reduction in motion artifacts for the entire thoracic aorta.
"Subtle dissections limited to the aortic root and proximal aorta can be dismissed as artefacts. EKG-gated or triggered CT scans reduce motion artefacts and have been shown to improve diagnostic accuracy [10,11], but this imaging modality is not routinely used in all centers. Second imaging tests are frequently obtained in cases of suspected aortic dissection, with echocardiography, either transthoracic or transesophageal, being the most common second modalities used . "
[Show abstract][Hide abstract] ABSTRACT: Though computed tomographic angiography has very high sensitivity and specificity to diagnose acute aortic dissection, false-negative studies can occur and secondary tests may be required to make the diagnosis.
We report the case of a 57-year-old Caucasian man with a typical presentation for acute type A aortic dissection in whom the initial non-cardiac gated computed tomographic angiogram was negative, leading to a delay in surgical management. Transesophageal echocardiography and post hoc 3D reconstruction of the original computed tomographic scan revealed a dissection flap confined to the aortic root, immediately superior to the sinuses of Valsalva and masquerading as part of the aortic valve apparatus.
This case demonstrates that false-negative computed tomographic angiograms taken to rule out type A aortic dissection can occur and that secondary imaging tests, such as echocardiography, should be performed in cases in which the pre-test probability of aortic dissection is high. Cardiac gating of computed tomographic angiograms to exclude aortic dissection may enhance diagnostic accuracy.
Journal of Medical Case Reports 12/2013; 7(1):285. DOI:10.1186/1752-1947-7-285
"Currently, multislice CT imaging is the method of choice for diagnosis of aortic dissection due to its high spatial and temporal resolution with nearly 100% sensitivity and specificity [26-28]. However, when involving the ascending aorta, type I and type II dissection imaging, even with 64 slices spiral CT and earlier DSCT, the pulsation artifact of the root-proximal ascending level cannot be eliminated [9,10]. Thus, the intimal tear location and intimal flap cannot be clearly displayed and cannot accurately measured. "
[Show abstract][Hide abstract] ABSTRACT: Aortic dissection is a lift-threatening medical emergency associated with high rates of morbidity and mortality. The incidence rate of aortic dissection is estimated at 5 to 30 per 1 million people per year. The prompt and correct diagnosis of aortic dissection is critical. This study was to compare the ascending aortic image quality and the whole aortic radiation dose of high-pitch dual-source CT angiography and conventional dual-source CT angiography.
A total of 110 consecutive patients with suspected aortic dissection and other aortic disorders were randomly divided into two groups. Group A underwent traditional scan mode and Group B underwent high-pitch dual-source CT scan mode. The image quality and radiation dose of two groups were compared.
Close interobserver agreement was found for image quality scores (kappa = 0.87). The image quality of ascending aorta was significantly better in the high-pitch group than in the conventional group (2.78 +/- 0.46 vs 1.57 +/- 0.43, P < 0.001). There was no significant difference of the CT attenuation values, the aortic image noise and SNR between two groups. The mean radiation dose of high-pitch group was also significantly lower than that of conventional group (2.7 +/- 0.6 mSv vs. 3.9 +/- 0.9 mSv, P < 0.001).
High-pitch dual-source CT angiography of the whole aorta can provide motion-artifact-free imaging of the ascending aorta at a low radiation dose compared to conventional protocol.
Journal of Cardiothoracic Surgery 12/2013; 8(1):228. DOI:10.1186/1749-8090-8-228 · 1.03 Impact Factor
"Multidetector-row CT (MDCT) of the aorta is more commonly used than MRI because of the rapid scan times and wider availability. CT is usually performed with electrocardiographic (ECG) gating in order to avoid motion artifacts in the ascending aorta that might produce a false appearance of dissection or result in inaccurate measurements . Since ECG gating is associated with significant increase in radiation dose, various dose reduction techniques such as prospective ECG triggering, ECG-based tube current modulation, automatic exposure control, lower peak kilovoltage (kVp), and iterative reconstruction algorithms are used [3–6]. "
[Show abstract][Hide abstract] ABSTRACT: Computed tomography (CT) and magnetic resonance imaging (MRI) are the most commonly used imaging examinations to evaluate thoracic aortic diseases because of their high spatial and temporal resolutions, large fields of view, and multiplanar imaging reconstruction capabilities. CT and MRI play an important role not only in the diagnosis of thoracic aortic disease but also in the preoperative assessment and followup after treatment. In this review, the CT and MRI appearances of various acquired thoracic aortic conditions are described and illustrated.
International journal of vascular medicine 12/2013; 2013(6):797189. DOI:10.1155/2013/797189
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