Article

Thoracic aorta: prospective electrocardiographically triggered CT angiography with dual-source CT--feasibility, image quality, and dose reduction.

Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Strasse 55, 79104 Freiburg, Germany.
Radiology (Impact Factor: 6.34). 02/2010; 255(1):207-17. DOI: 10.1148/radiol.09090860
Source: PubMed

ABSTRACT To prospectively investigate the feasibility, image quality, and radiation dose for prospective electrocardiographically (ECG) triggered sequential dual-source computed tomographic (CT) angiography of the thoracic aorta in comparison to retrospective ECG-gated helical dual-source CT angiography.
This study was approved by the institutional review board; informed consent was obtained. One hundred thirty-nine patients referred for ECG-assisted dual-source CT angiography of the thoracic aorta were prospectively enrolled. Inclusion criteria were stable sinus rhythm and heart rate of 80 beats per minute or less. Tube voltage was adjusted to body mass index (< 25.0 kg/m(2), 100 kV, n = 58; > or = 25.0 kg/m(2), 120 kV, n = 81). In both cohorts, patients were randomly assigned to prospective or retrospective ECG-assisted data acquisition. In both groups, tube current (250 mAs per rotation) was centered at 70% of the R-R cycle. The presence of motion or stair-step artifacts of the thoracic aorta was independently assessed by two readers. Effective radiation dose was calculated from the dose-length product.
Subjective scoring of motion and stair-step artifacts was equivalent for both techniques. Scan length was not significantly different (23.8 cm +/- 2.4 [standard deviation] vs 23.7 cm +/- 2.5 for prospective and retrospective ECG-triggered CT angiography, respectively; P = .54). Scanning time was significantly longer for prospective ECG-triggered CT angiography (18.8 seconds +/- 3.4 vs 16.4 seconds +/- 3.3, P < .001). Mean estimated effective dose was significantly lower for prospective data acquisition (100 kV, 1.9 mSv +/- 0.5 vs 4.1 mSv +/- 0.7, P < .001; 120 kV, 5.3 mSv +/- 1.1 vs 9.5 mSv +/- 3.0, P < .001).
Prospective ECG-gated sequential dual-source CT angiography of the thoracic aorta is feasible, despite the slightly longer acquisition time. Thus, motion-free imaging of the thoracic aorta is possible at significantly lower radiation exposure than retrospective ECG-gated helical dual-source CT angiography in certain patients with a regular heart rate.

0 Bookmarks
 · 
72 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the feasibility, image quality and radiation dose for high-pitch dual-source CT angiography (CTA) of the whole aorta without ECG synchronisation. Each group of 40 patients underwent CTA either on a 16-slice (group 1) or dual-source CT device with conventional single-source (group 2) or high-pitch mode with a pitch of 3.0 (group 3). The presence of motion or stair-step artefacts of the thoracic aorta was independently assessed by two readers. Subjective and objective scoring of motion and artefacts were significantly reduced in the high-pitch examination protocol (p < 0.05). The imaging length was not significantly different, but the imaging time was significantly (p < 0.001) shorter in the high-pitch group (12.2 vs. 7.4 vs. 1.7 s for groups 1, 2 and 3). The ascending aorta and the coronary ostia were reliably evaluable in all patients of group 3 without motion artefacts as well. High-pitch dual-source CT angiography of the whole aorta is feasible in unselected patients. As a significant advantage over regular pitch protocols, motion-free imaging of the aorta is possible without ECG synchronisation. Thus, this CT mode bears potential to become a standard CT protocol before trans-catheter aortic valve implantation (TAVI).
    European Radiology 09/2011; 22(1):129-37. · 4.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the feasibility of using a prospective ECG-gated wide-volume protocol in CT angiography (CTA) of the whole aorta and coronary arteries (CA). A total of 61 consecutive patients with suspected acute aortic diseases underwent CTA of the whole aorta using a prospective ECG-gated wide-volume CT protocol without heart rate (HR) control. The exposure window was set at 40-50 % of R-R interval (HR ≥70 bpm) or 70-80 % of R-R interval (HR <70 bpm) in a single heartbeat. The image quality of the ascending aorta, aortic valve and CA was evaluated for motion artefacts. The mean attenuation was measured at different levels of the aorta. The radiation dose and contrast medium volume were recorded. All of the examinations were performed successfully. The image quality was acceptable in the ascending aorta, aortic valve (100 %) and CA (94.4 %). The mean radiation dose was 18.42 ± 5.02 mSv. Of 61 patients, 14 were diagnosed with aortic aneurysm and 35 were diagnosed with aortic dissection or intramural haematoma. Coronary artery stenosis was detected in 12 patients. For patients with aortic diseases, CTA of the whole aorta using a prospective ECG-gated wide-volume protocol has the potential to provide additional information about the CA and aortic valve with lower radiation exposure. KEY POINTS : • Computed tomography is increasingly used to assess the coronary arteries and the aorta. • This novel study investigates prospective ECG-gated wide-volume 320-row CT angiography. • Heart rate variation did not influence the image quality of coronary arteries. • Abnormalities in the coronary arteries and aorta can be simultaneously assessed noninvasively.
    European Radiology 06/2012; 22(11):2432-40. · 4.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: CT angiography (CTA) is a well established first line imaging modality used to assess diseases of the vasculature. In recent years new technologies, such as cardiac-gating, dual energy, high-pitch helical scanning, and iterative reconstruction have offered new and innovative means of imaging diseases of the thoracic aorta. In addition, recent research has further deepened our understanding of many of these well known diseases. A brief review of new CT technologies, our new knowledge of aortic diseases, and how to utilize modern CTA techniques to evaluate diseases of the aorta is presented herein.
    Current Cardiovascular Imaging Reports 5(5).