Browsing by Author "Yaghmai, Vahid"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Impact of beta-blockade premedication on image quality of ECG-gated thoracic aorta CT angiography.
    (Acta radiologica (Stockholm, Sweden : 1987), 2014-12) Entezari, Pegah; Collins, Jeremy; Chalian, Hamid; Tore, Huseyin Gurkan; Carr, James; Yaghmai, Vahid
    BACKGROUND: Thoracic aortic aneurysm is one of the most common aorta pathologies worldwide, which is commonly evaluated by computed tomography angiography (CTA). One of the routine methods to improve the image quality of CTA is heart rate reduction prior to study by beta-blockade administration. PURPOSE: To assess the effect of beta-blockade on image quality of the ascending aorta in electrocardiography (ECG)-gated dual-source CTA (DSCTA) images. MATERIAL AND METHODS: In this retrospective study, ECG-gated thoracic aorta CTA images of 40 patients without beta-blocker administration were compared with ECG-gated images of 40 patients with beta-blockade. Images of the aorta were analyzed objectively and subjectively at three levels: sinus of Valsalva (sinus), sinotubular junction (STJ), and mid ascending aorta (MAA). Quantitative sharpness index (SI) and signal-to-noise ratio (SNR) were calculated and two radiologists evaluated the image quality using a 3-point scale. RESULTS: Mean heart rate in beta-blocker and non-beta-blocker groups was 61.7 beats per minute (bpm) (range, 58.1-63.9 bpm) and 72.9 bpm (range, 69.3-84.1 bpm), respectively (P < 0.05). Aorta wall SI, SNR, and subjective grading were comparable between the two groups at all three levels (P > 0.05). CONCLUSION: Beta-blocker premedication may not be necessary for imaging of ascending aorta with ECG-gated DSCTA.
  • Thumbnail Image
    ItemOpen Access
    Optimization of reduced-dose MDCT of thoracic aorta using iterative reconstruction.
    (Journal of computer assisted tomography, 2014-01) Töre, Hüseyin Gürkan; Entezari, Pegah; Chalian, Hamid; Gonzalez-Guindalini, Fernanda Dias; Botelho, Marcos Paulo Ferreira; Yaghmai, Vahid
    OBJECTIVE: To evaluate the contribution of iterative reconstruction on image quality of reduced-dose multidetector computed tomography of the thoracic aorta. METHODS: A torso phantom was scanned using two tube potentials (80 and 120 kVp) and five different tube currents (110, 75, 40, 20, and 10 mAs). All images were reconstructed with both filtered back projection (FBP) and iterative reconstruction. Aortic attenuation, image noise within the thoracic aorta, signal-to-noise ratio, and sharpness of the aortic wall were quantified in the phantom for the two reconstruction algorithms. Data were analyzed using paired t test. A value of P < 0.05 was considered significant. RESULTS: The aortic attenuation was similar for FBP and iterative reconstruction (P > 0.05). Image noise level was lower (P < 0.0001), and image sharpness was higher (P = 0.046) with iterative reconstruction. Signal-to-noise ratios were higher with iterative reconstruction compared with those with FBP (P < 0.0001). Signal-to-noise ratio at 80 kVp with iterative reconstruction (9.8 ± 4.4) was similar to the signal-to-noise ratio at 120 kVp with FBP (8.4 ± 3.3) (P = 0.196). CONCLUSIONS: Less image noise and higher image sharpness may be achieved with iterative reconstruction in reduced-dose multidetector computed tomography of the thoracic aorta.