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Low radiation dose non-contrast cardiac CT: is it of value in the evaluation of mechanical aortic valve.

Abstract

BACKGROUND
Prosthetic bileaflet mechanical valve function has been traditionally evaluated using echocardiography and fluoroscopy. Multidetector computed tomography (MDCT) is a novel technique for cardiac evaluation.
PURPOSE
To evaluate bileaflet mechanical aortic valves using a low-milliampere (mA), non-contrast MDCT protocol with a limited scan range.
MATERIAL AND METHODS
Forty patients with a bileaflet mechanical aortic valve were evaluated using a non-contrast, low-mA, ECG-gated 64 MDCT protocol with a limited scan range. MDCT findings of opening and closing valve angles were correlated to fluoroscopy and echocardiography. Also, the valve visibility was evaluated on MDCT and fluoroscopy according to a 3-point grading scale.
RESULTS
The visualization score with the MDCT was significantly superior to the fluoroscopy (3 vs. 2.7). A strong correlation was noted between the opening (r = 0.82) and closing (r = 0.96) valve angles with MDCT and fluoroscopy without a statistically significant difference (P = 0.31 and 0.16, respectively). The mean effective radiation dose of the suggested protocol was 4 ± 0.5 mSv. Five valves were evaluated using transesophageal echocardiography because the valves were difficult to evaluate with transthoracic echocardiography, and all of these valves were evaluated optimally with MDCT. A high-pressure gradient was noted in nine valves, and the MDCT showed that seven of these valves inadequately opened, and two valves opened well, which resulted in patient valve mismatch. Incomplete valve closure was noted in five valves, and the echocardiography showed significant transvalvular regurgitation in all five valves.
CONCLUSION
MDCT can provide a precise measurement of valve function and can potentially evaluate high-pressure gradients and transvalvular regurgitation.

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  • Publisher Full Text
  • Authors

    Bazeed MF, Moselhy MS, Rezk AI, Al-Murayeh MA

    Institution

    Department of Diagnostic Radiology, Faculty of Medicine, Mansoura University, Egypt. m_bazeed@yahoo.com

    Source

    Acta radiologica (Stockholm, Sweden : 1987) 53:4 2012 May 1 pg 389-93

    MeSH

    Adult
    Aortic Valve
    Cardiac-Gated Imaging Techniques
    Echocardiography, Transesophageal
    Female
    Fluoroscopy
    Heart Valve Prosthesis
    Humans
    Male
    Prospective Studies
    Radiation Dosage
    Radiographic Image Interpretation, Computer-Assisted
    Tomography, X-Ray Computed

    Pub Type(s)

    Comparative Study
    Journal Article

    Language

    eng

    PubMed ID

    22422269