TY - JOUR
T1 - Parametric harmonic-to-fundamental ratio contrast echocardiography
T2 - A novel approach to identification and accurate measurement of left ventricular area under variable levels of ultrasound signal attenuation
AU - Yoshifuku, Shiro
AU - Chen, Shigao
AU - McMahon, Eileen M.
AU - Yoshikawa, Akiko
AU - Sengupta, Partho P.
AU - Korinek, Josef
AU - Belohlavek, Marek
PY - 2007/5
Y1 - 2007/5
N2 - Objectives: We introduced a harmonic-to-fundamental ratio (HFR) of the radiofrequency (RF) signals that reduces confounding effects of attenuation. We studied whether HFR analysis of RF signals received from contrast microbubbles allows accurate measurement of the left ventricular (LV) cavity area under varying levels of attenuation. Background: Attenuation is a fundamental problem in ultrasound imaging and limits the use of clinical echocardiography. Methods: RF data from short axis systolic and diastolic scans were obtained from 14 open-chest dogs following left-atrial bolus of Optison. Attenuation was induced by interposed silicone pads calibrated to induce 7 dB or 14 dB reductions of the backscattered RF signal. RF images were reconstructed from the RF signals, HFR values calculated for each image pixel for 0 dB, 7 dB and 14 dB attenuation conditions, and LV area obtained by summation of "LV cavity pixels". A reference LV cavity area was obtained from endocardial border tracings in enhanced scans by experts. Results: Correlation of the HFR-defined and reference areas at systole was R = 0.95, R = 0.94, and R = 0.91 for 0 dB, 7 dB and 14 dB levels of attenuation, respectively, and at diastole was R = 0.95 for 0 dB, 7 dB and 14 dB levels of attenuation. The mean difference from both systolic and diastolic values was <1.45 cm2 (i.e. negligible) in all attenuation settings. Conclusion: Our novel HFR method supports precise measurement of the LV cavity area in contrast images with simulated high attenuation of ultrasound signals.
AB - Objectives: We introduced a harmonic-to-fundamental ratio (HFR) of the radiofrequency (RF) signals that reduces confounding effects of attenuation. We studied whether HFR analysis of RF signals received from contrast microbubbles allows accurate measurement of the left ventricular (LV) cavity area under varying levels of attenuation. Background: Attenuation is a fundamental problem in ultrasound imaging and limits the use of clinical echocardiography. Methods: RF data from short axis systolic and diastolic scans were obtained from 14 open-chest dogs following left-atrial bolus of Optison. Attenuation was induced by interposed silicone pads calibrated to induce 7 dB or 14 dB reductions of the backscattered RF signal. RF images were reconstructed from the RF signals, HFR values calculated for each image pixel for 0 dB, 7 dB and 14 dB attenuation conditions, and LV area obtained by summation of "LV cavity pixels". A reference LV cavity area was obtained from endocardial border tracings in enhanced scans by experts. Results: Correlation of the HFR-defined and reference areas at systole was R = 0.95, R = 0.94, and R = 0.91 for 0 dB, 7 dB and 14 dB levels of attenuation, respectively, and at diastole was R = 0.95 for 0 dB, 7 dB and 14 dB levels of attenuation. The mean difference from both systolic and diastolic values was <1.45 cm2 (i.e. negligible) in all attenuation settings. Conclusion: Our novel HFR method supports precise measurement of the LV cavity area in contrast images with simulated high attenuation of ultrasound signals.
KW - Contrast echocardiography
KW - Fundamental signal
KW - Harmonic signal
KW - Left ventricle cavity area
KW - Radiofrequency signal
KW - Ultrasound attenuation
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U2 - 10.1016/j.ultras.2006.12.002
DO - 10.1016/j.ultras.2006.12.002
M3 - Article
C2 - 17276474
AN - SCOPUS:34247473057
SN - 0041-624X
VL - 46
SP - 109
EP - 118
JO - Ultrasonics
JF - Ultrasonics
IS - 2
ER -