INTRODUCTION AND OBJECTIVES To determine whether the reproducibility of left ventricular outflow tract (LVOT) area measurement is greater with three-dimensional echocardiographic (3D-echo) planimetry than with conventional 2D-echo. To determine the LVOT circularity index by means of 3D-echo. To determine the usefulness of measuring the LVOT area by 3D-echo for quantifying the severity of valvul...

PURPOSE To compare the sensitivity of conventional spin-echo, fast spin-echo, fast fluid-attenuated inversion recovery (FLAIR), and turbo gradient spin-echo MR sequences in the detection of multiple sclerosis lesions. METHODS Conventional spin-echo, fast spin-echo, fast FLAIR, and turbo gradient spin-echo sequences were performed on a 1.0-T MR imager in seven patients with clinically definite...

This paper presents evaluations of a nonlinear-echo suppressor based on a frequency-domain model of highly nonlinear residual echo. The residual-echo model, which is based on correlation between spectral amplitudes of residual echo and echo replica, is evaluated by a regression analysis. The results justify the nonlinear-echo suppressor structure. The output signals are subjectively evaluated b...

Acoustic echo arises due to acoustic coupling between the loudspeaker and the microphone of a communication device. Acoustic echo cancellation and suppression techniques are used to reduce the acoustic echo. In this work we propose to first cancel the early echo, which is related to the early part of the echo path, and subsequently suppress the late echo, which is related to the later part of t...

PURPOSE To compare lesion enhancement after injection of gadopentetate dimeglumine on spin-echo and gradient-echo T1-weighted images. METHODS A total of 48 contrast-enhancing intracranial lesions were evaluated using a spin-echo and two gradient-echo T1-weighted pulse sequences. Percent contrast, contrast-to-noise, and signal-to-noise measurements were made on the spin-echo T1-weighted, three...

Acoustic echoes arise whenever there is acoustic coupling between a loudspeaker and a microphone. A traditional solution for eliminating the undesired echo signal is an acoustic echo canceler (AEC), which identifies the echo path between a loudspeaker and a microphone by means of an adaptive filter. The echo signal can be canceled successfully when the modeling filter approaches the true echo p...

شرایط افروزش و اشتعال سوخت‌های گداخت هسته‌ای در حضور ناخالص­‌ها، یکی از موارد مهمی است که طراحی قرص‌های سوخت باید مورد توجه قرار گیرد. این مقاله اثر ناخالصی هسته سنگین طلا بر کلیه فرایندهای احتراق پلاسمای غیرتعادلی دوتریم- تریتیم مدل چهار دمایی آن شکل تابع توزیع انرژی رفتار فوتون‌ها تأثیر می‌گذارد بررسی گرفته است. مطالعه شامل اثرات منفی سوخت، طول زمان تشکیل لکه داغ نتایج محاسبات عددی به­ دست آم...