We consider the problem of estimating the Doppler shift and rate of a linearly modulated digital signal subject to time-selective Rician fading. We derive the Cram er-Rao bounds for the parameters; we propose an estimator, based on the Higher-order Ambiguity Function (HAF), and show that it is consistent. We also establish some interesting results in the context of estimating the parameters of ...

This issue of the Journal contains two papers in which Doppler ultrasound was used in the first trimester of pregnancy. We must confess that we were in a deep quandary as to whether to proceed to publish them in Ultrasound in Obstetrics and Gynecology. This was not because they were of inferior quality. Both papers were well designed and addressed important aspects of early developmental physio...

ABSTRACT 2. JAMMING SIGNAL MODEL This paper considers the problem of detecting and classifying a radar target against jamming signals emitted by electronic countermeasure (ECM) systems. The detectionclassification algorithm proposed here exploits the presence in the jamming spectrum of spurious terms due to phase quantization performed by the radio frequency digital memory (DRFM) device. A puls...

BACKGROUND Quantification of regional myocardial function is a major unresolved issue in cardiology. We evaluated the accuracy of pulsed Doppler tissue imaging (DTI), a new echocardiographic technique, to quantify regional myocardial dysfunction induced by acute ischemia and reperfusion. METHODS AND RESULTS In nine open-chest anesthetized pigs, various degrees of regional wall motion abnormal...

Carotid duplex ultrasonography is a noninvasive technique for hemodynamically significant stenosis detection and cardiovascular risk estimation. Anatomic information of carotid arteries is provided by B-mode scanning. Hemodynamic features are displayed color-flow and pulsed Doppler imaging. Examination technique, normal carotid anatomy and flow pattern, and potential limitations are presented.

Transthoracic Doppler echocardiography (TDE) is a non-invasive and easy reproducible method to assess the left internal mammary artery (LIMA) graft patency after coronary artery bypass graft surgery (CABG). LIMA graft dysfunction is rare, its rate being 10% at 10 to 15 years after revascularization. The most common cause of graft dysfunction is the competitive flow with the native coronary arte...

Brain tumors arising in the neonatal period are rare and diagnosis is usually delayed. We encountered a case of choroid plexus papilloma (CPP) in a term newborn infant. The sonographic findings of this case demonstrated a striking similarity to intraventricular hemorrhage, an entity commonly seen in premature infants. A preoperative diagnosis was made, however, with the application of the pulse...

Tricuspid valve regurgitation was assessed quantitatively by measuring blood flow velocity in the vena cava using a pulsed Doppler velocimeter. A non-invasive index of regurgitation was obtained by calculating the ratio between the maximum amplitudes of the systolic and diastolic components of the velocity curves. The index was compared with the angiographic grading of regurgitation in 70 patie...

Objective. To show that pulsed ultrasound from a clinical ultrasonic imaging system can stimulate the fetus. Stimulation is defined mainly as increased fetal gross body movements in response to excitation. Methods. Fetuses of a group of 9 volunteer women (mean gestational age, 33.37 weeks; range, 25–40 weeks) were evaluated for body movement under 3 different conditions: (1) control, with no ul...

Accurate quantitation of mitral regurgitation offers a major clinical dilemma. The clinical clues depend largely on cardiac auscultation, the accuracy of which needs to be rigorously tested (1). Mitral regurgitation may not be associated with a clinically audible systolic murmur, and the auscultatory features of severity of regurgitation are generally based on increased volume of diastolic flow...