Duplex systems often combine a pulsed Doppler with a spectral display and a real time imaging system. A duplex scanner has usually an imaging transducer or a separate transducer used to collect continuous wave or pulsed Doppler signals, either simultaneously with imaging or sequentially.

Dynamic focusing controls the axial position of the focus of an ultrasound beam. Dynamic focusing is often managed by controlling the phase of the signals detected by a transducer array.

See also Real-Time Transducer.

Echocardiography is the ultrasound examination of the heart. Depending on the used ultrasound system, echocardiograms can be two-dimensional slices or 3D real-time images of the heart. Based on the ultrasound principles the direction and speed of blood flow can be utilized e.g., to diagnose a leaking or stenosed valve or to identify intracardiac shunts.

Different types of echocardiography:
The transthoracic echocardiogram (images are taken through the chest wall) is a non-invasive, highly accurate and quick assessment of the overall health of the heart.
A more invasive method is to insert a specialized scope containing an echocardiography transducer (TEE probe) into the esophagus, and record images from there. The advantages are clearer images, since the transducer is closer to the heart.
Contrast echocardiogram (CE) is already a valuable tool to delineate endocardial borders, direct invasive procedures, detect intracardiac shunts, assess myocardial perfusion and viability, and quantify coronary flow reserve and blood volumes (see also hemoglobin). The mechanism of microbubble CE is based on the physical principles of rarefaction and compression, leading to volume pulsations of microbubbles, and it is this change that results in CE signal.
Stress echocardiograms are echocardiography exams used for detection of coronary artery disease.

See also Diastole, Bicycle Stress Echocardiography, Resistive Index, and M-Mode Echocardiography.

From Fukuda Denshi Co., Ltd.;
'Ultrasound Scanner with built-in Electrocardiograph
Realizes Diagnostic Ultrasound Imaging and 12-lead ECG examination with one unit
Large 10.4-inch TFT color LCD adopted
Cine memory of maximum 64 frames is available
Four types of Color Scale Imaging facilitate identification of delicate signals
High Frame Rate mode powerfully supports the Cardiovascular region
Image data filing in IC card for data management and for easy comparison with past data
M-mode continuous recording available with 3-ch ECG data from the cine memory
A highly precise and quality printer is integrated
Enhanced 12-lead ECG analysis report provided
Hybrid and compact design ensures space saving'

Frame averaging is a form of lowpass filtering. With frame averaging temporal variation are smoothed by addition of consecutive frames in a real-time mode.