The 2D-mode (2-Dimensional-mode) is a spatially oriented B-mode (brightness) ultrasound. The imaged structures are displayed 2 dimensional as a function of depth and width. The brightness level is based on the echo signal amplitude.
Most of the ultrasound devices in medical imaging are 2D real-time scanner. The image is created by a rapidly back and forth swept sound beam over the region of interest.

See also Gray Scale.

Ultrasound technology with its advancements is vital for delivering high-quality patient care. Innovations including high-frequency ultrasound, 3D//4D imaging, contrast enhanced ultrasound, elastography, and point-of-care ultrasound, have expanded the capabilities of ultrasound imaging and improved diagnostic accuracy.
B-Mode imaging, also known as brightness mode, is the fundamental technique in ultrasound imaging. It produces two-dimensional images based on the echoes received from tissues and organs. Understanding the principles of B-Mode imaging, such as gain adjustment, depth control, and image optimization, is crucial for obtaining diagnostically valuable images. M-Mode imaging, on the other hand, allows for the visualization of motion over time, enabling assessment of cardiac structures and function, as well as fetal heart rate.
High-frequency ultrasound refers to the use of ultrasound waves with frequencies greater than 10 MHz. This technology enables improved resolution, allowing for detailed imaging of superficial structures like skin, tendons, and small organs. High-frequency ultrasound has found applications in dermatology, ophthalmology, and musculoskeletal imaging.
Traditional 2D ultrasound has been augmented by the advent of 3D ultrasound technology. By acquiring multiple 2D images from different angles, this technique construct a volumetric representation of the imaged area. The addition of 4D ultrasound in real-time motion adds further value by capturing dynamic processes.
Doppler imaging employs the Doppler effect to evaluate blood flow within vessels and assess hemodynamics. Color Doppler assigns color to different blood flow velocities, providing a visual representation of blood flow direction and speed. Spectral Doppler displays blood flow velocities as a waveform, allowing for detailed analysis of flow patterns, resistance, and stenosis.
Contrast enhanced ultrasound employs microbubble contrast agents to enhance the visualization of blood flow and tissue perfusion. By injecting these agents intravenously, sonographers can differentiate between vascular structures and lesions. Elastography is a technique that measures tissue elasticity or stiffness. It assists in differentiating between normal and abnormal tissues, aiding in the diagnosis of various conditions such as liver fibrosis, breast lesions, and thyroid nodules.
Fusion imaging combines ultrasound with other imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET). By overlaying or merging ultrasound images with those obtained from other modalities, the user can precisely locate and characterize abnormalities, guide interventions, and improve diagnostic accuracy. Fusion imaging has proven particularly useful in areas such as interventional radiology, oncology, and urology.
See also Equipment Preparation, Environmental Protection, Handheld Ultrasound, Portable Ultrasound and Ultrasound Accessories and Supplies.

(US) Also called echography, sonography, ultrasonography, echotomography, ultrasonic tomography.
Diagnostic imaging plays a vital role in modern healthcare, allowing medical professionals to visualize internal structures of the body and assist in the diagnosis and treatment of various conditions. Two terms that are commonly used interchangeably but possess distinct meanings in the field of medical imaging are 'ultrasound' and 'sonography.'
Ultrasound is the imaging technique that utilizes sound waves to create real-time images, while sonography encompasses the entire process of performing ultrasound examinations and interpreting the obtained images. Ultrasonography is a synonymous term for sonography, emphasizing the use of ultrasound technology in diagnostic imaging. A sonogram, on the other hand, refers to the resulting image produced during an ultrasound examination.
Ultrasonic waves, generated by a quartz crystal, cause mechanical perturbation of an elastic medium, resulting in rarefaction and compression of the medium particles. These waves are reflected at the interfaces between different tissues due to differences in their mechanical properties. The transmission and reflection of these high-frequency waves are displayed with different types of ultrasound modes.
By utilizing the speed of wave propagation in tissues, the time of reflection information can be converted into distance of reflection information. The use of higher frequencies in medical ultrasound imaging yields better image resolution. However, higher frequencies also lead to increased absorption of the sound beam by the medium, limiting its penetration depth. For instance, higher frequencies (e.g., 7.5 MHz) are employed to provide detailed imaging of superficial organs like the thyroid gland and breast, while lower frequencies (e.g., 3.5 MHz) are used for abdominal examinations.

Ultrasound in medical imaging offers several advantages including:

Diagnostic ultrasound imaging is generally considered safe, with no adverse effects. As medical ultrasound is extensively used in pregnancy and pediatric imaging, it is crucial for practitioners to ensure its safe usage. Ultrasound can cause mechanical and thermal effects in tissue, which are amplified with increased output power. Consequently, guidelines for the safe use of ultrasound have been issued to address the growing use of color flow imaging, pulsed spectral Doppler, and higher demands on B-mode imaging. Furthermore, recent ultrasound safety regulations have shifted more responsibility to the operator to ensure the safe use of ultrasound.

See also Skinline, Pregnancy Ultrasound, Obstetric and Gynecologic Ultrasound, Musculoskeletal and Joint Ultrasound, Ultrasound Elastography and Prostate Ultrasound.

2D ultrasound imaging is a widely used technique in medical imaging that provides two-dimensional visual representations of internal structures. A handheld device known as a probe or transducer contains piezoelectric crystals that emit and receive ultrasound waves which penetrate tissues and bounce back as echoes. The echoes are detected and converted into electrical signals. These signals are processed and displayed on a monitor, creating a real-time 2D grayscale image, with different shades of gray representing various tissue densities. The brighter areas on the image correspond to structures that reflect more ultrasound waves, while darker areas represent structures that reflect fewer waves or are attenuated by intervening tissues. The 2D-mode (or B-mode) provides cross-sectional views of the scanned area, showing a single plane or slice of the scanned area at a time.

Key Features and Uses of 2D Ultrasound:

Comparison with 3D and 4D Ultrasound:
See also Ultrasound Technology, Sonographer, Ultrasound Elastography, Obstetric and Gynecologic Ultrasound.

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.