Pregnancy ultrasound plays a crucial role in monitoring the health and development of the fetus throughout pregnancy. It serves as a screening tool with various applications, including:

See also Doppler Fluximetry in Pregnancy, Fetal Ultrasound, Obstetric and Gynecologic Ultrasound and Vaginal Probe.

Diagnostic ultrasound imaging has no known risks or long-term side effects. Discomfort to the patient is very rare if the sonogram is accurately performed by using appropriate frequencies and intensity ranges. However, the application of the ALARA principle is always recommended.
There are reports of low birth weight of babies after applying more than the recommended ultrasound examinations during pregnancy. Women who think they might be pregnant should raise this issue with the doctor before undergoing an abdominal ultrasound, to avoid any harm to the fetus in the early stages of development.
Since ultrasound is energy, sensitive tissues like the reproductive organs could possibly sustain damage if vibrated to a high degree by too intense ultrasound waves. In diagnostic ultrasonic procedures, such damage would only result from improper use of the equipment.

Possible ultrasound bioeffects:
The thermal effect is controlled by the displayed thermal index and the mechanical index indicates the risk of cavitation.
An ultrasound gel is applied to obtain better contact between the transducer and the skin. This has the consistency of thick mineral oil and is not associated with skin irritation or allergy.
Specific conditions for which ultrasound may be selected as a treatment may be attached with higher risks.

See also Ultrasound Imaging Procedures, Fetal Ultrasound and Obstetric and Gynecologic Ultrasound.

(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.

Cardiac ultrasound, also known as echocardiography or echocardiogram, is used to provide several different levels and types of heart testing. Cardiac ultrasound utilizes the same ultrasound principles as used for obstetric and gynecologic evaluations of pregnant women, gallbladder ultrasound and other abdominal structures.
The ultrasound is directed out of a hand held probe which can be moved to image the heart from different positions. Additionally, so that heart events can be timed, ECG leads are placed on the chest. The reflected wave is converted into an actual image of the heart and displayed in a real-time mode or M-mode ultrasound format. M-mode recordings permit measurement of cardiac dimensions and detailed analysis of complex motion patterns depending on transducer angulations. Also the time relationships with other physiological variables such as ECG, heart sounds, and pulse tracings, can be recorded simultaneously. A stress echocardiogram provides information about the cardiac performance.
Two-dimensional tomographic images of selected cardiac sections give more information than M-mode about the shape of the heart and also show the spatial relationships of its structures during the cardiac cycle (diastole to systole).

See also M-Mode Echocardiography, and Myocardial Contrast Echocardiography.

Ultrasound machines, widely used in medical imaging, are essential tools in the field of diagnostic ultrasound. These devices utilize high-frequency sound waves to create real-time images of internal body structures. Ultrasound machines consist of several key components that work together to generate diagnostic images. These include:
B-mode machines represent the vast majority of machines used in echocardiology, obstetrical scans, abdominal scans, gynecological scans, etc. B-mode ultrasound machines usually produce the sector (or pie segment-shaped) scans. These ultrasound scans require either a mechanical scanner transducer (the transducer moves to produce the sector scan), or a linear array transducer operated as a phased array.


Ultrasound machines come in different types, each catering to specific clinical needs. The two primary types are stationary and portable ultrasound machines:


See also Handheld Ultrasound, Ultrasound System Performance, Equipment Preparation, Coaxial Cable, and Microbubble Scanner Modification, Environmental Protection and Ultrasound Accessories and Supplies.