3D ultrasound is a medical ultrasound technique, often used in fetal, cardiac, trans-rectal and intra-vascular applications. 3D ultrasound refers specifically to the volume rendering of ultrasound data. When involving a series of 3D volumes collected over time, it can also be referred to as 4D ultrasound (three spatial dimensions plus one time dimension) or real-time 3D ultrasound. [1]
When generating a 3D volume, the ultrasound data can be collected in four common ways by a sonographer:
The general risks of ultrasound also apply to 3D ultrasound. Essentially, ultrasound is considered safe. While other imaging modalities use radioactive dye or ionizing radiation, for example, ultrasound transducers send pulses of high frequency sound into the body and then listen for the echo.
In summary, the primary risks associated with ultrasound would be the potential heating of tissue or cavitation. The mechanisms by which tissue heating and cavitation are measured are through the standards called thermal index (TI) and mechanical index (MI). Even though the FDA outlines very safe values for maximum TI and MI, it is still recommended to avoid unnecessary ultrasound imaging. [3]
3D ultrasound is useful, among other things, for facilitating the characterization of some congenital defects, such as skeletal anomalies and heart issues. With real-time 3D ultrasound, the fetal heart rate can be examined in real-time. [4] [5]
Applications of three-dimensional ultrasound in cardiac treatment have achieved outstanding progress in scanning and treating heart issues. When 3D ultrasound is used to visualize the cardiac state of an individual, it is called 3D echocardiography. [6] With the integration of other technologies, it is possible to obtain quantitative measurements such as chamber volume during the cardiac cycle. It also provides other useful information, for example, tracking the blood flow, or the speed of contractions and expansions. [7] With 3D echocardiography, physicians can detect artery diseases with relative ease, and can finely examine various cardiac defects. 3D echocardiography can achieve real-time imaging of the cardiac structure. [8]
Traditionally, with 2D ultrasound, the specific position of organs and tissues, which is useful in surgery, could not be located, especially in the oblique plane. With the advent of 3D ultrasound, the imaging technique has evolved such that it enables the surgeon to obtain a real-time picture of tissues and organs, visualizing the complete scan more efficiently. [9] In addition, 3D ultrasound provides surgical guidance in organ transplantation and cancer treatment, especially by employing rotational visualizing during scan. [10] Various methods are used in this area, including rotational scanning, slice projection, and the use of integrated array transducers. [11] With 3D ultrasound, it is possible to treat a broader range of tumors, as more tissues can be diagnosed and inspected. [12]
Blood vessels and arteries are relatively difficult to image, due to their distribution. 3D ultrasound has made it easier to track the dynamic movement of blood cells, veins and arteries. [13] Various types of diagnostic tasks can be achieved with 3D ultrasound, such as measuring blood vessel diameter and diagnosing arterial walls. Some of these tasks can be undertaken with a magnetic tracker, integrated with the ultrasound, which assists in accurate positioning. [14]
Real-time 3D ultrasound is used during peripheral nerve blockade procedures to identify the relevant anatomy and monitor the spread of local anesthetic around the nerve. Peripheral nerve blockades prevent the transmission of pain signals from the site of injury to the brain without deep sedation, which makes them particularly useful for outpatient orthopedic procedures. Real-time 3D ultrasound allows muscles, nerves and vessels to be clearly identified while a needle or catheter is advanced under the skin. This type of ultrasound is capable of imaging the needle regardless of the plane of the image, which is a substantial improvement over 2D ultrasound. Additionally, the image can be rotated or cropped in real time to reveal anatomical structures within a volume of tissue. Physicians at the Mayo Clinic in Jacksonville have been developing techniques using real time 3D ultrasound to guide peripheral nerve blocks for shoulder, knee, and ankle surgery. [15] [16]
Medical ultrasound includes diagnostic techniques using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics or to generate an informative audible sound. The usage of ultrasound to produce visual images for medicine is called medical ultrasonography or simply sonography, or echography. The practice of examining pregnant women using ultrasound is called obstetric ultrasonography, and was an early development of clinical ultrasonography. The machine used is called an ultrasound machine, a sonograph or an echograph. The visual image formed using this technique is called an ultrasonogram, a sonogram or an echogram.
Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to reveal internal structures hidden by the skin and bones, as well as to diagnose and treat disease. Medical imaging also establishes a database of normal anatomy and physiology to make it possible to identify abnormalities. Although imaging of removed organs and tissues can be performed for medical reasons, such procedures are usually considered part of pathology instead of medical imaging.
In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols , , or , is the volumetric flow rate of the heart's pumping output: that is, the volume of blood being pumped by a single ventricle of the heart, per unit time. Cardiac output (CO) is the product of the heart rate (HR), i.e. the number of heartbeats per minute (bpm), and the stroke volume (SV), which is the volume of blood pumped from the left ventricle per beat; thus giving the formula:
Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an echocardiogram, a cardiac echo, or simply an echo.
Obstetric ultrasonography, or prenatal ultrasound, is the use of medical ultrasonography in pregnancy, in which sound waves are used to create real-time visual images of the developing embryo or fetus in the uterus (womb). The procedure is a standard part of prenatal care in many countries, as it can provide a variety of information about the health of the mother, the timing and progress of the pregnancy, and the health and development of the embryo or fetus.
A transesophageal echocardiogram, or TEE, is an alternative way to perform an echocardiogram. A specialized probe containing an ultrasound transducer at its tip is passed into the patient's esophagus. This allows image and Doppler evaluation which can be recorded. It is commonly used during cardiac surgery and is an excellent modality for assessing the aorta, although there are some limitations.
Intravascular ultrasound (IVUS) or intravascular echocardiography is a medical imaging methodology using a specially designed catheter with a miniaturized ultrasound probe attached to the distal end of the catheter. The proximal end of the catheter is attached to computerized ultrasound equipment. It allows the application of ultrasound technology, such as piezoelectric transducer or CMUT, to see from inside blood vessels out through the surrounding blood column, visualizing the endothelium of blood vessels.
A transthoracic echocardiogram (TTE) is the most common type of echocardiogram, which is a still or moving image of the internal parts of the heart using ultrasound. In this case, the probe is placed on the chest or abdomen of the subject to get various views of the heart. It is used as a non-invasive assessment of the overall health of the heart, including a patient's heart valves and degree of heart muscle contraction. The images are displayed on a monitor for real-time viewing and then recorded.
Doppler echocardiography is a procedure that uses Doppler ultrasonography to examine the heart. An echocardiogram uses high frequency sound waves to create an image of the heart while the use of Doppler technology allows determination of the speed and direction of blood flow by utilizing the Doppler effect.
Abdominal ultrasonography is a form of medical ultrasonography to visualise abdominal anatomical structures. It uses transmission and reflection of ultrasound waves to visualise internal organs through the abdominal wall. For this reason, the procedure is also called a transabdominal ultrasound, in contrast to endoscopic ultrasound, the latter combining ultrasound with endoscopy through visualize internal structures from within hollow organs.
Fetal echocardiography, or Fetal echocardiogram, is the name of the test used to diagnose cardiac conditions in the fetal stage. Cardiac defects are amongst the most common birth defects. Their diagnosis is important in the fetal stage as it might help provide an opportunity to plan and manage the baby as and when the baby is born. Not all pregnancies need to undergo fetal echo.
Occasionally, there is a single umbilical artery (SUA) present in the umbilical cord, as opposed to the usual two. This is sometimes also called a two-vessel umbilical cord, or two-vessel cord. Approximately, this affects between 1 in 100 and 1 in 500 pregnancies, making it the most common umbilical abnormality. Its cause is not known.
In the fields of cardiology and medical imaging, speckle tracking echocardiography (STE) is an echocardiographic imaging technique. It analyzes the motion of tissues in the heart by using the naturally occurring speckle pattern in the myocardium.
Cone beam computed tomography is a medical imaging technique consisting of X-ray computed tomography where the X-rays are divergent, forming a cone.
Cardiac imaging refers to minimally invasive imaging of the heart using ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), or nuclear medicine (NM) imaging with PET or SPECT. These cardiac techniques are otherwise referred to as echocardiography, Cardiac MRI, Cardiac CT, Cardiac PET and Cardiac SPECT including myocardial perfusion imaging.
Prehospital ultrasound is the specialized application of ultrasound by physicians and other emergency medical services (EMS) to guide immediate care and treatment procedures. Like conventional ultrasound, it is a device that produces cyclic sound pressure to penetrate a medium and reveal details about the inner structure of the medium.
Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform imaging of the movement of tissues and body fluids, and their relative velocity to the probe. By calculating the frequency shift of a particular sample volume, for example, flow in an artery or a jet of blood flow over a heart valve, its speed and direction can be determined and visualized.
The anomaly scan, also sometimes called the anatomy scan, 20-week ultrasound, or level 2 ultrasound, evaluates anatomic structures of the fetus, placenta, and maternal pelvic organs. This scan is an important and common component of routine prenatal care. The function of the ultrasound is to measure the fetus so that growth abnormalities can be recognized quickly later in pregnancy, to assess for congenital malformations and multiple pregnancies, and to plan method of delivery.
Functional ultrasound imaging (fUS) is a medical ultrasound imaging technique of detecting or measuring changes in neural activities or metabolism, for example, the loci of brain activity, typically through measuring blood flow or hemodynamic changes. The method can be seen as an extension of Doppler imaging.
A specific branch of contrast-enhanced ultrasound, acoustic angiography is a minimally invasive and non-ionizing medical imaging technique used to visualize vasculature. Acoustic angiography was first developed by the Dayton Laboratory at North Carolina State University and provides a safe, portable, and inexpensive alternative to the most common methods of angiography such as Magnetic Resonance Angiography and Computed Tomography Angiography. Although ultrasound does not traditionally exhibit the high resolution of MRI or CT, high-frequency ultrasound (HFU) achieves relatively high resolution by sacrificing some penetration depth. HFU typically uses waves between 20 and 100 MHz and achieves resolution of 16-80μm at depths of 3-12mm. Although HFU has exhibited adequate resolution to monitor things like tumor growth in the skin layers, on its own it lacks the depth and contrast necessary for imaging blood vessels. Acoustic angiography overcomes the weaknesses of HFU by combining contrast-enhanced ultrasound with the use of a dual-element ultrasound transducer to achieve high resolution visualization of blood vessels at relatively deep penetration levels.
clinic in Sacramento, CA that specializes in performing 3D ultrasound and training sonographers.
