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Although there is no direct medical benefit of receiving an elective 3D ultrasound, there may be many indirect benefits, as listed below. It is important to note that there has been no conclusive evidence in the medical literature to support these benefits, and in fact, the medical literature shows conflicting studies on these benefits. However, on the individual level, a pregnant woman may find any of the following benefits for herself personally.
May reduce alcohol intake
Controversially, Christian/Catholic non-profit organizations have employed 3D ultrasounds for young pregnant women in order to influence their decisions regarding abortion. Charitable donations or public funds help pay for the 3D ultrasound machine.
Generally, the risks of 3D ultrasounds mirror those of 2D ultrasounds, as it uses the same ultrasound waves at the same intensity. Unlike the comparison of CT scans to x-rays, 3D ultrasounds do not employ multiple snapshots of 2D ultrasounds but uses the 2D ultrasounds images taken at various angles to construct an image. So the potential risk of 3D ultrasounds, if any, would depend on the duration of the ultrasound session rather than whether it is 2D or 3D.
The risk of ultrasounds, theoretically, would depend on the following factors:
4D GYN |
CCA Intima |
3D,4D Liver |
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3D Female fets |
3D Fetal face |
3D Liver |
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4 D Bladder |
3D Duodenum |
3D 4D Bladder |
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3S 4D Obs |
3D 26 week fetal heart |
4D Fetal feet and toes |
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3D Fetal spain |
3D Stimulated Ovary |
4D Image of 25 week fetus in Cube |
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What is 3D Ultrasound?
3D ultrasound is a medical ultrasound technique, often used during pregnancy, providing three dimensional images of the fetus. Often these images are captured rapidly and animated to produce a "4D ultrasound".
There are several different scanning modes in medical and obstetric ultrasound. The standard common obstetric diagnostic mode is 2D scanning. In 3D fetal scanning, however, instead of the sound waves being sent straight down and reflected back, they are sent at different angles. The returning echoes are processed by a sophisticated computer program resulting in a reconstructed three dimensional volume image of fetus's surface or internal organs, in much the same way as a CT scan machine constructs a CT scan image from multiple x-rays. 3D ultrasounds allow one to see width, height and depth of images in much the same way as 3D movies but no movement is shown. 4D ultrasounds involve the addition of movement by stringing together frames of 3D ultrasounds in quick succession.
3D ultrasound was first developed by Olaf von Ramm and Stephen Smith at Duke University in 1987
Clinical use of this technology is an area of intense research activity especially in fetal anomaly scanningbut there are also popular uses that have been shown to improve fetal-maternal bonding. 4D ultrasounds are similar to 3D scans except that they show fetal movement as shown in the video clip.
If the system is used only in the Obstetrics Application, the ultrasound energy is limited by the manufacturer below FDA limits for obstetric ultrasound, whether scanning 2, 3 or 4 dimensionally. (The FDA limit for obstetric ultrasound is 94 mW/cm2.) While there has been no conclusive evidence for harmful effects of 3D/4D ultrasound on a developing fetus, there still remains controversy over its use in non-medical situations, and generally, the AIUM recommends that 3D ultrasounds should be undertaken with the understanding that a risk may exist.
What is 4D Ultrasound?
Analog vs. Digital Beamforming
In analog beamforming (ABF) and digital beamforming (DBF) ultrasound systems, the received pulses reflected from a particular focal point along a beam are stored for each channel, then aligned in time, and coherently summed—this provides spatial processing gain because the noise of the channels is uncorrelated. Images may be formed as either a sequence of analog levels that are delayed with analog delay lines, summed, and converted to digital after summation (ABF)—or digitally by sampling the analog levels as close as possible to the transducer elements, storing them in a memory (FIFO), and then summing them digitally (DBF).
Figures 4 and 5 show basic respective block diagrams of ABF and DBF systems. Both types of systems require perfect channel-to-channel matching. Note that the variable-gain amplifiers (VGAs) are needed in both implementations—and will continue to be in the digital case until ADCs with a large enough dynamic range become available at reasonable cost and low enough power. Note that an ABF imaging system needs only one very high resolution and high speed ADC, but a DBF system requires many high speed, high resolution ADCs. Sometimes a logarithmic amplifier is used in the ABF systems to compress the dynamic range before the ADC.
Simplified block diagram of ABF system.
Simplified Block Diagram of Digtial Beamformer
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Material
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Speed of Propagation
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bone
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4080 m/s
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blood
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1570 m/s
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tissue
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1540 m/s
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fat
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1450 m/s
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air
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330 m/s
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The portion of a sound that is returned from the boundary of a medium. (echo) The angle of incidence influences the reflected and refracted waves.
Frequencies for adult imaging - 2.0mHz to 3.0mHz.
Frequencies for pediatric imaging - 5.0mHz to 7.5mHz to 12mHz.
Effect of higher frequencies on penetration - the higher the frequency the less penetration, the lower the frequency the greater the penetration.
A sub-beamforming method and apparatus are applied to a portable, one-dimensional ultrasonic imaging system. The sub-beamforming circuitry may be included in the probe s assembly housing the ultrasonic transducer, thus minimizing the number of signals that are communicated between the probe assembly and the portable processor included in the imaging system. Including the sub-beamformer in the probe assembly also relieves the portable processor of some of the signal processing tasks. The sub-beamforming apparatus may be implemented digitall or analog components.
Its very important to evaluate that how much money you should invest in your Ultrasound equipment. We recommened you to invest that you can get back in three years maximum.
So evaluate your practice to have an idea of your earning from Ultrasonography
There may be several financing options to help you acquire ultrasound machines, including outright purchase, traditional leasing, and others.
We SONOTECH offers financing to our customers.
Your primary application should be the main determining factor when deciding on a specific platform. Although many ultrasound systems are capable of scanning an OB patient, a system specifically built for an OB practice will often include many features and benefits that will produce better scans and reduce scanning times. However, it's still important to consider the basics of any ultrasound machine, such as the frequencies that will be used, the power source, requirements and power output, the size and weight, battery life, and so on. You should question paying for technologies that at not yet reimbursed from insurance. Intima Medial Thickness (IMT) is a great example of added technology that has not yet received widespread reimbursement.
When purchasing an ultrasound machine for your organization, you may have the choice of buying/leasing new or pre-owned ultrasound equipment. Just like with most things such as automobiles you can typically save thousands of dollars looking for a pre-owned ultrasound with all of the specifications you need and is a couple of years old. It is best to look for a system that has been under continuous service contract or coverage. Having a system inspection and certification at the time of delivery ensures that the system is in good operational condition and ready for use.
The choice of whether a stationary, installed ultrasound machine or a mobile, portable ultrasound machine would work best for you depends to a large degree on your application, facility and available space. Although portable ultrasounds offer a great solution when you need to move between remote sites, they can be very limiting. Usually only one transducer can be connected at one time, and with the small keyboard many buttons serve dual or triple function adding complexity to the ease of use.
Since ultrasound machine is sophisticated machinery, it is important to make sure that maintenance and repairs are considered in the overall value proposition. Most new ultrasound machines comes with normal warranties; one year is the most common but may have a 3-5 service agreement added on to the price. There are some very good, national, non-OEM service organizations that can offer comprehensive service agreements for all pre-owned ultrasound equipment. Before you sign on the dotted line, make sure you understand exactly what will be covered and how. Are the transducers covered if you drop them, are there any limitations on the coverage. You don't want to find out after the fact that you only thought you had coverage.
Unless you and your staff are already proficient in the operation of your new ultrasound machine, you'll want to make sure that training is part of the overall package. Application training may only involve what we call “knob-ology” which is getting the sonographers up to steam on what knobs and buttons do what on a specific ultrasound system. If you are making the jump to a more sophisticated pre-owned ultrasound system, more detailed application training may be required. Make sure to understand what training needs are, both initially and on an on-going basis.
Echocardiography - evaluation of the anatomy, physiology, and hemodynamics (blood flow) of the heart, its valves and related blood vessels.
Vascular Technology - evaluation of the anatomy, physiology, and hemodynamics (blood flow) of all the blood vessels in the body excluding the heart.
The professional responsibilities include, but are not limited to:
Many sonographers also assist in electronic record keeping, and computerized image storage. Sonographers may also have managerial or supervisory responsibilities.
Color Doppler Imaging has added a new to dimension to sonography. It is an established non–invasive technique, predominantly to study blood flow. Color flow imaging (CFM) is being used to determine organ expansion and functioning. The technique is based on the Doppler principle, first described by Christian Doppler in 1842. The effect is a change in the perceived frequency of sound emitted by a moving source. A working example of this change is the pitch of a train whistle as it moves past a stationary observer. Though the train is whistling at the same pitch the stationary person perceives an increasing and decreasing pitch as the train moves towards and away from him respectively.
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Doppler ultrasound takes advantage of the Doppler effect to create a moving image of the inside of the body. In this technique, an ultrasound transducer is used to beam sound into the area of interest, and it reads the returning sound. When the sound bounces off a moving target like a blood vessel, the pitch changes as a result of the Doppler effect. The transducer can detect very subtle pitch changes and record them visually, creating an image which shows where blood is flowing, and in which direction.
Viewed in grayscale, the image can be a bit hard to read. This is where color Doppler ultrasound comes in, with the ultrasound machine assigning color values which depend on whether blood is moving towards or away from the the transducer. In addition to showing the direction of flow, the colors also vary in intensity depending on the velocity of the flow, allowing people to see how quickly the blood is moving.
One obvious application of color Doppler ultrasound is in examination of a patient with a suspected aneurysm or occlusion. The ultrasound will reveal areas where the velocity of the bloodflow is changing, acting like a red flag to point out a problem. This technique can also be used to find blood clots, which will also be clearly visible within the color display.
Obstetric Ultrasound is the use of ultrasound scans in pregnancy. Since its introduction in the late 1950’s ultrasonography has become a very useful diagnostic tool in Obstetrics.
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1. Diagnosis and confirmation of early pregnancy.
The gestational sac can be visualized as early as four and a half weeks of gestation and the Yolk sac at about five weeks. The embryo can be observed and measured by about five and a half weeks. Ultrasound can also very importantly confirm the site of the pregnancy is within the cavity of the uterus.
2. Vaginal bleeding in early pregnancy.
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diagnosed. In such cases, it is reasonable to repeat the ultrasound scan in 7-10 days to avoid any error. The timing of a positive pregnancy test may also be helpful in this regard to assess the possible dates of conception. A positive pregnancy test 3 weeks previously for example, would indicate a gestational age of at least 7 weeks. Such information would be useful against the interpretation of the scans.
In the presence of first trimester bleeding, ultrasonography is also indispensible in the early diagnosis of ectopic pregnancies and moral pregnancies.
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Fetal body measurements reflect the gestational age of the fetus. This is particularly true in early gestation. In patients with uncertain last menstrual periods, such measurements must be made as early as possible in pregnancy to arrive at a correct dating for the patient. See. In the latter part of pregnancy measuring body parameters will allow assessment of the size and growth of fetus and will greatly assist in the diagnosis and management of intrauterine growth retardation ( IUGR ).
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The gestational Sac (GS)
A structure that develops in the uterus early in pregnancy, enclosing the developing baby and amniotic fluid. In an ultrasound, the gestational sac should be visible by five weeks of pregnancy. Measurement of the gestational sac diameter (GS) should increase by about 1 mm per day in early pregnancy.
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The Crown-rump length (CRL)
This measurement can be made between 7 to 13 weeks and gives very accurate estimation of the gestational age. Dating with the CRL can be within 3-4 days of the last menstrual period. (An important point to note is that when the due date has been set by an accurately measured CRL, it should not be changed by a subsequent scan. For example, if another scan done 6 or 8 weeks later says that one should have a new due date which is further away, one should not normally change the date but should rather interpret the finding as that the baby is not growing at the expected rate.
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The Biparietal diameter (BPD)
The diameter between the 2 sides of the head. This is measured after 13 weeks. It increases from about 2.4 cm at 13 weeks to about 9.5 cm at term. Different babies of the same weight can have different head size, therefore dating in the later part of pregnancy is generally considered unreliable. (Chart and further comments) Dating using the BPD should be done as early as is feasible.
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The Femur length (FL)
Measures the longest bone in the body and reflects the longitudinal growth of the fetus. Its usefulness is similar to the BPD. It increases from about 1.5 cm at 14 weeks to about 7.8 cm at term. (Chart and further comments) Similar to the BPD, dating using the FL should be done as early as is feasible.
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At this stage, the menstrual period has just ended and your body is getting ready for ovulation. For most women, ovulation takes place about 11 - 21 days from the first day of the last menstrual period. During intercourse, several hundred million sperm are released in the vagina. Sperm will travel through the cervix and into the fallopian tubes. When conception takes place, the sperm will penetrate an egg and create a single set of 46 chromosomes called a zygote - the basis for a new human being. The fertilized egg, called a morula, spends a couple of days traveling through the fallopian tube toward the uterus and dividing into cells (this dividing process is where many chromosomal abnormalities occur). The morula becomes a blastocyst and will eventually end up in the uterus. Anywhere from day 6 - 12 after conception, the blastocyst will imbed into the uterine lining and begin the embryonic stage.
Weeks 3-4 - Gestational Age (Fetal Age 2 weeks)
Development
The earliest change that can be seen through a vaginal ultrasound at this time will be the “decidual reaction” which is the thickening of the endometrium. The endometrium lining thickens as the blastocyst burrows into it. This cannot always be detected by ultrasound—sometimes it may take a special eye or very good equipment to see this “reaction” in the endometrium lining.
*A key fact to remember when using ultrasounds is that a transvaginal ultrasound can detect development in the uterus about a week earlier than a transabdominal ultrasound.
Hormones
hCG: Once implantation occurs, the pregnancy hormone Human Chorionic Gonadotropin (hCG) will develop and begin to rise. This hormone will signal that you are pregnant on a pregnancy test. hCG can be detected through two different types of blood tests or through a urine test. A quantitative blood test measures the exact amount of hCG in the blood, and a qualitative hCG blood test gives a simple yes or no answer to whether you are pregnant or not.
Human chorionic gonadotropin (hCG) levels can have quite a bit of variance at this point. Anything from 18 - 7,340 mIU/ml is considered normal at 5 weeks. Once the levels have reached at least 2000, some type of development is expected to be seen in the uterus using high resolution vaginal ultrasound. If using a transabdominal ultrasound, some type of development should be seen when the hCG level has reached 3600 mIU/ml. Although development may be seen earlier, these levels provide a guide of when something is expected to be seen.
The hCG levels will peak at about 8-12 weeks of pregnancy and then will decline, remaining at lower levels throughout the remainder of the pregnancy. If the levels are questionable, an ultrasound scan should be used to diagnose the pregnancy outcome. Ultrasound findings are much more accurate at diagnosing pregnancy viability after 5-6 weeks gestation than hCG levels are.
Vaginal ultrasound is used for very early pregnancy, and sometimes for heavier women with more abdominal fat. This type is done trans-vaginally, using a long 'wand' (transducer) that is covered with a condom (!), lubricated, and placed inside the vagina. If the scan is being done by a male doctor. (a female attendant should also be present in these cases, or you can request ahead of time to have a female technician instead).
The 'wand' is then moved around the vagina to allow the sonologist to 'see' up into the uterus and abdomen as needed. Occasionally it needs to be pressed up on either side of cervix firmly to 'see' the ovaries clearly, which can be a bit uncomfortable for some women, but the discomfort is usually tolerable.
Generally speaking, the trans-vaginal ultrasound is used in the first trimester, since the uterus has not yet grown big enough to lift out of the pelvic cavity. It is very useful in getting a clearer picture to determine whether there is an ectopic pregnancy, whether the fetus is viable, if there are multiple fetuses, etc. It is especially useful in heavyset women and perhaps in women with a retrograde uterus.
Because the transducer is right up by the cervix and thus right next to the baby, the ultrasound waves do not have to go through the abdomen before reaching the baby, and the picture is often clearer than with an abdominal ultrasound at this point. However, it also means the transducer is much closer to the baby than with an abdominal ultrasound, and critics worry about the safety of this. Does the baby receive increased levels or intensity of ultrasound this way, and is this more harmful particularly because it is usually used during the first trimester? No one knows.
The closeness of the trans-vaginal transducer (and its ability to use somewhat higher frequencies) is a particular advantage in the case of very heavy women with extensive abdominal adiposity. Although abdominal ultrasounds definitely work on heavy women later on in pregnancy, sometimes they are not very effective earlier in pregnancy. Thus transvaginal ultrasounds are especially common in women of size early in pregnancy. However, it is also not unusual for women of all sizes (not just heavy women) to have difficulty getting a clear abdominal ultrasound early in pregnancy. When ultrasounds are done in very early pregnancy, they are usually done transvaginally. It is only a little later that there is a difference in ultrasound method due to size and this does not last for long.
At some point around the end of the first trimester, most average-sized women can have an abdominal ultrasounds done, but in some larger women, a transvaginal ultrasound may still need to be used for a few weeks yet in order to get a more effective picture. However, every woman is different and many larger women have reported being able to use an abdominal ultrasound at about that time too. Each case will be different and has to be decided at the time, but be aware that transvaginal ultrasounds may have to be used just a bit longer in larger women.
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An ultrasound is done in most pregnancies around the mid part of a pregnancy. This is sonographical study is known as the fetal anatomy survey or the fetal anomaly screen. It is recommended to do a scan on 18-22 weeks of pregnanancy.
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The way this scan is done is that woman will have a full bladder before the start of the exam. Sonologist will do ultrasound . woman pregnant belly will have a special gel placed on it to help enhance the picture from the sound waves of the ultrasound. you, or in some cases the physician, will use the ultrasound transducer wand and move it over her abdomen.
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An ultrasound is done in most pregnancies around the mid part of a pregnancy. This is sonographical study is known as the fetal anatomy survey or the fetal anomaly screen. It is recommended to do a scan on 18-22 weeks of pregnanancy. The way this scan is done is that woman will have a full bladder before the start of the exam. Sonologist will do ultrasound . woman pregnant belly will have a special gel placed on it to help enhance the picture from the sound waves of the ultrasound. you, or in some cases the physician, will use the ultrasound transducer wand and move it over her abdomen.
Ultrasonologist determine things about baby and pregnancy. You need to look on the size of baby in comparison to others babies of the same gestational age or they may look at placenta.
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We often talk about how the first thing we'll do after our baby is born is to count fingers and toes. Now ultrasound technology can enable use to count fingers and toes prior to birth. Though being able to count each finger and toe can depend on how cooperative baby is being during the ultrasound exam.
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It is more likely that sonologistwill be able to see bigger areas like baby's limbs - arms and legs. Ultrasound technician will measure baby's thigh bone (femur), the tibia and fibula. These will also help calculate how well baby is growing for his or her gestational age.In addition to look at the legs, Sonologist should also measure parts of baby's arms. The bones of the arms (radius, ulna) are measured when possible.
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| BPD The diameter between the 2 sides of the head. This is measured after 13 weeks. It increases from about 2.4 cm at 13 weeks to about 9.5 cm at term. Different babies of the same weight can have different head size, therefore dating in the later part of pregnancy is generally considered unreliable. (Chart and further comments) Dating using the BPD should be done as early as is feasible.
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BPD |
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The single most important measurement to make in late pregnancy. It reflects more of fetal size and weight rather than age. Serial measurements are useful in monitoring growth of the fetus. (Chart and further comments) AC measurements should not be used for dating a fetus.
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Abdominal Circumference
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The Femur length Measures the longest bone in the body and reflects the longitudinal growth of the fetus. Its usefulness is similar to the BPD. It increases from about 1.5 cm at 14 weeks to about 7.8 cm at term. (Chart and further comments) Similar to the BPD, dating using the FL should be done as early as is feasible.
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Ultrasonography has become indispensible in the localization of the site of the placenta and determining its lower edges, thus making a diagnosis or an exclusion of placenta previa. Other placental abnormalities in conditions such as diabetes, fetal hydrops, Rh isoimmunization and severe intrauterine growth retardation can also be assessed. |
Placenta |
Transvaginal Scan With specially designed probes, ultrasound scanning can be done with the probe placed in the vagina of the patient. This method usually provides better images (and therefore more information) in patients who are obese and/ or in the early stages of pregnancy. The better images are the result of the scanhead's closer proximity to the uterus and the higher frequency used in the transducer array resulting in higher resolving power. Fetal cardiac pulsation can be clearly observed as early as 6 weeks of gestation.
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TVS Scan 6 week |
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The sex of the baby can usually be determined by ultrasound at any time after 16 weeks, often at the dating scan around 20 weeks into the pregnancy depending upon the quality of the sonographic machine and skill of the operator. This is also the best time to have an ultrasound done as most infants are the same size at this stage of development. Depending on the skill of the sonographer, ultrasound may suffer from a high rate of false negatives and false positives. This means care has to be taken in interpreting the accuracy of the scan. |
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Transducer Care & Safety Guidelines
