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MRI / PET / Ultrasound

What is MRI scan?

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A scan of magnetic resonance imaging (MRI) is a common procedure worldwide.

To create detailed images of the organs and tissues within the body, MRI uses a strong magnetic field and radio waves.

Doctors and researchers have continued to develop MRI methods to assist with medical procedures and analysis since its invention. Medicine was revolutionized by the invention of MRI.

Specifically this article looks at MRI scans, how they function and how doctors use them.

Important facts about MRI scanning

  • MRI scanning is a non-invasive and painless procedure.
  • Raymond Damadian created the first MRI full-body scanner, which he nicknamed the Indomitable.
  • The cost of a basic MRI scanner starts at $150,000 but can exceed several million dollars.
  • Japan has the most MRI scanners per capita, with 48 machines for every 100,000 citizens.

What is an MRI scan?

A doctor using MRI scan
MRI scans can produce a detailed image.

An MRI scan produces a accurate, cross-sectional image of internal organs and structures using a large magnet, radio waves and a computer.

Usually the scanner itself resembles a large tube with a table in the middle, allowing the patient to slide in.

An MRI scan is distinct from CT scans and X-rays as it does not use ionizing radiation that is potentially harmful.

Uses

MRI scan technology represents a tremendous achievement for the medical world.

Doctors, scientists, and researchers may now use a non-invasive method to explore the inside of the human body in great detail.

The following are examples in which an MRI scanner would be used:

  • anomalies of the brain and spinal cord
  • tumors, cysts, and other anomalies in various parts of the body
  • breast cancer screening for women who face a high risk of breast cancer
  • injuries or abnormalities of the joints, such as the back and knee
  • certain types of heart problems
  • diseases of the liver and other abdominal organs
  • the evaluation of pelvic pain in women, with causes including fibroids and endometriosis
  • suspected uterine anomalies in women undergoing evaluation for infertility

That list isn’t exhaustive at all. The use of MRI technology continues to grow in scope and use.

Preparation

A person can listen to music in headphones to mask the loud and sometimes alarming sound of the MRI machine.
A person can listen to music in headphones to mask the loud and sometimes alarming sound of the MRI machine.

Upon arrival at the hospital, doctors could recommend that the patient change into a gown.

Since magnets are being used it is important that there are no metal artifacts in the scanner. The doctor will recommend that the patient remove any metal jewelry or accessories that can interfere with the system.

A individual is likely to be unable to have an MRI if they have any metal inside their body, such as bullets, shrapnel or other foreign metallic bodies. Medical devices such as cochlear implants, aneurysm clips, and pacemakers may also be included.

Individuals anxious or worried about nearby spaces should inform their doctor. These medicines may also be given before the MRI to help make the procedure more comfortable.

Often patients may receive an injection of intravenous (IV) contrast liquid to enhance the visibility of a specific tissue appropriate for the scan.

A doctor specialized in medical images, the radiologist will then speak to the patient about the MRI scanning process and answer any questions they may have about the procedure.

Upon entering the scanning room the patient will be helped by the doctor to lie down on the scanner table. By having covers or cushions, staff must ensure that they are as comfortable as possible.

They should have earplugs or headphones to block the scanner’s loud noises. The latter is popular with kids, because they can listen to music during the procedure to relieve any anxiety.

During an MRI scan

The MRI technician will communicate with the patient through the intercom while inside the scanner to make sure they are relaxed. They don’t start scanning until the patient is ready.

Staying still is vitally necessary during the scan. Any motion can interrupt the pictures, just like a camera attempting to capture a moving object. The scanner will bring out loud clanging noises. That would be perfectly normal. Depending on the photos, the person can at times need to hold his breath.

If the patient feels nervous during the treatment, they will use the intercom to talk to the MRI technician and ask for the scan to be halted.

After an MRI scan

The radiologist will review the images after the scan to test if any more are needed. If the radiologist is happy the patient will be able to go home.

The radiologist must write a report for the doctor who requests it. Normally patients are asked to make an appointment with their doctor to discuss the findings.

Side effects

It is highly unlikely for a patient to experience side effects from an MRI scan.

However, in some people the contrast dye can cause nausea, headaches, and pain or burning at the injection point. Similarly, allergy to the contrast material is rarely seen but possible, and can cause hives or itchy eyes. Notify the technician should there be any adverse reactions.

Often people who experience claustrophobia or feel insecure in confined spaces communicate difficulties with an MRI scan.

Function

water molecules
MRI scans work by rearranging water molecules in the body with magnets.

An MRI scanner has two strong magnets in it. These are the most important pieces of equipment.

The human body consists largely of water molecules which consist of atoms of hydrogen and oxygen. An even smaller particle called a proton lies at the core of each atom, which acts as a magnet and is prone to any magnetic field.

The water molecules in the body are usually distributed randomly, but when an MRI scanner is entered the first magnet causes the water molecules to move in one direction, either north or south.

The second magnetic field is then turned on and off in a series of rapid pulses, causing each hydrogen atom to change its orientation when turned on and then turn back quickly when switched off to its original relaxed state.

It generates the magnetic field by transferring electricity through gradient coils, which also causes the coils to vibrate, creating a knocking sound within the scanner.

Although the patient can not feel these changes, they can be identified by the scanner and, in combination with a computer, the radiologist can produce a detailed cross-sectional image.

Functional magnetic resonance imaging (fMRI)

Functional MRI (fMRI) magnetic resonance imaging uses MRI technology to assess cognitive function by measuring blood flow to certain parts of the brain.

In areas where neurons are involved the blood flow increases. This provides an insight into neuronal activity within the brain.

This technique has revolutionized brain mapping, enabling researchers to examine the brain and spinal cord without requiring invasive procedures or injections of drugs.

Functional MRI lets researchers learn about normal, diseased, or damaged brain functions.

For clinical research fMRI is also used. Normal MRI scans are useful to detect tissue structural abnormalities. Nevertheless, an fMRI scan can help detect activity abnormalities.

In short, the fMRI checks what tissues are doing rather than acting like they are.

As such, doctors use fMRI to determine brain surgery risks by defining regions of the brain that are involved in vital functions such as speaking, shifting, sensing, or preparing.

Often, functional MRI may be used to assess the symptoms of cancers, stroke, brain and head trauma, or neurodegenerative disorders such as Alzheimer’s.

FAQs

How long will an MRI scan take?

MRI scans vary between 20 and 60 minutes depending on which part of the body is examined and how many images are required.

If the images are not clear enough for the radiologist after the first MRI scan, they can specifically ask the patient to undergo a second scan.

I have braces or filings, should I still undergo the scan?

Though the scan does not affect braces and fillings, they can distort those images. That will be addressed in advance by the doctor and technician. If additional images are needed the MRI scan can take longer.

Can I move while I am in the MRI tunnel?

Staying as still as possible is important while in the MRI scanner. The scanner will be blurred by any movement and therefore the images created will be blurry. The MRI technician may allow a short break halfway through the procedure in specially long MRI scans.

I am claustrophobic, what can I do?

The doctor and radiologist should be able to speak about the whole process to the patient and discuss any anxieties. Open MRI scanners for some areas of the body are available in certain places to aid people with claustrophobia.

A person can take medication prior to the test to ease anxiety.

Do I need an injection of contrast before my MRI scan?

A contrast dye can improve diagnostic accuracy by highlighting certain tissues.

Some patients may need to have a contrast agent injected before the scan.

Can I have an MRI scan if I am pregnant?

Unfortunately, the answer isn’t easy. Until the exam, let a doctor know about your pregnancy. Relatively few studies have been performed about the effect of MRI scans on pregnancy. Guidelines published in 2016 have, however, shed further light on the issue.

Doctors usually don’t prescribe comparison content for pregnant women.

In the first trimester MRI scans should be restricted, unless the information is deemed necessary. The MRI scans are healthy at 3.0 tesla (T) or less during the second and third trimesters. The tesla is a measure of magnetic resistance.

The Guidelines also note that first trimester exposure to MRI is not related to long-term effects and do not raise health concerns.

MRI / PET / Ultrasound

What’s to know about amniotic fluid?

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Amniotic fluid is a clear, yellow fluid that is present within the amniotic sac during the first 12 days after conception. It encircles the growing baby in the uterus.

Amniotic fluid has several essential functions and is vital for healthy fetal development. However, if there is too little or too great an amount of amniotic fluid inside the uterus, complications can occur.

This article discusses the various roles of amniotic fluid, and what happens when amniotic fluid levels are either too high or too low.

Important facts about amniotic fluid

  • At first, amniotic fluid consists of water from the mother’s body, but gradually, the larger proportion is made up of the baby’s urine.
  • It also contains important nutrients, hormones, and antibodies and it helps protect the baby from bumps and injury.
  • If the levels of amniotic fluid levels are too low or too high, this can pose a problem.

What is amniotic fluid?

Amniotic fluid protects and nourishes the baby in the womb.
Amniotic fluid protects and nourishes the baby in the womb.

While a baby is in the womb, it is inside the amniotic sac, a bag consisting of two membranes, the amnion and the chorion. Within this sac the fetus grows and develops, surrounded by an amniotic fluid.

Initially the fluid is made up of mother-generated water. However this is completely replaced by fetal urine by about 20 weeks gestation, when the fetus swallows and excretes the fluid.

Amniotic fluid as well contains vital components, such as nutrients, hormones, and infection-fighting antibodies.

It means that when amniotic fluid is green or brown the baby has absorbed meconium before birth. The term for the first bowel movement is Meconium.

Meconium can be problematic in the fluid. It may cause meconium aspiration syndrome, a breathing issue that happens when the meconium reaches the lungs. Babies can in some cases need treatment after birth.

Functions

Amniotic fluid is responsible for:

  • Protecting the fetus: The fluid cushions the baby from outside pressures, acting as a shock absorber.
  • Temperature control: The fluid insulates the baby, keeping it warm and maintaining a regular temperature.
  • Infection control: The amniotic fluid contains antibodies.
  • Lung and digestive system development: By breathing and swallowing the amniotic fluid, the baby practices using the muscles of these systems as they grow.
  • Muscle and bone development: As the baby floats inside the amniotic sac, it has the freedom to move about, giving muscles and bones the opportunity to develop properly.
  • Lubrication Amniotic fluid prevents parts of the body such as the fingers and toes from growing together; webbing can occur if amniotic fluid levels are low.
  • Umbilical cord support: Fluid in the uterus prevents the umbilical cord from being compressed. This cord transports food and oxygen from the placenta to the growing fetus.

Normally, the level of amniotic fluid is at its highest around 36 of pregnancy, measuring around 1 quart. As birth nears, this level decreases.

The amniotic sac gets tears when the waters break. The amniotic fluid inside the sac then starts flowing out of the cervix and vagina.

Usually the waters split at the end of the first labor stage. Only about 15 percent of waters break upon the onset of labor, according to Today ‘s Parent. It is time to contact the healthcare professional when this happens, as delivery can be imminent.

Disorders

Some conditions can cause amniotic fluid to be more or less than the normal amounts.

Oligohydramnios is when there is too little amniotic fluid.

Polyhydramnios, also referred to as hydramnios or amniotic fluid disorder, is when there is too much fluid.

Oligohydramnios

Low levels of amniotic fluid, or oligohydramnios, occur in 4% of all pregnancies, and 12% of post-date pregnancies.

Oligohydramnios is present when the ultrasound value of the amniotic fluid index (AFI) is less than 5 cm (the normal index is 5-25 cm) and the vertical maximum pocket (MVP) is less than 2 cm.

This can be evident when leaking fluid from a tear in the amniotic membranes, measuring small for a certain stage of pregnancy, or when the fetus does not move as much as expected.

For mothers with a history of any of the following medical conditions, this may also happen:

  • prior growth-restricted pregnancies
  • chronic high blood pressure (hypertension)
  • problems with the placenta, for example, abruption
  • preeclampsia
  • diabetes
  • lupus
  • multiple pregnancies, for example twins or triplets
  • birth defects, such as kidney abnormalities
  • delivering past the due date
  • other unknown reasons, known as idiopathic

Oligohydramnios can occur during any trimester but during the first 6 months of pregnancy it is more of a concern. There is a greater chance of birth defects, loss of pregnancy, premature birth or neonatal loss of life during that period.

If fluid levels are low in the last trimester, the risks include:

  • slow fetal growth
  • labor complications
  • the need for a Cesarean delivery

The rest of the pregnancy will be monitored closely to ensure normal development is taking place.

Doctors may use the following tests:

  • Nonstress tests: This is to check the baby’s heartbeat when it is resting and when it is moving.
  • Biophysical profiling: An ultrasound scan can detect the baby’s movements, muscle tone, breathing and amniotic fluid levels. This may be followed up with a nonstress test.
  • Fetal kick counts: This is to time how long it takes for the baby to kick a certain number of times.
  • Doppler studies: These use sound waves to check the flow of blood in the baby.

For certain cases , doctors may agree that to protect the mother or the infant, labor may need to be induced. Amnioinfusion (saline infusion into the uterus), an increase in maternal fluids, and bed rest may also be needed.

Due to the risk of umbilical cord compression, there is a greater chance of labor complications. During labor, amnioinfusion can be required. In certain cases it may be appropriate to offer a cesarian delivery.

Polyhydramnios

This is called polyhydramnios, when there is too much amniotic fluid. It happens in 1 percent of all births, according to the American Pregnancy Association.

Polyhydramnios occurs when the AFI reaches 24 centimeters (cm) and the MVP measures more than 8 cm.

Fetal disorders that can lead to polyhydramnios include:

  • gastrointestinal disorders, including duodenal or esophageal atresia, gastroschisis, and diaphragmatic hernia
  • brain or nervous system disorders, such as anencephaly or myotonic dystrophy
  • achondroplasia, a bone growth disorder
  • fetal heart rate problems
  • infection
  • Beckwith-Wiedemann syndrome, which is a congenital growth disorder
  • fetal lung abnormalities
  • hydrops fetalis, in which an abnormal level of water builds up inside multiple body areas of a fetus
  • twin-to-twin transfusion syndrome, where one child gets more blood flow than the other
  • mismatched blood between mother and child, for example Rh incompatibility or Kell diseases

Poorly controlled maternal diabetes increases risks as well.

During multiple pregnancies too much fluid may also be created when the mother carries more than one fetus.

Maternal symptoms can include abdominal pain, and breathing problems due to uterine enlargement.

Other complications include:

  • preterm labor
  • premature rupture of membranes
  • placental abruption
  • stillbirth
  • postpartum hemorrhage
  • fetal malposition
  • cord prolapse

Maternal diabetes testing can be recommended, and regular ultrasounds are obtained to monitor the amniotic fluid levels in the uterus.

Mild cases of polyhydramnios typically resolve untreated.

For more serious cases, either amniocentesis or a medication called indomethacin may need to minimize the fluid. Which reduces the amount of urine released by the infant.

Leaking amniotic fluid

Fluid leaks sometimes before waters break. Only 1 in 10 women will feel a rapid flood of fluid as the waters break, according to the American Pregnancy Association. It’ll start as a trickle, or leak, for most.

Occasionally, since the uterus is pulling on the bladder, what appears like fluid leaking is actually urine.

If there is no color and no smell in the fluid, it will be amniotic fluid, and you should contact a health care provider as work normally starts soon.

This may suggest the existence of meconium or an infection if the fluid is green, brownish-green or foul-smelling. Medical advice should be sought.

Premature rupture of membranes

If leakage or rupture occurs before 37 weeks this is called premature membrane rupture (PROM). It can have serious consequences for the mother and the unborn child, depending on how early that happens. Around 2 in 100 pregnancies are affected.

It is known as premature preterm rupture, but premature rupture is also possible on term. That is when 37 weeks of pregnancy or more are complete, but labor does not start spontaneously within 6 hours of the rupture of the membrane.

As this may lead to an infection, it is necessary to seek medical attention as soon as possible and to stop having intercourse or putting something into the vagina.

Someone who concerns about leakage or amniotic fluid levels during pregnancy should discuss this with their health care provider.

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MRI / PET / Ultrasound

What is a PET scan, and are there risks?

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A positron emission tomography, also known as a PET scan, uses radiation to reveal cellular activity within the body.

This is most commonly used in cancer therapy, neurology, and cardiology.

Combined with a CT or MRI scan, a PET scan can produce multidimensional, color images of the human body’s inner workings.

It not only reveals what an organ looks like but how it functions.

A PET scan is used to identify certain disorders of health, to schedule care, to assess how an current disease progresses and to see how successful a medication is.

Important facts about PET scans

  • PET scans are often used to diagnose a condition or to track how it is developing.
  • Used alongside a CT or MRI scan, it can show how a part of the body is working.
  • PET scans are often used to investigate epilepsy, Alzheimer’s disease, cancer, and heart disease
  • A scan is not painful, but patients should not consume any food for at least 4 to 6 hours before a scan. They should drink plenty of water.

How it works

Pet scan
PET scans demonstrate the physical state and function of organs.

A computer measures radiation, released by a radiotracer, in a PET scan.

A radiotracer consists of radioactive material which, like glucose, is attached to a natural chemical.

This radiotracer is injected into the body, where it travels to energy-consuming cells consuming glucose.

The more energy a group of cells requires, the more the radiotracer at that position can build up. This will show up on computer-reconstructed images.

The cells, or activity, will show as “hot spots” or “cold spots.” On a PET scan the active areas are bright.

These are known as “hot spots.” Where cells need less energy, the areas would be less bright. They are “cold spots.”

Cancer cells are very involved in the use of glucose relative to normal cells, and a glucose-made radiotracer light up areas of cancer.

The image created on the screen will be analyzed by a radiologist and a doctor will report the findings.

Fluorodoxyglucose (FDG) is an example of a glucose dependent radiotracer. In FDG, molecules of radioactive fluoride are labelled to create a radiotracer by glucose. FDG is the most commonly used radiotracer today.

Oxygen can be used, rather than glucose.

Uses

A doctors and his patient
PET scans are an important part of the diagnostic process in cancer and epilepsy, and can directly inform the next stage of treatment.

PET scans are also combined with CT or MRI scans to help make a diagnosis or to collect more details about a health condition and any medical progress.

Whereas an MRI or CT scan reveals how body part looks, a PET scan will help to demonstrate how it functions.

PET scans are widely used to study different conditions.

Epilepsy: It will show which part of the brain causes epilepsy.

It can help doctors determine which care is most suitable, and it can be useful if surgery is required.

Alzheimer’s disease: PET scans may help identify Alzheimer’s disease through assessing sugar intake in different brain regions.

Brain cells that have Alzheimer’s affect appear to use glucose more slowly than normal cells.

Cancer: PET scans will reveal a cancer’s existence and stage, demonstrate whether and where it has spread and help doctors decide on the treatment.

A PET scan can provide an indication of how well chemotherapy works, and a recurrent tumor can be identified earlier than other techniques.

Heart disease: A PET scan can help detect weakened or scarred parts of the heart, and can help identify circulation problems in the heart’s function.

Such knowledge can aid in the planning of heart disease treatment options.

Medical research: Scientists can learn valuable information using PET scans, in particular about brain functioning.

Differences between PET, CT, and MRI scans

A CT or MRI scan can determine the size and shape of body organs and tissue, but can’t measure how these work.

A PET scan will demonstrate how an organ functions but it can be difficult to determine the exact position of activity inside the body without a CT or MRI image.

A PET scan combined with a CT scan will provide a more detailed image of the patient’s situation

Procedure

Example of pet image scan
PET images show the active cells as bright or ‘hot’ spots.

In general, a PET scan is an outpatient treatment.

The patient does not usually eat any food for at least 4 to 6 hours before the scan but should drink plenty of water. They may need to stop coffeine at least 24 hours before scanning.

First, a small volume of radiotracer would be administered into a vein by the doctor Also, the tracer may be breathed in as a gas, taken by mouth or directly injected into an organ.

Depending on which organ is involved, it may take the radiotracer 30-90 minutes to reach the targeted body part.

Meanwhile, the patient is usually told to stay quiet and not speak. Some patients can receive calming medication.

The patient is likely to need to wear a robe, and will need to remove jewelry.

When the patient is ready for the scan, they are taken to a different room scan. They’ll lie on a cushioned test table.

The table slides into a large hole to encircle the patient.

Patient will stay as calm as possible. They may be able to listen to the music.

The computer takes pictures during the scan.

This will take about 30 minutes depending on which part of the body is being scanned.

It’s not even uncomfortable. If the patient feels unwell, they may press a buzzer to alert the workers.

During the scan a professional doctor must look at the patient.

Usually, the whole testing process takes about 2 hours. Most patients are permitted to go home once the scan is complete.

Patients can eat plenty of water to wash the toxic substances out of their body quicker. The radiotracers would have left the body in 3 to 4 hours, absolutely.

Risks

Exposure to radiation runs a risk.

The benefits of getting a PET scan, for most people, outweigh the risks.

However, it is not appropriate for everyone since a PET contains radioactive material.

A pregnant woman does not usually have a PET scan, because the radioactive material may affect the fetus or the baby.

If a woman is breastfeeding, she will follow directions for breast milk pumping and discarding, and ask the doctor when it is appropriate to restart breastfeeding based on the test completed.

Any woman who is pregnant or breast-feeding will immediately inform her doctor before getting a PET scan.

A patient may be advised to remain away from pregnant women, babies, and young children for a few hours after a PET scan, as the radioactivity presents a slight risk.

An individual can very rarely have an allergic reaction to the tracer.

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Medical Devices / Diagnostics

How do ultrasound scans work?

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An ultrasonic scan uses sound waves of high frequency to produce images of the body’s inside. Good for use during pregnancy.

Ultrasound scans, or sonography, are safe because, instead of radiation, they use sound waves or echos to create an image.

Ultrasound scans are used to determine fetal growth, and they can detect liver, heart, kidney or abdominal problems. Also, they can help with other forms of biopsy.

The created image is called a sonogram.

Important facts about ultrasound scans

  • Ultrasound scans are safe and widely used.
  • They are often used to check the progress of a pregnancy.
  • They are used for diagnosis or treatment.
  • No special preparation is normally necessary before an ultrasound scan.

Concept

Ultrasound scans are carried out by a sonographer.
Ultrasound scans are carried out by a sonographer.

The individual doing an ultrasound scan is called a sonograph, so radiologists, cardiologists, or other experts interpret the images.

Typically the sonographer carries a transducer, a handheld instrument, like a wand which is positioned on the skin of the patient.

Ultrasound is a sound moving through soft tissue and fluids, but it bounces backwards, or echoes, off denser surfaces. So it creates a image.

The term “ultrasound” refers to sound at a frequency which can not be heard by humans.

Typically the ultrasound for diagnostic uses varies between 2 and 18 megahertz (MHz).

Higher frequencies provide better images of quality, but are more readily absorbed by the skin and other tissues, so they can not penetrate as deeply as lower frequencies.

Higher frequencies penetrate deeper, but inferior in image quality.

How does it capture an image?

Ultrasound, for example, passes through blood in the heart cavity, but if it reaches a heart valve, it returns, or bounces back.

If there are no gallstones, it will pass straight into the gallbladder but if there are stones, it will bounce back from them.

The denser the target hits the scanner, the more it bounces back.

This bouncing back, or echo, gives its features to the ultrasonic picture. Increasing shades of grey represent increasing densities.

Ultrasound transducers

The transducer, or wand, is usually mounted on the patient’s body surface but certain kinds are mounted internally.

This will include photos which are simpler and more detailed.

Examples include:

  • an endovaginal transducer, for use in the vagina
  • an endorectal transducer, for use in the rectum
  • a transesophageal transducer, passed down the patient’s throat for use in the esophagus

Some very small transducers can be placed on a catheter’s end and inserted into the blood vessels to examine the blood vessel walls.

Uses

Ultrasound image
Ultrasound images are made from reflected sound, and a diagnosis can then be made.

Ultrasound is commonly used during procedures such as biopsies, for diagnosis, treatment and guidance.

It may be used to analyze internal organs including the liver and kidneys, the pancreas, the thyroid gland, the testes among ovaries, and others.

An ultrasonic scan will show whether a lump is a tumor. This may be cancerous, or a cyst overflowing with blood.

It can help to diagnose soft tissue disorders, muscles, blood vessels, tendons, and joints. A frozen shoulder, tennis elbow, carpal tunnel syndrome and others are examined.

Circulatory problems

Ultrasound Doppler can measure blood flow in a vessel or blood pressure. It can assess blood flow rate and any obstructions.

One example of Doppler ultrasound is an echocardiogram (ECG). It can be used to construct cardiovascular system images, and at different points to measure blood flow and cardiac tissue movement.

An ultrasound from Doppler can determine the function and condition of cardiac valve areas, any heart defects, valvular regurgitation, or blood leakage from valves, and it can demonstrate how well the heart pumps out blood.

It can also be used to:

  • examine the walls of blood vessels
  • check for DVT or an aneurysm
  • check fetal heart and heartbeat
  • evaluate for plaque buildup and clots
  • assess for blockages or narrowing of arteries

A carotid duplex is a type of carotid ultrasonography which may include an ultrasonic Doppler. This will demonstrate how blood cells pass through the arteries of the carotid.

Ultrasound in anesthesiology

Ultrasound is commonly used by anesthetists to direct a needle past nerves with anesthetic solutions.

An ultrasound can be performed in a doctor’s office, in an ambulatory clinic, or in a hospital.

Most scans take 20 to 60 minutes to complete. Usually, it’s not uncomfortable, and no noise.

No special planning is required in most cases, but patients may want to wear loose-fitting and comfortable clothing.

If the liver or gallbladder is affected, the patient can have to either run for several hours before the operation, or eat nothing.

The patient should drink plenty of water for a scan during pregnancy, and especially early pregnancy, and try to avoid urinating for some time before the test.

The scan provides a better image of the uterus when the bladder is full.

The scan normally takes place inside a hospital’s radiology department. The test is carried out by a doctor or a specially trained sonographer.

External ultrasound

The sonographer places a lubricating gel on the skin of the patient, and puts a transducer above the lubricated surface.

The transducer is placed over the body part which needs to be checked. Examples include ultrasonic tests of the heart of a patient or a fetus in the uterus.

The patient should not be feeling pain or discomfort. They are just going to feel the transducer over the skin.

The full bladder can cause slight discomfort during pregnancy.

Internal ultrasound

If it is appropriate to examine the internal reproductive organs or urinary system, the transducer can be positioned in a man’s rectum or in a woman’s vagina.

For example, an endoscope can be used to examine any portion of the digestive system, the esophagus, chest lymph nodes, or the stomach.

At the end of the endoscope, which was placed into the patient’s body, a light and an ultrasound tool was connected, normally through the mouth.

Patients are given drugs prior to the operation to reduce any discomfort.

Internal ultrasonic scans are less convenient than external ones, and the chance of internal bleeding is small.

Safety

Most types of ultrasound are noninvasive, and do not involve exposure to ionizing radiation. It’s believed the procedure is very healthy.

Nonetheless, unnecessary “keepsake” scans during pregnancy are not recommended because the long-term risks are not known. Ultrasound is recommended only when medically needed during pregnancy.

Anyone who’s allergic to latex will Inform their doctor not to use a latex-covered probe.

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