Ct Scans Of The Thyroid: Normal Anatomy And Imaging Techniques
The thyroid gland is a vascular, encapsulated structure made up of right and left lobes, which are connected at the midline by the isthmus. Each lobe is about 2 cm thick, 3 cm wide, and 5 cm long. The thyroid apex is located superiorly at the level of the mid-thyroid cartilage. The inferior margin of the gland is at the level of the fifth or sixth tracheal ring. The thyroid gland is encapsulated by the middle layer of deep cervical fascia and is part of the visceral space in the infrahyoid neck. It wraps around the trachea and is separated from the oesophagus by the tracheoesophageal groove on each side, which houses the recurrent laryngeal nerves. The thyroid has variable lymphatic drainage to the internal jugular chain, para-tracheal region, mediastinum, and retropharyngeal area. It has homogeneous high attenuation values on a CT scan, as compared to adjacent muscles, due to its high iodine concentration. It shows avid iodine contrast enhancement due to its hypervascularity .
Multi-detector volumetric acquisition from the skull base to the tracheal bifurcation is usually obtained. Multiplanar 2-mm axial, coronal, and sagittal images are typically available. Examination can be acquired with or without administration of intravenous iodinated contrast.
Who Should Be Tested
If you think you have symptoms of a thyroid problem, ask your doctor if you should be tested. People with symptoms or risk factors may need tests more often. Hypothyroidism more frequently affects women over age 60. Hyperthyroidism is also more common in women. A family history raises your risk of either disorder.
Your Next Steps + Treating Your Thyroid
If you suspect that you have an enlarged or swollen thyroid gland then you may be wondering what are you supposed to do next.
The world of thyroid management can be difficult to navigate, but Ive created a list of steps below that you can check off to ensure that you are on the right track.
Following this list will help you with proper diagnosis and treatment .
- Get a full physical exam and history from your physician . This will include feeling your thyroid gland in your neck and asking about any other symptoms you may be dealing with.
- If your thyroid is enlarged then your next step is to get ultrasound imaging . Ultrasound will help determine if you need a biopsy or if you can simply monitor your thyroid gland every few months.
- If necessary get a biopsy via FNA .
- If necessary get thyroid blood tests .
- Obtain a diagnosis as to what is CAUSING your enlarged or swollen thyroid. You need to NAME the issue you are dealing with. Potential diagnoses include Hashimotos thyroiditis, thyroid cancer, thyroid nodule, thyroid cyst, thyroiditis, etc.
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Incidental Thyroid Findings On Ct Scan
The thyroid gland can have variable CT scan findings, such as calcifications, single or multiple nodules, cysts, or diffuse enlargement.
An incidentally discovered colloid nodule with calcification, shown on CT scan of a 58-year-old female patient. a Non-enhanced axial CT scan of the neck demonstrates a coarse calcification at the left thyroid inferior pole. b Sagittal grey scale ultrasound of the thyroid demonstrates a heterogeneous nodule with predominant cystic component. Calcification was not seen in the ultrasound, probably due to its lower location in the superior mediastinum
A 51-year-old female patient post left hemi-thyroidectomy, with incidentally discovered right thyroid colloid nodule on CT scan. a Enhanced axial CT scan of the neck demonstrates a well-defined, hypodense right thyroid nodule with no internal calcifications or cervical lymphadenopathy. b Transverse greyscale thyroid ultrasound demonstrates a well-defined, hypoechoic right thyroid lobe nodule with a central echogenicity including comet tail artefacts . No vascularity or calcifications were detected
Do They Go Away On Their Own
According to an ATA study, thyroid nodules that occur due to iodine deficiency may resolve on their own over time if people increase their iodine intake. In 618 participants with thyroid nodules, roughly one-third of single nodules were no longer present at the 11-year follow-up.
The researchers concluded that increasing iodine intake through iodized salt might be the reason for the disappearance of the nodules.
In other cases, benign thyroid nodules may grow larger over time, and people may need treatment to remove them.
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Imaging And Evaluating Your Thyroid
Ultrasound is a nearly painless procedure that allows radiologists to look at the size, shape, texture, and other characteristics of your thyroid gland.
Because the thyroid gland is near to the surface of your skin it can easily be assessed with this type of imaging.
Doctors are often taught that the only way to hurt someone with ultrasound is by throwing the machine at them.
Ultrasound is very important if you have an enlarged thyroid because it can further help to diagnose what exactly you are dealing with.
If you have a single large thyroid nodule, an ultrasound can pick up that nodule and give information regarding the size, shape, and consistency of the nodule.
This information can help to determine if the nodule is benign ) or potentially cancerous and also help determine if you need a biopsy.
Other conditions which cause thyroid enlargement may be consistent and make your thyroid look irregularly inconsistent throughout the entire gland.
Conditions that cause this type of pattern tend to result in inflammation of the entire gland or may be caused by nutrient deficiencies such as iodine deficiency.
In addition to ultrasound testing, there are other ways to check your thyroid gland such as uptake tests or CT scans .
Understanding Lumps On The Neck
A lump on the neck is also called a neck mass. Neck lumps or masses can be large and visible, or they can be very small. Most neck lumps arent harmful. Most are also benign, or noncancerous. But a neck lump can also be a sign of a serious condition, such as an infection or a cancerous growth.
If you have a neck lump, your healthcare provider should evaluate it promptly. See your healthcare provider right away if you have an unexplained neck mass.
Many conditions can cause neck lumps. Here is a list of 19 possible causes.
Warning graphic images ahead.
- Infectious mononucleosis is usually caused by the Epstein-Barr virus
- It mainly occurs in high school and college students
- Symptoms include fever, swollen lymph glands, sore throat, headache, fatigue, night sweats, and body aches
- Symptoms may last for up to 2 months
- These are solid or fluid-filled lumps that develop in the thyroid gland
- Theyre classified as cold, warm, or hot, depending on whether they produce thyroid hormones or not
- Thyroid nodules are usually harmless, but may be a sign of disease like cancer or autoimmune dysfunction
- Swollen or lumpy thyroid gland, cough, hoarse voice, pain in the throat or neck, difficulty swallowing or breathing are possible symptoms
- Symptoms can indicate an overactive thyroid or underactive thyroid
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Where Neck Lumps Come From
A lump in the neck can be hard or soft, tender or non-tender. Lumps can be located in or under the skin, as in a sebaceous cyst, cystic acne, or lipoma. A lipoma is a benign fatty growth. A lump may also come from tissues and organs within your neck.
Where the lump originates plays an important role in determining what it is. Because there are many muscles, tissues, and organs near the neck, there are many places neck lumps can originate, including:
- parathyroid glands, which are four small glands located behind the thyroid gland
- recurrent laryngeal nerves, which enable movement of the vocal cords
- nerves of the sympathetic and parasympathetic nervous system
- the brachial plexus, which is a series of nerves that supply your upper limbs and trapezius muscle
- salivary glands
Common Causes Of Swollen Glands In Neck
Knowing what causes swollen glands can help identify whether you need medical attention. There are varieties of factors that can cause swollen glands in your neck. Depending on the severity, this swelling can occur on one or both sides of your neck. The following are some causes of enlarged lymph nodes in the neck:
Infections like tuberculosis, Lyme disease, and malaria can cause swollen glands. Bacterial infections and viral infections may also cause your glands to swell. These types of conditions are often mild and resolve on their own without treatment.
- Viral infections: Infections such as mononucleosis, influenza, and HIV
- Bacterial infections: streptococcal infection or meningitis
Swollen glands in adults necks may result from cancer. Cancerous tumors can cause inflammation of the lymph nodes, resulting in swollen glands.
In cancer, the tumor can press on nearby organs, causing them to swell and feel complete. The lymph nodes in the neck may also enlarge as they try to fight off the cancer cells.
About 20% of adults with swollen glands in their necks have cancer. Cancerous tumors are often found in the lymph nodes, tiny sacs containing white blood cells and other substances that help fight infection and disease.
4. Hormonal changes
Hormonal changes can also be one of the causes of swollen glands in your neck. If your hormone levels change over time, it can affect your bodys ability to regulate them.
5. Genetic problems
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What Are The Symptoms Of Goiter
The size of a goiter can range from very small and barely noticeable to very large. Most goiters are painless, but if you have thyroiditis , it can be painful.
The main symptoms of goiter include:
- A lump in the front of your neck, just below your Adam’s apple.
- A feeling of tightness in your throat area.
How Is Goiter Diagnosed
Your healthcare provider usually diagnoses goiter when they perform a physical examination and feel that you have an enlarged thyroid. However, the presence of a goiter indicates that theres an issue with your thyroid gland. Theyll need to figure out what the issue is.
Your provider can use several tests to diagnose and evaluate goiter, including the following:
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What Are The Limitations Of An Ultrasound Of The Thyroid
If one or more nodules are detected within the thyroid gland, the radiologist will examine the features of the nodules. Some features are strongly suggestive that a nodule is benign in nature, and some raise concern that the nodule may be a true tumor. In other cases, the radiologist cannot distinguish between benign and malignant lumps with complete certainty. A fine needle biopsy and review of tissue under a microscope may be recommended for further evaluation, but in some cases surveillance and a repeat sonogram after a few months looking for stability may suffice.
It is not possible to determine thyroid functionthat is, whether the thyroid gland is underactive, overactive, or normalwith ultrasound. For that determination, your doctor may order a blood test or a radioactive iodine uptake test.
What Is An Ultrasound Of The Thyroid
Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. It is safe and painless. It produces pictures of the inside of the body using sound waves. Ultrasound imaging is also called sonography. It uses a small probe called a transducer and gel placed directly on the skin. High-frequency sound waves travel from the probe through the gel into the body. The probe collects the sounds that bounce back. A computer uses those sound waves to create an image. Ultrasound exams do not use radiation . Because ultrasound captures images in real-time, it can show the structure and movement of the body’s internal organs. The images can also show blood flowing through blood vessels.
An ultrasound of the thyroid produces pictures of the thyroid gland and the adjacent structures in the neck. The thyroid gland is located in front of the neck just above the collar bones and is shaped like a butterfly, with one lobe on either side of the neck connected by a narrow band of tissue called the thyroid isthmus. It is one of nine endocrine glands located throughout the body that make and send hormones into the bloodstream.
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Who Does Goiter Affect
Anyone can have a goiter, but its about four times more likely to develop in people assigned female at birth compared to people assigned male at birth. Your risk of developing goiter also increases as you age. Theyre more common after age 40.
People who have any of the following conditions may also be more likely to develop goiter:
Common Underlying Causes Of Neck Lumps
An enlarged lymph node is the most common cause of a neck lump. Lymph nodes contain cells that help your body fight off infections and attack malignant cells, or cancer. When youre sick, your lymph nodes can become enlarged to help fight the infection. Other common causes of enlarged lymph nodes include:
There are other illnesses that can cause a neck lump:
- Autoimmune diseases, cancer, and other disorders of the thyroid gland, such as goiter due to iodine deficiency, can cause enlargement of part or all of your thyroid gland.
- Viruses, such as mumps, can make your salivary glands enlarged.
- Injury or torticollis can cause a lump in your neck muscles.
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How Common Is Thyroid Cancer
Thyroid cancer is a rare form of cancer, accounting for less than 1% of all cancer cases in the UK.
It’s most common in people aged 35 to 39 years and in those aged 70 years or over.
Women are 2 to 3 times more likely to develop thyroid cancer than men. It’s unclear why this is, but it may be a result of the hormonal changes associated with the female reproductive system.
Preparing To Do A Thyroid Neck Check
To prepare for a thyroid swallowing test at home, stand in front of a mirror so that you can see your neck.
Remove any items, such as a scarf, necktie, jewelry, or turtleneck, that could block your view of your neck.
If you’re going to use a hand-held mirror, make sure it’s focused on the lower-front part of your neck.
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Thyroid Goiter: When Is A Ct Scan Ordered
When physical examination and or ultrasound cannot completely determine how far the goiter actually goes, then a CT scan should be ordered. The CT scan will show areas that the thyroid goiter extends and prepare the expert thyroid surgeon their safe and effective approach to remove all of the goiter gland and spare all other structures. Even though a thyroid goiter may extend extensively below the sternum and go well into the chest, these goiters can almost routinely be removed through a relatively straight forward low collar incision in the lower neck. If your surgeon is telling you that they need to “split your chest” or “open your sternum”, make sure that you have identified a highly experience thyroid surgeon. Again, such approaches are almost never actually required.
What Causes Thyroid Cancer
In most cases, the cause of thyroid cancer is unknown. However, certain things can increase your chances of developing the condition.
Risk factors for thyroid cancer include:
- having a benign thyroid condition
- having a family history of thyroid cancer
- having a bowel condition known as familial adenomatous polyposis
- acromegaly a rare condition where the body produces too much growth hormone
- having a previous benign breast condition
- weight and height
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Symptoms Of An Enlarged Thyroid
A goiter may be small, moderate or at times, it may be so large compressing the trachea and esophagus. Typically, a goiter is painless, but if it grows large, it causes other uncomfortable and unpleasant symptoms. Symptoms resulting from the goiter primarily include:
- Problems associated with swallowing and experiencing a sensation like food is getting stuck in your upper throat after when eating.
- Shortness of breath including waking up feeling like you cannot breathe.
- Hoarseness and stridor. Stridor is a wheezing sound that results from the turbulent air flow in and out of the obstructed trachea.
When hyperthyroidism or hypothyroidism is the reason behind your enlarged thyroid, other symptoms associated with thyroid disorders such as fatigue or sweating a lot can accompany those discussed above.
Causes Of Swollen Glands In The Neck
When the lymph nodes in your neck are swollen, it’s a sign that they’re trying to protect you, Sterling Ransone, MD, president of the American Academy of Family Physicians, told Health.
“They’re catching the bad guys. Our immune system is chewing them up,” said Dr. Ransone. The swelling results from extra blood cells coming to the site to fight infection.
According to Dr. Zack, swollen lymph nodes in the neck are likely a sign that you have a cold.
“This is very common with upper respiratory cold viruses,” explained Dr. Zack. “This is the immune system of the body fighting the viral infection.”
According to the National Library of Medicine, in addition to upper respiratory cold viruses, enlarged lymph nodes in the neck could also be a sign of the following infections:
- An abscessed or impacted tooth
- Skin infections
In rare cases, swollen lymph nodes may be a sign of cancerprecisely, lymphoma, per the National Library of Medicine. Lymphoma is a type of cancer affecting the lymphatic system, where the lymph nodes reside.
Some bacterial infections STIs, like human immunodeficiency virus or autoimmune diseases, such as rheumatoid arthritis, may also cause swollen lymph nodes. But in those situations, you’ll have swollen lymph nodes in multiple areas of your body instead of just one localized spot like your neck.
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