What is the difference between a CT scan and a CAT scan? How do they work, and what are their applications in medical diagnostics? Get a comprehensive overview with expert insights.

Understanding the CT Scan vs. CAT Scan Conundrum

Computerized Tomography (CT) and Computerized Axial Tomography (CAT) scans are both advanced imaging techniques used in medical diagnostics, but many people are unsure about the differences between the two. Are they the same thing? Or are there distinct variations in their technology and applications? Let’s delve into the details to unravel this common source of confusion.

The Mechanics of CT and CAT Scans

Both CT and CAT scans utilize X-rays to generate detailed, cross-sectional images of the body’s internal structures. The primary difference lies in the technology used to acquire and process the data.

A CT scan employs a series of narrow X-ray beams that move through the body in an arc, with the X-ray detector able to discern hundreds of different levels of density. This data is then transmitted to a computer, which assembles a three-dimensional, cross-sectional picture of the scanned area.

In contrast, a CAT scan uses the same fundamental X-ray technology, but the term “Computerized Axial Tomography” reflects the specific method of data acquisition and image reconstruction. CAT scans capture a series of individual “slices” or cross-sections of the body, which are then compiled by a computer to create a three-dimensional representation.

Applications and Advantages of CT and CAT Scans

Both CT and CAT scans are invaluable tools in modern medicine, with a wide range of diagnostic applications. They are particularly useful for visualizing soft tissues, blood vessels, the lungs, brain, abdomen, and bones.

CT scans are often the preferred method for diagnosing various cancers, as they can confirm the presence, location, size, and impact of a tumor on nearby tissues. They are also highly effective in assessing bone diseases, injuries, and vascular conditions.

While MRI scans may be better suited for examining the spinal cord and tendons, CT scans excel at providing quick, detailed images of organ damage, internal bleeding, and other trauma-related injuries.

Preparing for and Undergoing a CT or CAT Scan

Before a CT or CAT scan, patients may need to abstain from food and drink for a specific period. They may also be required to drink a contrast dye or receive an injection of a contrast agent, which can help enhance the visibility of certain structures during the imaging process.

During the scan, the patient will lie on a motorized examination table that slides into the CT scanner. In most cases, the patient will be positioned on their back, facing upward, but side or prone positions may be necessary depending on the area being imaged.

Balancing the Benefits and Risks

While CT and CAT scans are invaluable diagnostic tools, it’s important to note that they involve the use of ionizing radiation, which can potentially increase the risk of cancer. Patients should discuss the benefits and risks with their healthcare providers to ensure that the scans are necessary and performed in a way that minimizes exposure.

The Bottom Line: CT and CAT Scans – Synonymous or Distinct?

In summary, while CT and CAT scans are often used interchangeably, they are not exactly the same. CT scans utilize a specific X-ray technology to generate detailed, three-dimensional images, while CAT scans refer to the process of acquiring and reconstructing those cross-sectional images. Regardless of the terminology, both are invaluable diagnostic tools that play a crucial role in modern healthcare.

FAQs

What is the difference between a CT scan and a CAT scan?

The primary difference between a CT scan and a CAT scan is the terminology used to describe the imaging process. A CT (Computed Tomography) scan employs a series of narrow X-ray beams to generate detailed, cross-sectional images of the body’s internal structures. A CAT (Computerized Axial Tomography) scan refers to the same fundamental technology, but the term “Axial Tomography” reflects the specific method of data acquisition and image reconstruction used in the process.

How do CT and CAT scans work?

Both CT and CAT scans use X-rays to capture multiple images of the body, which are then compiled by a computer to create a three-dimensional representation. The key difference is that a CT scanner emits a series of narrow X-ray beams that move through the body in an arc, while a CAT scanner captures a series of individual “slices” or cross-sections of the body. The data from these scans is then processed by a computer to generate the final 3D image.

What are the common applications of CT and CAT scans?

CT and CAT scans are used for a wide range of diagnostic purposes, including the detection and evaluation of various cancers, assessment of bone diseases and injuries, visualization of blood vessels and organs, and the examination of head and neck structures. They are particularly useful for obtaining detailed images of soft tissues, the lungs, abdomen, and brain.

What should I expect during a CT or CAT scan?

Before a CT or CAT scan, patients may need to refrain from eating or drinking for a specific period and may be required to drink a contrast dye or receive an injection of a contrast agent. During the scan, the patient will lie on a motorized examination table that slides into the CT scanner. The patient may need to lie on their back, side, or prone, depending on the area being imaged.

Are CT and CAT scans safe?

CT and CAT scans use ionizing radiation, which can potentially increase the risk of cancer. Patients should discuss the benefits and risks with their healthcare providers to ensure that the scans are necessary and performed in a way that minimizes exposure. The healthcare team will take precautions to protect the patient’s health and safety during the imaging process.

When would a doctor recommend a CT scan over an MRI?

Doctors may recommend a CT scan over an MRI when they need to quickly obtain detailed images of the body’s internal structures, particularly in cases of trauma, internal bleeding, or organ damage. CT scans are also preferred for visualizing the lungs, chest cavity, and certain types of cancer, as they provide superior imaging of these areas compared to MRI.

Can a CT scan detect tumors?

Yes, CT scans are highly effective in detecting and evaluating various types of tumors, including those in the brain, abdomen, lungs, and other organs. The detailed cross-sectional images generated by a CT scan can confirm the presence, size, and location of a tumor, as well as its impact on surrounding tissues.

CT scan or CAT scan: How does it work?

A computerized tomography (CT) or computerized axial tomography (CAT) scan combines data from several X-rays to produce a detailed image of structures inside the body.

CT scans produce 2-dimensional images of a “slice” or section of the body, but the data can also be used to construct 3-dimensional images. A CT scan can be compared to looking at one slice of bread within a whole loaf.

CT scans are used in hospitals worldwide.

A CT scanner emits a series of narrow beams through the human body as it moves through an arc.

This is different from an X-ray machine, which sends just one radiation beam. The CT scan produces a more detailed final picture than an X-ray image.

The CT scanner’s X-ray detector can see hundreds of different levels of density. It can see tissues within a solid organ.

This data is transmitted to a computer, which builds up a 3-D cross-sectional picture of the part of the body and displays it on the screen.

Sometimes, a contrast dye is used because it can help show certain structures more clearly.

For instance, if a 3-D image of the abdomen is required, the patient may have to drink a barium meal. The barium appears white on the scan as it travels through the digestive system.

If images lower down the body are required, such as the rectum, the patient may be given a barium enema. If blood vessel images are the target, a contrast agent will be injected into the veins.

The accuracy and speed of CT scans may be improved with the application of spiral CT, a relatively new technology. The beam takes a spiral path during the scanning, so it gathers continuous data with no gaps between images.

CT is a useful tool for assisting diagnosis in medicine, but it is a source of ionizing radiation, and it can potentially cause cancer.

The National Cancer Institute advise patients to discuss the risks and benefits of CT scans with their doctors.

Share on PinterestA CT scan can detect abnormalities in the soft tissue.

It is useful for obtaining images of:

• soft tissues
• the pelvis
• blood vessels
• lungs
• brain
• abdomen
• bones

CT is often the preferred way of diagnosing many cancers, such as liver, lung, and pancreatic cancers.

The image allows a doctor to confirm the presence and location of a tumor, its size, and how much it has affected nearby tissue.

A scan of the head can provide important information about the brain, for instance, if there is any bleeding, swelling of the arteries, or a tumor.

A CT scan can reveal a tumor in the abdomen, and any swelling or inflammation in nearby internal organs. It can show any lacerations of the spleen, kidneys, or liver.

As a CT scan detects abnormal tissue, it is useful for planning areas for radiotherapy and biopsies, and it can provide valuable data on blood flow and other vascular conditions.

It can help a doctor assess bone diseases, bone density, and the state of the patient’s spine.

It can also provide vital data about injuries to a patient’s hands, feet, and other skeletal structures. Even small bones are clearly visible, as well as their surrounding tissue.

CT versus MRI

The main differences between CT and MRI are:

• A CT scan uses X-rays, but an MRI uses magnets and radio waves.
• Unlike an MRI, a CT scan does not show tendons and ligaments.
• MRI is better for examining the spinal cord.
• A CT scan is better suited to cancer, pneumonia, abnormal chest x-rays, bleeding in the brain, especially after an injury.
• A brain tumor is more clearly visible on MRI.
• A CT scan shows organ tear and organ injury more quickly, so it may be more suitable for trauma cases.
• Broken bones and vertebrae are more clearly visible on a CT scan.
• CT scans provide a better image of the lungs and organs in the chest cavity between the lungs.

The patient may need to abstain from food, and possibly drink, for a specific period before the scan.

On the day

In most places, the patient will need to undress, usually down to their underwear, and put on a gown that the health center will provide. Avoid wearing jewelry.

If the hospital does not provide a gown, the patient should wear loose-fitting clothes free of metal buttons and zippers.

Some patients may have to drink a contrast dye, or the dye may be given as an enema, or injected.This improves the picture of some blood vessels or tissues.

Any patient who has an allergy to contrast material should tell the doctor beforehand. Some medications can reduce allergic reactions to contrast materials.

As metal interferes with the workings of the CT scanner, the patient will need to remove all jewelry and metal fastenings.

During the scan

The patient will need to lie down on a motorized examination table that slides into a doughnut-shaped CT scanner machine.

In most cases, the patient will lie on their back, facing up. But, sometimes, they may need to lie facedown or sideways.

After one x-ray picture, the couch will move slightly, and then the machine will take another image, and so on. The patient needs to lie very still for the best results.

During the scan, everybody except for the patient will leave the room. An intercom will enable two-way communication between the radiographer and the patient.

If the patient is a child, a parent or adult might be allowed to stand or sit nearby, but they will have to wear a lead apron to prevent radiation exposure.

Share on PinterestThe doctor should explain why the scan is needed, any other options available, and the pros and cons of having a CT scan.

A CT scan involves a small, targeted dose of radiation.

These levels of radiation, even in people who have undergone several scans, has not proven to be harmful.

The chance of developing cancer as the result of a CT scan is thought to be less than 1 in 2,000.

The amount of radiation involved is estimated to be around the same as a person would be exposed to in a space of between several months and several years of natural exposure in the environment.

A scan is only given if there is a clear medical reason to do so. The results can lead to treatment for conditions that could otherwise be serious. When the decision is taken to perform a scan, doctors will ensure that the benefits outweigh any risk.

Problems that could possibly arise from radiation exposure include cancer and thyroid issues.

This is extremely unlikely in adults, and also unlikely in children. However, are more susceptible to the effects of radiation. This does not mean that health issues will result, but any CT scans should be noted on the child’s medical record.

In some cases, only a CT scan can show the required results. For some conditions, an ultrasound or MRI might be possible.

Can I have a CT scan if I am pregnant?

Any woman who suspects she may be pregnant should tell her doctor beforehand, because there is a risk that the x-rays could harm the fetus.

Citing the American College of Radiography, the American Pregnancy Association (APA) point out that “No single diagnostic x-ray has a radiation dose significant enough to cause adverse effects in a developing embryo or fetus. ”

However, the APA notes that CT scans are not recommended for pregnant women, “Unless the benefits clearly outweigh the risk.”

CT scans and breastfeeding

If a lactating, or breastfeeding, mother needs an iodinated intravenous dye for contrast, she should avoid breastfeeding for about 24 hours as may pass into the breast milk.

I have claustrophobia: Can I have a CT scan?

A patient who has claustrophobia should tell their doctor or radiographer beforehand. The patient may be given an injection or tablet to calm them down before the scan.

Your health care provider will usually be able to recommend a suitable facility for a scan. You can check if a radiologist is accredited by searching on the website of the American College of Radiology.

CT Scan (CAT Scan): Procedure, Risks, and Results

For certain medical conditions, imagery from an X-ray or ultrasound test isn’t enough. A computed tomography (CT) scan provides a more detailed view of your tissues, blood vessels, and bones.

Doctors and other healthcare professionals have years of training in their field, but there are still many things they can’t diagnose simply by looking at or listening to your body. That’s where tests like a CT are helpful.

In this article, we look closely at how a CT scan works, what it’s typically used for, and what the procedure is like.

A CT scan uses computers and rotating X-ray machines to create cross-sectional images of the body. These images provide more detailed information than typical X-ray images. They can show the soft tissues, blood vessels, and bones in various parts of the body.

A CT scan may be used to visualize the:

• head
• shoulders
• spine
• heart
• abdomen
• knee
• chest

During a CT scan, you lie in a tunnel-like machine while the inside of the machine rotates and takes a series of X-rays from different angles.

These pictures are then sent to a computer, where they’re combined to create images of slices, or cross-sections, of the body. They may also be combined to produce a 3-D image of a particular area of the body.

CT scan vs. CAT scan: What’s the difference?

A CT scan and a CAT scan are the same thing. CT stands for computerized tomography and CAT stands for computerized axial tomography.

The original name for this scan was an EMI scan, named after the company that created the technology. That evolved to CAT scan, and CT is simply a more modern, simplified version of this name.

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CT scans can provide detailed images of bones, tissues, and even blood vessels inside your body.

However, the images that are produced by these scans appear in shades of blacks and grays. It can be difficult at times even for a trained eye to differentiate one tissue type from another in certain situations.

Contrast dyes contain barium or iodine and can be given in a number of ways, including orally and intravenously (in your vein). These dyes increase the contrast level and resolution of the final images produced with the CT scan for a more exact diagnosis.

However, there are a few risks associated with using contrast dyes. For example, there’s a higher chance of allergic reactions to the dyes, and they’re also not good for your kidneys.

Still, every CT scan exposes you to a certain level of radiation, and a CT scan with contrast may produce better results than one without. It may also prevent the need for a repeated scan.

Below is a comparison of when CT scans may be used with or without a contrast dye.

A CT scan has many uses, but it’s particularly well-suited for diagnosing diseases and evaluating injuries. The imaging technique can help your doctor:

• diagnose infections, muscle disorders, and bone fractures
• pinpoint the location of masses and tumors, including cancer
• study the blood vessels and other internal structures
• assess the extent of internal injuries and internal bleeding
• guide procedures, such as surgeries and biopsies
• monitor the effectiveness of treatments for certain medical conditions, including cancer and heart disease

The test is minimally invasive and can be conducted quickly.

A CT scan is painless, but it does take a few steps to get successful images.

How to prepare for a CT scan

CT scans don’t require much preparation. If needed, you can do a CT scan with or without contrast very quickly. In fact, this happens in most cases where a CT scan is needed to diagnose traumatic injuries or a stroke.

If you’re scheduled for a CT scan with contrast dye, it may help to refrain from eating solid foods for up to 4 hours before your test. This is especially true if your CT scan is being done to get images of your abdomen.

If your doctor is using oral contrast for your CT scan, you’ll probably be given the contrast before the day of your scan and instructed on how to prepare and drink it. Generally, you will want to start drinking the solution within an hour or two of your scan, drinking a portion of the solution every 15 minutes.

Your doctor or radiologist will give you specific instructions. If you’re having intravenous (IV) contrast, a catheter will be inserted into your vein when you arrive at the testing facility.

Otherwise, the only preparations you need to take before a CT scan are to remove metallic objects and medication devices from your body. This includes:

• jewelry and piercings
• watches
• glasses
• hairpins
• hearing aids
• dentures
• bras with underwire
• “antimicrobial” clothing with silver technology
• nicotine patches
• other medication patches

What to expect during a CT scan

When you arrive for your CT scan, you’ll be asked to change into a hospital gown. The technician doing your scan may insert an IV catheter in your arm or leg and ask whether you have removed any metal devices or medication patches prior to your arrival.

They may also review why you’re having the scan, any allergies you may have, and other special instructions.

When it’s time to begin the scan, you’ll be positioned on a long narrow table, and you may be secured in place with velcro straps or other safety devices. The table will slide in and out of the circular scanner depending on which parts of your body need to be visualized.

The technician will leave the room before operating the scanner and may give you instructions over an intercom.

As the table moves in and out of the scanner, the machine will rotate around you making a loud noise. You may be asked to hold your breath or maintain certain positions. Otherwise, you should hold as still as possible to prevent the scanner from capturing blurry images.

The entire process should take between 20 minutes and 1 hour.

After your CT scan

Once the CT scan is over, the images are sent to a radiologist for examination. A radiologist is a doctor who specializes in diagnosing and treating conditions using imaging techniques, such as CT scans and X-rays.

Your doctor will follow up with you to explain the results.

There are very few risks associated with a CT scan. These include:

• exposure to radiation
• allergic reactions to contrast dyes
• increased cancer risk with multiple scans

If you have an allergy to contrast dye, your doctor may choose to do the scan without contrast. If using contrast is absolutely necessary, your doctor may treat you with steroids or other medications to help prevent an allergic reaction.

After the scan, the contrast dye you were given will be eliminated naturally from your body through your urine and stool. Contrast dye can cause some strain to the kidneys, so you may be instructed to drink a lot of water after your exam.

Can I have a CT scan if I’m pregnant?

You might be nervous about the risks of imaging scans while pregnant, but the American College of Obstetricians and Gynecologists (ACOG) says the doses of radiation in a CT scan are far below what would cause harm to a developing fetus.

Ultrasounds and MRI scans are usually the first choices for pregnant people, but CT scans are safe and should not be avoided if medically necessary, according to ACOG.

A contrast dye can still be used, but its use should be limited unless it can significantly improve the accuracy of a diagnosis.

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CT scan results are considered typical if the radiologist didn’t see any of the following in the images:

• tumors
• blood clots
• fractures
• other atypical characteristics

If any atypical characteristics are detected during the CT scan, you may need further tests or treatments depending on the type of atypicality found.

CT scans are an excellent tool for diagnosing problems with soft tissues, blood vessels, and other body parts that can’t be seen with X-ray or ultrasound imaging.

These painless scans don’t require much preparation and can be done quickly in emergency situations. A CT scan takes less than an hour to do, but you may not get results right away, depending on who is interpreting the results.

Your doctor will let you know if a contrast dye is necessary for your scan and what action you need to take after the images are evaluated.

Use of MRI and CT for pets

MRI and CT

Magnetic resonance imaging (MRI) and X-ray computed tomography (CT) are methods of examining various organs by computer-assisted reconstruction of sliced ​​or 3D images. Currently, these are one of the most accurate methods for diagnosing structural disorders of bones, joints, brain, blood vessels, internal organs, and soft tissues in animals.

MRI – what is it

Magnetic resonance imaging is a complex highly informative diagnostic method based on the phenomenon of nuclear magnetic resonance of hydrogen atoms in the cells of the body. With MRI pulses in a magnetic field, vibrations of hydrogen atoms are received in the form of echo signals, which are converted into a picture by means of a computer program. This image can be in different planes. Analysis of these images helps establish the diagnosis. X-ray or other types of ionizing radiation are not used in MRI, only a magnetic field.

When MRI is used for animal diagnostics

Animal MRI is most commonly used for effective soft tissue assessment. For example, studies of the organs of the central nervous system (brain and spinal cord), spine and ligamentous and muscular systems (musculoskeletal system), as well as organs of the small pelvis and abdominal cavity. MRI for dogs allows you to assess the structure of the soft tissues of internal organs, identify developmental disorders, traumatic changes, tumors, etc. (photo 1, 2).

What is CT

Computed tomography is one of the most modern methods of X-ray diagnostics. A CT scanner is a coil (gantry) into which the patient enters during the examination, located on the table. The gantry rotates the source or sources generating radiation around the patient, then the x-ray image data is processed by a computer and an x-ray image is obtained. Scanning the patient’s body with x-rays from all sides at different angles, a CT scanner creates a layered x-ray image of the internal organs.

When to use CT

This examination method is well established for assessing bone and cartilage structures, tumors and fluids. CT in animals is widely used to diagnose bone damage, trauma and bleeding. It is used as a method of angiography and can evaluate the excretory (excretory) properties of organs (photo 3, 4, 5, 6).

What is the difference between MRI and CT

The main difference between MRI and CT lies in the different physical phenomena used in the devices. In the case of CT, this is X-ray radiation, which gives an idea of ​​the physical state of a substance, and in the case of MRI, it is a constant magnetic field and radio frequency electromagnetic radiation, which gives information about the chemical structure of tissues. These methods combine the possibility of layer-by-layer tissue scanning.

Both methods are widely used in veterinary medicine in patients with neurological problems, but there is a particular difference. On MRI in dogs, the structures of the brain, spinal cord and peripheral nerves are well visualized, while on CT they are not so well visualized. On CT, the vertebrae themselves, intervertebral discs and spinal canals are well visualized.

Both methods additionally include the possibility of contrasting. Injected contrast agents can accumulate in the pathological tissue and improve the visualization of the necessary structures. This is especially true in the diagnosis of tumors of various localization.

CT is preferred for diagnosing lung pathologies.

Before prescribing a study, it is necessary to understand which of the methods will be most informative and useful to a specialist. In some cases, it is necessary to use MRI and CT at the same time. These techniques require general anesthesia in animals, and therefore some patients may have contraindications to anesthesia. Metal objects (constructions for osteosynthesis, pacemakers) are a contraindication to MRI.

Dear pet owners! At the moment, MRI and CT diagnostics are not performed at the veterinary center of Dr. Vorontsov. If necessary, we send these studies to other institutions. We review the brought pictures and records to make a diagnosis.

Where to get a CT scan for a dog or cat in St. Petersburg

Computed tomography (CT) has been used in human and veterinary medicine since the last quarter of the 20th century. The first CT scanners appeared in veterinary clinics in St. Petersburg about 5 years ago.

The essence of the method (for the owner)

Tomography is a visual diagnostic method that allows you to examine the internal structure of an object using X-rays.

To obtain information about the internal structure of an object, X-rays are passed through the object. Initially, the method was called “X-ray Computed Tomography”. Unlike radiography, the result of which is a projection image of a translucent object, as a result of computed tomography, a series of sequential slice images is obtained.

The tomograph consists of a movable patient table, a gantry (“donut”, in the “hole” of which the table with the patient moves), and a computer that controls the scanning process and processes the information received.

Inside the gantry is an X-ray tube and an array of detectors mounted opposite each other on a rotor and rotating around the patient. The tube emits a narrow fan-shaped beam of x-rays. The radiation passes through the patient. Different tissues absorb x-rays differently. An array of detectors collects information about how much X-ray radiation was absorbed at a particular point in the object. This information is collected every quarter degree of rotation of the rotor. The computer calculates this information and builds a slice image.

The animal table moves into the gantry, the rotor rotates around it, the computer counts. In a 16-slice tomograph, 16 slices can be obtained in one revolution of the rotor.

Each slice is a two-dimensional digital picture consisting of squares (pixels). The usual slice resolution is 512×512 pixels. Slices are thick. Typically, the slice thickness can be from 0.6 to 3 mm, it depends on the tomograph model and the selected scanning protocol. Since the slice has a thickness, then we can talk not about “squares”, but about “cubes” (“volumetric pixels”).

Each image cube contains information about how much X-ray radiation was absorbed by the corresponding cube in the object under study. That is, the density of the corresponding element of the object for x-rays. This density is measured in units of the Hounsfield scale (HU). The zero of this scale is the absorption of X-rays in distilled water, and 1000 is the absorption of X-rays in air. The density of adipose tissue is about 120HU. Density of tissues of parenchymal organs is about +30…+70HU, bone density is above +300. The X-ray density values ​​in each volume element can be displayed in various ways when working with an image. Most often, density information is displayed using grayscale.

In fact, we distinguish between the borders of different tissues, due to the fact that they have different densities. Not all structures will be clearly visible on a scan. Many tissues have similar or identical X-ray densities. In this case, they will be indistinguishable in the image. In many cases, image quality and the value of the information obtained can be improved using various contrast methods. Contrasting is understood as the introduction of a radiopaque substance into a hollow organ, vessel, joint cavity, under the membrane of the spinal cord, etc. Usually, radiopaque liquids are administered (nowadays, non-ionic preparations containing iodine are mainly used).

Let me remind you that we have more than one slice. One study series usually contains from several hundred to one and a half thousand sections. Since we have a batch of sequential slices, then we have a three-dimensional model of the object. You can work with this model, for example, reconstruct a slice in an arbitrary plane, reconstruct slices with a greater thickness, or visualize the surface of any anatomical structure.

There are many sections in the study series. And in one study there can be several series. For example, in the first series, the elbow joints were examined, and in the second, the cervical spine. Or the first series is “native”, and the second and subsequent series scanned the same area, at certain intervals after intravenous administration of a radiopaque substance, assessing the time of its appearance in vessels, organs, and the bladder.

What pathologies is CT used for in animals?

Here are some of the most common reasons pets are referred for CT:

• Lame young dogs of large breeds. These are very common patients on CT scans. In many cases, radiography is not sufficient to detect joint pathology. Even taking pictures of the joint of interest in several projections, the orthopedist may not reveal pathology. This patient is referred for CT. In this case, both limbs are usually examined (it is very convenient to compare the diseased paw with a healthy one) and not one joint, but several. Not always the cause of lameness lies in one joint. Also, why not explore other joints that may have breed-specific disease. Often, according to the results of such a CT scan, arthroscopic surgery is prescribed.

Male, 3 y.o. Panosteitis (endosteal growth in the medullary canal of the left femur).

• Polytrauma. For example, animals that have fallen out of a window or been hit by a car. When you need to quickly assess all the injuries that have occurred, from fractures of the bones of the limbs, spine, skull, to damage to the organs and walls of the chest and abdominal cavity. The completeness of the diagnosis is necessary here in order to assess the patient’s condition and decide which injuries require urgent intervention.
• Dogs and cats with suspected congenital portosystemic shunts. Congenital portosystemic shunts are not uncommon in indoor dog breeds. Normally, venous blood from the stomach, intestines, pancreas and spleen is collected in the portal vein and enters the liver through it. The liver here plays the role of a “filter” that cleanses the blood, which contains a large amount of toxins formed in the intestines. After being “cleansed” in the liver, the blood gets rid of toxins and merges into the caudal vena cava. A shunt is a pathological vessel through which part of the blood from the portal vein, bypassing the liver, merges into the systemic venous circulation. On CT angiography, you can visualize the location and describe the shunt, which is necessary for planning the operation.

Yorkshire terrier with congenital portosystemic shunt and stones in the bladder cavity.

• Kidneys and ureters. CT can detect stones in the ureters and bladder. To visualize the ureters, excretory urography is used: the patient is injected intravenously with a radiopaque drug, which is excreted by the kidneys, enters the ureters and bladder. To visualize the cavity of the bladder and the lumen of the urethra, a radiopaque drug is usually administered retrograde – through a urethral catheter.

Cat, 7 years old. Stones in the lumen of the left ureter.

Dog, 14 years old. excretory urography. Dilated renal pelvis and ureters.

• Animals with free fluid in the pleural cavities. There are many reasons for the appearance of free fluid. From inflammation of the pleura, to a blood clot in a vessel or compression of the main vessel by a tumor. CT can diagnose most of the causes of fluid. To visualize the vessels, a radiopaque contrast agent is injected intravenously, this is called CT angiography. During the study, fluid is usually aspirated, both to obtain material for the laboratory and to reduce respiratory failure.

Cat, 16 years old. Free fluid in the pleural cavities, volvulus of the cranial lobe of the right lung.

• Pathologies of the middle and inner ear and nasopharynx. CT allows assessing the presence of fluid in the tympanic cavity (otitis media), destruction of the petrous part of the temporal bone in case of purulent internal otitis media, and nasopharyngeal polyps.
• Dental pathologies.

Male, 10 years old, last 6 months, an abscess under the right eye periodically forms. Radical cysts.

• Chronic cough. Very many pathologies that cause coughing do not manifest themselves in any way on x-rays. If the cough does not respond to symptomatic treatment, the therapist prescribes a CT scan. According to the results of CT, tracheobronchoscopy may be additionally prescribed.

Male, 4 years old, chronic bronchitis, bronchial obstruction, broncholiths.

• Orthopedic planning. With bone deformities, CT allows you to get a three-dimensional image of the bones of the deformed limb, which allows you to decide how to correct the deformity. If necessary, a three-dimensional model of the bones is printed.
• Spine. A CT scan is sent to examine the spine in many cases. More often these are diseases of the discs, the assumption of compression of the spinal cord. In some cases, scanning without contrast is sufficient (for example, without contrast, about 95% of extrusions of intervertebral discs in dachshunds are well visualized). In some cases, contrasting is necessary (to assess spinal cord compression, contrast is injected into the subarachnoid space by spinal puncture, this method of contrasting is called myelography). If instability of any vertebrae is suspected, several series are made with a different position of the patient (with flexion and extension of the studied department, this is called a stress study). Often CT has to be supplemented with magnetic resonance imaging.

French lap dog, 6 years old, intervertebral disc extrusion.

Dog, 2 years old. CT myelography. Spinal cord compression in the cervical region.

• Cancer search. The key to successful management of patients with tumors requires the most complete study to assess existing metastases and search for comorbidities. This is necessary for a correct assessment of the severity of the tumor process and for treatment planning. With CT, it is possible to scan the patient completely in order to detect the presence of metastases in the lungs, abdominal organs, and bones. Locate and measure enlarged lymph nodes. Assess the location of the tumor and its relationship to organs and large vessels. Plan surgical approach and radiation therapy. Assess the effectiveness of the treatment. If necessary, CT-guided tumor biopsy can be performed.

Dachshund 5 years old, it’s not a tumor, it’s a peritoneal-pericardial hernia, with the exit of the liver lobe.

Cat, 11 years old. Osteoma of the right zygomatic bone.

Male, 7 years old, tumor of the sternum with mediastinal invasion and lung metastases

West Highland White Terrier, 10 years old. Tumor of the liver, compression of the caudal vena cava and portal veins.

Dog, 9 years old. Tumor of the cranial mediastinum. Biopsy.

Why it is necessary to conduct a study

Because it is impossible to treat an animal without making a diagnosis. CT is another non-invasive (i.e. “no surgery”) imaging technique, and in many cases this technique helps in making a diagnosis.

Examination limitation

There are several situations in which CT will not be possible or there will be certain risks.

Risk associated with anesthesia in severely unstable animals. Often these are animals with a serious degree of heart or respiratory failure, dehydrated animals. The decision on the need for CT in such patients is made by the referring physician, with the participation of the anesthesiologist and the CT physician. Anesthesia in such cases may require preliminary preparation of the patient.

Risk associated with intravenous administration of radiopaque agents in patients with severe renal insufficiency. Deterioration of kidney function in such patients has been described in human medicine and is referred to as contrast-induced nephropathy. There are no studies in veterinary medicine on the effect of radiopaque agents in animals with renal insufficiency, but it is assumed that such effects are possible.

Human medicine describes individual allergic reactions to iodine-containing radiopaque preparations. Isolated cases are also described in veterinary medicine. In the event of such reactions, they are stopped by the anesthesiologist immediately upon occurrence. With modern non-ionic radiopaque agents, these cases are extremely rare.

Pregnant females should not be subjected to CT due to X-ray exposure to fetuses.

Bulky metal structures degrade image quality due to X-ray scattering artifacts. We are talking about plates for osteosynthesis, artificial joints, transpedicular fixators.

Chips used to identify dogs and cats produce virtually no artifacts and do not need to be removed prior to CT.

Residues of barium sulfate in the gastrointestinal tract also cause artifacts. If possible, it is best to do a CT scan 4-7 days after the X-ray with barium sulfate.

How the examination works

Computed tomography can take from 4-5 to 20-40 minutes. The study time depends on the diagnostic tasks, the scanning area, the protocols used, and the size of the animal.

A CT scan is usually done under anesthesia. It is very rare to get away without anesthesia. It is possible to scan without anesthesia patients in a coma. It is rarely possible to avoid anesthesia in cases with very obedient dogs or calm cats sitting in textile carriers, but, as a rule, such patients still move when they hear the noise of the apparatus and feel the movement of the table.

Any movement of the patient in one way or another degrades the quality (sometimes to complete illegibility) of those sections that were scanned at the moment of movement. In addition, most CT examinations require not only the immobility of the patient, but also his placement in the optimal position, which is impossible to do without anesthesia.

An anesthetist attends to the animal during the examination. It constantly monitors the patient’s condition using a monitor (pulse, ECG, respiratory rate, carbon dioxide level in the exhaled air).

We usually use inhalation anesthesia for CT scans. Inhalation anesthesia is considered the most manageable and safe for the patient. An intravenous catheter is placed before the study. A hypnotic agent (usually propofol) is injected through the catheter. Immediately during the injection, the animal falls asleep. The hypnotic does not work for long, a few minutes, it is needed in order to intubate the animal – to insert a breathing tube through the larynx into the trachea. This tube is connected to an anesthetic-respiratory machine, which delivers a mixture of oxygen and isoflurane vapor (a volatile liquid used for anesthesia) into the animal’s lungs. The animal essentially self-regulates the depth of its sleep: it starts to wake up, breathing becomes deeper and more frequent, more gas enters the lungs and sleep becomes deeper. And when the study is completed, the animal will wake up a few minutes after the gas vapor stops flowing into the lungs.

The animal is placed and fixed in the position required for the study. For the study of the organs of the chest and abdominal cavity, this is most often the position on the stomach. For joints – more often lateral. For the spine, either on the stomach or on the back.

Monitor sensors are attached to the animal, with which the anesthesiologist will monitor the patient’s condition in order to manage anesthesia.

The imaging doctor makes the first series of scans, the so-called topogram – a two-dimensional picture, according to which all subsequent series of scans are planned. And adjusts the research protocols for the diagnostic tasks to be solved. The protocol is understood as the scanning parameters that allow obtaining sufficient image quality with minimal radiation exposure. Reconstruction parameters that make it possible to obtain several reconstructions from one scan series, for example, with better visualization of soft tissues or the boundaries of bone structures. A sequence of several synchronized series after the administration of a contrast agent.

Next, the actual scanning takes place, which may consist of one or more series.

Immediately after the scan, the animal is transferred to the hospital, where it wakes up and is under the supervision of the hospital doctors for about an hour.

While the animal is waking up, the imaging doctor works with the obtained images, burns a disk with the study, which will be given to the animal’s owners and writes a conclusion. We try to describe the study during the time that the animal is in the hospital (that is, about an hour after CT). But this does not always work out: there may be extraordinary emergency patients, or there may be a complex case that will take more time to describe. Then we send the conclusion by e-mail within a day.

Our advantages

CT is carried out on the basis of the Pride veterinary center.

Pride Diagnostic Center has a friendly team of veterinarians.