C.T. OR CAT SCAN. ( COMPUTED AXIAL TOMOGRAPHY )

                     C.T. OR CAT SCAN ( COMPUTED AXIAL TOMOGRAPHY)

What is a C.T. scan ? ......CT (computed tomography), sometimes called CAT scan, uses special x-ray equipment to obtain image data from different angles around the body, and then uses computer processing of the information to show a cross-section of body tissues and organs.CT imaging is particularly useful because it can show several types of tissue :lung, bone, soft tissue and blood vessels with great clarity. Using specialized equipment and expertise to create and interpret CT scans of the body, radiologists can more easily diagnose problems such as cancers, cardiovascular disease, infectious disease, trauma and musculoskeletal disorders.Because it provides detailed, cross-sectional views of all types of tissue, C T is one of the best tools for studying the chest and abdomen. It is often the preferred method for diagnosing many different cancers, including lung, liver and pancreatic cancer, since the image allows a physician to confirm the presence of a tumor and measure its size, precise location, and the extent of the tumor's involvement with other nearby tissue. CT examinations are often used to plan and properly administer radiation treatments for tumors, to guide biopsies and other minimally invasive procedures, and to plan surgery and determine surgical resectability. CT can clearly show even very small bones, as well as surrounding tissues such as muscle and blood vessels. This makes it invaluable in diagnosing and treating spinal problems and injuries to the hands, feet and other skeletal structures. CT images can also be used to measure bone mineral density for the detection of osteoporosis. In cases of trauma, CT can quickly identify injuries to the liver, spleen, kidneys, or other internal organs. Many dedicated shock-trauma centers have a CT scanner in the emergency room. CT can also play a significant role in the detection, diagnosis and treatment of vascular diseases that can lead to stroke, kidney failure, or even death.

HOW SHOULD I PREPARE FOR THE CAT SCAN ? ....You should wear comfortable, loose-fitting clothing for your C T exam. Metal objects can affect the image, so avoid clothing with zippers and snaps. You may also be asked to remove hairpins, jewelry, eyeglasses, hearing aids and any removable dental work, depending on the part of the body that is being scanned. You may be asked not to eat or drink anything for one or more hours before the exam. Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant

                                                                A LOOK AT THE EQUIPMENT.

                                           Slightly different designs, but they all operate the same.

The CT scanner is a large, square machine with a hole in the center, something like a doughnut. The patient lies still on a table that can move up or down, and slide into and out from the center of the hole. Within the machine, an X-ray tube on a rotating gantry moves around the patient's body to produce the images, making clicking and whirring noises as the table moves. Though the technologist will be able to see and speak to you, you will be alone in the room during the exam.

HOW DOES THE PROCEDURE WORK ? .....In many ways, CT scanning works very much like other x-ray examinations. Very small, controlled amounts of x-ray radiation are passed through the body, and different tissues absorb radiation at diffrent rates. With plain radiology, when special film is exposed to the absorbed x-rays, an image of the inside of the body is captured. With CT, the film is replaced by an array of detectors, which measure the x-ray profile.

Inside the CT scanner is a rotating gantry that has an x-ray tube mounted on one side and an arc-shaped detector mounted on the opposite side. An x-ray beam is emitted in a fan shape as the rotating frame spins the x-ray tube and detector around the patient. Each time the x-ray tube and detector make a 360 degree rotation and the x-ray passes through the patient's body, the image of a thin section is acquired. During each rotation, the detector records about 1,000 images (profiles) of the expanded x-ray beam. Each profile is then reconstructed by a dedicated computer into a two-dimensional image of the section that was scanned. Multiple computers are typically used to control the entire CT system.

HOW IS THE CAT SCAN PERFORMED ? ....The technologist begins by positioning the patient on the CT table. The patient's body may be supported by pillows to help hold it still and in the proper position during the scan. As the study proceeds, the table will move slowly into the CT scanner "doughnut." Depending on the area of the body being examined, the increments of movement may be so small that they are almost undetectable, or large enough that the patient feels the sensation of motion.A CT examination often requires the use of different contrast materials to enhance the visibility of certain tissues or blood vessels. The contrast material may be injected through an IV directly into the blood stream, swallowed or administered by enema, depending on the type of examination. Before administering the contrast material, the radiologist or technologist will ask whether the patient has any allergies, especially to medications or iodine, and whether the patient has a history of diabetes, asthma, a heart condition, kidney problems, or thyroid conditions. These conditions may indicate a higher risk of reaction to the contrast material or potential problems eliminating the material from the patient's system after the exam. A CT examination usually takes five minutes to half an hour. When the exam is over, the patient may be asked to wait until the images are examined to determine if more images are needed.

WHAT WILL I EXPERIENCE DURING THE PROCEDURE ? .... CT scanning causes no pain, and with spiral CT, the need to lie still for any length of time is reduced. For different parts of the body, the patient preparation will be different. You may be asked to swallow either water or a positive contrast material, a liquid that allows the radiologist to better see the stomach, small bowel and colon. Some patients find the taste of the contrast material mildly unpleasant, but most can easily tolerate it. Your exam may require the administration of the material by enema if the colon is the focus of the study. You will experience a sense of abdominal fullness and may feel an increasing need to expel the liquid. Be patient; the mild discomfort will not last long.

Commonly, a contrast material is injected into a vein to better define the blood vessels and kidneys, and to accentuate the appearance between normal and abnormal tissue in organs like the liver and spleen. Some people report feeling a flush of heat and sometimes a metallic taste in the back of the mouth. These sensations usually disappear within a minute or two. Some people experience a mild itching sensation. If it persists or is accompanied by hives (small bumps on the skin), the itch can be treated easily with medication. In very rare cases, a patient may become short of breath or experience swelling in the throat or other parts of the body. These can be indications of a more serious reaction to the contrast material that should be treated promptly, so tell the technologist immediately if you experience these symptoms. Fortunately, with the safety of the newest contrast materials, these adverse effects are very rare.

You will be alone in the room during the scan; however, the technologist can see, hear and speak with you at all times. In pediatric patients, a parent may be allowed in the room with the patient to alleviate fear, but will be required to wear a lead apron to prevent radiation exposure.

                                                               X-RAYS.

          A Typical X-Ray Machine   

An x-ray is a photo taken with a machine which passes electromagnetic radiation through the body, capturing an image of the internal structures.X-rays are a form of electromagnetic radiation (like light); they are of higher energy, however, and can penetrate the body to form an image on film. Structures that are dense (such as bone) will appear white, air will be black, and other structures will be shades of gray depending on density. X-rays can provide information about obstructions, tumors, and other diseases, especially when coupled with the use of barium and air contrast within the bowel.

                                                      ULTRA SOUND SCAN.

                                                  

What are Ultra Sound Scans?

ultrasound scans are images of the internal organs created from sound waves. The images are produced when the sound waves are directed into the body then reflected back to a scanner that measures them.

What are ultrasound scans used for ? ....Ultrasound scanning is used to help monitor and diagnose conditions in many parts of the body, including the kidneys, the liver and the heart. It is often used to examine conditions affecting the organs in a woman's pelvis - the uterus, Fallopian tubes and ovaries. Ultrasound scanning is not dangerous and has no side effects, so it is safe to use during pregnancy.

How does ultrasound work ? .....The ultrasound scanner looks like a small paint roller. As it moves back and forth over the body, it sends sound waves through the skin and muscles. These waves are then turned into an image that appears on a TV screen. The scan can also be copied onto paper or X-ray film.

                       How is an ultrasound scan performed ?           

The way the ultrasound scan is performed depends on the purpose of the examination. The scanner can be used externally on the skin, or through the natural openings of the body, such as the vagina.

For example, if the kidneys or liver are being examined the patient will be told to lie on their back or side on an examination table. Some special gel is spread over the skin, enabling the scan to define the organs as clearly as possible.

However, if a woman's pelvic organs are under examination, a transvaginal scan would provide a better picture. A small probe is gently inserted into the vagina up to the cervix to get the best image. It should not cause more than a slight discomfort.An ultrasound scan does not hurt but the gel used for the examination can feel a bit cold.

                                                FIBRO SCAN

                                                                  

A new piece of equipment that is currently being use is a FIBRO SCAN

FibroScan examination process   

A mechanical pulse is generated at the skin surface, which is propogated through the liver. The velocity of the wave is measured by Ultrasound. The velocity is directly correlated to the stiffness of the liver, which in turn reflects the degree of fibrosis. The stiffer the liver the greater the degree of fibrosis.

The examination is composed of 10 acquisitions. Easy to perform, and rapid, the measurement is expressed with a clear figure in KPa.

The patient lies on his/her back, with the right arm raised behind the head. The measurement is made on the right lobe of the liver, with the probe being placed in an intercostal space.

The results are delivered at the end of the 10 acquisitions.

This is non invasive and painless.                        

                                                                LIVER BIOPSY.  

There are two types of biopsy that can be performed, they are :

•  Percutaneous liver biopsy.

•  Transjugular liver biopsy.

Evaluating a liver condition .....The doctor will always take a medical history and perform a physical exam. Blood studies, known as liver function tests (LFT), give an overview of the health of the liver. If LFT results are persistently abnormal, the doctor will then perform additional medical studies to determine the exact cause of the problem. Finding the cause is important because there are now effective treatments for many liver disorders. Finally, the doctor will want to know not only the specific cause of the problem, but also how severe the condition may be. The liver biopsy helps answer these questions

What is a liver biopsy ? ..... A biopsy is a tiny sample of body tissue -- in this case, liver tissue. The tissue is prepared and stained in a laboratory, so the doctor can view it under a microscope. This usually helps the doctor make a specific diagnosis and determine the extent and seriousness of the condition. It is vital information for determining treatment.

                           ENTRANCE SITE                                  SAMPLE BEING TAKEN

The procedure for a percutaneous Liver Biopsy.

The liver biopsy is usually performed on an outpatient basis. A mild sedative may be given to the patient prior to the procedure. Sometimes, an ultrasound or echo machine is used to identify the best location to make the biopsy. Usually, the doctor can make this determination simply by examination. The patient lies quietly on the back or slightly to the left side. That area of the skin where the biopsy will be done is carefully cleaned. Then, a local anesthetic agent is used to numb the skin and tissue below. A specially designed thin needle is inserted through the skin. At this point, the physician will tell the patient how to breathe. The needle is advanced into and out of the liver. This takes only 1 or 2 seconds. A slender core of tissue is removed with the needle, and is then processed through the laboratory. The entire procedure from start to finish lasts only 15 to 20 minutes.

                                                                TRANSJUGULAR LIVER BIOPSY.                          

                  The procedure for a transjugular Liver Biopsy.

Transjugular liver biopsy is an important alternative to the traditional method of liver biopsy through the skin. With the transjugular method, the biopsy needle is inserted (through a vein in the neck) into the liver from the inside of a vein. Thus, if any bleeding occurs, it will do so back into the blood vessel. This technique a safe means of liver biopsy for patients who have problems with blood clotting or if a large amount of fluid has accumulated in the abdomen around the liver. During the biopsy procedure, vein pressure measurements can also be obtained that help to assess the amount of liver disease present.Transjugular liver biopsy is accomplished by inserting a small catheter into the jugular vein in the neck. The catheter is then guided into the hepatic vein. A biopsy needle is inserted through the tube directly into the liver where a small sample of tissue is taken.transjugular liver biopsies are frequently performed in patients with impaired blood coagulation.

Recovery ....The patient is kept at rest for several hours following the exam. Nurses check the heart rate and blood pressure during this time. There may be some discomfort in the chest or shoulder, however, this is usually temporary. Medication is available for this discomfort, if needed. Before being discharged. In most instances, a liver biopsy is obtained quickly with no problems. As noted, there is occasionally some fleeting discomfort in the right side or shoulder. Internal bleeding can sometimes occur, as can a leak of bile from the liver or gallbladder. These problems are rare and can usually be handled without the need for surgery.A liver biopsy is a simple, rapid method of obtaining a sample of liver for analysis. It provides important information for evaluating and treating liver disorders. While some complications can occur, they are unusual. The benefits of the exam always outweigh the risk. Early, specific, and effective therapy can often prevent irreversible liver damage.

                                                                     PARACENTISIS.

Ascites  ...  Draining off of fluid.

                             A Typical Patient Prior to being drained. (severe)                                                

                                                      What is Paracentisis ?