Where Caring Begins and Outcomes Make the Difference



CT Scan using 3DCT

The Rochester Diagnostic Center has recently acquired the latest technology in 3D SPIRAL Multi Slice CT (MSCT) SCANNING: THE TOSHIBA AQUILION.

This top of the line machine has broadened the diagnostic capabilities of the RDC even further and is one of the many ways the RDC maintains its status as one of the premier diagnostic facilities in the nation.

3D CT allows the RDC to perform extensive scanning of all body parts. To review some examples of such tests, just Click on these pictures:

Total Body Scan - Rochester Medical Center Virtual Colonoscopy - Rochester Medical Center

The Rochester Diagnostic Center has already distinguished itself with CORONARY ANGIOGRAPHY to detect CORONARY BLOCKAGES.  This remarkable achievement has positioned the RDC as 1 of few national centers performing this procedure . 

Frequently Asked Questions:
What are some common uses of the procedure?
How should I prepare for the procedure?
How does the procedure work?
How is the procedure performed?
What will I experience during the procedure?
What are the limitations of CT Scanning of the body?
What are the Benefits vs. Risks?

What are some common uses of the procedure?

    Because it provides detailed, cross-sectional views of all types of tissue, CT is one of the best tools for studying the brain, chest, abdomen, and pelvis. 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 to 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, and to guide biopsies and other minimally invasive procedures. 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 trauma department. CT can also play a significant role in the detection, diagnosis, and treatment of vascular diseases that can lead to stroke, heart attack, gangrene or kidney failure. 
    The 3D MSCT allows for powerful reconstruction of body structures and volume rendering.  This makes techniques such as VOYAGES and FLY- THROUGH possible.  Voyages and Fly-through allow you to virtually travel through blood vessels and body cavities, like the colon (virtual colonoscopy) or the lungs (virtual bronchoscopy).  

How should I prepare for the procedure?

    You should wear comfortable, loose-fitting clothing for your CT exam. Metal objects can affect the image, so avoid clothing with zippers and snaps. You may will 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.

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 different 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 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 3-dimensional image of the section that was scanned. 
    The Aquilion 16 has an extremely rapid gantry rotation of 400 milliseconds.  It also slices down to 0.5 millimeters allowing for the most sensitive and rapid imaging available today.
    You might think of it like looking into a loaf of bread by cutting it into thin slices. When the image slices are reassembled by computer, the result is a very detailed, multidimensional view of the body's interior.
    Spiral (helical) 3D CT has improved the accuracy of CT for many diseases. A new vascular imaging technique - spiral CT angiography - is noninvasive and less expensive than conventional angiography, and allows doctors to see blood vessels without the need for more invasive procedures.
    The term "spiral CT" comes from the shape of the path taken by the x-ray beam during scanning. The examination table advances at a constant rate through the scanner gantry while the x-ray tube rotates continuously around the patient, tracing a spiral path through the patient. This spiral path gathers continuous data with no gaps between images.
    With spiral CT, refinements in detector technology support faster, higher-quality image acquisition with less radiation exposure. It is typically eight to 10 times faster than conventional CT. Such speed is beneficial in all patients but especially in elderly, pediatric, or critically ill patients, populations in which the length of scanning was often problematic. A spiral scan can usually be obtained during A SINGLE BREATH HOLD
    With conventional CT, small lesions may frequently go undetected when a patient breathes differently on consecutive scans, as a lesion may be missed by unequal spacing between scans. The speed of spiral scanning and single breath hold increases the rate of lesion detection.

How is the procedure 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 automatically 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 directly into the blood stream or swallowed depending on the type of examination.  Before scheduling the 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.
    The Rochester Diagnostic Center uses only LOW OSMOLAR CONTRAST MEDIA (LOCM).  This is an expensive dye that has the least potential for allergic reactions and the best profile for renal excretion (this means that it leaves your body better than other dyes do).
    For patients who need contrast for their examination and are known to have allergic reactions to iodine, special precautions are taken to ensure their safety and well-being prior, during, and after the exam. 
    A CT examination usually takes from fifteen 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 a liquid contrast material that allows the radiologist to better see the stomach, small bowel, and colon. Some patients find the taste mildly unpleasant, but most can easily tolerate it.  For virtual colonoscopy, CO2 inflation will be used to minimize discomfort.  You will experience a sense of abdominal fullness, however, 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 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.

What are the limitations of CT Scanning of the Body?

Very fine soft-tissue details in areas such as the knee or shoulder can be more readily and clearly seen with MRI (magnetic resonance imaging). In some situations, soft tissues may be obscured by nearby bone structures in a CT. The exam is not generally indicated for pregnant women.

What are the benefits vs. risks?

bulletUnlike other imaging methods, CT scanning offers detailed views of many types of tissue, including the lung, bones, soft tissues, and blood vessels.
bulletCT examinations are fast and simple. Especially in trauma cases, they can reveal internal injuries and bleeding quickly enough to help save lives.
bulletCT scanning can identify both normal and abnormal structures, making it a useful tool to guide radiotherapy, needle biopsies, and other minimally invasive procedures.
bulletCT scanning is painless, noninvasive, and accurate.
bulletDiagnosis made with the assistance of CT can eliminate the need for invasive exploratory surgery and surgical biopsy.
bulletCT has been shown to be a cost-effective imaging tool for a wide range of clinical problems.
bulletCT does involve exposure to radiation in the form of x-rays, but the benefit of an accurate diagnosis far outweighs the risk. The typical radiation dose from a CT exam is equivalent to the amount of natural background radiation received over a year's time. Among all radiological procedures, radiation exposure from CT of the body is intermediate.
bulletSpecial care is taken during x-ray examinations to ensure maximum safety for the patient by shielding the abdomen and pelvis with a lead apron, with the exception of those examinations in which the abdomen and pelvis are being imaged. Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.
bulletNursing mothers should wait for 24 hours after contrast injection before resuming breast feeding.
bulletThe risk of serious allergic reaction to iodine-containing contrast material is rare, and radiology departments are well equipped to deal with them.


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