What is Dental Cone Beam CT?
Dental cone beam computed tomography (CT) is a special type of x-ray machine used in situations where regular dental or facial x-rays are not sufficient. It is not used routinely because the radiation exposure from this scanner is significantly more than regular dental x-rays. See the Safety page for more information about x-rays. This type of CT scanner uses a special type of technology to generate three dimensional (3-D) images of dental structures, soft tissues, nerve paths and bone in the craniofacialregion in a single scan. Images obtained with cone beam CT allow for more precise treatment planning.
You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.
Metal objects, including jewelry, eyeglasses, dentures and hairpins, may affect the CT images and should be left at home or removed prior to your exam. You may also be asked to remove hearing aids and removable dental work. Women will be asked to remove bras containing metal underwire. You may be asked to remove any piercings, if possible.
Cone beam CT is not the same as conventional CT. However, dental cone beam CT can be used to produce images that are similar to those produced by conventional CT imaging.
With cone beam CT, an x-ray beam in the shape of a cone is moved around the patient to produce a large number of images, also called views. CT scans and cone beam CT both produce high-quality images.
Dental cone beam CT was developed as a means of producing similar types of images but with a much smaller and less expensive machine that could be placed in an outpatient office.
Cone beam CT provides detailed images of the bone and is performed to evaluate diseases of the jaw, dentition, bony structures of the face, nasal cavity and sinuses. It does not provide the full diagnostic information available with conventional CT, particularly in evaluation of soft tissue structures such as muscles, lymph nodes, glands and nerves. However, cone beam CT has the advantage of lower radiation exposure compared to conventional CT.
What are some common uses of the procedure?
Dental cone beam CT is commonly used for treatment planning of orthodontic issues. It is also useful for more complex cases that involve:
surgical planning for impacted teeth.
diagnosing temporomandibular joint disorder (TMJ).
accurate placement of dental implants.
evaluation of the jaw, sinuses, nerve canals and nasal cavity.
detecting, measuring and treating jaw tumors.
determining bone structure and tooth orientation.
locating the origin of pain or pathology.
What is Hysterosalpingography?
Hysterosalpingography, also called uterosalpingography, is an x-ray examination of a woman’s uterus and fallopian tubes that uses a special form of x-ray called fluoroscopy and a contrast material.
An x-ray (radiograph) is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Imaging with x-rays involves exposing a part of the body to a small dose of ionizing radiation to produce pictures of the inside of the body. X-rays are the oldest and most frequently used form of medical imaging.
Fluoroscopy is a special x-ray technique that makes it possible to see internal organs in motion. During a hysterosalpingogram, the uterus and fallopian tubes are filled with a water-soluble contrast material and the radiologist is able to use fluoroscopy to view and assess their anatomy and function.
What are some common uses of the procedure?
Hysterosalpingography is primarily used to examine women who have difficulty becoming pregnant by allowing the radiologist to evaluate the shape and structure of the uterus, the openness of the fallopian tubes, and any scarring within the uterine or peritoneal (abdominal) cavity.
The procedure can be used to investigate repeated miscarriages that result from congenital or acquired abnormalities of the uterus and to determine the presence and severity of these abnormalities, including:
Hysterosalpingography is also used to evaluate the openness of the fallopian tubes, and to monitor the effects of tubal surgery, including:
Blockage of the fallopian tubes due to infection or scarring
The closure of the fallopian tubes in a sterilization procedure and a sterilization reversal
The re-opening of the fallopian tubes following a sterilization or disease-related blockage
How should I prepare?
The hysterosalpingography procedure is best performed one week after menstruation but before ovulation to make certain that you are not pregnant during the exam.
This procedure should not be performed if you have an active inflammatory condition. You should notify your physician or technologist if you have a chronic pelvic infection or an untreated sexually transmitted disease at the time of the procedure.
On the night before the procedure, you may be asked to take a laxative or an enema to empty your bowels, so that the uterus and surrounding structures can be seen clearly.
Prior to the procedure, you may be given a mild sedative or over-the-counter medication to minimize any potential discomfort. Some physicians prescribe an antibiotic prior to and/or after the procedure.
You should inform your physician of any medications being taken and if there are any allergies, especially to iodinated contrast materials. Also inform your doctor about recent illnesses or other medical conditions.
Also, tell your doctor if you have any signs of pelvic infection or pelvic inflammatory disease.
You will be asked to remove some of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, removable dental appliances, eye-glasses and any metal objects or clothing that might interfere with the x-ray images.
Women should always inform their physician and x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so as not to expose the fetus to radiation. If an x-ray is necessary, precautions will be taken to minimize radiation exposure to the baby. See the Safety page for more information about pregnancy and x-rays.
How is the procedure performed?
This examination is usually done on an outpatient basis.
The procedure is like a gynecological exam. The patient is positioned on her back on the exam table, with her knees bent or her feet held up with stirrups and a speculum is inserted into the vagina. The cervix is then cleansed, and a catheter is inserted into the cervix. The speculum is removed and the patient is carefully positioned underneath the fluoroscopy camera. The contrast material then begins to fill the uterine cavity, fallopian tubes and peritoneal cavity through the catheter and fluoroscopic images are taken.
In some cases, if certain abnormalities are encountered, the patient will be asked to rest and wait up to 30 minutes so that a delayed image can be obtained. This delayed image may provide clues to a patient’s condition that the original images with contrast material do not. On occasion, an x-ray will be taken the next day to ensure that there is no scarring surrounding the ovaries.
When the procedure is complete, the catheter will be removed and the patient will be allowed to sit up.
When the examination is complete, you may be asked to wait until the radiologist determines that all the necessary images have been obtained.
The hysterosalpingogram is usually completed within 30 minutes.
What will I experience during and after the procedure?
This exam should cause only minor discomfort.
There may be slight discomfort and cramping when the catheter is placed and the contrast material is injected, but it should not last long. There may also be slight irritation of the peritoneum, the lining of the abdominal cavity, causing generalized lower abdominal pain, but this should also be minimal and not long lasting. Most women experience vaginal spotting for a few days after the examination, which is normal.
Who interprets the results and how do I get them?
A radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you.
Follow-up examinations may be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow-up exam is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. A follow-up examination may also be necessary so that any change in a known abnormality can be monitored over time. Follow-up examinations are sometimes the best way to see if treatment is working or if a finding is stable or changed over time.
What are the benefits vs. risks?
Hysterosalpingography is a minimally invasive procedure with rare complications.
Hysterosalpingography is a relatively short procedure that can provide valuable information on a variety of abnormalities that cause infertility or problems carrying a fetus to term.
Hysterosalpingography can occasionally open fallopian tubes that are blocked allowing the patient to become pregnant afterwards.
No radiation remains in a patient’s body after an x-ray examination.
X-rays usually have no side effects in the typical diagnostic range for this exam.
There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
The effective radiation dose for this procedure varies. See the Safety page for more information about radiation dose.
In the event of a chronic inflammatory condition, pelvic infection or untreated sexually transmitted disease, be certain to notify the physician or technologist before the procedure to avoid worsening of infection.
Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant. See the Safety page for more information about pregnancy and x-rays.