CT-guided biopsy

Definition

A CT-guided biopsy is a procedure by which the physician uses a very thin needle and a syringe to withdraw a tissue or fluid specimen from an organ or suspected tumor mass. The needle is guided while being viewed by the physician on a computed tomography (CT) scan.

Purpose

A definite diagnosis of cancer is almost always based on the histological examination of cell or tissue samples. The procedure used to obtain a specimen for this testing is called a biopsy. Biopsies can be performed by surgical removal of the specimen if the suspicious area is located near the surface of the body or during surgery. If, however, the suspected tumor is located deep inside the body and cannot be seen or felt by the physician, he may decide to perform a CT-guided biopsy. The main advantage of a CT-guided biopsy is that it does not require an incision, but the disadvantage is that in some cases, the needle may not be able to remove enough tissue for analysis.

Precautions

CT-guided biopsy can be performed on almost all organs of the body, for example on the lungs, liver, kidneys, adrenal glands, pancreas, and pelvis. The procedure is not indicated for the spleen because there is a high risk of severe post-biopsy hemorrhage. CT-guided biopsy is not indicated for patients with bleeding disorders such as hemophilia, or who are at risk for bleeding as a result of cancer treatments (chemo-radiation) or the cancer itself, as when a patient develops thrombocytopenia .

Description

The development of CT technology provided a powerful means to visualize the inner features of the human body which previously could only be seen during surgery or autopsy. Before CT, if a patient had a tumor located in the chest, abdomen, or pelvis, biopsies could only be performed with a surgical procedure. If the patient needed surgery so as to treat the tumor, then biopsy specimens were also collected at the same time for analysis. However, there was no way to obtain samples from patients whose tumors could not be treated with surgery, such as patients with metastatic cancer or with general conditions not allowing surgery. CT-guided needle biopsy has become a welcome alternative to surgical exploration and biopsy.

Preparation

The technique will vary depending on the site of specimen collection and the patient's general condition. In most procedures, the patient lies on the CT table on his back, or on either side, depending on where the needle is to be inserted. Some patients may require intravenous injection of pain killers. A CT scan is first performed, to locate the best site for needle insertion. The skin is then disinfected and anesthetized with its underlying tissue. The needle is inserted through the skin into the body. Another CT scan is perfomed to confirm that the tip of the needle lies at the desired location. When the tip of the needle is seen to be in the proper position, the biopsy specimen is withdrawn through the needle.

Aftercare

After the procedure, the patient is monitored in the hospital or clinic department or in an observation unit for a few hours, and then sent home.

Risks

CT-guided biopsy is a fairly safe procedure. The risks are certainly less than the risks involved with the alternative method, surgical biopsy. In any case, recovering from CT-guided biopsy takes considerably less time than it would if the biopsy were surgically performed.

The risks associated with CT-guided biopsy depend on the site where the biopsy specimen is collected. They include:

• Bleeding: Most patients have had their blood evaluated before the procedure. Although rare, bleeding can occur and may require surgery to control.
• Infection: An infection is possible whenever an object, —such as the needle used in CT-guided biopsy—, pierces the skin, —even if sterile procedures are always followed during the procedure. This is a very rare complication.
• Pneumothorax: Partial or total collapse of a lung is a reported complication in approximately 25% of lung biopsies. It is also a risk during CT-guided biopsies of the liver and adrenal glands.

Normal results

A preliminary evaluation of the CT-guided biopsy specimen is often performed by the physician. If enough tissue has been obtained for the required tests, the procedure is terminated and the specimen is sent to the histology lab for analysis.

Abnormal results

If the CT-guided biopsy has not been successful, it may be repeated or another biopsy procedure may be selected. Abnormal results indicate that a malignancy or other abnormality is present.

See Also Imaging studies; Biopsy

Resources

BOOKS

Seeram, E. Computed Tomography: Physical Principles, Clinical Applications and Quality Control. W. Saunders & Co., 2001

Webb, R. et al. Fundamentals of Body CT. W. Saunders & Co., 1998.

PERIODICALS

Ben-Yehuda, D., Polliack, A., Okon, E., Sherman, Y., Fields, S., Lebenshart, P., Lotan, H., and E. Libson. "Image-guided core-needle biopsy in malignant lymphoma: experience with 100 patients that suggests the technique is reliable." Journal of Clinical Oncology 14 (September 1996):2431-34.

Golder, W. A., Borchert, M., and K.J. Wolf. "Outcomes and benefits of CT-guided biopsy." Academy of Radiology 5 (September 1998)Suppl.2:S317-20.

Nashed, Z., Klein, J. S., and M.A. Zarka. "Special techniques in CT-guided transthoracic needle biopsy." American Journal of Roentgenology 171 (December 1998):1665-68.

Sklair-Levy, M., Polliack, A., Shaham, D., Applbaum, Y. H., Gillis, S., Ben-Yehuda, D., Sherman, Y., and E. Libson. "CT-guided core-needle biopsy in the diagnosis of mediastinal lymphoma." European Radiology 10 (2000):714-8.

Monique Laberge, Ph.D.

KEY TERMS

Anesthesia

—Loss of normal sensation or feeling. Insensitivity to pain.

Autopsy

—Postmortem surgical procedure performed to examine body tissues and determine the cause of death.

Hemorrhage

—Escape of blood from blood vessels; bleeding.

Histology

—The study of tissue with a microscope.

Incision

—Cutting through the skin.

Metastasis

—The transfer of cancer from one organ to another one not directly connected to it.

Pelvis

—Bassin-shaped body cavity containing and protecting the bladder, the rectum and the reproductive organs.

Pneumothorax

—A collapse of the lung due to a sudden change of pressure within the chest cavity.

Sterile

—Procedures carried out with instruments that have been sterilized, meaning that they are completely free from microorganisms (germs) that could cause infection.

QUESTIONS TO ASK THE DOCTOR

• Will the CT-guided biopsy procedure be painful?
• How many times will I need to have one?
• What is the normal success rate in obtaining enough tissue to make a diagnosis?
• What kind of complications may I experience at the biopsy site?
• When will I know the results?

CT-Guided Biopsy

Definition

Computed tomography (CT) is a process that images anatomic information from a cross-sectional plane of the body. Biopsy is the process of taking a sample of tissue from the body for analysis. CT is commonly used in biopsies to provide images that help guide the tools or equipment necessary to perform the biopsy to the appropriate area of the body.

Purpose

CT is used in the process of performing a biopsy, such as a needle biopsy, in order to guide the needle to the site of the biopsy and to provide rapid and precise localization of the needle. CT enables imaging of areas that are normally beyond visible boundaries. This enables the physician to see the target area clearly and help to ensure that the tissue being removed is from the target lesion.

Precautions

The patient that suffers from claustrophobia will want to discuss this with their physician. This procedure involves the patient being placed into the CT scanner, typically a small, enclosed area. Depending on the specific type of biopsies being performed, certain anesthetics will be used, so discuss drug allergies with your physician.

Description

CT can assist in providing more enhanced images of a suspicious lesion. It helps to determine whether a tumor is truly solitary or not. CT can characterize the tumor and aid in the estimation of malignancy.

Preparation

Since there are many different types of biopsies, you should follow the instructions from your physician to prepare for your CT-guided biopsy. Patients who suffer from claustrophobia should discuss their concerns with the physician. In some cases, medicine can be given that will relax the patient during the procedure.

Risks

CT-guided biopsy does not increase the risk of the biopsy any more than any other radiologic imaging such as x ray.

Normal results

Because the area being biopsied, as well as the specific type of biopsy procedure can vary, results will vary. Before undergoing the procedure, notification procedure should be clearly defined.

Resources

BOOKS

Stedman's Medical Dictionary. 27th ed. Philadelphia: Lippincot Williams & Wilkins, 2000.

Tierney, Lawrence, et. al. Current Medical Diagnosis and Treatment. Los Altos: Lange Medical Publications, 2001.

PERIODICALS

Garpestad, E., et. al. "CT Fluoroscopy Guidance for Transbronchial Needle Aspiration." Chest 119 (February 2001).

Shaffer, K. "Role of Radiology for Imaging and Biopsy of Solitary Pulmonary Nodules." Chest 116 (December 1999).

White, C.S., C.A. Meyer, and P. A. Templeton. "CT Fluoroscopy for Throacic Interventional Procedures." Radiologic Clinics of North America 38 (March 2000).

White, C.S., et. al. "Transbronchial Needle Aspiration: Guidance with CT Fluoroscopy." Chest 118 (December 2000).

KEY TERMS

Lesion— A pathologic change in tissues.

Malignancy— A locally invasive and destructive growth.