Ultrasound-Guided Biopsy: Uses, Types, and Procedure

Introduction:

The field of clinical diagnosis is seeing various novel transformations periodically. Various imaging tests such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET) are used to locate and diagnose a disorder. Though these tests suggest the presence of a disease, they do not validate or characterize the condition, which is crucial in the treatment and overall prognosis. Hence, it is essential to analyze the abnormal tissue instead of the abnormality to establish a confirmatory diagnosis.

A biopsy is a technique in which a small tissue sample is taken from the affected body part and sent for laboratory analysis. A biopsy helps to view the abnormal tissue with the naked eye, thus confirming the origin, presence, and magnitude of the disease. Certain procedures can help while taking a biopsy by giving the precise location of the sample tissue. These procedures are known as image-guided biopsy, and ultrasound-guided is one of them.

What Is an Ultrasound-Guided Biopsy?

Ultrasound-guided biopsy is a procedure where the radiologist uses an ultrasound as a guide to locate the specific site and remove the tissue sample. Ultrasound uses sound waves to create images of an organ or tissue. The ultrasound unit emits high-frequency sound waves into the body that bounce back upon striking some structures within the body. A computer then processes these returning sound waves into images based on the frequency, loudness, and time taken to return. Concurrently, a small hollow needle is inserted into the same site to obtain the tissue sample. The advantage of an ultrasound-guided biopsy over a conventional biopsy is the site precision. Furthermore, it is less invasive, as the biopsy uses a tiny needle, reducing organ distortion and causing negligible scarring.

What Are the Uses of Ultrasound-Guided Biopsy?

• Ultrasound-guided biopsies have revolutionized the diagnostic workup in the field of oncology. It is most frequently used in organs such as the liver, breast, lymph nodes, uterus, thyroid, kidney, and abdomen.

• It can also be used along with endoscopy or bronchoscopy for tumors in the gastrointestinal tract or lungs.

• Ultrasound-guided biopsies are the first choice of diagnosis in suspicious lumps or masses.

• To diagnose benign and malignant tumors.

What Are the Different Types of Ultrasound-Guided Biopsies?

Ultrasound can be used to perform the following four biopsy procedures:

• Fine Needle Aspiration Cytology: This procedure uses a very tiny needle to remove cells, fluid, or tissues for examination.

• Core Needle Biopsy: Uses a large hollow needle to remove a piece of the tissue sample.

• Vacuum-Assisted: This technique helps collect multiple tissues simultaneously by using a vacuum-driven instrument.

• Wire Localization: This technique uses a thin wire to mark the spot of abnormal tissue. This procedure is primarily used in the diagnosis of breast cancer.

What Are the Preparations to Be Done Before the Procedure?

• Patients need to wear comfortable clothing and remove any jewelry or accessories before going for the procedure.

• They should inform their doctor of any history of allergies.

• Patients on blood thinners or Aspirin may have to stop these medicines for three to five days before the procedure to avoid unnecessary bleeding.

• No fasting is needed for breast, thyroid, or liver biopsies. Patients will be advised to fast for any abdominal biopsy six to eight hours before the procedure. They can consume water for up to two hours before the procedure.

• Diabetic patients should also inform the doctor as they might receive special instructions about the procedure.

• The patient should inform the doctor about their prescription, supplements, or over-the-counter medicines.

• Patients undergoing breast biopsy should avoid deodorant, talcum powder, and lotions over the breast or under their armpits.

• Doctors may advise certain blood tests before the procedure. Patients should carry their recent reports and prescription medicine for the procedure.

How Is an Ultrasound-Guided Biopsy Done?

• A trained radiologist usually does ultrasound-guided biopsies as an outpatient procedure. Depending on the site, the entire procedure may take 30 to 45 minutes or even longer.

• The patient should wear a hospital gown and lie on the examination table.

• A clear gel is spread over the site to be examined and biopsied. Next, a small device called a transducer is moved over the place. This transducer emits high-frequency sound waves into the body, which are then processed into images by a computer.

• The images are visible on a screen.

• Once the radiologist confirms the site, the area is cleaned, and a local anesthetic is applied to numb the skin. The patient may experience a burning sensation when the local anesthetic is injected but no pain.

• A small hollow needle punctures the site and removes the tissue. The ultrasound monitors this process as the needle is advanced into the lesion.

• This tissue will be immediately placed in a formalin bottle and sent for pathological examination.

• The wound over the site is dressed with a bandage.

What Are the Instructions After the Procedure?

• Patients can carry on with their routine activities.

• Some pain or discomfort may be present for a day or two, which can be minimized with some painkillers. Patients can also apply an ice pack to reduce any swelling if present.

• Patients should avoid strenuous physical activity for at least two days after the procedure.

• The results would be available in three to five days.

What Are the Benefits of the Procedure?

• No radiation is involved.

• Less invasive hence less scarring.

• Increased reliability and precision in obtaining the tissue samples.

• Faster and well tolerated by the patients.

• Real-time images guide the needle placement and advancement through the lesion.

• Less expensive than an open surgical biopsy.

• An ultrasound-guided biopsy can access complex anatomic sites such as the axilla, nipple, or chest wall.

• Possible to biopsy multiple lesions at the same time.

What Are the Risks Associated With the Procedure?

• Possibility of bleeding or formation of a blood clot.

• Chances of infection.

• Rare risk of the needle penetrating the chest wall in breast biopsy resulting in air entrapment around the lung and lung collapse.

• Chances that the tissue retrieved is insufficient for a diagnosis could result in a repeat biopsy.

What Are the Limitations of the Procedure?

• Ultrasound-guided biopsy is contraindicated in patients with a severe bleeding disorder.

• This procedure is not feasible in uncooperative patients or patients with intellectual disabilities.

• It is challenging to achieve access if the lesion is tiny.

• The lesion should be visible on ultrasound. If small calcifications are present outside a mass, they may not be visible on an ultrasound.

When to Seek Medical Advice?

Patients should report to their doctor if they experience any of the below-mentioned symptoms after the procedure, as they could be signs of infection.

• Persistent fever.

• Bleeding or discharge from the biopsied site.

• Uncontrolled pain, redness, or swelling at the site.

Conclusion:

Ultrasound-guided biopsy is a safe and conclusive diagnostic procedure. Therefore, it is the prime choice in diagnosing and staging various cancers. In addition, the precision, reliability, and minimal invasiveness of the technique render ultrasound-guided biopsy more significant than the conventional biopsy technique.