Image-Guided Percutaneous Needle Biopsy

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What are the major indications for image-guided percutaneous needle biopsy?

Image-guided percutaneous needle biopsy (IPNB) is an established, effective nonsurgical procedure that is performed in selected patients to obtain a pathologic diagnosis or to guide appropriate patient management. Indications for percutaneous needle biopsy include:

• To determine if a lesion is benign or malignant.

• To obtain material for microbiological analysis in suspected infection.

• To stage disease in patients with known or suspected malignancy.

• To obtain material for biomarker, protein, or genotype analysis to subsequently guide targeted therapies in select patients.

• To determine the primary cell type in patients with metastatic disease and an unknown primary tumor.

• To diagnose certain diffuse parenchymal diseases (e.g., in the liver and kidneys).

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What are the available imaging modalities for IPNB?

Image guidance for percutaneous needle biopsy is provided to precisely localize a lesion that is not palpable and, therefore, requires imaging for localization. IPNB can be performed using fluoroscopy, ultrasonography (US), computed tomography (CT), or magnetic resonance imaging (MRI), and the use of these modalities is dependent on the target organ, the type of lesion, and patient parameters. Lesions that can be easily seen on a radiograph may be biopsied fluoroscopically, including large lung lesions and some bone lesions. To ensure proper needle placement, fluoroscopic equipment must be able to provide complex angle imaging. Fluoroscopy is less desirable due to increased radiation exposure to personnel during the procedure. Its use for lung biopsies has decreased over time, as CT is able to detect and provide needle guidance of small lung lesions.

US is perhaps the most versatile modality for IPNB. It is a safe and accurate method that uses real-time imaging to guide needles into abdominal and pelvic organs and masses. It is also typically used to sample thyroid and breast lesions. Its advantage over CT-guided biopsies is that it can be done portably, is less expensive, and does not use ionizing radiation. However, some lesions are not visualized sonographically because of size or location. US is typically used to sample lesions within superficial lymph nodes ( Figure 68-1 ), liver ( Figure 68-2 ), and kidneys, but has little role in sampling lesions in the chest unless the lesion is in the pleura or chest wall.

CT allows for biopsy of lesions not seen fluoroscopically or sonographically and provides the most accurate visualization of anatomy for accurate and safe access to lesions, avoiding transgression of vital structures. It is used for sampling of lesions in the neck, lung, pleura, mediastinum ( Figure 68-3 ), abdomen, and pelvis, including deep retroperitoneal and pelvic lymph nodes ( Figure 68-4 ).

Some lesions can only be visualized by MRI, which can also be utilized on rare occasion. MRI has limited use because of expense, difficulty in accessing the patient within the magnet, and difficulties with use of ferromagnetic instruments within the magnetic field.

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What are the contraindications for percutaneous biopsy?

There are no absolute contraindications for IPNB. Consideration of performance of a biopsy must be carefully weighed against the risks of the procedure. There are several relative contraindications, which in some cases may preclude the performance of a percutaneous biopsy. Relative contraindications for percutaneous needle biopsy include:

• Coagulopathy that cannot be adequately corrected.

• Hemodynamic instability or severely compromised cardiopulmonary function.

• Patient inability to cooperate or to be adequately positioned for the procedure.

• Lack of a safe pathway through tissues to the lesion.

• Pregnancy (when image guidance requires exposure to ionizing radiation).

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What criteria are used to determine whether or not a lesion is amenable to IPNB?

When contemplating IPNB, there are several things to consider. For a lesion to be amenable to IPNB, it must be visible on one of the imaging modalities discussed above. Additionally, there must be a safe route to access the lesion without likely damage to vital organs or vascular structures. Vascular lesions should not undergo percutaneous needle biopsy. If a lesion is considered amenable to IPNB, patients must then be assessed to make sure they are candidates for this procedure.

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How effective is percutaneous needle biopsy?

Percutaneous biopsy is a very effective procedure with high diagnostic yield. Low false-positive and false-negative results are achieved in most organs. The success of IPNB is affected by multiple variables, including the number of samples obtained, the size and location of the target lesion, the type of needle used, the availability of an on-site cytologist, and the experience of the performing physician and the pathology staff. The reported overall success rate of IPNB ranges between 70% and 96% among all organs.

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