Overview of Lung Biopsy Techniques and Clinical Significance
Sometimes, finding the exact problem with lung nodules and masses can be tough, and may need intense procedures.[1] One common and accepted method of doing this is a lung biopsy. This involves taking a small piece of lung tissue to diagnose a variety of lung disorders. To examine the tissue, experts use several methods:[2]
* Percutaneous Transthoracic Lung Biopsy (PTLB): This method uses a needle to take a sample of tissue from your lung. The needle travels through the chest wall and is directed to the right spot with the help of an imaging technique, like CT scan or fluoroscopy.[1]
* Open Lung Biopsy (OLB): This involves surgically removing a part of the lung tissue under general anesthesia to examine it for signs of disease.
* Video-Assisted Thoracic Surgery (VATS): This is a procedure where a small camera is inserted through the chest wall to help doctors remove lung tissue.
* Transbronchial Biopsy (TBLB): This procedure uses a flexible tube which is passed through the nose or mouth. This is usually the preferred method for lesions that are easily reached.
* Cryobiopsy (Cryo-TBB): This method involves freezing and removing tissue with the help of nitrous oxide and a special, flexible instrument.
Besides these traditional methods, new techniques like the EBUS (Endobronchial Ultrasound) biopsy, Electromagnetic Navigation Bronchoscopy, Cone Beam CT, and Robotic Bronchoscopy are also being used.
This summary helps to explain the different ways a lung biopsy can be performed. It highlights the value of a team effort, which includes not only doctors, but also nursing staff, who provide assistance and educate the patient about the procedure.
Anatomy and Physiology of Lung Biopsy Techniques and Clinical Significance
Here, we’ll discuss the key parts of the lung that are relevant to lung biopsies. Our lungs have individual sections called bronchopulmonary segments, each with its own airway (bronchus), and blood supply. Your right lung has 10 of these, while your left lung has 8. Sometimes, they come with an extra one, known as a bronchopulmonary accessory segment.
Your right lung is divided into three sections or ‘lobes’ by two cuts or ‘fissures’, and these lobes are further subdivided into ten segments:
1. Right Upper Lobe: This has three segments, the apical, posterior, and anterior segments.
2. Right Middle Lobe: This has two, the lateral and medial segments.
3. Right Lower Lobe: This has five, the superior, medial, anterior, lateral, and posterior segments.
Meanwhile, your left lung has only one cut dividing it into two lobes, each with its own segments:
1. Left Upper Lobe: This has four segments, the apicoposterior, anterior, superior lingular, and inferior lingular segments.
2. Left Lower Lobe: This has four, the superior, anteromedial, lateral, and posterior segments.
All the tissues and cells in the lungs drain fluid out into the body’s lymphatic system, which is a network of vessels that take this fluid (lymph) and filter it through small structures known as ‘lymph nodes’. The majority of this fluid from your lungs ends up in the right lymphatic duct, except the fluid from the left upper lobe which goes into the thoracic duct via the left collarbone (subclavian) vein. The network of lymphatic vessels at the surface of the lungs (subpleural lymphatics) drains into the nodes at the bronchopulmonary segments. These flow into the lymph nodes deep in your lungs, which are found alongside the bronchial tree and lung vessels. These deep nodes then filter into the nodes at the base of the windpipe (tracheobronchial lymph nodes) and finally, into the thoracic duct.
The different lymph node locations in and around your lungs have been mapped out into 14 groups or ‘stations’, and 7 zones, based on where they are in relation to certain surgical landmarks such as the windpipe, airways, lining of the lungs (pleura), and major blood vessels. Each station is named and numbered, from 1 (supraclavicular) to 14 (subsegmental).
Lastly, let’s talk about your chest wall. This is made up of the rib cage, which forms the firm, bony part; the outer layer of skin; the muscle layers beneath it; and a layer of fibrous tissue, called fascia. From exterior to deep inside, the chest wall is organized as follows: Skin, superficial fascia, deep fascia, serratus anterior muscle, ribs and muscles in-between (intercostal), and the deep fibrous layer lining the chest wall (endothoracic fascia).
Why do People Need Lung Biopsy Techniques and Clinical Significance
If new spots or changes are noticed on a chest scan, a team of lung specialists, surgeons, and radiologists should review these findings. They will decide what should happen next depending on what they see. In some cases, a lung biopsy might be needed to confirm a diagnosis. A biopsy is a procedure where a small bit of lung tissue is removed for further testing.
According to the British Thoracic Society (BTS) guidelines, a lung biopsy may be required in certain situations. These situations may be:
– There is a new or growing mass or single nodule (small bump or lump) on a chest scan. If a CT scan or a bronchoscopy (a procedure where a thin tube is inserted into the lungs) can’t confirm a diagnosis, or if the mass or nodule is located somewhere difficult to access with a bronchoscopy, then a biopsy is needed.
– A patient has multiple nodules and no previous history of cancer, has been in remission for a long time, or has had more than one primary cancer.
– Focal infiltrates, or areas of the lung that look cloudy and dense on a scan and have not been diagnosed yet, even after sputum (mucus you cough up), blood samples, or a bronchoscopy has been tested.
– There’s a mass in the area of the chest near the heart and lungs (hilar region).
Different procedures can be used for a lung biopsy. A transthoracic needle biopsy (TTNB) is sometimes done to evaluate an unexplained lung nodule or mass. It depends on how likely it is that the mass is cancer and whether or not cancer has spread elsewhere in the body. This procedure can be helpful for diagnosing infections shown as nodules or consolidation (a term used to describe areas of the lung that have filled with fluid).
Transbronchial biopsy (TBLB) can be helpful in diagnosing both widespread and localized lung disorders. For example, when there are centrilobular lesions – sores or abnormalities in the region of the lungs surrounding the bronchioles – TBLB is often the first diagnostic tool. This procedure can help diagnose conditions such as sarcoidosis, interstitial lung disease, hypersensitivity pneumonitis, eosinophilic pneumonia, or tuberculosis.
Another procedure, called Video-Assisted Thoracoscopic Surgery (VATS), is often preferred due to fewer complications and quicker recovery times. This procedure can be used for biopsies of the lymph nodes near the lungs, lung tissue biopsies, biopsies of the pleura (the protective lining of the lungs), or in cases of certain undiagnosed lung diseases.
Traditionally, an open or surgical biopsy (OLB) has been the go-to method for diagnosing problems in the lung tissue. However, less invasive methods are typically tried first, unless there are major reasons not to. An open biopsy should only be considered if the diagnosis would change the course of medical treatment and if the underlying disease is not usually fatal.
When a Person Should Avoid Lung Biopsy Techniques and Clinical Significance
There are a few situations where a PTLB (Percutaneous Transthoracic Lung Biopsy) might not be suitable as mentioned in the BTS guidelines:
If the patient doesn’t understand the procedure fully or hasn’t given consent, the doctor needs to consider a different method for diagnosis. Similarly, if a patient previously had a lung removed (a procedure known as a pneumonectomy), they usually can’t undergo PTLB. However, if the area in question can be reached without puncturing any lung tissue, it’s a possibility.
When the CT scan suggests that there might be blood vessels or what are called “AVMs” (abnormal connections between arteries and veins) at the location of the procedure, the PTLB shouldn’t be considered. Instead, a team of healthcare experts should discuss what alternative steps should be taken.
When a patient is on mechanical ventilation (a machine that helps them breathe), the PTLB procedure might not be possible due to limited access to the lungs.
Uncooperative patients who might move around during the procedure would require an alternative diagnostic method. Similarly, abnormalities in the lungs or blood clotting could also result in considering alternatives.
For a type of biopsy known as a transthoracic biopsy, certain conditions make the procedure too risky. These include severe emphysema (a lung condition that causes shortness of breath), presence of bullae (air-filled spaces) that would obstruct the biopsy path, patients who cannot stop coughing, patients on mechanical ventilation, and patients with high blood pressure in the lungs (also known as pulmonary hypertension).
When getting a biopsy via flexible bronchoscopy (a procedure where a flexible tube is passed through the mouth and into the lungs), lack of informed consent, severe risk of bleeding, low oxygen in the blood, high levels of waste products in the blood due to kidney failure (uremia), low platelet counts (thrombocytopenia), and pulmonary hypertension are reasons not to perform the procedure.
In addition to all these, if a patient cannot tolerate breathing with just one lung during a procedure called VATS (Video-Assisted Thoracic Surgery), or if they have poor general health, blood clotting disorders, or if they recently had a heart attack (MI), they would not be fit for the procedure.
Equipment used for Lung Biopsy Techniques and Clinical Significance
CT-Guided Lung Biopsy: This is a procedure where a doctor uses a specialized needle to take a sample from your lung, using a CT scan for guidance. The type of needle used can depend on several factors such as the size and location of the area to be sampled, and the preferences of the person managing the procedure. Two types of needles could be used: a 22-gauge Chiba needle or a 20-gauge biopsy gun, which help to obtain different types of tissue samples. This procedure is supervised by a team including a radiologist who takes the images, and a cytopathologist who checks that the sample is suitable for further testing.
Transbronchial Biopsy: For this procedure, doctors use a flexible scope, called a bronchoscope, which lights up and offers a video view inside your lungs. The device has tiny forceps, similar to tweezers, which grab the tissue samples. It’s important to have equipment ready to provide additional oxygen, a machine that can create suction, and resources for emergency heart and lung support systems, just in case.
Cryo-TBB: This method uses a specialized tool to freeze and sample lung tissue at very cold temperatures, achieved using nitrous oxide gas. This frozen lung tissue sample can then be examined.
VATS: Known as Video-Assisted Thoracoscopic Surgery, this method requires specific tools, including a video camera for the chest cavity, a tool to cut tissue with heat, sponge holders, tweezers for collecting samples, stapling tools for closing incisions, and cannulas which are thin tubes used for insertion into the body. Additionally, provisions are made for a chest drain and suction devices, to be used if necessary.
Open Lung Biopsy: This procedure is carried out under general anesthesia and involves creating a direct opening to access the lungs, requiring a surgery kit which includes tweezers, stapling tools, and other necessary surgical tools. This is a more invasive procedure and hence, all required tools are prepared in advance.
Who is needed to perform Lung Biopsy Techniques and Clinical Significance?
Your medical procedure may involve a variety of medical professionals based on its type and where it is being done. These individuals might include:
A chest specialist, who is a doctor with specialized training in diagnosing and treating conditions of the chest.
A radiologist, who uses different types of scans to look inside your body and help diagnose conditions.
A surgeon, who is a doctor the performs operations. They can remove, repair, or replace parts of the body to treat diseases or injuries.
Anesthesiologists, they are doctors who will ensure you’re pain-free during the procedure. They put you to sleep or numb certain areas of your body.
Nursing staff, who help take care of you during your stay in the hospital. They work closely with doctors to ensure you are comfortable and understand what’s going on with your care.
Assistants, who work under the supervision of doctors and nurses to help take care of patients. They assist with tasks like checking your vitals, helping you move around, and providing basic care.
Students/interns/residents, they are individuals who are training to be doctors. They often participate in patient care to gain hands-on experience, always supervised by experienced doctors.
Technicians, they help with technical aspects of your care, like operating medical equipment or conducting laboratory tests.
Preparing for Lung Biopsy Techniques and Clinical Significance
Before certain medical procedures take place, your doctor may perform a series of tests to make sure you’re healthy enough for the procedure. These checks often include blood tests that look at how your blood clots. The three tests usually reviewed focus on factors like the amount of time it takes for your blood to clot (prothrombin time or PT), the functionality of different proteins that help your blood clot (apart from those studied in the PT test, these are studied in the activated partial thromboplastin time or APTT test), and the number of platelets (tiny blood cells that stick together to start the clotting process). If your blood takes longer to clot than normal or if you have fewer platelets than usual, you may need to see a specialist before the procedure can take place, as this could affect your body’s ability to heal. Some patients may be taking medications that prevent blood clotting; these medicines should be stopped before the procedure, following specific instructions.
Breathing tests are also important to evaluate before some procedures. If you have been tested and your ability to exhale forcefully (FEV, which stands for “Forced Expiratory Volume”) is less than 35% of what it should be, you might need to talk with more than one specialist to see if the benefits of the procedure outweigh the risks, especially if it’s a procedure involving the lungs. Also, any history of heart issues, such as a recent heart attack within the last six weeks, may require the delay of certain procedures that involve viewing the inside of the lungs through a small device known as a bronchoscope.
Lastly, it’s crucial that patients have all the information they need about the procedure. The doctor should talk to you about what to expect and provide you with written details as well. You will need to sign a consent form to show that you understand the procedure and agree to have it. There should also be people available to help monitor your health before, during, and after the procedure.
How is Lung Biopsy Techniques and Clinical Significance performed
A CT guided percutaneous lung biopsy is a procedure where the doctor uses the images from a CT scan or CT fluoroscopy (a type of X-ray that creates real-time images) to guide a needle to the part of the lung where they need to collect tissue. This is typically done with you under moderate sedation, which means you’re awake but relaxed and unbothered by the procedure. The doctor may use a technique to lessen the number of times the needle has to puncture your lung. The collected tissue is then sent immediately to a lab for examination.
A transbronchial biopsy is a different type of lung biopsy that is done using a bronchoscope. This is a flexible tube that the doctor inserts via your mouth or nose and guides towards the area of the lung they want to sample. In simple terms, it’s like a tiny crane that can navigate your airways and grab tissue. This biopsy is typically the go-to method for diagnosing issues with your central airways.
During a transbronchial biopsy, the doctor carries out a thorough check of all segments of your lungs. The doc then identifies the biopsy area, uses the bronchoscope to reach the location, then a small tool at the end of the tube is used to collect tissue samples. This process is repeated for about four to six times or until enough tissue is collected.
Another type of biopsy is a transbronchial cryobiopsy (cryo-TBB). In this procedure, a specialized, flexible probe is used that uses nitrous oxide (laughing gas) to freeze the tissue at the tip of the probe. The surrounding, frozen tissue is then removed with the tip of the probe, reducing damage to the surrounding healthy tissue.
VATS, or video-assisted thoracoscopic surgery, is another type of biopsy. Before the procedure, you’ll be given anesthesia and a double-lumen tube (a tube with two pathways) would be inserted for breathing. This procedure involves making three small incisions and inserting a camera and operating tools. The rest of the procedure depends on what exactly needs to be done. After the surgery, you’ll be provided with appropriate pain control and care for your lungs and the incisions.
The final method is an open lung biopsy. This is done under general anesthesia and involves making a small incision near your nipple line while you’re lying on your back. The doctor then goes between the fifth and sixth rib and dissects to the lung tissue. A small piece of lung tissue is then removed using a stapler. This tissue is then sent for examination.
Possible Complications of Lung Biopsy Techniques and Clinical Significance
When we take a sample of lung tissue (known as a PTLB), there can sometimes be serious risks involved. Some of these risks can even be deadly, such as severe bleeding in the lungs, air bubbles in lung veins, or a large collection of blood in the chest, also known as a hemothorax. The most common complication, however, is a punctured lung (known as pneumothorax), followed by bleeding in the lungs, a buildup of blood in the chest, and pressure buildup around the heart (cardiac tamponade). Also, there’s a chance that cells can spread along the path of the needle used in the procedure.
In a procedure called a transbronchial biopsy, where the lung tissue sample is taken through the bronchial tubes, complications might include reactions to local anesthetics, injury caused by the tube used for breathing (ET tube), muscle spasms in the throat or airway, not breathing enough, a punctured lung, and bleeding.
There’s another procedure called VATS (video-assisted thoracic surgery) that offers a safer option for obtaining lung tissue samples, with fewer complications and faster recovery times. This is why it’s become the most popular choice, replacing the traditional “open” surgeries around the world. Still, some risks need to be kept in mind when using VATS, such as pain after surgery, air leaks, low blood oxygen levels, collapse or closure of a lung part (atelectasis), bleeding, and wound infection.
What Else Should I Know About Lung Biopsy Techniques and Clinical Significance?
Sometimes, doctors need to take a small sample of lung tissue to examine it more closely, which is called a lung biopsy. This procedure is conducted only when necessary and usually involves a group of specialists like lung experts (pulmonologists) and imaging experts (radiologists).
Lung biopsy is often recommended in lung diseases where the patient has symptoms like weight loss, fever, coughing up blood, signs of inflamed blood vessels (vasculitis), or where the lung disease is progressing rapidly. It can also be helpful if the patient has other symptoms that can’t be easily explained, or if there’s a disease affecting the blood vessels in the lungs that the doctors can’t identify clearly. A lung biopsy can help rule out certain cancers and infections that mimic long-term, progressive lung diseases.
A non-emergency lung biopsy could significantly change the course of treatment and doesn’t pose a big risk to the patient. However, emergency biopsies are rarely beneficial and could pose a significant risk.
CT-Guided Biopsy (a biopsy done with the help of CT imaging) is a safe and effective way to diagnose lung conditions. It’s most suitable for lesions (abnormal tissue or growths) that look cancerous or when there’s a high suspicion of cancer. An initial CT scan can help determine the best way to access the lesion and the potential risk of a collapsed lung after the procedure (pneumothorax).
Transbronchial lung biopsy (TBLB), which involves taking lung tissue through a bronchoscope (a thin tube passed through the mouth or nose into the lungs), is a conventional method for lung biopsy. It’s a safe outpatient procedure that doesn’t require general anesthesia, and it’s useful for diagnosing a wide range of diseases including lung diseases, vascular diseases, small airway diseases, and cancers.
However, TBLB may not be as effective for lesions smaller than 2cm. For these cases, percutaneous (through the skin) and surgical lung biopsies may be more helpful. Cryo-TBB (a form of TBLB that uses cold temperature) is safe and usually doesn’t have major complications. However, there’s still the risk of heavy bleeding, post-procedure pneumothorax, and, although rare, death.
There are cases where surgical lung biopsy (done by making a small incision in the chest to remove the tissue) may be preferred over a VATS (which is a minimally invasive surgery using a small video camera). These include patients with severe lung disease or conditions that could lead to severe bleeding, and patients with severe low oxygen levels or those who require breathing support (mechanical ventilation).
New diagnostic methods involving advanced technology, like endobronchial ultrasound, electromagnetic navigational bronchoscopy, Cone beam CT and robotic bronchoscopy, are becoming more common. These help in early diagnosis with fewer complications, ultimately leading to quicker and more effective treatment.
