Hello and welcome back. This is part three of our series of mini lectures on image directed tissue sampling for lymph node staging in lung cancer. In this part three, we'll be going over image guided techniques. So just to reiterate, our objectives are to talk about the different methods of lymph node sampling that we have available, and to show how we can use imaging to help determine the best methods of sampling in individual patients. In the first part of this series of mini lectures, we went over the surgical techniques, in the second part, we talked about the medical techniques and now, we'll go over the image guided techniques, namely, CT guided biopsy and ultrasound guided biopsy. But first, let's have a pre-lecture question. Here we have a patient who has multiple small FDG avid lymph nodes in the low neck, in the supra-clavicular regions bilaterally. So these are in station one. These lymph nodes were not palpable. What would be the best way to sample non-palpable station one lymph nodes? So here are your choices. You can choose from mediastinoscopy, endo bronchial ultrasound, CT guided biopsy, and ultrasound guided biopsy. So please pick your one best answer here, and we'll get back to this at the end of the talk. Well let's get started now with CT guided lymph node biopsies in the mediastinum. Mediastinal CT lymph node biopsies are not routine at most institutions and we do not routinely do those at the University of Michigan. They can be very technically difficult due to intervening vital structures. We can sometimes get to the mediastinum by using special methods. For example, we can go next to the sternum, occasionally, we can even go right through the sternum. We can place our needle next to the spine, maybe under the xiphoid or perhaps in the suprasternal notch. And occasionally just by repositioning the patient, we can access the lymph node in the mediastinum that we're targeting. So occasionally, a lateral decubitus position can help bring that structure out from under the sternum. Occasionally, we'll use other techniques such as injecting saline to widen an extra pleural path, so that we can stay outside of the lung parenchyma and try to avoid a pneumothorax. Here's an example of a woman who was a smoker. She had COPD and shortness of breath. A chest x-ray showed a lung nodule which then led to a CT scan which I'm showing you here. So we see this spiculated nodule here in the right lung, very suspicious for a lung cancer. And on the soft tissue windows, we notice that there is a soft tissue nodule, so a lymph node here in the anterior mediastinum. It's not a very typical location to get a lymph node metastasis from lung cancer, but it can occasionally happen, so we were concerned about that. We needed to figure out what station that was in, and that would fall into station 3a, but then we get to the more important question. How would we sample this station 3a lymph node? So here are some choices for you. Would you choose mediastinoscopy, endobronchial ultrasound, CT guided biopsy or a VATS procedure or more than one procedure perhaps? So go ahead and pick your best choice or choices. Well the best choices here would be CT biopsy as well as a VATS procedure. This is right under the pleural surface, so potentially, this could be sampled using that technique. You couldn't get to this with mediastinoscopy because it's no where near the trachea. And for the same reason, you couldn't sample it with endobronchial ultrasound. This patient actually did go on to have a CT guided biopsy. My colleague put the patient into a right lateral decubitus position which brought this lymph node out from under the sternum. He was able to place this needle over here. It went right through the chest wall into the mediastinum without going through any lung tissue. That was very helpful in avoiding a pneumothorax, and the pathologic sample showed metastatic non-small cell lung cancer. That then brings us to our very last lymph node biopsy technique and that is ultrasound-guided biopsy. So what station is best for ultrasound guided biopsy? Well that would only be station one as we see on this diagram. So ultrasound can be used to help biopsy non-palpable station one lymph nodes. Why do I say nonpalpable? Well because if they're palpable, you don't need any guidance at all. You can simply go ahead and do your biopsy. So station one lymph nodes and the supraclavicular, low cervical and sternal notch regions can be access with ultra-sonography. And in this patient, we see multiple small lymph nodes in station one bilaterally tiny lymph nodes over here and over here which were not palpable and this brings us right to our post lecture question. This is the same patient. So we see this small lymph nodes that were not palpable. They were very FDG avid, so here is your post lecture question. What would be the best way to sample these station one lymph nodes? You can choose mediastinoscopy, endobronchial ultrasound, CT guidance or ultrasound guidance. Go ahead and make your choice. And clearly, the best choice here would be to biopsy under ultrasound guidance. Okay, so that brings us to our take home points. So first of all, CT guided mediastinal lymph node biopsies may be very technically difficult due to intervening vital structures and/or the sternum and this procedure is uncommonly performed at most institutions. Ultrasound guidance is optimal for nonpalpable lymph nodes in the low neck and supraclavicular regions. Okay, so where do we go from here. We have talked about lots of different lymph node biopsy techniques. The surgical ones, the medical techniques as well as the image guided techniques. What we've been focusing on in these first three lecture parts has mostly been anatomy, which lymph nodes are accessible anatomically, but there are lots of other features we need to think about when deciding how, and what type of technique to use. And we'll look at that and next lecture, we'll try to put it all together. So thank you very much for listening, and I will talk to you soon.
