Fig. 18.1
Management algorithm for pulmonary nodules detected on CT scan (This is adapted at the Department of Endoscopy of the National Cancer Center, Japan, and is based on the “Guidelines for the Management of Pulmonary Nodules Detected by Low-dose CT Lung Cancer Screening Version 3” advocated by The Japanese Society of CT Screening [2]). CT computed tomography, CTNB CT-guided needle biopsy, GGN ground glass nodule
18.4 Preparation of the Guide Sheath Kit
The disposable GS kit includes one each GS, biopsy forceps, cytology brush, ET stopper, and US stopper. ET stoppers for the biopsy forceps and cytology brush and US stoppers for the ultrasound probe need to be prepared in such a way that the distal tip of the GS will accommodate the needed length of each device, as described in detail in Fig. 18.2. Proper preparation will allow smooth R-EBUS scanning and precise biopsy sampling. At our department, we prefer to use an adhesive tape as a stopper for the fragile R-EBUS probe that is prone to breakage.
Fig. 18.2
Preparation of a guide sheath kit. Adjust the ET stoppers (orange arrows) for the (a) cytology brush and (b) biopsy forceps so that the distal tip of the GS will accommodate the needed length of each device. For the cytology brush, the distal GS tip should coincide with the distal tip of the plastic sheath covering the brush. For the biopsy forceps, the distal GS tip should coincide with the base of the cup in order to allow protrusion of the distal forceps tip by 2.5–3.0 mm; this would facilitate smooth opening of the cups during biopsy. In setting the (c) ultrasound probe, a US stopper (red arrow) is provided by the manufacturer; at our department, we prefer to use an adhesive medical tape (yellow arrowhead) as a marker that will allow the transducer to protrude out of the GS
The ultrasound probe should be connected to the probe driving unit, with the connecting pin pointing upward and the wing downward (Fig. 18.3). If connected the wrong way, the ultrasound probe can sometimes get stuck to the probe driving unit. During examination, the ultrasound probe should be secured in the probe holder to prevent contamination and entry of air bubbles into the surrounding area of the oscillator (Fig. 18.4).
Fig. 18.3
Connecting the ultrasound probe to the probe driving unit. The ultrasound probe should be connected to the probe driving unit with the connecting pin pointing upward and the wing downward
Fig. 18.4
Securing the radial EBUS probe. Using a probe holder (a), secure the ultrasound probe (b)
18.5 Procedures
18.5.1 Insertion to the Involved Bronchus
Using computed tomography images, confirm the bifurcation of the involved bronchus as far peripheral as possible. Additional use of virtual bronchoscopic navigation system is recommended because selection of a wrong bronchus may prolong examination time and decrease diagnostic yield. Once the bronchial bifurcation is identified, insert the R-EBUS probe with GS toward the target bronchus. The key is to completely suction secretions from the bronchial lumen and bronchoscope working channel and to wedge properly the bronchoscope tip into the involved orifice.
18.5.2 Confirmation of R-EBUS Findings
While observing the positional relationship with the target lesion under X-ray fluoroscopy, insert the R-EBUS probe further to the periphery, and confirm the R-EBUS findings. Once the probe comes to the vicinity of the lesion and is positioned in the center of the display, it will be visualized as a hypoechoic area. When the lesion is visualized, move the R-EBUS back and forth (i.e., toward the periphery and the center) to confirm the range of the lesion and decide where to place the GS. Basically, the GS should be placed 2–3 cm proximal to the site where EBUS visualization is maximal. This is to allow the forceps cup and cytology brush to reach the area of maximal tumor diameter during biopsy. It is also important to note the R-EBUS findings of accompanying blood vessels (Fig. 18.5) and necrotic changes within a lesion, which appear as inhomogeneous hyperechoic areas; these areas should be avoided during specimen collection.
Fig. 18.5
Radial EBUS findings of blood vessels in a peripheral pulmonary lesion. Back-and-forth movement of the probe through the target site shows an anechoic region (orange arrow), which corresponds to a blood vessel
18.5.3 Collecting Specimens
The next step is to place the GS to the target lesion and to collect specimen. At our department, after palpating the lesion using a bronchial brush and with simultaneous X-ray fluoroscopy guidance, we usually prepare a smear sample for rapid on-site cytology evaluation (ROSE). Subsequently, we collect specimen using biopsy forceps while waiting for the results of ROSE; repeat R-EBUS scanning to confirm GS placement in the lesion is performed as appropriate. Of note, we always make it a point to secure the bronchoscope and the GS firmly to avoid displacement during sampling, especially when lesions are in the inferior lobe, where diaphragmatic movements during respiration may easily cause displacement of the soft GS. It was reported that diagnostic yield reaches a plateau after more than five specimens are collected [4]; therefore, we recommend performing repeated forceps biopsy until at least five pieces of specimen are collected.
The GS kit comes in two types; K-201 (Olympus, Tokyo, Japan) is supplied with a small-sized biopsy forceps, whereas K-203(Olympus, Tokyo, Japan) comes with normal-sized ones (Fig. 18.6). The small-sized forceps might be prone to yield a small amount of specimen and may lead to diagnostic failure. Our department recommends using normal-sized forceps, especially for peripheral pulmonary lesions that do not invade the mucosa of the involved subsegmental bronchus because the normal-sized forceps has a large cup that allows collection of a larger specimen. In addition, the swing mechanism at the neck supporting its cup enables a stronger force to grip a specimen for easy collection.
