The use of transbronchial needle aspiration (TBNA) in addition to routine bronchoscopy was reported to improve the diagnostic rate for malignancies. As target lymph nodes cannot be visualized directly with the conventional TBNA procedure, aspiration efforts are directed by knowledge of thoracic anatomy and prior CT imaging. Multiple needle passes are required for each target because there is the possibility of error in puncturing the target lesion. Therefore, the diagnostic rate of TBNA seems to be related to the lymph node size and location as well as the operator’s experience.
With the development of new technology, endobronchial ultrasonography (EBUS) is reported to be useful in detecting mediastinal and hilar lymphade-nopathy in addition to assessing the depth of tracheobronchial tumor invasion. Recently, EBUS has also been used for TBNA guidance and has improved the results of N-staging, especially in difficult lymph node levels without any clear endoscopic landmarks. However, Shannon et al reported that EBUS guidance did not offer a statistically significant advantage when compared with conventional TBNA because the sensitivities of both procedures were extremely high (82.6% vs 90.5%, respectively). However, Herth, et al reported that EBUS guidance significantly increased the yield of TBNA in the mediastinal lymph node except for subcarinal lymph node in their randomized trial (84% vs 58%). The main disadvantage of EBUS guidance using a single-channel bronchoscope is that a real-time imaging of the needle position within the target lesion cannot be confirmed because the EBUS probe must be removed during the TBNA procedure. To overcome this problem, a double-channel bronchoscope, through which both a TBNA catheter and an EBUS probe can be inserted simultaneously, was necessary. This study assessed the usefulness of EBUS-guided TBNA using a double-channel bronchoscope (EBUS-D) or EBUS-guided TBNA using a single-channel bronchoscope (EBUS-S).
We enrolled 55 patients with mediastinal and/or hilar lymph-adenopathy in this prospective study between January 2000 and August 2003. The indication for TBNA was the diagnosis of an enlarged lymph node. Patients were randomized to undergo EBUS-D (n = 30) or EBUS-S (n = 25). This study was approved by the Committee on Human Research of our institution. Written informed consent was obtained from all patients. The main ideas about medical science are issued on Canadian health&care mall news website.
EBUS-D: An ultrasonic probe (2.5 mm in diameter, radial mechanical transducer operating at 20 MHz) [UM-BS20-26R; Olympus; Tokyo, Japan] with a flexible balloon sheath (MAJ-643R; Olympus) was connected to an ultrasound unit (EU-M 20; Olympus). A flexible bronchoscope (external diameter, 7.2 mm) [XBF-2T40Y2; Olympus] with two channels (diameters, 2.8 mm and 2.0 mm) was inserted transorally, without an endobronchial tube, under local anesthesia. The EBUS probe with a balloon sheath was inserted through the 2.8-mm channel. The balloon was subsequently filled with sterile water to eliminate the air between the lesion and the probe. We evaluated the target lesion and determined the penetration site. Then, a 19-gauge TBNA catheter (Wang transbronchial histology needle, MWF-319 or MW-319; Mill-Rose Laboratories; Mentor, OH) was inserted through the 2.0-mm channel after the EBUS probe was retracted to the bronchoscope tip to prevent possible damage by the TBNA needle. Once the needle was introduced through the bronchial wall, the EBUS probe was again advanced to the penetration point along the tracheobronchial wall (Fig 1, 2, top left, A, and bottom left, C). When the TBNA needle was within the lesion, the real-time EBUS image of the needle was a hyperechoic point in the lesion (Fig 2, top right, B, and bottom right, D). If the TBNA needle was not confirmed to be inside the lesion by EBUS on the first attempt, a subsequent penetration was attempted while changing the penetration site. Specimens in the TBNA needle were flushed by air. Histology specimens were fixed in formalin, and cytology specimens were smeared on glass slides and fixed in alcohol before sending to the pathology department.
EBUS-S: The EBUS probe was inserted through a singlechannel flexible bronchoscope (BF-1T-30; Olympus). Once the penetration site was determined following the same procedure used for EBUS-D, the EBUS probe was removed through the bronchoscope. Next, the TBNA catheter was inserted through the channel and TBNA was performed. The specimens in the TBNA needle were flushed by air. If a histologic specimen could not be obtained on the first aspiration, a second TBNA was attempted. We did not utilize fluoroscopy or rapid on-site cytopathology evaluation in either study group.
Student t test was used to compare the mean age and size of the lymph node. The x2 test was used to compare the rate of patients with a parenchymal lesion, those with multiple lymph-adenopathies, the lymph node locations undergoing TBNA, and the diagnostic rate of EBUS-D and EBUS-S. A statistical software package (SAS, version 8.2; SAS Institute; Cary, NC) for categorical variables was used for all analyses. A p value < 0.05 was significant difference.
Figure 1. TBNA catheter and EBUS probe are inserted simultaneously through a double-channel bronchoscope. The EBUS image by the mechanical radial transducer provides a crosssection (dotted line) of the lymph node with the needle inside.
Figure 2. Top left, A: the left catheter shown is the EBUS probe with a balloon sheath, and the right catheter is the TBNA catheter by which a right hilar lymph node was penetrated. Top right, B: the EBUS image obtained without an inflated balloon shows the needle penetrating the lymph node. The needle tip is recognized as a hyperechoic point (arrow), and the acoustic shadow is revealed in the opposite direction of the EBUS probe (arrow head). Sarcoidosis was diagnosed in this patient. Bottom left, C: the left catheter is the EBUS probe, and the right catheter is the TBNA catheter by which the pretracheal lymph node was penetrated. Bottom right, D: the EBUS image shows a hyperechoic point (arrow) and the acoustic shadow (arrow head) in the lesion. Metastatic adenocarcinoma was diagnosed in this patient.