Endobronchial ultrasound

doi:10.1016/S0169-5002(01)00349-X

Lung Cancer

Volume 34, Supplement 2, December 2001, Pages S109-S113

https://doi.org/10.1016/S0169-5002(01)00349-X Get rights and content

Abstract

Endobronchial ultrasound (EBUS) is a new diagnostic tool, which has expanded the view of the bronchoscopist beyond the confinements of the airways. It has great potential for diagnosis of mediastinal processes and staging of lung cancer. These will be discussed and illustrated. EBUS will become a superior tool for staging of lung cancer, and several comparative studies on EBUS as compared with standard techniques in order to assess its role in the staging procedure are just on their way or already completed.

Introduction

The endobronchial application of ultrasound has first been described in 1992 [1]. The following years technical difficulties had to be solved and a clear view on the indication and diagnostic properties of endobronchial ultrasound (EBUS) had to be developed. Currently, since 1999 EBUS is commercially available and is gradually introduced in the bronchoscopic practice. This has broadened the view of the bronchoscopist and augmented the diagnostic possibilities for both bronchial and mediastinal pathology.

Some aspects have yet to be assessed when the technique is spread more widely. The investment for the equipment of currently approximately 50 000–80 000 EURO seems to be reasonable considering the wide range of indications that includes up to 50% of all regular bronchoscopies for additional information. Refunding, however, currently is still not yet awarded universally. Considering the fact that it takes at least 50 sessions to acquire basic experience even in regular diagnostic bronchoscopy [2] it takes considerably more effort to gain expertise in this new diagnostic method, showing structures like the tracheal wall that were not available for diagnosis up to now, and imaging mediastinal structures from uncommon angles and points of view [3], [4]. Thus besides basic instruction some time of continuous coaching seems to be important. Currently, new ways of tele-teaching for this period are under investigation.

For optimal imaging the miniaturized 20 MHz US probes that we apply (Olympus UM-BS20-26R) are fitted with a catheter that carries a water-inflatable balloon at the tip. Once inflated, this optimizes the contact between the probe and the bronchial wall and allows acquisition of detailed images of the surrounding structures. Complete occlusion of major airways rarely causes considerable discomfort, but is usually well tolerated even under local anesthesia [3], [5]. Obstruction of the main bronchi did not compel to interrupt the procedure as long as the other side is well ventilated. Sometimes although cough might increase during inflation of the balloon [1]. General anesthesia has the advantage of allowing apnea for up to 3 min, which provides enough time to obtain information on airways and mediastinal structures.

Section snippets

Sonographic airway anatomy

The ultrasonographic structure of the cartilaginous portion of the wall of the trachea and the central bronchi is described as a five or seven layer structure by different authors [6], [7]. The original publication of Hürter and Hanrath mentioned a three layered pattern for the lobar bronchial wall containing cartilage [1]. Kurimoto defined the anatomical substrate of ultrasonic structures by comparing the ultrasound image with the histopathologic image after sticking needles into the different

Indications

The indications for EBUS have been extensively studied but so far only in a limited number of institutions EBUS is used regularly in daily practice. Its greatest potential lies in staging of lung cancer, diagnosis of mediastinal processes and diagnosis of peripheral intrapulmonary lesions (Table 1).

Mediastinal processes can be located precisely, with special attention to their relation to mediastinal structures. EBUS seems more suitable to detect infiltration of mediastinal organs by tumor,

Staging of lung cancer

The contribution of EBUS to the staging of lung cancer concerns both the local tumor (T), the lymph node involvement (N) and might even confirm the presence of pulmonary metastases (M).

Pre-malignant lesions or small intrabronchial tumors are usually detected accidentally in patients who are investigated for other clinical reasons. Recently new methods for screening (autofluorescence bronchoscopy/AF) in patients at risk for developing bronchial carcinoma have been introduced, as conventional

Peripheral lesions

The use of EBUS for investigation of the lung parenchyma is severely hampered by total reflection of the ultrasound signal due to air. However, due to their difference in echogeneity solid processes can be precisely located by EBUS, and to our experience in many cases can replace fluoroscopy for guiding bioptic procedures. Furthermore analysis of the structure of the lesion by EBUS might provide additional insight into the nature of peripheral abnormalities, as different lesions such as

Conclusion

From our current experience we are confident that in the future the value of EBUS as diagnostic tool for both mediastinal abnormalities and the staging of lung cancer will be further established. As experience grows and teaching will be more readily available an increasing number of bronchoscopists will gain experience with this new endobronchial technique and the role of EBUS in diagnostic bronchoscopy will expand. An increasing number of prospective data describing the diagnostic properties

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Cited by (27)

Role of ultrasound-guided transbronchial biopsy in the diagnosis of peripheral pulmonary lesions
2013, Lung Cancer
Citation Excerpt :
Although lung cancer might be suspected on some radiological features of the lesion, a histological diagnosis is often mandatory and needs invasive approaches [1]. In this setting, bronchoscopy is usually performed and endobronchial ultrasound (EBUS) can be used as a valid alternative to fluoroscopy in providing an image guidance for transbronchial biopsy (TBB) [2,3]. It is known that EBUS-guided TBB has a higher diagnostic accuracy than TBB without any guidance in the diagnosis of PPLs [4].
Endobronchial ultrasound (EBUS) can be used as an alternative to fluoroscopy to visualize a peripheral pulmonary lesion (PPL) and to provide an image guidance for transbronchial biopsy (TBB). The aim of this study was to verify the accuracy of EBUS-guided TBB in the diagnosis of PPLs.
All the patients with CT-scan evidence of PPL who underwent bronchoscopy with EBUS in the period between 2008 and 2011 were retrospectively evaluated. EBUS was performed using a radial-type miniature ultrasound probe. Once obtained an EBUS image of the PPL, we measured the distance of the PPL from the outer orifice of the working channel of the bronchoscope in order to perform TBB at PPL site.
A total of 662 patients were examined. The mean diameter of lesions was 36 ± 20 mm. PPLs were visualized in 494 patients (75%) and the TBB was performed in 479 patients. Thirty-two patients were lost in follow-up and data from 447 patients were analyzed. TBB results were 255 cancers and 192 non-malignant lesions. The final diagnosis reported was 359 cases of cancer and 88 of benign lesion. EBUS-guided TBB had a sensitivity of 71% for the diagnosis of cancer, a negative predictive value of 46% and an overall diagnostic accuracy of 77%.
These data obtained from a large series of patients and using an original method show that EBUS represents a valid support to bronchoscopy and that the EBUS-guided TBB has a high diagnostic yield in the diagnosis of PPLs.
Diagnosis of peripheral lung cancer with three echoic features via endobronchial ultrasound
2007, Chest
Endobronchial ultrasonography (EBUS) is useful in localizing peripheral lung lesions. Previous reports have revealed that several characteristic echoic patterns correlate well with the histopathologic findings of benign and malignant lesions. Therefore, EBUS may be also useful in the differential diagnosis of malignant lesions of the lung.
To assess the feasibility of EBUS in the differential diagnosis between malignant and benign lesions by the following three characteristic echoic features indicating malignancy: continuous margin; absence of a linear-discrete air bronchogram; and heterogeneous echogenicity.
EBUS images from 224 patients who undergone bronchoscopy for a peripheral lung lesion were analyzed. The sensitivity and specificity for each echoic feature or in combination in diagnosing malignancy or benignity were determined.
Continuous margin, absence of linear-discrete air bronchogram, and heterogeneous echogenicity are three echoic features indicating malignancy. The absence of linear-discrete air bronchogram has the highest sensitivity in the diagnosis of malignancy (91.9%), but the lowest specificity (62.4%). By contrast, a well-defined margin has the highest specificity (93.1%), but the lowest sensitivity (27.6%). The sensitivity and specificity for heterogeneous echogenicity are intermediate (65.0% and 90.1%, respectively). The negative predictive value for the malignancy of a lesion with none of these three echoic features is 93.7%. The positive predictive value for malignancy of a lesion with any two of the three echoic features is 89.2%.
These results indicate that EBUS is useful as an adjunct in lung cancer diagnosis, especially when peripheral lung lesions are not visible in traditional bronchoscopy.
Endobronchial ultrasonography with distance for peripheral pulmonary lesions
2007, Respiratory Medicine
Citation Excerpt :
Endobronchial ultrasonography (EBUS), first introduced in 1990 by Hurter and Hanrath, has been evaluated in several clinical studies and shown to provide information about the location and size of pulmonary lesions.1–3
We assessed the effectiveness of applying the distance from the orifice of the bronchus to visualized peripheral pulmonary lesion (PPL) under endobronchial ultrasonography (EBUS) to transbronchial biopsy (TBB), as an alternative to EBUS with a guide sheath (GS) and fluoroscopy.
From October 2004 to July 2005, a total of 158 consecutive patients with solitary PPLs, which were not visualized under flexible video bronchoscopy, were received EBUS for advanced localization subsequently. One hundred and thirteen of 158 patients with solitary PPLs which were visualized on EBUS image were included in this prospective study and randomly divided into two groups for TBB using different methods. In group EBUS-D (57 patients) the distance from the bronchial orifice to pulmonary lesion was measured, then the biopsy forceps were advanced to this measured distance and biopsy followed. In group EBUS (56 patients) the biopsy forceps were advanced regardless of distance. The diagnostic yields were then compared.
TBBs in group EBUS-D patients had a significantly higher diagnostic yield (45/57, 78.9%) than group EBUS patients (32/56, 57.1%) [ $P = 0.013$ ]. Size and location of lesion, duration of EBUS, diagnosis of malignancy, and whether the probe was located within the lesion on EBUS image did not differ between these two groups. Mild bleeding occurred in three patients in group EBUS-D and two in group EBUS. One group EBUS patient had a self-limited pneumothorax.
Measuring and applying the distance between the orifice of bronchus and the lesion could increase the diagnostic yield of EBUS-guided TBBs for PPLs.
Endobronchial ultrasound-driven biopsy in the diagnosis of peripheral lung lesions
2005, Chest
Citation Excerpt :
Its sensitivity is low, and a negative result cannot rule out the presence of a malignancy. The possibility of using ultrasound has widened the bronchoscopic vision beyond the bronchial wall, with a substantial increase in diagnostic sensitivity.11 While the role of EBUS-driven biopsies in central malignancy diagnosis or in the evaluation of lymph nodes involvement is well established, there are few studies investigating its role in the diagnosis of peripheral lesions.
Study objectives: The aim of our study was to compare the diagnostic yield of two bronchoscopic procedures: endobronchial ultrasound-driven transbronchial biopsy (EBUS-TBB) and transbronchial biopsy (TBB) in peripheral pulmonary lesions.
Design: Prospective, randomized, blinded study.
Setting: University Hospital of Rome, Italy
Patients and methods: We examined 799 patients with peripheral lung lesions using bronchoscopy. Patients who could undergo a complete clinical diagnostic follow-up (n = 293) were enrolled in the study and randomly assigned to EBUS-TBB or TBB. We performed these two procedures on 221 patients (97 EBUS-TBB and 124 TBB). Patients in whom biopsies were not diagnostic underwent more invasive procedures to obtain a final diagnosis, and a complete follow-up was possible in 206 patients (87 EBUS-TBB and 119 TBB).
Results: Lung cancer was diagnosed in 61 patients in the EBUS-TBB group and in 83 patients in the TBB group. Pulmonary diseases other than cancer were diagnosed in 26 patients and 36 patients, respectively. For patients with lung cancer, sensitivity was 0.79 in the EBUS group and 0.55 in the TBB group (p = 0.004), and accuracy was 0.85 and 0.69, respectively (p = 0.007). The analysis of a subset of patients with lesions > 3 cm showed no significant difference in diagnostic ability between the two procedures. In lesions < 3 cm, we found a considerable decline in TBB sensitivity and accuracy (0.31 and 0.50) while EBUS-TBB maintained their diagnostic yield (0.75 and 0.83) [p = 0.0002 and p = 0.001, respectively]. A similar difference was observed when we compared the sensitivity of the two procedures in lesions < 2 cm (0.23 vs 0.71, p < 0.001).
Conclusions: EBUS-TBB can be an important option in the early diagnosis of peripheral lung cancer, especially in small-sized lesions and in patients who are not eligible for surgery.
Ultrasound in Pulmonology: The Current Situation
2003, Archivos de Bronconeumologia
The restaging issue
2003, Lung Cancer
Patients with persisting involvement of mediastinal lymph nodes after neo-adjuvant therapy have a poor prognosis and do not benefit from surgical resection. Precise restaging after induction treatment is important to determine further treatment and prognosis. Computed tomography (CT) and magnetic resonance imaging (MRI) have a low accuracy in predicting response after induction therapy. Positron emission tomography (PET) has a high sensitivity to detect residual viable disease in the primary tumour but not in the mediastinal lymph nodes. Invasive staging remains necessary to precisely assess mediastinal response. Remediastinoscopy, although technically difficult, has an accuracy of 80% and provides histological proof of mediastinal downstaging. In this way, it is a useful procedure to select patients for thoracotomy after induction therapy. The ultimate overall pathologic response can only be determined by thoracotomy with excision of the primary tumour, hilar and mediastinal lymph nodes.

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¹: On behalf of the The Rotterdam Oncologic Thoracic Study group, ROTS

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Endobronchial ultrasound

Abstract

Introduction

Section snippets

Sonographic airway anatomy

Indications

Staging of lung cancer

Peripheral lesions

Conclusion

Chest

Chest

Chest

Endobronchial sonography: feasability and preliminary results

Thorax

An Italian study of endobronchial ultrasonography (EBUS): preliminary results

Eur. Resp. J.

Endobronchial ultrasound of the airways and the mediastinum

Evaluation of tracheo-bronchial wall invasion using transbronchial ultrasonography (TBUS)

Eur. J. Cardiothor. Surg.

Endobronchial ultrasound—a new perspective in bronchoscopy

Lung Cancer