EBUS-TBNA

INTRODUCTION
Endobronchial ultrasound (EBUS) is a
bronchoscope technique that uses
ultrasound to visualize structures within
and around the airway wall as well as
the lung ..

• The overall sensitivity and the negative
predictive value (NPV) of EBUS-TBNA in
mediastinal staging of lung cancer are 89%
(46%-97%) and 91% (60%-99%) respectively
• The overall Mediastinal lymphomas in The
overall sensitivity, specifi city, positive
predictive value (PPV), NPV, and accuracy were
89%, 97%, 98%,83%, and 91%, respectively.

ULTRASOUND FREQUENCY
Ultrasound frequency is an important consideration for
EBUS application.
LOWER FREQUENCIES - better penetration depth
-less resolution
HIGHER FREQUENCIES -better spatial resolution
- less penetration depth.
For EBUS applications, the frequencies range from 7.5 to
30 MHz.
Currently, there are three EBUS probes available for
different applications:
(1) Ultraminiature radial probes (20 and 30 MHz),
(2) radial balloon probes (20 MHz), and
(3) convex probe or curvilinear EBUS (7.5MHz).

CLINICAL APPLICATIONS
Visualize mediastinal and peribronchial
lymph nodes and metastases and allow
EBUSguided
TBNA
Determine depth of tumor invasion of
tracheobronchial lesions
Define positional relationships with pulmonary
artery and veins and hilar structures
 Localize and diagnose peripheral pulmonary
lesions (benign or malignant

Staging of non-small cell lung cancer
(NSCLC)
Diagnosis and to evaluate pathologic
conditions like pulmonary sarcoma and
pulmonary embolism

ADVANTAGES
EBUS is a minimally-invasive
Real-time imaging permits the sampling of lymph
nodes that are smaller than 10 mm in short axis
and/or near major blood vessels
High diagnostic yield
 Safe procedure that can be performed on an
outpatient basis using local anesthesia and conscious
sedation.
EBUS can access a wide range of mediastinal lymph
nodes as well as hilar lymph nodes (2R, 2L, 3P, 4R,
4L, 7, 10R, 10L, 11R, 11L) , and sample centrally
located pulmonary lesions with high sensitivity.

Complications are uncommon, while sampling
is performed in real time.

DISADVANTAGES
 EBUS cannot image or sample subaortic and
paraesophageal lymph nodes.
Its availability is institution-specific, and
expertise is required to interpret images and
obtain diagnostic samples.
Small sample size

TYPES OF EBUS
• Two types of endobronchial ultrasound
(EBUS) exist:
• Radial Probe EBUS (RP-EBUS)
• Convex Probe EBUS (CP-EBUS)

RP vs CP EBUS
• RP-EBUS typically has higher resolution than
CP-EBUS such that airway structure and
parenchymal lesions are visualized in better
detail.
• However, unlike CP-EBUS, RP-EBUS cannot be
used to biopsy targets in real time. Thus, for the
purposes of sampling, CP-EBUS is more
frequently used to acquire tissue, while RP-
EBUS is often used to locate a target lesion
suitable for sampling (eg, peripheral nodules).

RADIAL BALLOON PROBE
Utilises radial ultrasound probe
Pass through the working channel of therapetic
bronchoscope
1.7 mm probe inserted through the working
channel of therapetic bronchoscope
Frequency is 20 MHZ
 The radial balloon EBUS probe provides 360-
degree visualization of paratracheal and
peribronchial structures
Enables the evaluation of peripheral nodules

CP-EBUS BRONCHOSCOPE
• Incorporated into tip of dedicated bronchoscope
• Allows real time imaging and sampling of tissue
• CP-EBUS bronchoscope) has linear curved array ultrasonic
transducer of 7.5 MHz at the distal tip, which has capability of
displaying B-mode and color Doppler mode.
• The CP-EBUS ultrasound probe that scans 80 degrees perpendicular
from the longitudinal axis, a 35-degree forward oblique video view,
and a 2.0-mm working channel through which a dedicated biopsy
needle can be passed.
• Dedicated biopsy needles (21 or 22 gauge) are inserted through the
2-mm working channel to perform aspirations of the target lesion

This needle has various adjuster knobs which work as
a safety device to prevent damage to the channel
• The needle is also equipped with an internal sheath
which is withdrawn after passing the bronchial wall,
avoiding contamination during TBNA. This internal
sheath is also used to clear out the tip of the needle
after passing the bronchial wall.
• The use of this sheath has significantly increased the
yield of EBUS-TBNA. The exit of the needle is at 20°
with respect to the outer covering of the insertion
tube.
• The needle can be visualized through the optics and
on the ultrasound image .

CP-EBUS TECHNIQUE
• A regular fiberoptic bronchoscopy should be done first to
determine anatomy and exclude endobronchial lesion.
• CP-EBUS is usually performed orally, as ultrasound
probe in it prevents using nasal route.
• The image quality is lower to that of a regular
bronchoscope.
• A disposable latex balloon is attached to the ultrasound
probe.
• The tip of the bronchoscope should be positioned more
anteriorly while passing through the vocal cords to avoid
sticking the EBUS bronchoscope on the posterior part of
vocal cords.
•

Once in the airways, a syringe filled with sterile water is
attached to the balloon channel of the scope and the balloon is
filled with water to achieve contact with the airways. Lymph
nodes are identified with its typical sonographic appearance.
Lymph nodes should be differentiated from vascular
structures, which are also hypoechoic. Doppler accurately
differentiates lymph nodes and vascular structures. All
mediastinal lymph node stations should be evaluated
systematically. Subcarinal lymph node can be visualized either
from right main or left main bronchus.
The bronchoscopic and ultrasonic views can be toggled
alternatively or two-screen display of both views can be used
in the monitor.
The tip should be flexed up for ultrasound image and down fo
endoscopic image. The ultrasound image can be frozen,
allowing the size of lesions to be measured.

Real-time TBNA
• Real-time TBNA is defined as simultaneous sonographic
visualization and sampling of the lesion.
• Once the target lesion is identified, the dedicated 22-
gauge needle is inserted through the working channel of
the bronchoscope and fastened to it.
• The tip of bronchoscope should be in neutral position to
allow the sheath to come out of the distal end of working
channel. The needle should remain within the catheter
during passage through the working channel in order to
prevent injury to the bronchoscope.
• Once the catheter emerges out of the bronchoscope, the
needle is advanced from the catheter and locked into
position.
• The insertion point of needle is localized and it is then
pushed through the bronchial wall into the target lymph
node under direct ultrasound visualization.

• With the needle in the target lymph node, the internal
sheath is removed. This cleans the lumen of the needle
system, which usually becomes contaminated with
bronchial cells. Suction is applied using a 20-mL syringe,
and the catheter is moved back and forth. Suction is
released and the needle is pulled back into the flexible
catheter. The entire transbronchial needle system is then
removed from the bronchoscope in a single, smooth
motion. The tissue core is removed from the needle lumen
by reinserting the internal sheath.
• The number of needle aspirations per site can impact the
yield and range from 3-7 depending on the study, but the
first pass has the highest yield.
• If the TBNA is being done for staging of NSCLC, the
sampling should be started from N3 followed by N2 and
N1 lymph nodes to avoid contamination and upstaging

• Radial probe EBUS imaging can provide additional
information to help support a clinician’s assessment
of whether a pulmonary nodule is benign or
malignant .
• In one retrospective study of 124 patients, based
upon the appearance of the nodule, three classes of
peripheral nodules were distinguished :
• ●Type I – A homogeneous nodule
• ●Type II – A nodule with hyperechoic dots and linear
arcs
• ●Type III – A heterogeneous nodule
• Approximately 92 percent of the type I lesions were
benign, and 99 percent of the type II and III lesions
were malignant.

CONTRAINDICATIONS
• Contraindications to endobronchial ultrasound (EBUS) are
similar to contraindications to flexible bronchoscopy and include
following:
• Life-threatening cardiac arrhythmias
• Current or recent myocardial ischemia
• Poorly controlled heart failure
• Severe hypoxemia
• Uncooperative patient
• Additional contraindications to EBUS-TBNA are related to
bleeding risk and include following:
• Current anti-platelet agents
• Current anticoagulant therapy
• Coagulopathy
• Thrombocytopenia
• Elevated blood urea nitrogen or serum creatinine

COMPLICATIONS
• EBUS and EBUS-TBNA are usually safe procedures.
• No serious complications were found on a systematic
review of effectiveness and safety of CP-EBUS-TBNA of
regional lymph nodes.
• Reported complications are agitation, cough, hypoxia,
laryngeal injury, fever, bacteremia and infection,
bleeding, pneumothorax, and broken equipment
becoming stuck in the airway.
• Mediastinal abscess has been reported as a case report.
• Complications related to upper airway local anesthesia
are laryngospasm, laryngeal edema, bronchospasm,
methemoglobinemia, and cardiac arrhythmias.
• Complications attributable to procedural sedation are
respiratory depression, cardiovascular instability,
vomiting, and aspiration.

SPECIMEN PREPARATION
• Aspirated specimen is smeared onto glass slides
and air dried so that an on-site cytopathologist
can evaluate the specimen.
• The use of rapid on-site evaluation significantly
improves the diagnostic yield of transbronchial
aspiration, and it is a cost-effective approach.It
leads to avoidance of additional biopsies without
loss in diagnostic yield and also reduces the
complication rate of bronchoscopy.Histological
cores are fixed with formalin and sent to the
pathology department. The samples can be used
for molecular analysis.

DETERMINATION OF TARGET AREA BY EBUS
Based on previous reports, lymph nodes that had the following
sonographic characteristics on B-mode and vascular pattern on power
Doppler were deemed as probably malignant:
short-axis size .1 cm,
round shape,
distinct margin,
heterogeneous echogenicity
and abundant blood flow with
varying vessel diameters and tortuosity .
The presence of at least one or a combination of these features in a LN
was designated as the target area for EBUS-TBNA. When multiple
LNs were detected in the same station, the biggest LN with suggestive
malignant features was chosen

ELASTOGRAPHY TECHNIQUE
• Real-time tissue elastography (RTE)
performed during endobronchial ultrasound is
a relatively new method for characterizing
tissue compliance, RTE with different color
shows the difference of tissue after different
compression deformation .

The elastic code reflects the nodal hardness with
the colors associated with hard(blue),
intermediate, and soft tissues being green, and
red respectovely
Most of the hard nodes turned out to be malignant
Non blue nodes turned out to be benigh

EBUS-TBNA

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