Diagnostic procedures in Respiratory Disease.pptx

1. Diagnostic Procedures in
Respiratory Disease

2. ● BEDSIDE PLEURAL PROCEDURES
● THORACIC SURGICAL PROCEDURES
● BRONCHOSCOPY
● MEDICAL IMAGING
● TRANSTHORACIC NEEDLE ASPIRATION
● MISCELLANEOUS TESTING

3. THORACENTESIS
● Percutaneous aspiration of fluid from the pleural space.
● Point-of-care ultrasonography to mark the site of needle puncture
● This reduces the risks of “dry tap” as well as complications such as
pneumothorax.
● Beside palliation of symptoms associated with pleural effusion (most
commonly dyspnea), thoracentesis may be performed for diagnostic
purposes.
● Newer assays such as mesothelin-1 testing for neoplastic diseases (chiefly
mesothelioma)

4. CLOSED PLEURAL BIOPSY
● Percutaneous sampling of the parietal pleural lining.
● This procedure can be performed either “blindly” (typically with an Abrams
needle) or by using imaging guidance such as CT or ultrasound.
● Closed pleural biopsy without ultrasound guidance
● Image-guided closed pleural biopsy

5. THORACOSCOPY AND THORACOTOMY
● Spectrum of surgical procedures that involve accessing and operating within
the pleural space, either via one or more small entry ports using
thoracoscopic tools or via larger incisions as in thoracotomy
● Pleuroscopy (also known as medical thoracoscopy) and accesses the pleural
space through a single port for parietal pleural biopsy or for limited
therapeutic purposes such as minor lysis of adhesions, thoracoscopic
pleurodesis, or indwelling pleural catheter placement.
● VATS and RATS are more invasive procedures but with more controlled
environments entailing general anesthesia with single-lung ventilation,
creation of multiple entry ports, and several additional diagnostic and
therapeutic including lung biopsy, lymph node sampling, lobectomy,
decortication, and creation of a pericardial window.
● Open thoracotomy -Clagett window for chronic bronchopleural fistula with
empyema.

6. MEDIASTINOSCOPY AND MEDIASTINOTOMY
● Surgical access to the mediastinum, either through a small port
(mediastinoscopy) or a wider incision (mediastinotomy), enables diagnostic
sampling of mediastinal structures such as mediastinal lymph nodes as part
of lung cancer staging.
● In cases of negative needle-based sampling where suspicion for malignant
nodal involvement remains sufficiently high.

7. BRONCHOSCOPY
● Flexible bronchoscopy enables access to more distal parts of the respiratory
tract.
● The rigid bronchoscope has the added advantage of providing a secure
airway for ventilation; artificial breaths can then be administered through the
scope itself as part of a closed circuit or through open jet ventilation.
● The rigid bronchoscope also provides a conduit for diagnostic or therapeutic
instruments to be passed freely, rather than through the relatively constrained
working channel of a flexible bronchoscope.

8. Bronchoalveolar Lavage
● Gold standard method for obtaining respiratory secretions for hematologic,
biochemical, microbiological, and/or cytologic analyses.
● Advantage and Indications.
● After wedging the bronchoscope in a distal airway in order to prevent fluid
escape around the scope, sterile saline or distilled water is instilled through
the scope’s working channel (typically in one to three aliquots of
approximately 50 mL each).
● Immediately thereafter, suction is applied to aspirate as much of the fluid as
possible.
● This allows sampling of distal airways and lung parenchyma—areas not
directly viewable or accessible.

9. Brushing and Endobronchial Biopsy
● Bronchoscopic brushing is a minimally invasive sampling technique that can
be used to sample the mucosal biofilm for microbiologic analyses as well as
the bronchial epithelial layer for cytologic analyses.
● Endobronchial biopsy allows sampling of abnormal bronchial mucosa and
submucosa for histopathologic analysis (as may be indicated in cases of
endobronchial amyloidosis or sarcoidosis, for example)

10. Transbronchial Biopsy Including Cryobiopsy
● Removing a piece of alveolated lung tissue by passing a sampling tool into
the alveolar space.
● The most commonly employed biopsy tool is flexible forceps, typically 2.0 mm
or 2.8 mm in caliber.
● When random sampling of the lung parenchyma is desired.e.g., to assess for
posttransplant lung rejection, either fluoroscopic guidance or tactile feedback
is commonly used to position the forceps in the subpleural lung parenchyma
● Number of biopsy samples
● Malignant Lung Nodules
● Acute cellular rejection

11. ● An increasingly popular biopsy tool is the cryoprobe, a flexible catheter with a
blunt tip that delivers liquid nitrogen or carbon dioxide over a few seconds to
freeze a portion of lung parenchyma and make it adhere to the probe itself.
● Before the tissue can thaw and detach
● Cryobiopsy has a higher diagnostic yield than forceps biopsy for diffuse
parenchymal illnesses such as idiopathic pulmonary fibrosis but comes with a
higher risk of major bleeding and pneumothorax.

12. Transbronchial Needle Aspiration
● Transbronchial needle aspiration (TBNA) involves using a hollow-bore needle
for obtaining aspirated specimen.
● TBNA has diagnostic sensitivity superior to that of transbronchial biopsy for
malignant peripheral nodules.
● This makes intuitive sense given that the lesion may lie extraluminally and
require traversing the airway wall, which only the needle may be able to
accomplish.
● TBNA + Transbronchial biopsy

13. Endobronchial Ultrasound-Guided Transbronchial Needle
Aspiration
1. Represent a major advance in diagnostic bronchoscopy over the turn of the
twentieth century, largely replacing surgical methods for lymph node
sampling.
2. EBUS-TBNA involves using a specialized flexible bronchoscope that
simultaneously operates a video camera and a convex ultrasound probe
(which is installed at its distal end).
3. Newer variants of this technique involve the use of core needles or mini-
forceps, providing tissue specimens rather than aspirates that can be sent for
histopathologic analysis.
4. Sensitivity
● Lymphoma
● Sarcoidosis(higher if combined with endobronchial and transbronchial
biopsies).
● Epithelial Maligancy.

14. ● Ancillary testing in cases of malignancy, such as immunostaining or genetic
testing.
● Sampling mediastinal structures through the esophagus, which can be a
useful adjunct to EBUS-TBNA as it may provide better access to certain
mediastinal lymph node station.
● Esophageal sampling can be accomplished by
● EBUS-TBNA is accompanied by rapid on-site cytologic evaluation (ROSE),
wherein a portion of the aspirated specimen is immediately examined by a
cytotechnologist or pathologist using rapid staining.
● This rapid assessment, while often inadequate for a definitive final diagnosis,
can be helpful in establishing adequacy of sampled material by providing the
bronchoscopist with real-time feedback on whether additional sampling is
advisable.

15. Guided Peripheral Bronchoscopy
Guided peripheral bronchoscopy involves the use of advanced tools to aid
with one or more of three tasks involved in successful bronchoscopic
sampling of peripherally located lesions, such as lung nodules.
● Navigating to the appropriate lobe/segment/subsegment: Electromagnetic
navigational bronchoscopy (which involves GPS-like feedback as the
bronchoscope is advanced toward the target) and virtual bronchoscopy
(which overlays live endoscopic images onto a CT-derived virtual
bronchoscopic map) can help with successful navigation through the airways.
● The aforementioned technologies can also help localize a lesion, although
they are limited by relying on previously acquired CT images that may or may
not accurately represent precisely where the lesion is currently located in a
three-dimensional space.
● Other alternatives-Radial EBUS .

16. ● Alternatively, fluoroscopic imaging can be used to recalibrate the precise
target location on navigational bronchoscopic platforms, potentially improving
localization as well.
● The tools available for peripheral sampling include biopsy forceps, brushes,
and aspiration needles as described above, with TBNA having the highest
diagnostic sensitivity for discrete malignant lesions.

17. MEDICAL IMAGING
Technologies such as x-ray, CT, MRI, and positron emission tomography (PET)
can provide
● Noninvasive assessments of alveolar perfusion
● Metabolic activity of a lung nodule
● Bronchovascular source of hemoptysis
● Earliest disease-related changes in parenchymal structure.

18. CHEST X-RAY
1. The most commonly used CXR images for respiratory medicine are the
posteroanterior (PA) and lateral films in the outpatient setting and
anteroposterior (AP) films for those studies obtained at the bedside.
2. Differing views can be used to examine superimposed structures (for
example, a parenchymal opacity in the retrocardiac space).
● The contours of the chest wall
● Silhouette of the heart
● Great vessels
● Mediastinum
● Appearance of the parenchyma and bronchovascular bundle.

19. ● Many of the smaller structures such as the lymphatics and distal airways are
beyond the ability of conventional x-ray technology to resolve.
● Larger structures such as the pulmonary vasculature may also be indistinct
because of body position and the redistribution of blood flow to more
gravitationally dependent regions.
● Diseases involving these structures may enhance or obscure their
appearance.
● Congestive heart failure where the lymphatics become engorged (Kerley B
lines)
● Nondependent vasculature more prominent (cephalization)
● Outer boundaries of the bronchial walls blurred (bronchial cuffing).
● Thickened interstitium may be due to hydrostatic pulmonary edema, it may
also be indicative of interstitial lung disease or carcinomatosis.
● An elevated hemidiaphragm, fibrosis of the mediastinum, or hyperlucency of
the lung parenchyma all reflect processes that cause dyspnea, but their
treatment and prognosis differ markedly

20. COMPUTED TOMOGRAPHY
● The acquisition of a CT scan involves the same basic process as an x-ray
with a patient placed between a source of photons and a detector, but the
image reconstruction and advanced analytics that can be applied to those
images differ markedly.
● The passage of photons through the body is impeded in proportion to tissue
density.
● This absorption or attenuation of photon passage is measured in Hounsfield
units (HU) and clinical CT scanners are regularly calibrated to a standard
scale with water having an HU of 0 and air –1000 HU.
● A window width and level (the range and center of the range of HU values to
display) is selected to optimize viewing structures of interest.

21. ● The visual interpretation of thoracic CT is based upon the appearance of the
secondary pulmonary lobule.
● Fundamental subunit of the lung consisting of a central airway and pulmonary
artery, parenchyma, and then surrounding interstitium with the lymphatics and
pulmonary veins.
● Processes affecting the small airways such as respiratory bronchiolitis may appear
as centrilobular nodule.
● Parenchymal diseases such as emphysema
● Pathology of the lymphatics or interstitium
● The diagnostic information provided by the appearance of the secondary pulmonary
lobule is further augmented by the distribution of these patterns of injury across the
lung.CLE and PLE
● Interstitial thickening in the apices is more likely to be nonspecific interstitial
pneumonitis (NSIP) while a basal and dependent predominant distribution of that
same process is more consistent with idiopathic pulmonary fibrosis (IPF).

22. ● Finally, morphology of the central airways and vessels can be used to
diagnose disease and estimate its severity.
● Bronchiectatic dilation of the airways may be cylindrical and predominantly in
the lower lobes
● Cystic dilation in the upper lobes
● Focal nonspecific dilation of an airway
● Pathologic dilation of the airways may also be due to disease of the
surrounding parenchyma.
● Because of the mechanical interdependence of the bronchial tree and
parenchyma, conditions that reduce lung compliance may result in traction
bronchiectasis.
● The caliber of the central pulmonary arterial (PA) trunk proximal to its first
bifurcation is directly related to pulmonary arterial pressure.

23. ● PA/A provides a metric of disease severity and in the case of chronic
respiratory diseases such as COPD is prognostic for both acute respiratory
exacerbations and death.
● Assessment of the intraparenchymal pulmonary vasculature is typically
augmented through the intravenous infusion or bolus of iodinated contrast.
● Dark filling voids in otherwise bright white vessels.

24. MAGNETIC RESONANCE IMAGING
● Behavior of protons in a magnetic field.
● A strong magnetic field is applied to align the protons and then a pulse of
radiofrequency current is then applied to the subject.
● This perturbs the protons and the speed at which they subsequently realign
differs based upon the properties of the tissues within the region of interest.
● Abundance of air in the lung creates an artifact that impairs direct assessment
of the parenchyma.
● Gadolinium and is increasingly exploring the use of inhaled agents such as
hyperpolarized noble gas.
● Regions of the lung that are poorly ventilated due to disease of the airways or
distal airspaces have low concentrations of 3He and appear as dark regions
in an otherwise bright blue organ.
● Modality of choice in the pediatric population or clinical situations where
repeated assessments are required.

25. POSITRON EMISSION TOMOGRAPHY
● An image based upon the aggregation of radiolabeled tracers.
● The most common agent used for these purposes is [18F]-fluoro-2-
deoxyglucose (FDG).
● Taken up by cells in direct proportion to their metabolic activity.
● It is most commonly used for the discrimination of benign and malignant lung
nodules, as well as lung cancer staging.
● Given the relatively low resolution of PET, co-registration with CT is common
and the aligned imaging modalities allow the reader to determine the
structural source of heightened metabolic activity.

26. Thank you