**1. Introduction**

Sarcoidosis is an enigmatic disorder with a propensity for lung involvement in the majority of cases (90%) and is characterized by noncaseating granulomatous inflammation on histological analysis. The techniques to establish the diagnosis have evolved over time, and a clear diagnostic algorithm for clinicians dealing with this disease is desirable. Thoracic computed tomography is the imaging modality of choice in pulmonary sarcoidosis and provides accurate assessment of the stage, parenchymal involvement, and response to immunomodulatory therapies. The advent of EBUS-TBNA has been a step forward with an excellent diagnostic yield in the presence of mediastinal/hilar lymphadenopathy and has replaced the traditional approach of obtaining biopsy samples via transbronchial and endobronchial routes. The preferred initial investigation for the confirmation of diagnosis is dependent upon the organ involved and the expertise available. A core biopsy of cervical lymph nodes is a less invasive and economical alternative in selected cases


#### **Figure 1.**

*Chest radiograph appearances according to stage of sarcoidosis.*

of suspected pulmonary sarcoidosis and warrants further evaluation in a prospective manner to establish if it can be considered a first-line investigation in all new cases suspected to have pulmonary sarcoidosis. A multidisciplinary approach is crucial for the diagnosis and management; a simplified algorithm is proposed to help guide clinicians dealing with this disease of myriad clinical and radiological manifestations.

Sarcoidosis is a disease of uncertain etiology characterized by evidence of nonnecrotizing granulomatous inflammation on histological assessment. As the disease commonly affects the lungs, the patients are likely to be referred to pulmonologists for further investigations. Chest radiography is usually the first investigation carried out in the primary care setting suggesting the possibility of hilar lymph node enlargement, and sarcoidosis has traditionally been staged according to chest radiographic appearances (**Figure 1**).

Radiological assessment of sarcoidosis has been revolutionized by highresolution computed tomography (HRCT) scanning of lungs and is currently the best available modality to assess the extent of involvement of lung parenchyma/ interstitial compartment and response to immunomodulatory therapies to evaluate alveolitis and reversibility of the disease process. The current diagnostic techniques for histological assessment in pulmonary sarcoidosis are invasive, and there is a need for a less invasive approach to obtain tissue sample(s). This chapter aims to discuss the available diagnostic techniques in sarcoidosis and propose an algorithm to the pulmonologists/radiologists and clinicians dealing with sarcoidosis as a tool to aid for reaching the diagnosis with minimally invasive investigations. It is recommended that an ultrasound-guided core biopsy of cervical lymph nodes (along with assessment of parotid glands) may be considered first-line investigation in the presence of mediastinal and or hilar lymphadenopathy, a suitable target to sample neck lymph nodes.

#### **2. Diagnostic techniques**

The diagnosis of sarcoidosis is best supported by the presence of noncaseating/ necrotizing granulomatous inflammation on histological analysis, following the exclusion of other granulomatous disorders such as mycobacterial or fungal diseases on special immunohistochemical stains. The diagnostic techniques for sarcoidosis can be subclassified into four groups:

**19**

**Figure 2.**

*Current Diagnostic Techniques in Sarcoidosis DOI: http://dx.doi.org/10.5772/intechopen.90692*

• Radiological techniques

• Surgical techniques

*2.1.1 Chest radiography*

parenchymal distortion.

• Bronchoscopic techniques

**2.1 Radiological imaging techniques**

• Ultrasound-guided biopsy techniques

positron emission tomography (PET) scanning.

*2.1.2 High-resolution computed tomography*

These include chest radiography, high-resolution computed tomography, and

The typical chest radiographic appearances in sarcoidosis consist of symmetric bilateral hilar and mediastinal lymphadenopathy. Fibrosis is noticed in 5–25% of patients with sarcoidosis on initial chest radiograph [1]. **Figure 2** demonstrates an example of advanced stage sarcoidosis with the development of fibrosis and

High-resolution computed tomography has improved the diagnostic accuracy of sarcoidosis in terms of parenchymal involvement (**Figure 3**) and assessed any reversible component such as alveolitis that may not be readily evident on chest radiography. Moreover, the abnormalities on HRCT scan do correlate better with

Sarcoidosis is a disease with a myriad of radiological abnormalities on HRCT, including hilar and mediastinal lymphadenopathy, ground glass abnormality, and fibrosis in a peribronchovascular, perilymphatic distribution, pulmonary parenchymal nodules, and beading of the fissures. There is a mid- to upper-zone preponderance of these abnormalities and usually distributed along the bronchovascular

respiratory functional impairment than chest radiograph findings [2].

*Stage III sarcoidosis with evidence of hilar lymphadenopathy and parenchymal involvement.*

*Current Diagnostic Techniques in Sarcoidosis DOI: http://dx.doi.org/10.5772/intechopen.90692*

• Radiological techniques

*Sarcoidosis and Granulomatosis - Diagnosis and Management*

*Chest radiograph appearances according to stage of sarcoidosis.*

of suspected pulmonary sarcoidosis and warrants further evaluation in a prospective manner to establish if it can be considered a first-line investigation in all new cases suspected to have pulmonary sarcoidosis. A multidisciplinary approach is crucial for the diagnosis and management; a simplified algorithm is proposed to help guide clinicians dealing with this disease of myriad clinical and radiological

Sarcoidosis is a disease of uncertain etiology characterized by evidence of nonnecrotizing granulomatous inflammation on histological assessment. As the disease commonly affects the lungs, the patients are likely to be referred to pulmonologists for further investigations. Chest radiography is usually the first investigation carried out in the primary care setting suggesting the possibility of hilar lymph node enlargement, and sarcoidosis has traditionally been staged according to chest

Radiological assessment of sarcoidosis has been revolutionized by highresolution computed tomography (HRCT) scanning of lungs and is currently the best available modality to assess the extent of involvement of lung parenchyma/ interstitial compartment and response to immunomodulatory therapies to evaluate alveolitis and reversibility of the disease process. The current diagnostic techniques for histological assessment in pulmonary sarcoidosis are invasive, and there is a need for a less invasive approach to obtain tissue sample(s). This chapter aims to discuss the available diagnostic techniques in sarcoidosis and propose an algorithm to the pulmonologists/radiologists and clinicians dealing with sarcoidosis as a tool to aid for reaching the diagnosis with minimally invasive investigations. It is recommended that an ultrasound-guided core biopsy of cervical lymph nodes (along with assessment of parotid glands) may be considered first-line investigation in the presence of mediastinal and or hilar lymphadenopathy, a suitable target to sample

The diagnosis of sarcoidosis is best supported by the presence of noncaseating/ necrotizing granulomatous inflammation on histological analysis, following the exclusion of other granulomatous disorders such as mycobacterial or fungal diseases on special immunohistochemical stains. The diagnostic techniques for sarcoidosis

**18**

manifestations.

**Figure 1.**

neck lymph nodes.

**2. Diagnostic techniques**

can be subclassified into four groups:

radiographic appearances (**Figure 1**).

