*2.1.2 High-resolution computed tomography*

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 respiratory functional impairment than chest radiograph findings [2].

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

bundles [3]. HRCT may be able to demonstrate lymphadenopathy in mediastinal distribution better than a chest radiograph and sometimes demonstrate evidence of calcification within these nodes (**Figure 4**).

The precise role of HRCT in the clinical monitoring of sarcoidosis is unknown. However, it may prove to be a useful tool to assess acute alveolitis and inflammation in selected cases of refractory sarcoidosis, where treatment decisions to commence

#### **Figure 3.**

*Parenchymal distortion with fibrosis in a peribronchovascular distribution in bilateral upper lobes in sarcoidosis.*

#### **Figure 4.**

*Calcified mediastinal lymphadenopathy with bilateral hilar nodal enlargement in a patient with confirmed sarcoidosis.*

**21**

EBUS-TBNA [20].

sarcoidosis [12].

site to sample suspected multisystem disease.

bronchovascular and centrilobular structures.

**2.2 Bronchoscopic techniques**

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

*2.1.3 Positron emission tomography scan*

biologic therapies such as infliximab are being made [3]. A study by De Boer et al. showed that the total extent of parenchymal disease on the CT scan on a lobar basis could predict the likelihood of transbronchial biopsy being positive following

Positron emission tomography scan can be a useful tool to detect the extent of the disease, identify multisystem disease such as cardiac sarcoidosis, and may help to identify a desirable site for biopsy [5]. Moreover, it could be invaluable in the decision to initiate immunosuppression and assess the efficacy of treatment [6, 7]. Furthermore, it may help in predicting relapse in pulmonary sarcoidosis [8]. A retrospective study by Teirstein et al. showed that a combination of diagnostic modalities such as 18F-fluorodeoxyglucose (FDG-PET) and CT scan is more sensitive than PET-only imaging [9]. Whole-body FDG-PET was found to be significantly better in identifying occult and reversible granulomas. Moreover, a positive PET scan in isolation should not be considered as an indication for treatment. In another study by Yu et al., the sensitivity and specificity for benign and malignant disease were 94.2% and 73.8%, respectively [10]. It was, however, noted that maximum standard uptake value (SUVMax) as semiquantitative measurement

bronchoscopy [4], demonstrating its utility on diagnostic grounds.

alone could not be used to differentiate benign vs. malignant lesions.

*2.2.1 Bronchoalveolar lavage (BAL) and transbronchial biopsy (TBB)*

The FDG-PET scan has a cumulative effect in cardiac sarcoidosis. PET scan has also been evaluated in predicting supraventricular arrhythmias, and it was noted that patients with left atrial enlargement were associated with increased likelihood of supraventricular arrhythmias [11]. Smedema et al. reported that biventricular late gadolinium enhancement was the strongest predictor of adverse outcome, and an asymptomatic myocardial scar of less than 8% in the left ventricular mass was associated with a favorable outcome in patients with pulmonary

On the basis of current available evidence, the role of PET-CT is limited in routine clinical care of patients with pulmonary sarcoidosis. However, it may be a useful imaging modality in multisystem sarcoidosis, in particular when the clinical suspicion for cardiac involvement is high and the diagnostic techniques such as echocardiography and or cardiac MRI have unequivocal results. Moreover, PET-CT may become a useful adjunct to assess the response to immunosuppression with corticosteroids and/or antimetabolites and may guide us to an appropriate biopsy

Bronchoscopic techniques have been employed in the evaluation of pulmonary sarcoidosis for a very long time and have been the mainstay of histological confirmation historically. Granulomatous inflammation in sarcoidosis usually involves the

Transbronchial biopsies help to obtain the histological diagnosis in support of clinical-radiological diagnosis especially when the superficial mucosal or cutaneous lesions are not amenable for sampling [13, 14]. The diagnostic sensitivity of TBB in the diagnosis of a broad spectrum of interstitial lung diseases (ILDs) ranges from 29 to 79% [15–19]. The British Thoracic Society Sarcoidosis Registry data has previously showed that transbronchial biopsies have lesser diagnostic yield than

*Sarcoidosis and Granulomatosis - Diagnosis and Management*

calcification within these nodes (**Figure 4**).

bundles [3]. HRCT may be able to demonstrate lymphadenopathy in mediastinal distribution better than a chest radiograph and sometimes demonstrate evidence of

*Parenchymal distortion with fibrosis in a peribronchovascular distribution in bilateral upper lobes in* 

*Calcified mediastinal lymphadenopathy with bilateral hilar nodal enlargement in a patient with confirmed* 

The precise role of HRCT in the clinical monitoring of sarcoidosis is unknown. However, it may prove to be a useful tool to assess acute alveolitis and inflammation in selected cases of refractory sarcoidosis, where treatment decisions to commence

**20**

**Figure 4.**

*sarcoidosis.*

**Figure 3.**

*sarcoidosis.*

biologic therapies such as infliximab are being made [3]. A study by De Boer et al. showed that the total extent of parenchymal disease on the CT scan on a lobar basis could predict the likelihood of transbronchial biopsy being positive following bronchoscopy [4], demonstrating its utility on diagnostic grounds.
