High resolution computed tomography of the chest is the ideal modality for evaluating:
B i.e. Interstitial Lung disease - Routine chest CT examinations consist of adjacent 8-10 mm sections through the area of interest. Intravenous contrast medium may be injected when the primary purpose of examination is to show the mediastinum or hilar structures. High resolution CT (HRCT) uses very thin 1-2 mm thick.(2 High resolution chest CT (HRCT chest) is the procedure of choice for hyper sensitivity pneumonitis (HP) or extrinsic allergic alveolitisQ such as farmer's / mushroom worker's / bird fancier's / chemical worker's / hot tub / coffee worker's etc - lung. HRCT - chest is superior to plain Xray chest for early detection and confirmation of suspected interstial lung disease (ILD)Q such as fibrosing alveolitis, lymphangitic carcinoma, idiopathic pulmonary fibrosis, sarcoidosis, eosinophilic granuloma, asbestosis, berylliosis and other industrial lung diseases etc. When lung biopsy is required, HRCT is useful for determining most appropriate area from which biopsy sample should be taken. Chest CT is specific and imaging modality of choice for confirming diagnosis of bronchiectasisQ. CT findings include airway dilation (detected as "parallel tram tracks" or "signet ring sign"), lack of bronchial tapering (showing presence of tubular structure within 1 cm from pleural surface), bronchial wall thickening, inspissated secretions (tree-in-bud pattern), or cysts originating from bronchial wall. Helical CT scanning allows collection of continuous data over a larger volume of lung during a single breath holding maneuver (faster scan with improved contrast enhancement & thinner collimation) that allows less motion aifact. Data from single imaging procedure can be reconstructed as images in planes other than the traditional axial (cross-sectional) view, including coronal, or saggital planes or even 3D representation (viual bronchoscopy) mimicking visualization through a bronchoscope. Multidetector CT (MDCT) uses higher number of detectors (upto 64) along scanning (Z) axis to obtain multiple slices in a single rotation that are thinner and can be acquired in a shoer period of time, resulting in enhanced resolution and increased image reconstruction ability. Shoer breath holds are especially beneficial for children, elderly and critically ill patients, however, at the risk of increased radiation dose. MDCT has led to improved imaging of pulmonary vasculature and the ability to detect segmental & subsegmental emboli. In contrast to pulmonary angiography, CT pulmonary angiography (CTPA) by MDCT usually allows simultaneous detection of parenchymal abnormalities; and has rapidly become the test of choice in evaluation of pulmonary embolismQ (b/o equal accuracy and less risk in comparison to pulmonary angiography).
Pleural effusion
Interstitial lung disease
Lung mass
Mediastinal adenopathy