Elastography is an imaging of tissue elasticity or stiffness and is currently emerging as a mainstream tool for ultrasound-based diagnosis. This compressibility property of materials, mathematically expressed as the change in tissue displacement as a function of its distance from the compressing device, is known as strain and is the parameter that is imaged in an elastogram.

Elastography has currently shown promising result in differentiating viscoelastic nature of various organs, which is a consequence of certain underlying diseases.

At present, there are limited literatures revealing the application and feasibility of ultrasonic elastography in lung lesions. This is essentially important as it may serve as an adjuvant to B-mode ultrasound. The investigators aimed at exploring the application and feasibility of ultrasonic elastography on lung lesions.

Patients performed conventional B-mode ultrasound, subsequently followed by ultrasound elastography. The strain ration was measured and was compared between necrosis, atelectasis, consolidation and tumor.

A. Inclusion Criteria:

Patients with radiographic findings of:

1. consolidation
2. obstructive pneumonitis
3. tumors

B. Exclusion Criteria:

1. Patients with poor acoustic window
2. Unable to hold breathing
3. Not cooperative
4. Presence of pleural effusion

Patients with radiographic findings of consolidation, obstructive pneumonitis or tumors, detected on chest computed tomography (CT), who received ultrasound study with or without ultrasound-guided biopsy for tissue proof and UE, from December 2011 to March 2013.