There is a fundamental difference between pneumonia and sputum in the lungs. Sputum in the lungs is one of the lesions of pneumonia, but it does not necessarily mean pneumonia, but can also be seen in bronchitis. The presence of phlegm in the lungs is a sign that can be heard on auscultation through physical examination. Bronchiectasis can appear to have this sign, but it will diminish or even disappear as the patient coughs and sputters, and the location of the vesicular sounds will change when the patient is rechecked, not being fixed to a particular place in the lungs. Pneumonia suggesting sputum in the lungs has blistering sounds that are mainly fixed at the lesion and do not diminish or disappear with coughing and sputum. Differences are also made by CT or MRI of both lungs or X-ray chest films, which can clarify the shadow of an obvious infected lesion in the lungs as pneumonia. Although sputum can be heard in the lungs, bronchiectasis is only seen as a thickening of the lung texture on imaging.