Although useful for the diagnosis of lower respiratory tract infections, chest X-rays have a weak specificity in the etiological diagnosis. It is of particular interest when complications are suspected. A radiological follow-up allows to exclude sequellae or a preexisting pulmonary abnormality; however follow-up X-rays are to be delayed 2 to 3 weeks after the clinical recovery due to the late radiological recovery. CT is indicated as a complementary investigation in cases of complications and sequellae.