CT scanning demonstrations of Legionella pneumonia are diverse, which is characterized by multiple lobe and segment involvement. Large flakes and patches of shadows are the most common, with accompanying pleura lesions. Cavities can be found, with irregular thick wall or regular thin wall. No fluid level is found, with commonly accompanying large flakes or small patches of shadows. Occasionally, multiple air sacs in different sizes can be found in both lungs, which resemble those seen in Staphylococcus aureus pneumonia. Chest CT scanning demonstrates more lesions and more clearly defined lesions than chest X-ray. Therefore, chest CT scanning provides more reliable evidence for the diagnosis and therapeutic assessment.

Legionnaires’ disease is a systemic infectious disease. Currently, the lesions of the central nervous system are believed to be caused by Legionella toxin, with diverse clinical manifestations. In mild cases, flulike symptoms occur, while in severe cases, the symptoms include drowsiness, vomiting, headache, disorientation, limb dyskinesia, disturbance of consciousness, and limb and facial paralysis, with typical pathological reflex and meningeal irritation sign. CT scanning demonstrates low-density shadows in the cerebrum or brainstem and small lesions of hemorrhage. MR imaging demonstrates encephalitis. And FLAIR MRI demonstrates high signal. MR imaging and SPECT demonstrate abnormal brain perfusion. Functional imaging facilitates the diagnosis of Legionella encephalopathy.