Densified shadows seen in the maxillary sinuses bilaterally may be maxillary sinus cysts, thickened mucosa of the sinuses, purulent secretions, and so on. Patients should undergo other related examinations according to the doctor’s recommendation to clarify the cause of the disease. 1. Maxillary sinus cyst: when the maxillary sinus cyst, the imaging will appear in the bilateral maxillary sinus see increased density shadow. Usually there are no obvious symptoms in the early stage, with the progress of the disease can appear nasal congestion, facial swelling, headache and other symptoms. 2. Sinus mucosal thickening: such as chronic maxillary sinusitis, acute maxillary sinusitis and other patients, there may be maxillary sinus mucosal thickening, resulting in the appearance of bilateral maxillary sinus see increased density shadow. 3. Purulent secretion: When there is purulent secretion (nasal mucus) in the sinuses, there may be bilateral maxillary sinus with increased density shadow. This is usually accompanied by runny nose, nasal congestion, headache and other symptoms. Densified shadows seen in the bilateral maxillary sinuses is an imaging term that can be caused by a number of reasons. It is recommended that the patient undergoes other relevant tests to clarify the cause of the condition according to the doctor’s advice.