 CT will be performed after 3-4 weeks. At the CT-lab an ENT-surgeon will drip 2 ml iodixanol contrast medium diluted with saline NaCl to 20 into the tympanostomy tube while the patient lies on his her back with the head slightly turned to the opposite side. After turning the head to a neutral position and a delay of 10 minutes the CT examination will be conducted using 200 milliampere mA and 120 kilo volt kV. 