Low dose CT scan is used mainly for the paranasal sinus; however, the bony facial skull may also be examined. Technology makes it now possible to lower the radiation dose without diminishing the quality of the scan or changing its diagnostic value.
This method is preferably used in screening situations in laryngological and allergological cases wherein the thickening of the mucous membrane of the paranasal sinus and the air content of the sinuses may be observed. The bony facial skull scan is mostly performed in trauma cases.
No preparation is required since the scan does not usually require contrast material.
Should the scan show that contrast material is necessary a new appointment will have to be requested and the instructions below followed.
The day before the scan:
- Do not eat after midnight and drink only non-carbonated drinks, preferably, water.
- Take your usual medications.
- If you are taking diabetes medication containing metformin, do not take the medication 48 hours before and 48 hours after the scan.
- Laboratory test for kidney function (blood creatinine) is required as follows:
- Out-patients - less than 1 month before the scan
- In-patients - less than 1 week before the scan.