To perform transillumination, the physician shines a bright light against the cheek or forehead in a dark room. If the light does not pass through the maxillary or frontal sinus areas, then disease in these sites is likely. Transillumination is fast, safe, inexpensive, and a good first diagnostic step, but it is not very accurate. It can, however, be very useful when used in combination with x-rays. If the physician strongly suspects the presence of true acute sinusitis but the results of the physical examination are ambiguous, x-rays may be taken.
Some experts argue that one x-ray is adequate for diagnosis of maxillary sinusitis.
Single x-rays are not useful, however, in diagnosing frontal and sphenoid sinusitis. Additionally, single x-rays, particularly in cases involving children, cannot differentiate between inflammation caused by bacteria from that caused by viruses, so a series of four views is usually taken. X-rays do not detect ethmoid sinusitis, which is often the primary site of an infection that has spread to the maxillary or frontal sinuses. Sinus Puncture and Endoscopy. Sinus puncture involves using a needle to withdraw a small amount of fluid from the sinuses.