sinus infection is present or not. Indeed, I NEVER order a sinus x-ray. Just how unreliable are sinus x-rays?
It may be literally a flip of the coin whether the sinus x-ray is providing a correct diagnosis compared with the gold standard CT sinus.
Depending on what study you look at, the specificity of a sinus x-ray hovers around 50% (how often it correctly states normal sinuses). Sensitivity is a little better at around 80% (how often it correctly detects actual sinusitis).
Several studies have concluded that sinus plain film x-rays are unreliable and no longer routinely indicated for the evaluation of nasal and paranasal sinus disease. When radiographic evaluation is indicated a limited CT series provides superior information.
Take home message?
Do not order a sinus x-ray when evaluating for sinus disease/sinusitis!!! Why bother ordering a test that is going to be wrong almost half the time?
(If a CT sinus comes back normal, the patient most definitely does NOT have acute or chronic sinusitis.)
Radiographic evaluation for nasal dysfunction: computed tomography versus plain films. Head Neck. 11 (5), 405-9. 1989
Comparison of sinus x-rays with computed tomography scans in acute sinusitis. Acad Emerg Med. 1 (3), 235-9. 1994