A new low-dose CT examination compared with standard-dose CT in the diagnosis of acute sinusitis.

A low-dose CT of the paranasal sinuses was designed with few, thin sections, non-uniform intersection gaps, low milliampere settings and avoidance of direct radiation to the eye lens. The low-dose CT was prospectively compared with standard-dose CT in patients with suspicion of acute sinusitis. Forty-seven patients were examined with low-dose CT immediately after standard-dose CT. The effective dose and the lens dose were calculated and compared. Using standard-dose CT as a gold standard the sensitivity and specificity of low-dose CT was calculated for each sinus group. The effective dose and the lens dose of the low-dose CT were reduced to, respectively, 3 and 2% of the standard-dose CT. The diagnostic yield of the low-dose CT with regard to acute sinusitis was good with a high specificity (> or =96%) for all sinus groups. The sensitivity was also high (> or =95%) except for the frontal sinus where the sensitivity was 83%. Low-dose CT offers considerable dose reduction and should be the standard for imaging patients with suspected acute inflammatory paranasal disease.