[Sinus radiography and low-dose CT in the diagnosis of acute sinusitis. ]

Background. Although CT is considered the method of choice in the evaluation of inflammatory sinus disease, plain film radiography is still used, as repetitive CT examinations may impart a considerable radiation dose to the lens. We designed a new low-dose CT examination and compared this and plain film radiography to standard-dose CT. Methods and materials. The new CT low-dose protocol consisted of ten coronal scans at 40 mAs and 1 mm collimation. 47 patients referred for acute sinusitis were examined with plain film radiography, low-dose and standard-dose CT on the same day. The latter was used as "the gold standard". Results. The sensitivity of plain film radiography was low (< 50 %) except for the maxillary sinus (80 %). The overall sensitivity of low-dose CT was 95 % and the specificity 97 %. Effective dose and lens dose of low-dose CT were 3 % and 2 % respectively compared to standard-dose CT. Corresponding values for conventional radiography were 13 % and 2 %. Interpretation. Low-dose CT had image quality comparable to standard-dose CT and a dose to the eye lens equal to plain film radiography. Low-dose CT should be the method of choice in patients referred for acute sinusitis.