Objective: To determine whether the presence of opacification in the paranasal sinuses of children and adolescents without rhinosinusitis implies an increased risk of later development of upper respiratory tract symptoms. Methods: This was a prospective study of a cohort of patients aged 0 to 18 years who underwent computerized tomography (CT) scans for indications unrelated to rhinosinusitis. Sinus opacification was evaluated using an opacification/ development ratio score. The patients' clinical progression was followed up using a questionnaire for 1 month after the scans. Results: Fifty-six percent (56%) of the 106 patients enrolled in the study had opacity, the majority due to mucosal thickening. Intense opacification was defined as "suspected" (score ≥ 15) and patients in this subset had a greater risk of developing symptoms during follow-up (odds ratio = 2.74; 95%CI 1.10-6.83) compared to those with no findings or discrete findings. Conclusions: Intense incidental sinus opacity on CT indicates a risk of future development of a clinical respiratory condition. Copyright © 2011 by Sociedade Brasileira de Pediatria.875433438Rosenfeld, M.R.I., Andes, D., Bhattacharyya, N., Cheung, D., Eisenberg, S., Ganiats, T.G., Clinical practice guideline: Adult sinusitis (2007) Otolaryngol Head Neck Surg, 137 (3 SUPPL.), pp. S1-S31Subcommittee on Management of Sinusitis and Committee on Quality Improvement. Clinical practice guideline: Management of sinusitis (2001) Pediatrics, 108, pp. 798-808. , American Academy of PediatricsZinreich, S.J., Kennedy, D.W., Rosenbaum, A.E., Paranasal sinuses: CT imaging requirements for endoscopic surgery (1987) Radiology, 163 (3), pp. 769-775McAlister, W.H., Parker, B.R., Kushner, D.C., Babcock, D.S., Cohen, H.L., Gelfand, M.J., Sinusitis in the pediatric population. American College of Radiology. ACR Appropriateness Criteria (2000) Radiology, 215 (SUPPL.), pp. 811-818Brasileiras De Rinossinusites, D., (2008) Rev. Bras. Otorrinolaringol., 74 (2 SUPPL.), pp. 6-59Rudloff, M.D., Wald, E.R., Radiographic sinusitis: Illusion or delusion? (1993) Pediatric Infectious Disease Journal, 12 (9), pp. 792-793Kristo, A., Uhari, M., Luotonen, J., Koivunen, P., Ilkko, E., Tapiainen, T., Paranasal sinus findings in children during respiratory infection evaluated with magnetic resonance imaging (2003) Pediatrics, 111 (5 PART 1), pp. e586-e589Kovalhuk, L.C., Rosário, N.A., Carvalho, A., Inflammatory mediators, cell counts in nasal lavage and computed tomography of the paranasal sinuses in atopic children (2001) J Pediatr, 77, pp. 271-278. , Rio JTalay, F., Kurt, B., Gurel, K., Yilmaz, F., Paranasal computed tomography results in asthma patients: Association between sinus sites and allergen types (2008) Allergy Asthma Proc, 29, pp. 475-479Turner, B.W., Cail, W.S., Hendley, J.O., Hayden, F.G., Doyle, W.J., Sorrentino, J.V., Physiologic abnormalities in the paranasal sinuses during experimental rhinovirus colds (1992) J Allergy Clin Immunol, 90 (3 PART 2), pp. 474-478Gwaltney Jr., J.M., Phillips, C.D., Miller, R.D., Riker, D.K., Computed tomographic study of the common cold (1994) New England Journal of Medicine, 330 (1), pp. 25-30. , DOI 10.1056/NEJM199401063300105Lesserson, J.A., Kieserman, S.P., Finn, D.G., The radiographic incidence of chronic sinus disease in the pediatric population (1994) Laryngoscope, 104, pp. 159-166Havas, T.E., Motbey, J.A., Gullane, P.J., Prevalence of incidental abnormalities on computed tomographic scans of the paranasal sinuses (1988) Arch Otolaryngol Head Neck Surg, 114, pp. 856-859Bolger, W.E., Butzin, C.A., Parsons, D.S., Paranasal sinus bony anatomic variations and mucosal abnormalities: CT analysis for endoscopic sinus surgery (1991) Laryngoscope, 101 (1 PART 1), pp. 56-64Glasier, C.M., Ascher, D.P., Williams, K.D., Incidental paranasal sinus abnormalities on CT of children: Clinical correlation (1986) American Journal of Neuroradiology, 7 (5), pp. 861-864Glasier, C.M., Mallory Jr., G.B., Steele, R.W., Significance of opacification of the maxillary and ethmoid sinuses in infants (1989) Journal of Pediatrics, 114 (1), pp. 45-50. , DOI 10.1016/S0022-3476(89)80599-2Hill, M., Bhattacharyya, N., Hall, T.R., Lufkin, R., Shapiro, N.L., Incidental paranasal sinus imaging abnormalities and the normal Lund score in children (2004) Otolaryngology - Head and Neck Surgery, 130 (2), pp. 171-175. , DOI 10.1016/j.otohns.2003.11.006Araújo Neto, S., Souza, A., Pereira, I., Baracat, E., Alterações incidentais dos seios da face na tomografia computadorizada do crânio e órbitas em crianças (2005) Radiol Bras, 38, pp. 245-250Manning, S.C., Biavati, M.J., Phillips, D.L., Correlation of clinical sinusitis signs and symptoms to imaging findings in pediatric patients (1996) International Journal of Pediatric Otorhinolaryngology, 37 (1), pp. 65-74. , DOI 10.1016/0165-5876(96)01381-XGarbutt, J.M., Gellman, E.F., Littenberg, B., The development and validation of an instrument to assess acute sinus disease in children (1999) Quality of Life Research, 8 (3), pp. 225-233. , DOI 10.1023/A:1008883508462Araújo Neto, S.A., Baracat, E.C., Felipe, L.F., A new score for tomographic opacification of paranasal sinuses in children (2010) Braz J Otorhinolaryngol, 76, pp. 491-498Bhattacharyya, N., Fried, M.P., The accuracy of computed tomography in the diagnosis of chronic rhinosinusitis (2003) Laryngoscope, 113 (1), pp. 125-129. , DOI 10.1097/00005537-200301000-00023Diament, M.J., Senac Jr., M.O., Gilsanz, V., Prevalence of incidental paranasal sinuses opacification in pediatric patients: A CT study (1987) Journal of Computer Assisted Tomography, 11 (3), pp. 426-431Wald, E.R., Management of sinusitis in infants and children (1988) Pediatr Infect Dis J, 7, pp. 449-452Lindbaek, M., Kaastad, E., Dolvik, S., Johnsen, U., Laerum, E., Hjortdahi, P., Antibiotic treatment of patients with mucosal thickening in the paranasal sinuses, and validation of cut-off points in sinus CT (1998) Rhinology, 36 (1), pp. 7-11Engels, E.A., Terrin, N., Barza, M., Lau, J., Meta-analysis of diagnostic tests for acute sinusitis (2000) Journal of Clinical Epidemiology, 53 (8), pp. 852-862. , DOI 10.1016/S0895-4356(00)00209-2, PII S0895435600002092Maly, P.V., Sundgren, P.C., Changes in paranasal sinus abnormalities found incidentally on MRI (1995) Neuroradiology, 37, pp. 471-474Lund, V.J., Kennedy, D.W., Staging for rhinosinusitis (1997) Otolaryngology - Head and Neck Surgery, 117 (3 II SUPPL.), pp. S35-S40