Validity of ultrasonography in diagnosis of acute maxillary sinusitis

Background: Accurate diagnosis of maxillary sinusitis is difficult on the b asis of clinical examination only because the signs and symptoms of sinusit is are nonspecific. A simple, rapid, and readily available method for diagn osing maxillary sinusitis in primary care would increase the accuracy of th e diagnoses and thus reduce unnecessary antibiotic treatment. Objective: To investigate the validity of ultrasonography compared with rad iography and magnetic resonance imaging (MRI) in detection of maxillary sin usitis. Design: Ultrasonography and plain-film radiography of the paranasal sinuses were performed on all patients and MRI was performed on 40 randomly select ed patients on day 7 of the study. Setting: Study office at the Department of Pediatrics of Turku University H ospital, Turku, Finland. Patients: One hundred ninety-seven young adults who contacted the study off ice within 48 hours of the onset of symptoms of the common cold. Main Outcome Measures: Detection rates of maxillary sinusitis by ultrasonog raphy, radiography, and MRI. Results: Acute maxillary sinusitis was diagnosed in 24% of the sinuses by r adiography and in 28% by MRI. Compared with MRI findings, the sensitivity o f ultrasonography for detection of maxillary sinusitis was 64% (specificity , 95%). Using a 2-step diagnostic approach in which radiological findings w ere additionally considered in cases of negative ultrasound findings, a sen sitivity of 86% (specificity, 95%) was observed. Conclusions: The high specificity of ultrasonography indicates that a posit ive ultrasound finding can be regarded as evidence of maxillary sinusitis. The addition of plain-film radiography in cases of negative ultrasound find ings increases the diagnostic sensitivity to clinically acceptable levels w ithout loss in specificity. Active use of ultrasonography would substantial ly decrease the need for radiological imaging of the sinuses and also help reduce unnecessary antibiotic treatment in primary care.