The recommendation is strong because ultrasound is easily available, safe (no radiation exposure) and cheap compared to radiography.
Sinus ultrasound has been compared to sinus puncture in five studies «Kuusela T, Kurri J, Sirola R. Ultraschall in der S...»1 «Laine K, Määttä T, Varonen H, Mäkelä M. Diagnosing...»2 «Revonta M, Suonpää J, Luukkala M, Meriläinen P. Di...»3 «Savolainen S, Pietola M, Kiukaanniemi H, Lappalain...»4 «van Buchem L, Peeters M, Beaumont J, Knottnerus JA...»5 on adult patients that were suspected to have acute maxillary sinusitis. These studies were combined in a meta-analysis «Varonen H, Mäkelä M, Savolainen S, Läärä E, Hilden...»7. Only studies on unselected patient population are considered here (studies on e.g. only allergic patients were excluded).
In the meta-analysis of studies [R1 to R5] the weighted mean sensitivity of these studies was 0.85 (95% CI 0.84 to 0.87) and specificity 0.82 (95% CI 0.80 to 0.83). The range of sensitivity was from 0.54 to 0.94 and that of specificity 0.53 to 0.94.
In a more recent study not included in the meta-analysis «Teppo H, Revonta M. Ultrasound device helps in rul...»8 the ultrasound device reached sensitivity of 87% (95% Cl 81–94%) and specificity of 72% (95% Cl 64–80%) compared with sinus puncture. Positive predictive value was 75% and negative predictive value 85%. Ultrasound detected correctly all 18 sinuses in which the secretion was abundant and considered to be purulent by the physician (sensitivity and negative predictive value 100%).
Sinus radiography has been compared to sinus puncture in six studies «Kuusela T, Kurri J, Sirola R. Ultraschall in der S...»1 «Laine K, Määttä T, Varonen H, Mäkelä M. Diagnosing...»2 «Revonta M, Suonpää J, Luukkala M, Meriläinen P. Di...»3 «Savolainen S, Pietola M, Kiukaanniemi H, Lappalain...»4 «van Buchem L, Peeters M, Beaumont J, Knottnerus JA...»5 «McNeill RA. Comparison of the findings on transill...»6 in patients with suspected acute maxillary sinusitis. The weighted mean sensitivity of these studies was 0.87 (95% CI 0.85 to 0.88) and specificity 0.89 (95% CI 0.88 to 0.91). The range of sensitivity was from 0.61 to 0.93 and that of specificity 0.62 to 0.98.
Sinus ultrasound has been compared to sinus radiography in two studies. In a study of 67 paediatric patients with mean age of 9 years «Fufezan O, Asavoaie C, Chereches Panta P et al. Th...»9, there was a diagnosis agreement between the two techniques in 112 out of 134 sinuses (83.5%). Compared to the standard X-ray, ultrasonography had a 95% sensitivity and a 98% specificity. In a study of patients with chronic nonpolypoid rhinosinusitis at 79 maxillary sinuses «Belic B, Erdevicki L, Stojanovic J et al. [A-mode ...»10, the reliability of the A-mode ultrasonography in diagnosing chronic nonpolypoid diseases in maxillary sinuses was of a somewhat greater degree in comparison to roentgenography, amounting to 72% in relation to 61%.
The results of ultrasound were more heterogeneous than those of sinus radiography. The performers of sinus ultrasound scans were most often clinicians, not radiologists. In experienced hands, sinus ultrasound has similar accuracy as that of sinus radiography.