Differentiation of Acute Rhinosinusitis From Chronic Rhinosinusitis Using Multidetector Computed Tomography

It is difficult to differentiate acute from chronic rhinosinusitis clinically, and to date they are assessedradiologically via air-fluid level or opacification, which can appear similar in both cases. Our purpose was toexamine whether air density analysis combined with classical radiological approaches can be used as a newtool to differentiate between acute and chronic sinusitis.This retrospective study included a total of 2419 sinuses in 550 patients who underwent paranasal sinusmultidetector computed tomography (MDCT). Patients were divided into three groups according to clinicaldiagnosis of sinus status: acutely inflamed as group 1 (n=176), the chronic sinusitis as group 2 (n=191) andhealthy sinuses (n=183) as group 3, the control group. The mean air density and standard deviations (SD)within the paranasal sinuses in each group were calculated by the measurements of air density with a regionof interest (ROI) of 0.5 cm2, located in the center of the air-filled sinus avoiding the sinus wall, and repeatedthe measurement in 4-6 consequent CT slices, where available.The mean air density was significantly higher in group 1 compared with group 2 and 3 (- 810 HU,-973 HUand -1010 HU respectively; p < 0.05), as well as SD (89.3 HU, 21.1 HU and 20.9 HU respectively; p < 0.05).In conclusion; increased air density in paranasal sinuses may aid in distinguishing acute from chronicrhinosinusitis.