Monday, July 14, 2008

Fungal Sinusitis

PNS Radiograph shows opacification of all the visualized sinuses suggestive of sinusitis. Here it is impossible to differentiate the type of sinusitis. And may be possibel with cross sectional imaging. Non contrast CT Scan axial and coronal reformatted images shows soft tissue density material seen in bilateral maxillary sinuses and in nasal cavity with focal areas of increased attenuation(arrows) suggestive of fungal sinusitis.

Fungal infections of the paranasal sinuses are uncommon and usually occur in individuals who are immunocompromised. However, recently, the occurrence of fungal sinusitis has increased in the immunocompetent population. Distinguishing invasive disease from noninvasive disease is important because the treatment and prognosis are different for each. The most common pathogens are from Aspergillus and Mucor species. Aspergillosis can cause noninvasive or invasive infections. Invasive infections are characterized by dark, thick, greasy material found in the sinuses. Invasive infections can cause tissue invasion and destruction of adjacent structures (eg, orbit, CNS). Noninvasive infections cause symptoms of sinusitis, and the sinus involved is opacified on radiographic studies. Routine cultures from the sinuses rarely demonstrate the fungus. Thus cross sectional imaging is the main stay of diagnosis of fungal infection. The demonstration of focal or diffuse areas of increased attenuation in paranasal sinus soft-tissue masses on unenhanced CT scans strongly suggests fungal involvement. MR imaging was even more sensitive than CT in identifying a fungal concretion in a limited number of patients. On the basis of preliminary studies, decreased signal intensity on T1 and very decreased signal intensity on T2-weighted MR images seem to be characteristic of mycetomas. This may be due to the presence of fenromagnetic elements within fungal concretions.

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