<prompt> A 2 year old child with purulent nasal discharge,fever and pain since 2 months. His fever is 102-103 F, and leucocyte count is 12000 cumm.X ray PNS showed opacification of left ethmoidal air cells.The culture of the eye discharge was negative. which of the following would be most useful fuher step in evaluation of this patient?CT ScanUrine cultureBlood cultureRepeat culture of the eye discharge  <response>: The best method to assess the state of ethmoidal air cells and its complications is CT Scan. CT is paicularly useful in ethmoid and sphenoid sinus infections and has replaced studies with contrast material. Ref Dhingra 5e,p 209. 