<prompt> Endoscopic sinus surgery prerequisite-MRI of paraanasal sinusCT of PNSMucocilliary clearing testingAcoustic tests  <response>: Refer: PL Dhingra, Diseases of Ear, Nose Throat, 7th edition, pg no. 220 221Endoscopic surgery of inflammatory diseases of paransal sinuses sinusitis or polyp requires a very detailed preoperative knowledge of the individual anatomical conditions and pathological changesCT scan are used best to visualize sinus areasCT scan provides excellent definition of paranasal sinuses and is a prerequisite for endoscopic surgeryCT scan limited study coronal cuts in bone window is prerequisite for endscopic sinus surgery---Mohan Bansal 