<prompt> The prerequisite for endoscopic sinus surgery isMRI of paranasal sinusesCT of paranasal sinusesMucocilliary clearing testingAcoustic tests  <response>: Endoscopic surgery of inflammatory diseases of paranasal sinuses sinusitis or polyp requires a very detailed preoperative knowledge of the individual anatomical conditions and pathological changesCT scan is used best to visualize sinus areasCT scan provides an excellent definition of paranasal sinuses and is a prerequisite for endoscopic surgeryRef: PL Dhingra, Diseases of Ear, Nose Throat, 7th edition, pg no. 220 - 221 