Anatomic variants at sinonasal CT

The threefold role of CT scanning in functional endoscopic sinus surgery is providing anatomic definition, determining significant variants, and relating these to current pathology. Significant variants were present in 330 (55%) of a series of 600 patients. These variants were sufficient to cause potential obstruction or to interfere with endoscopic access to the ostiomeatal complex and the frontal recess. Twenty-four percent of patients had more than one variant. This paper demonstrates the major variants that the surgeon encounters and may impair mucociliary drainage. It shows multiple variants in common combinations and also illustrates less common anomalies