The utility of computed tomography in idiopathic subglottic stenosis

1) To develop a standardized and reproducible protocol for evaluating airway stenosis on CT imaging. 2) To compare idiopathic subglottic stenosis (iSGS) measurements on CT imaging to intraoperative findings and determine the practical value of CT imaging in evaluation of the stenotic airway.

We conducted a single institution retrospective chart review of patients 18 years of age and older with a diagnosis of iSGS who had surgical intervention for iSGS performed at our institution and CT neck/chest within 6-months of first surgical intervention. We developed a standardized protocol for measuring cross-sectional area of the stenosis and percent stenosis based on CT imaging. Operative reports were queried for percent stenosis for comparison. Accuracy of CT measurements were assessed by interclass correlation coefficients (area of greatest stenosis, r = 0.936; distance below the vocal folds, r = 0.766).

A total of 37 patients were included. One hundred percent were female and 86 % were Caucasian. The average age at first operative intervention was 48 years. The most common imaging modality was CT neck with IV contrast (64 %). The average percent stenosis on imaging was 59 % versus 62 % intraoperatively (p = 0.03). The average difference between percent stenosis on imaging and intraoperatively for each individual patient was 11 %.

This study directly examines the correlation of stenosis measurements on CT to intraoperative airway dimensions in patients with iSGS. Our results demonstrate that imaging may tend to underestimate stenosis by an average of 11 %, and generally correlated with intraoperative findings in 90 % of cases.