CT virtual endoscopy of the upper airway

Purpose: The technical conditions,the optimized scanning protocols and the facilities of virtual endoscopy (VE) are presented in an overview. Methods: Phantom studies showed thar,for a single-row-detector helical CT, collimation of 3.0 mm combined with pitch of 1.5 provided an optimal compro mise between image quality and the scan duration per breath-hold. A multi-r ow-detector helical CT requires only a fraction of the scanning time. This is especially important for patients with dyspnea. Results: The threshold-dependent virtual endoscopic surface rendering is a reliable and rapidly practicable reconstruction algorithm for the imaging o f the upper airway. Conclusions: The VE technique is suitable for the imaging of space-occupyin g tumors and restricted stenoses. With VE follow-up examinations can be per formed non-invasively and interventional procedures can be prepared in an o ptimal way. Because of the computed tomographic data acquisition the struct ure of the mucosa is not assessable and there is no opportunity to obtain a biopsy specimen.