Semi-Automatic Measurement of the Airway Dimension by Computed Tomography Using the Full-Width-Half-Maximum Method: a Study on the Measurement Accuracy according to the CT Parameters and Size of the Airway.
- Author:
Namkug KIM
1
;
Joon Beom SEO
;
Koun Sik SONG
;
Eun Jin CHAE
;
Suk Ho KANG
Author Information
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords: Airway; Computed tomography (CT); FWHM (Full Width at Half Maximum); Measurement, phantom
- MeSH: Cone-Beam Computed Tomography/*methods; Feasibility Studies; Phantoms, Imaging; Respiratory System/*anatomy & histology
- From:Korean Journal of Radiology 2008;9(3):226-235
- CountryRepublic of Korea
- Language:English
- Abstract: OBJECTIVE: To assess the influence of variable factors such as the size of the airway and the CT imaging parameters such as the reconstruction kernel, field-of-view (FOV), and slice thickness on the automatic measurement of airway dimension. MATERIALS AND METHODS: An airway phantom was fabricated that contained eleven poly-acryl tubes of various lumen diameters and wall thicknesses. The measured density of the poly-acryl wall was 150 HU, and the measured density of the airspace filled with polyurethane foam was -900 HU. CT images were obtained using a 16-MDCT (multidetector CT) scanner and were reconstructed with various reconstruction kernels, thicknesses and FOV. The luminal radius and wall thickness were measured using in-house software based on the full-width-half-maximum method. The measured values as determined by CT and the actual dimensions of the tubes were compared. RESULTS: Measurements were most accurate on images reconstructed with use of a standard kernel (mean error: -0.03 +/- 0.21 mm for wall thickness and -0.12 +/- 0.11 mm for the luminal radius). There was no significant difference in accuracy among images with the use of variable slice thicknesses or a variable FOV. Below a 1-mm threshold, the measurement failed to represent the change of the real dimensions. CONCLUSION: Measurement accuracy was strongly influenced by the specific reconstruction kernel utilized. For accurate measurement, standardization of the imaging protocol and selection of the appropriate anatomic level are essential.
