Quantitative Assessment of Air Trapping Using Inspiratory and Expiratory Low-Dose Computed Tomography

DOI: 10.4236/ojmi.2015.54025   PDF   HTML   XML   2,902 Downloads   3,402 Views   Citations


Objective: The purpose of this study was to evaluate the effect of radiation dose reduction on the quantification of air trapping on expiratory CT. Materials and methods: This study was conducted as a retrospective evaluation of inspiratory and expiratory CT studies performed in routine clinical practice before and after alteration of the scanning protocol for expiratory CT at our institute. Eighty-six patients who had a clinical diagnosis of chronic obstructive pulmonary disease (COPD) and underwent inspiratory and expiratory CT and pulmonary function testing (PFT) were included. For the quantitative analysis, CT scans were obtained at six evenly spaced levels from the lung apices to the bases. The area of segmented lung without emphysema between -500 to -950 HU was obtained from the summation of six slices. The relative area between -900 and -950 HU for the area of the segmented lung (RA900-950) was calculated on both the inspiratory and expiratory scans. Comparisons of the RA-change between the standard-dose group (200 mA) and the low-dose group (80 mA) were performed by Mann-Whitney U test. Results: There was no significant difference between the standard-dose group and the low-dose group in the mean RA-change, and RA-change in both the standard-dose and low-dose groups correlated significantly with the results of PFT. In addition, there were no prominent differences in the correlation coefficients between the two groups. Conclusions: Low-dose CT could evaluate air trapping objectively and was not inferior to standard-dose CT for this purpose.

Share and Cite:

Saito, Y. , Matsuoka, S. , Yamashiro, T. , Matsushita, S. , Kotoku, A. , Yagihashi, K. , Tomita, H. , Sakamoto, S. , Saruya, S. and Nakajima, Y. (2015) Quantitative Assessment of Air Trapping Using Inspiratory and Expiratory Low-Dose Computed Tomography. Open Journal of Medical Imaging, 5, 199-203. doi: 10.4236/ojmi.2015.54025.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Pauwels, R.A., Buist, A.S., Calverley, P.M., Jenkins, C.R. and Hurd, S.S., GOLD Scientific Committee (2001) Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. NHLBI/WHO Global Initiative for Chronic Obstructive Lung Disease (GOLD) Workshop Summary. American Journal of Respiratory and Critical Care Medicine, 163, 1256-1276.
[2] Hogg, J.C., Macklem, P.T. and Thurlbeck, W.M. (1968) Site and Nature of Airway Obstruction in Chronic Obstructive Lung Disease. The New England Journal of Medicine, 278, 1355-1360.
[3] Yanai, M., Sekizawa, K., Ohrui, T., Sasaki, H. and Takishima, T. (1992) Site of Airway Obstruction in Pulmonary Disease: Direct Measurement of Intrabronchial Pressure. Journal of Applied Physiology, 72, 1016-1023.
[4] Gevenois, P.A., De Vuyst, P., Sy, M., Scillia, P., Chaminade, L., de Maertelaer, V., et al. (1996) Pulmonary Emphysema: Quantitative CT during Expiration. Radiology, 199, 825-829.
[5] Eda, S., Kubo, K., Fujimoto, K., Matsuzawa, Y., Sekiguchi, M. and Sakai, F. (1997) The Relations between Expiratory Chest CT Using Helical CT and Pulmonary Function Tests in Emphysema. American Journal of Respiratory and Critical Care Medicine, 155, 1290-1294.
[6] Bankier, A.A., Schaefer-Prokop, C., De Maertelaer, V., Tack, D., Jaksch, P., Klepetko, W., et al. (2007) Air Trapping: Comparison of Standard-Dose and Simulated Low-Dose Thin-Section CT Techniques. Radiology, 242, 898-906.
[7] Matsuoka, S., Kurihara, Y., Yagihashi, K. and Nakajima, Y. (2007) Quantitative Assessment of Peripheral Airway Obstruction on Paired Expiratory/Inspiratory Thin-Section Computed Tomography in Chronic Obstructive Pulmonary Disease with Emphysema. Journal of Computer Assisted Tomography, 31, 384-389.
[8] Matsuoka, S., Kurihara, Y., Yagihashi, K., Hoshino, M., Watanabe, N. and Nakajima, Y. (2008) Quantitative Assessment of Air Trapping in Chronic Obstructive Pulmonary Disease Using Inspiratory and Expiratory Volumetric MDCT. AJR. American Journal of Roentgenology, 190, 762-769.
[9] Busacker, A., Newell Jr., J.D., Keefe, T., Hoffman, E.A., Granroth, J.C., Castro, M., et al. (2009) A Multivariate Analysis of Risk Factors for the Air-Trapping Asthmatic Phenotype as Measured by Quantitative CT Analysis. Chest, 135, 48-56.
[10] Matsuoka, S., Yamashiro, T., Washko, G.R., Kurihara, Y., Nakajima, Y. and Hatabu, H. (2010) Quantitative CT Assessment of Chronic Obstructive Pulmonary Disease. Radiographics: A Review Publication of the Radiological Society of North America, 30, 55-66.
[11] Boiselle, P.M., Litmanovich, D.E., Michaud, G., Roberts, D.H., Loring, S.H., Womble, H.M., et al. (2013) Dynamic Expiratory Tracheal Collapse in Morbidly Obese COPD Patients. Copd, 10, 604-610.
[12] Newman, K.B., Lynch, D.A., Newman, L.S., Ellegood, D. and Newell Jr., J.D. (1994) Quantitative Computed Tomography Detects Air Trapping Due to Asthma. Chest, 106, 105-109.
[13] Yuan, R., Mayo, J.R., Hogg, J.C., Pare, P.D., McWilliams, A.M., Lam, S., et al. (2007) The Effects of Radiation Dose and CT Manufacturer on Measurements of Lung Densitometry. Chest, 132, 617-623.
[14] Gierada, D.S., Pilgram, T.K., Whiting, B.R., Hong, C., Bierhals, A.J., Kim, J.H., et al. (2007) Comparison of Standard- and Low-Radiation-Dose CT for Quantification of Emphysema. American Journal of Roentgenology, 188, 42-47.
[15] Boone, J.M., Geraghty, E.M., Seibert, J.A. and Wootton-Gorges, S.L. (2003) Dose Reduction in Pediatric CT: A Rational Approach. Radiology, 228, 352-360.

comments powered by Disqus

Copyright © 2020 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.