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Automated continuous quantitative measurement of proximal airways on dynamic ventilation CT: initial experience using an ex vivo porcine lung phantom.

Yamashiro T, Tsubakimoto M, Nagatani Y, Moriya H, Sakuma K, Tsukagoshi S, Inokawa H, Kimoto T, Teramoto R, Murayama S - Int J Chron Obstruct Pulmon Dis (2015)

Bottom Line: The software automatically traced a designated airway point in all frames and measured the cross-sectional luminal area and wall area percent (WA%).It is feasible to measure airway dimensions automatically at designated points on dynamic ventilation CT using research software.This technique can be applied to various airway and obstructive diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan.

ABSTRACT

Background: The purpose of this study was to evaluate the feasibility of continuous quantitative measurement of the proximal airways, using dynamic ventilation computed tomography (CT) and our research software.

Methods: A porcine lung that was removed during meat processing was ventilated inside a chest phantom by a negative pressure cylinder (eight times per minute). This chest phantom with imitated respiratory movement was scanned by a 320-row area-detector CT scanner for approximately 9 seconds as dynamic ventilatory scanning. Obtained volume data were reconstructed every 0.35 seconds (total 8.4 seconds with 24 frames) as three-dimensional images and stored in our research software. The software automatically traced a designated airway point in all frames and measured the cross-sectional luminal area and wall area percent (WA%). The cross-sectional luminal area and WA% of the trachea and right main bronchus (RMB) were measured for this study. Two radiologists evaluated the traceability of all measurable airway points of the trachea and RMB using a three-point scale.

Results: It was judged that the software satisfactorily traced airway points throughout the dynamic ventilation CT (mean score, 2.64 at the trachea and 2.84 at the RMB). From the maximum inspiratory frame to the maximum expiratory frame, the cross-sectional luminal area of the trachea decreased 17.7% and that of the RMB 29.0%, whereas the WA% of the trachea increased 6.6% and that of the RMB 11.1%.

Conclusion: It is feasible to measure airway dimensions automatically at designated points on dynamic ventilation CT using research software. This technique can be applied to various airway and obstructive diseases.

No MeSH data available.


Related in: MedlinePlus

An example of curved multi-planar reconstruction images with and without anatomical synchronization.Notes: (A) The reference (inspiratory) phase. (B) The middle expiratory phase without registration. (C) The full expiratory phase without registration. (D) The middle expiratory phase with registration. (E) The full expiratory phase with registration. The location of the crosscut point (short red lines on each image) is indicated by the blue arrow. It is obvious that the crosscut points of the airway (enlarged in the small windows) slide peripherally on the unregistered images (B and C), while they keep locations on the registered images (D and E).
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f2-copd-10-2045: An example of curved multi-planar reconstruction images with and without anatomical synchronization.Notes: (A) The reference (inspiratory) phase. (B) The middle expiratory phase without registration. (C) The full expiratory phase without registration. (D) The middle expiratory phase with registration. (E) The full expiratory phase with registration. The location of the crosscut point (short red lines on each image) is indicated by the blue arrow. It is obvious that the crosscut points of the airway (enlarged in the small windows) slide peripherally on the unregistered images (B and C), while they keep locations on the registered images (D and E).

Mentions: For continuous airway analysis using dynamic ventilation CT, it is essential that a selected airway point can be reproduced and measured at all respiratory phases on the crosscut sections that are perpendicular to the airway centerlines. For the software presented here, this process is facilitated by locating the anatomical position in one phase (frame) and automatically transferring the same position to all the other phases. When a crosscut section is manually selected on the centerline at one phase, the software automatically reproduces and measures the corresponding crosscut sections at all other phases. The algorithm of the software has basic four steps (Figure 1): in the first and second steps, the airway lumen segmentation and centerline construction are implemented on the reference phase. In the third step, the anatomical locations are synchronized from the reference phase to all the other phases. Finally, wall contours are estimated on all phases. By following these steps, the software is able to trace the designated airway point (Figure 2) and to demonstrate crosscut sections at all respiratory phases. Detailed information on the algorithm and software is available in the Supplementary materials section.


Automated continuous quantitative measurement of proximal airways on dynamic ventilation CT: initial experience using an ex vivo porcine lung phantom.

Yamashiro T, Tsubakimoto M, Nagatani Y, Moriya H, Sakuma K, Tsukagoshi S, Inokawa H, Kimoto T, Teramoto R, Murayama S - Int J Chron Obstruct Pulmon Dis (2015)

An example of curved multi-planar reconstruction images with and without anatomical synchronization.Notes: (A) The reference (inspiratory) phase. (B) The middle expiratory phase without registration. (C) The full expiratory phase without registration. (D) The middle expiratory phase with registration. (E) The full expiratory phase with registration. The location of the crosscut point (short red lines on each image) is indicated by the blue arrow. It is obvious that the crosscut points of the airway (enlarged in the small windows) slide peripherally on the unregistered images (B and C), while they keep locations on the registered images (D and E).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590570&req=5

f2-copd-10-2045: An example of curved multi-planar reconstruction images with and without anatomical synchronization.Notes: (A) The reference (inspiratory) phase. (B) The middle expiratory phase without registration. (C) The full expiratory phase without registration. (D) The middle expiratory phase with registration. (E) The full expiratory phase with registration. The location of the crosscut point (short red lines on each image) is indicated by the blue arrow. It is obvious that the crosscut points of the airway (enlarged in the small windows) slide peripherally on the unregistered images (B and C), while they keep locations on the registered images (D and E).
Mentions: For continuous airway analysis using dynamic ventilation CT, it is essential that a selected airway point can be reproduced and measured at all respiratory phases on the crosscut sections that are perpendicular to the airway centerlines. For the software presented here, this process is facilitated by locating the anatomical position in one phase (frame) and automatically transferring the same position to all the other phases. When a crosscut section is manually selected on the centerline at one phase, the software automatically reproduces and measures the corresponding crosscut sections at all other phases. The algorithm of the software has basic four steps (Figure 1): in the first and second steps, the airway lumen segmentation and centerline construction are implemented on the reference phase. In the third step, the anatomical locations are synchronized from the reference phase to all the other phases. Finally, wall contours are estimated on all phases. By following these steps, the software is able to trace the designated airway point (Figure 2) and to demonstrate crosscut sections at all respiratory phases. Detailed information on the algorithm and software is available in the Supplementary materials section.

Bottom Line: The software automatically traced a designated airway point in all frames and measured the cross-sectional luminal area and wall area percent (WA%).It is feasible to measure airway dimensions automatically at designated points on dynamic ventilation CT using research software.This technique can be applied to various airway and obstructive diseases.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan.

ABSTRACT

Background: The purpose of this study was to evaluate the feasibility of continuous quantitative measurement of the proximal airways, using dynamic ventilation computed tomography (CT) and our research software.

Methods: A porcine lung that was removed during meat processing was ventilated inside a chest phantom by a negative pressure cylinder (eight times per minute). This chest phantom with imitated respiratory movement was scanned by a 320-row area-detector CT scanner for approximately 9 seconds as dynamic ventilatory scanning. Obtained volume data were reconstructed every 0.35 seconds (total 8.4 seconds with 24 frames) as three-dimensional images and stored in our research software. The software automatically traced a designated airway point in all frames and measured the cross-sectional luminal area and wall area percent (WA%). The cross-sectional luminal area and WA% of the trachea and right main bronchus (RMB) were measured for this study. Two radiologists evaluated the traceability of all measurable airway points of the trachea and RMB using a three-point scale.

Results: It was judged that the software satisfactorily traced airway points throughout the dynamic ventilation CT (mean score, 2.64 at the trachea and 2.84 at the RMB). From the maximum inspiratory frame to the maximum expiratory frame, the cross-sectional luminal area of the trachea decreased 17.7% and that of the RMB 29.0%, whereas the WA% of the trachea increased 6.6% and that of the RMB 11.1%.

Conclusion: It is feasible to measure airway dimensions automatically at designated points on dynamic ventilation CT using research software. This technique can be applied to various airway and obstructive diseases.

No MeSH data available.


Related in: MedlinePlus