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Continuous quantitative measurement of the proximal airway dimensions and lung density on four-dimensional dynamic-ventilation CT in smokers.

Yamashiro T, Moriya H, Tsubakimoto M, Matsuoka S, Murayama S - Int J Chron Obstruct Pulmon Dis (2016)

Bottom Line: Concordance between the time curve of the MLD and that of the airway Ai values was expressed by cross-correlation coefficients.This suggested that the synchrony between the airway and lung movement was lost in patients with severe airflow limitation.Respiratory changes in the MLD and synchrony between the airway Ai and the MLD measured with dynamic-ventilation CT were correlated with patient's spirometric values.

View Article: PubMed Central - PubMed

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

ABSTRACT

Purpose: Four-dimensional dynamic-ventilation computed tomography (CT) imaging demonstrates continuous movement of the airways and lungs, which cannot be depicted with conventional CT. We aimed to investigate continuous changes in lung density and airway dimensions and to assess the correlation with spirometric values in smokers.

Materials and methods: This retrospective study was approved by the Institutional Review Board, and informed consent was waived. Twenty-one smokers including six patients with COPD underwent four-dimensional dynamic-ventilation CT during free breathing (160 mm in length). The mean lung density (MLD) of the scanned lung and luminal areas (Ai) of fixed points in the trachea and the right proximal bronchi (main bronchus, upper bronchus, bronchus intermedius, and lower bronchus) were continuously measured. Concordance between the time curve of the MLD and that of the airway Ai values was expressed by cross-correlation coefficients. The associations between these quantitative measurements and the forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) values were assessed by Spearman's rank correlation analysis.

Results: On the time curve for the MLD, the Δ-MLD1.05 values between the peak inspiratory frame to the later third frame (1.05 seconds later) were strongly correlated with the FEV1/FVC (ρ=0.76, P<0.0001). The cross-correlation coefficients between the airway Ai and MLD values were significantly correlated with the FEV1/FVC (ρ=-0.56 to -0.66, P<0.01), except for the right upper bronchus. This suggested that the synchrony between the airway and lung movement was lost in patients with severe airflow limitation.

Conclusion: Respiratory changes in the MLD and synchrony between the airway Ai and the MLD measured with dynamic-ventilation CT were correlated with patient's spirometric values.

No MeSH data available.


Related in: MedlinePlus

Example of continuous airway measurement using the software (4D Airways Analysis).Notes: On this image, a measurement point is set at the bronchus intermedius (red arrow). The corresponding measurement points in all 13 frames are shown at the bottom. A measured luminal area (Ai) of the sixth frame (yellow arrow) is shown in the center square (surrounded by a green line). Continuous measurements of the Ai are shown in the right upper square (red dashed line).Abbreviation: 4D, four dimensional.
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f1-copd-11-755: Example of continuous airway measurement using the software (4D Airways Analysis).Notes: On this image, a measurement point is set at the bronchus intermedius (red arrow). The corresponding measurement points in all 13 frames are shown at the bottom. A measured luminal area (Ai) of the sixth frame (yellow arrow) is shown in the center square (surrounded by a green line). Continuous measurements of the Ai are shown in the right upper square (red dashed line).Abbreviation: 4D, four dimensional.

Mentions: All scan data were anonymized and stored in a research computer. Using a commercially available research software (4D Airways Analysis; Toshiba Medical Systems), the continuous image data (320 images/frame × total 8–13 frames, by every 0.35 seconds) were synthesized for the cine-CT series. Detailed information of the software was described in our technical note.8 In brief, the software automatically created a tree of the centerlines from the trachea to all traceable peripheral bronchi throughout the cine-CT, on which the anatomical information of the measurement point was sustained and reproduced in each frame. Thus, once the operator set a measurement point on the airway centerline in a single frame, the corresponding measurement points in other frames were simultaneously determined (Figure 1; Video S2). In this study, airway Ai was continuously measured at a single point of the following airways: intrathoracic trachea, right main bronchus, right upper bronchus (RUB), bronchus intermedius, and right lower bronchus. In each of these regions, the approximate middle point of the airway was selected by the operator (TY, 14 years of experience in thoracic radiology) and no manual correction was applied for the automatic measurement. Due to the caudal scanning location, the CT data of one patient did not include the trachea or the RUB. All other proximal airways were measurable in all patients.


Continuous quantitative measurement of the proximal airway dimensions and lung density on four-dimensional dynamic-ventilation CT in smokers.

Yamashiro T, Moriya H, Tsubakimoto M, Matsuoka S, Murayama S - Int J Chron Obstruct Pulmon Dis (2016)

Example of continuous airway measurement using the software (4D Airways Analysis).Notes: On this image, a measurement point is set at the bronchus intermedius (red arrow). The corresponding measurement points in all 13 frames are shown at the bottom. A measured luminal area (Ai) of the sixth frame (yellow arrow) is shown in the center square (surrounded by a green line). Continuous measurements of the Ai are shown in the right upper square (red dashed line).Abbreviation: 4D, four dimensional.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4835141&req=5

f1-copd-11-755: Example of continuous airway measurement using the software (4D Airways Analysis).Notes: On this image, a measurement point is set at the bronchus intermedius (red arrow). The corresponding measurement points in all 13 frames are shown at the bottom. A measured luminal area (Ai) of the sixth frame (yellow arrow) is shown in the center square (surrounded by a green line). Continuous measurements of the Ai are shown in the right upper square (red dashed line).Abbreviation: 4D, four dimensional.
Mentions: All scan data were anonymized and stored in a research computer. Using a commercially available research software (4D Airways Analysis; Toshiba Medical Systems), the continuous image data (320 images/frame × total 8–13 frames, by every 0.35 seconds) were synthesized for the cine-CT series. Detailed information of the software was described in our technical note.8 In brief, the software automatically created a tree of the centerlines from the trachea to all traceable peripheral bronchi throughout the cine-CT, on which the anatomical information of the measurement point was sustained and reproduced in each frame. Thus, once the operator set a measurement point on the airway centerline in a single frame, the corresponding measurement points in other frames were simultaneously determined (Figure 1; Video S2). In this study, airway Ai was continuously measured at a single point of the following airways: intrathoracic trachea, right main bronchus, right upper bronchus (RUB), bronchus intermedius, and right lower bronchus. In each of these regions, the approximate middle point of the airway was selected by the operator (TY, 14 years of experience in thoracic radiology) and no manual correction was applied for the automatic measurement. Due to the caudal scanning location, the CT data of one patient did not include the trachea or the RUB. All other proximal airways were measurable in all patients.

Bottom Line: Concordance between the time curve of the MLD and that of the airway Ai values was expressed by cross-correlation coefficients.This suggested that the synchrony between the airway and lung movement was lost in patients with severe airflow limitation.Respiratory changes in the MLD and synchrony between the airway Ai and the MLD measured with dynamic-ventilation CT were correlated with patient's spirometric values.

View Article: PubMed Central - PubMed

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

ABSTRACT

Purpose: Four-dimensional dynamic-ventilation computed tomography (CT) imaging demonstrates continuous movement of the airways and lungs, which cannot be depicted with conventional CT. We aimed to investigate continuous changes in lung density and airway dimensions and to assess the correlation with spirometric values in smokers.

Materials and methods: This retrospective study was approved by the Institutional Review Board, and informed consent was waived. Twenty-one smokers including six patients with COPD underwent four-dimensional dynamic-ventilation CT during free breathing (160 mm in length). The mean lung density (MLD) of the scanned lung and luminal areas (Ai) of fixed points in the trachea and the right proximal bronchi (main bronchus, upper bronchus, bronchus intermedius, and lower bronchus) were continuously measured. Concordance between the time curve of the MLD and that of the airway Ai values was expressed by cross-correlation coefficients. The associations between these quantitative measurements and the forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) values were assessed by Spearman's rank correlation analysis.

Results: On the time curve for the MLD, the Δ-MLD1.05 values between the peak inspiratory frame to the later third frame (1.05 seconds later) were strongly correlated with the FEV1/FVC (ρ=0.76, P<0.0001). The cross-correlation coefficients between the airway Ai and MLD values were significantly correlated with the FEV1/FVC (ρ=-0.56 to -0.66, P<0.01), except for the right upper bronchus. This suggested that the synchrony between the airway and lung movement was lost in patients with severe airflow limitation.

Conclusion: Respiratory changes in the MLD and synchrony between the airway Ai and the MLD measured with dynamic-ventilation CT were correlated with patient's spirometric values.

No MeSH data available.


Related in: MedlinePlus