Effect of Reducing Field of View on Multidetector Quantitative Computed Tomography Parameters of Airway Wall Thickness in Asthma.
OBJECTIVE
We reduced the computed tomography (CT)-reconstructed field of view (FOV), increasing pixel density across airway structures and reducing partial volume effects, to determine whether this would improve accuracy of airway wall thickness quantification.


METHODS
We performed CT imaging on a lung phantom and 29 participants. Images were reconstructed at 30-, 15-, and 10-cm FOV using a medium-smooth kernel. Cross-sectional airway dimensions were compared at each FOV with repeated-measures analysis of variance.


RESULTS
Phantom measurements were more accurate when FOV decreased from 30 to 15 cm (P < 0.05). Decreasing FOV further to 10 cm did not significantly improve accuracy. Human airway measurements similarly decreased by decreasing FOV (P < 0.001). Percent changes in all measurements when reducing FOV from 30 to 15 cm were less than 3%.


CONCLUSIONS
Airway measurements at 30-cm FOV are near the limits of CT resolution using a medium-smooth kernel. Reducing reconstructed FOV would minimally increase sensitivity to detect differences in airway dimensions.
From the *Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St Louis, MI; †Department of Medical Physics, University of Wisconsin-Madison, Madison, WI; ‡Department of Surgery, University of Louisville School of Medicine, Louisville, KY; §Division of Biostatistics, Washington University School of Medicine, St Louis, MI; ∥Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA; ¶Department of Radiology, University of Iowa College of Medicine, Iowa City, IA; and #Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MI.
Ajay
A
Sheshadri
Alfonso
A
Rodriguez
Ryan
R
Chen
James
J
Kozlowski
Dana
D
Burgdorf
Tammy
T
Koch
Jaime
J
Tarsi
Rebecca
R
Schutz
Brad
B
Wilson
Kenneth
K
Schechtman
Joseph K
JK
Leader
Eric A
EA
Hoffman
Mario
M
Castro
Sean B
SB
Fain
David S
DS
Gierada
D000328:Adult; D000704:Analysis of Variance; D001249:Asthma / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001837:Body Weights and Measures / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult