Abstract
Purpose
In evaluating the impact of surgical repair of pectus excavatum, the Haller index
developed for preoperative decision-making purposes may be inadequate to quantify
postoperative changes in shape of the chest. Individual patients may also have chest
characteristics that impact the success of repair, many of which would be unlikely
to be measured by the Haller index alone. We have developed a protocol that measures
the cross-sectional chest area and the asymmetry index along with the Haller index
to more completely quantify the nature of the deformity. The purpose of this study
was to determine the reliability of this protocol in the interpretation of chest computed
tomography images from multiple sites. The protocol was developed as part of a multicenter
study of clinical outcomes after surgical repair of pectus excavatum.
Methods
Two radiologists independently selected 5 images from each of 32 computed tomography
scans from multicenter study participants according to the protocol. A digitizer was
used to measure the diameters and cross-sectional areas of the images selected; these
results were used to calculate the Haller and asymmetry indices. The protocol was
tested for intradigitizer and interradiologist reliability. Using the Haller and asymmetry
indices, we also assessed agreement between radiologists classifying patients as abnormal.
Results
Agreement was uniformly high for all comparisons (all Lin's concordance coefficients
>0.99 and all Cohen's κ's >0.85, all agreement on classification of patients >95%) indicating almost perfect
agreement. Disagreement on classification of patients using the Haller and asymmetry
index was at the cut points for abnormality.
Conclusion
The protocol was found to be a highly reliable method for deriving the cross-sectional
area of the chest and the Haller and asymmetry indices and for classifying patients
for surgical eligibility. Borderline cases should be examined carefully to determine
the appropriateness of surgical intervention. Cross-sectional area can be measured
reliably using this protocol and thus may be useful in quantifying the success of
surgical intervention.
Index words
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References
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Article Info
Identification
Copyright
© 2006 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
