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Comparison of three software systems for semi-automatic volumetry of pulmonary nodules on baseline and follow-up CT examinations . BACKGROUND Early diagnosis of lung cancer in a treatable stage is the main purpose of lung cancer screening by computed tomography ( CT ) . Accurate three-dimensional size and growth measurements are essential to assess the risk of malignancy . Nodule volumes can be calculated by using semi-automated volumetric software . Systematic differences in volume measurements between packages could influence nodule categorization and management decisions . PURPOSE To compare volumetric measurements of solid pulmonary nodules on baseline and follow-up CT scans as well as the volume doubling time ( VDT ) for three software packages . MATERIAL AND METHODS From a Lung Cancer Screening study ( NELSON ) , 50 participants were randomly selected from the baseline round . The study population comprised participants with at least one pulmonary nodule at the baseline and consecutive CT examination . The volume of each nodule was determined for both time points using three semi-automated software packages ( P1 , P2 , and P3 ) . Manual modification was performed when automated assessment was visually inaccurate . VDT was calculated to evaluate nodule growth . Volume , VDT , and nodule management were compared for the three software packages , using P1 as the reference standard . RESULTS In 25 participants , 147 nodules were present on both examinations ( volume : 12.0-436.6 mm ( 3 ) ) . Initial segmentation at baseline was evaluated to be satisfactory in 93.9 % of nodules for P1 , 84.4 % for P2 , and 88.4 % for P3 . Significant difference was found in measured volume between P1 and the other two packages ( P < 0.001 ) . P2 overestimated the volume by 38 ± 24 % , and P3 by 50 ± 22 % . At baseline , there was consensus on nodule size categorization in 80 % for P1 & P2 and 74 % for P1 & P3 . At follow-up , consensus on VDT categorization was present in 47 % for P1 & P2 and 44 % for P1 & P3 . CONCLUSION Software packages for lung nodule evaluation yield significant differences in volumetric measurements and VDT . This variation affects the classification of lung nodules , especially in follow-up examinations .
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Intervention_Other
Comparison of three software systems
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Intervention_Physical
computed tomography ( CT )
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Intervention_Physical
CT scans
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Intervention_Other
three software packages
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Intervention_Other
three semi-automated software packages
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Intervention_Educational
( P1 , P2 , and P3 )
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Outcome_Other
Comparison
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Outcome_Physical
volumetry of pulmonary nodules
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Outcome_Physical
volumetric measurements
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Outcome_Physical
volume doubling time ( VDT )
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Outcome_Physical
volume of each nodule
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Outcome_Physical
VDT
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Outcome_Physical
evaluate nodule growth .
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Outcome_Physical
VDT
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Outcome_Physical
nodule management
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Outcome_Physical
measured volume
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Participant_Condition
lung cancer
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Participant_Condition
Lung Cancer
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Participant_Sample-size
50