Brain tumor volume measurement: Comparison of manual and semiautomated methods

PURPOSE: To compare the reliability of two approaches to measuring enhancin g brain tumor volumes-the conventional manual trace method and a threshold- based, semiautomated computer software method. MATERIALS AND METHODS: Two operators rated contrast material-enhanced, T1-w eighted axial magnetic resonance (MR) image data sets from 16 patients aged 21-71 years with high-grade gliomas. Each MR data set was rated twice by u sing manual tracing and twice by using the semiautomated method. The semiau tomated measurement method involved a thresholding algorithm based on mixtu re modeling. The data collection time for each method was recorded. Reliabi lity was measured by using inter- and intraoperator agreement indexes. RESULTS: Mean intraoperator agreement indexes (+/-SD) were 0.90 +/- 0.09 (o perator 1) and 0.83 +/- 0.15 (operator 2) for the manual trace method and 0 .83 +/- 0.17 (operator 1) and 0.84 +/- 0.16 (operator 2) for the semiautoma ted measurement method. The mean interoperator agreement was 0.85 +/- 0.14 for the manual method and 0.82 +/- 0.18 for the semiautomated method. The s emiautomated method was faster than the manual trace method by an average o f 4.6 minutes per patient. CONCLUSION: The semiautomated computer method of measuring tumor volume was faster than the manual trace method. Semiautomated computer approaches off er an alternative to manual tracing for measuring serial tumor volumes in p atients with high-grade brain neoplasms.