Fully Automated Enhanced Tumor Compartmentalization: Man vs. Machine Reloaded

Nicole Porz, Simon Habegger, Raphael Meier, Rajeev Verma, Astrid Jilch, Jens Fichtner, Urspeter Knecht, Christian Radina, Philippe Schucht, Jürgen Beck, Andreas Raabe, Johannes Slotboom (+3 others)
2016 PLoS ONE  
Objective Comparison of a fully-automated segmentation method that uses compartmental volume information to a semi-automatic user-guided and FDA-approved segmentation technique. Methods Nineteen patients with a recently diagnosed and histologically confirmed glioblastoma (GBM) were included and MR images were acquired with a 1.5 T MR scanner. Manual segmentation for volumetric analyses was performed using the open source software 3D Slicer version (www.slicer.org). Semi-automatic
more » ... ation was done by four independent neurosurgeons and neuroradiologists using the computer-assisted segmentation tool SmartBrush® (referred to as SB), a semi-automatic user-guided and FDA-approved tumoroutlining program that uses contour expansion. Fully automatic segmentations were performed with the Brain Tumor Image Analysis (BraTumIA, referred to as BT) software. We compared manual (ground truth, referred to as GT), computer-assisted (SB) and fully-automated (BT) segmentations with regard to: (1) products of two maximum diameters for 2D measurements, (2) the Dice coefficient, (3) the positive predictive value, (4) the sensitivity and (5) the volume error. Results Segmentations by the four expert raters resulted in a mean Dice coefficient between 0.72 and 0.77 using SB. BT achieved a mean Dice coefficient of 0.68. Significant differences were found for intermodal (BT vs. SB) and for intramodal (four SB expert raters) performances. The BT and SB segmentations of the contrast-enhancing volumes achieved a PLOS ONE | did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The high correlation with the GT. Pearson correlation was 0.8 for BT; however, there were a few discrepancies between raters (BT and SB 1 only). Additional non-enhancing tumor tissue extending the SB volumes was found with BT in 16/19 cases. The clinically motivated sum of products of diameters measure (SPD) revealed neither significant intermodal nor intramodal variations. The analysis time for the four expert raters was faster (1 minute and 47 seconds to 3 minutes and 39 seconds) than with BT (5 minutes). Conclusion BT and SB provide comparable segmentation results in a clinical setting. SB provided similar SPD measures to BT and GT, but differed in the volume analysis in one of the four clinical raters. A major strength of BT may its independence from human interactions, it can thus be employed to handle large datasets and to associate tumor volumes with clinical and/or molecular datasets ("-omics") as well as for clinical analyses of brain tumor compartment volumes as baseline outcome parameters. Due to its multi-compartment segmentation it may provide information about GBM subcompartment compositions that may be subjected to clinical studies to investigate the delineation of the target volumes for adjuvant therapies in the future. Fully Automated Tumor Compartmentalization: Man vs. Machine Reloaded PLOS ONE | Fig 2. Stereotactic biopsy with the frameless neuronavigation system (Brainlab® VarioGuide) using BraTumIA segmentation. The figures indicate the T1w raw image and the BT subcompartment overlays during biopsy. Upper row left column: original T1wGd without tumor delineation, right column: all automatic segmented tumor subcompartments are visible. Bottom row left column: necrosis and contrast-enhancing tumor volume, right column: only necrotic tumor volume. Color code for segmentations: red = enhancing tumor, yellow = edema, blue = necrosis and green = non-enhancing tumor. Fig 4. The performances of the different raters (SB1 to 4) and methods (SB vs. BT) were compared with a Bonferroni corrected Wilcoxon signed-rank test in terms of Dice coefficient (A), absolute volume difference (B) and absolute SPD difference (C). A connection denotes a significant difference, with the encircled number being the p-value. The arrow points to the superior method with respect to the GT. The line thickness depicts the p-value in a qualitative manner. The color coding shows to which SB rater BT (white) is significantly different (red) or not (green).
doi:10.1371/journal.pone.0165302 pmid:27806121 pmcid:PMC5091868 fatcat:pxkak2tjnvfgnmjmpqkke2qp6y