Abstract
INTRODUCTION
Horos (LGPL 3.0) is a free, open source medical image viewer that has gained attention in the neurosurgical community because of the familiar OsiriX-based interface and its useful three-dimensional (3D) volumetric rendering capabilities. We present the use of Horos software as a postoperative tool for residual tumor volume analysis in children with high-grade gliomas.
METHODS
A retrospective study of 11 pediatric patients with histologically confirmed HGG underwent tumor resection (n=8) or biopsy (n=3) as definitive treatment from 6/2011 to 6/2019. Volumetric data and extent of resection were obtained via region of interest-based 3D analysis using Horos image-processing software. Age, initial tumor volume, extent of resection, and postoperative residual volume were assessed as predictors of overall survival or event free survival.
TECHNIQUE
Region of interest (ROI) segmentation was performed utilizing the “Closed Polygon Tool” to outline the tumor and the “Generate Missing ROIs” function to capture the entirety of the tumor within the MRI series. The “Computer Volume” function was used to render the 3D tumor volumes. The preoperative and postoperative tumor volumes were compared per patient to yield the percent extent of resection and residual volume.
RESULTS
The Horos software is a highly effective means of volumetric analysis for high-grade gliomas depicted in T1 and T2 MRI series. In our series, eight (73%) patients underwent tumor resection and three (27%) underwent biopsy. Patients who underwent resection were older than biopsy patients [12 (8-18) vs. 9 (8-21) years old]. Age, initial tumor volume, extent of resection, and postoperative residual volume were not significant predictors of overall survival or event free survival.
CONCLUSION
Horos software provides increased accuracy and confidence in determining post-operative volume and is useful in assessing the impact of residual volume on outcome after maximal safe resection in pediatric patients with high-grade gliomas.