Stratification of pseudoprogression and true progression of glioblastoma multiform based on longitudinal diffusion tensor imaging without segmentation.

Xiaobo Zhou,Michael D Chan,Hua Tan,Jian Zhang,Weilin Zhao,Xiaohua Qian

doi:10.1118/1.4963812

Abstract

Purpose:Pseudoprogression (PsP) can mimic true tumor progression (TTP) on magnetic resonance imaging in patients with glioblastoma multiform (GBM). The phenotypical similarity between PsP and TTP makes it a challenging task for physicians to distinguish these entities. So far, no approved biomarkers or computer-aided diagnosis systems have been used clinically for this purpose.Methods:To address this challenge, the authors developed an objective classification system for PsP and TTP based on longitudinal diffusion tensor imaging. A novel spatio-temporal discriminative dictionary learning scheme was proposed to differentiate PsP and TTP, thereby avoiding segmentation of the region of interest. The authors constructed a novel discriminative sparse matrix with the classification-oriented dictionary learning approach by excluding the shared features of two categories, so that the pooled features captured the subtle difference between PsP and TTP. The most discriminating features were then identified from the pooled features by their feature scoring system. Finally, the authors stratified patients with GBM into PsP and TTP by a support vector machine approach. Tenfold cross-validation (CV) and the area under the receiver operating characteristic (AUC) were used to assess the robustness of the developed system.Results:The average accuracy and AUC values after ten rounds of tenfold CV were 0.867 and 0.92, respectively. The authors also assessed the effects of different methods and factors (such as data types, pooling techniques, and dimensionality reduction approaches) on the performance of their classification system which obtained the best performance.Conclusions:The proposed objective classification system without segmentation achieved a desirable and reliable performance in differentiating PsP from TTP. Thus, the developed approach is expected to advance the clinical research and diagnosis of PsP and TTP.

Highlights

The median survival for Glioblastoma multiforme (GBM) patients is about 14–16 months and the average 2-yr survival rate is only 26%–33%, even though they have received standard care including surgical resection followed by concurrent radiotherapy and chemotherapy with temozolomide
The radiotherapy and chemotherapy are effective for the treatment of GBM, and increase the difficulty of distinguishing true tumor progression (TTP) and pseudoprogression (PsP)
Differentiation of PsP and TTP in GBM patients is still challenging for physicians since PsP can mimic tumor progression at the tumor site or resection margins, and its appearance on magnetic resonance imaging (MRI) is comparable to that of TTP

Summary

Introduction

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor, with an incidence of approximately 3 cases per 100000 people life-years in Europe and North America. The median survival for GBM patients is about 14–16 months and the average 2-yr survival rate is only 26%–33%, even though they have received standard care including surgical resection followed by concurrent radiotherapy and chemotherapy with temozolomide. The radiotherapy and chemotherapy are effective for the treatment of GBM, and increase the difficulty of distinguishing true tumor progression (TTP) and pseudoprogression (PsP). PsP is a subacute and post-treatment reaction with increased contrast enhancement and vasogenic edema that mimics tumor progression at the tumor site or resection margins, but subsequently regresses or remains stable. The incidence of PsP is around 20% in all GBM patients with standard treatment.2Clinically, it is crucial to differentiate PsP from TTP because management strategies are different. The median survival for GBM patients is about 14–16 months and the average 2-yr survival rate is only 26%–33%, even though they have received standard care including surgical resection followed by concurrent radiotherapy and chemotherapy with temozolomide.. The radiotherapy and chemotherapy are effective for the treatment of GBM, and increase the difficulty of distinguishing true tumor progression (TTP) and pseudoprogression (PsP).. PsP is a subacute and post-treatment reaction with increased contrast enhancement and vasogenic edema that mimics tumor progression at the tumor site or resection margins, but subsequently regresses or remains stable.. The incidence of PsP is around 20% in all GBM patients with standard treatment.. The only method for distinguishing between PsP and TTP is to perform follow-up MRI examinations based on the changes in the lesion site.

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Conclusion