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Contribution of tissue textural pattern and conventional index to glioma staging in FDopa-PET/CT

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HAL Id: inserm-01145618

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Contribution of tissue textural pattern and conventional index to glioma staging in FDopa-PET/CT

Christophe Nioche, Fanny Orlhac, Marine Soret, Eric Gontier, Irène Buvat

To cite this version:

Christophe Nioche, Fanny Orlhac, Marine Soret, Eric Gontier, Irène Buvat. Contribution of tissue textural pattern and conventional index to glioma staging in FDopa-PET/CT. Journées RITS 2015, Mar 2015, Dourdan, France. p50-51 Section imagerie phénotypique et génotypique. �inserm-01145618�

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Actes des Journées Recherche en Imagerie et Technologies pour la Santé - RITS 2015 50

Contribution of tissue textural pattern and conventional index to glioma staging in FDopa-PET/CT

Christophe Nioche 1*, Fanny Orlhac 2, Marine Soret 1, Eric Gontier 1, Irène Buvat 2

1 HIA du Val-de-Grâce, Paris, France.

2 IMIV, U1023 Inserm / CEA-I2BM-SHFJ / Université Paris-Sud, ERL 9218 CNRS, Orsay, France.

*Corresponding author, christophe.nioche@gmail.com

Abstract – Aim: We studied whether the characterization of tumor texture in FDopa-PET/CT could assist in the identification of tumor grades in both primitive and recurrent gliomas. Materials and Methods: Eighty one patients with gliomas were studied, including 52 newly diagnosed tumors and 29 recurrent tumors. For each tumor, the SUVpeak and metabolic volume (MV) were measured, as well as 32 textural indices (TI). The ability of SUVpeak, MV and TI was investigated by using each index alone first (with ROC analyses), and then by using couples consisting of one TI with SUVpeak in a binomial model (with ROC analyses and a reclassification method). The pathological examination was assumed to provide the gold standard grade.

Results: Neither SUVpeak nor MV could discriminate low-grade tumors (LG) from high-grade tumors (HG) in newly-diagnosed tumors, while SUVpeak alone could discriminate LG from HG in recurrent tumors (p=0.02).

Combining a TI with SUVpeak led to a significant LG / HG discrimination for newly-diagnosed tumors (p = 0.01). Among all TI, entropy led to the best reclassification performance. Conclusion: The co- analysis of FDopa-PET/CT SUVpeak and well-selected TI (such as entropy) made it possible to improve the classification of newly-diagnosed gliomas.

Index terms – Image Processing, Medical Physics, Nuclear imaging.

I. INTRODUCTION

In oncology, the coexistence in tumors of biological heterogeneity like the presence of necrosis, fibrosis or of specific receptors affects the evolution of cancer and the choice of therapy. Therefore, several groups have explored the interest of texture indices (TI) measured from PET images to characterize tumor heterogeneity for various types of cancer [1-2]. In addition, studies demonstrated that FDopa-PET/CT can distinguish between high-grade tumors (HG) and low-grade tumors (LG) in recurrent gliomas using Standardized Uptake Value (SUV) to characterize the tumor [3]. We studied whether the characterization of tumor texture in FDopa- PET/CT could assist in the identification of tumor grades in both primitive and recurrent gliomas.

II. MATERIALS AND METHODS II.1. Patients and PET/CT protocol

Eighty one patients (age: 49±13) with gliomas were studied. Each patient underwent a 40 min dynamic FDopa-PET on a Philips Gemini TF scanner 3-min post injection without carbidopa premedication nor fasting. All patients underwent resection or biopsy and the pathological examination provided what was assumed to be the gold standard grade.

II.2. Volume of interest delineation and Texture analysis

Tumors were segmented using a thresholding method accounting for the background activity [4]. For each tumor, the SUVpeak and metabolic volume (MV) were measured, as well as 32 TI. Before calculating TI, voxel intensities were resampled between 0 and the maximum SUV of all tumors using 64 discrete values. After this step, we computed 3 texture matrices: co-occurrence matrix, gray-level run length matrix and gray-level zone length matrix. We extracted 32 TI: Homogeneity, Energy, Correlation, Contrast, Entropy, Dissimilarity, SRE, LRE, LGRE, HGRE, SRLGE, SRHGE, LRLGE, LRHGE, GLNUr, RLNU, RP, Coarseness, Contrast, Busyness, SZE, LZE, LGZE, HGZE, SZLGE, SZHGE, LZLGE, LZHGE, GLNUz, ZLNU, ZP, Sphericity [5].

II.3. Statistical analysis

The ability of SUVpeak, MV and TI to identify the tumor grade was investigated by using each index alone first (with p-value and ROC analyses) and by using couples consisting of one TI with SUVpeak in a binomial model (with ROC analyses and a reclassification method NRI [6]).

III. RESULTS

The 52 newly-diagnosed tumors consisted of 29 HG and 23 LG, while the 29 recurrent tumors included 21 HG and 8 LG. The results of ROC and NRI analysis are

SESSION IMAGERIE PHÉNOTYPIQUE ET GÉNOTYPIQUE

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51 Actes des Journées Recherche en Imagerie et Technologies pour la Santé - RITS 2015

SESSION IMAGERIE PHÉNOTYPIQUE ET GÉNOTYPIQUE

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