Combined amino acid PET-MRI for identifying recurrence in post-treatment gliomas: together we grow

Abstract

Purpose The aim of this study is to compare the diagnostic accuracy of amino acid PET, MR perfusion and diffusion as stand-alone modalities and in combination in identifying recurrence in post-treatment gliomas and to qualitatively assess spatial concordance between the three modalities using simultaneous PET-MR acquisition. Methods A retrospective review of 48 cases of post-treatment gliomas who underwent simultaneous PET-MRI using C11 methionine as radiotracer was performed. MR perfusion and diffusion sequences were acquired during the PET study. The following parameters were obtained: TBRmax, TBRmean, SUVmax, and SUVmean from the PET images; rCBV from perfusion; and ADCmean and ADCratio from the diffusion images. The final diagnosis was based on clinical/imaging follow-up and histopathology when available. ROC curve analysis in combination with logistic regression analysis was used to compare the diagnostic performance. Spatial concordance between modalities was graded as 0, 1, and 2 representing discordance, < 50% and > 50% concordance respectively. Results There were 35 cases of recurrence and 13 cases of post-treatment changes without recurrence. The highest area under curve (AUC) was obtained for TBRmax followed by rCBV and ADCratio. The AUC increased significantly with a combination of rCBV and TBRmax. Amino acid PET showed the highest diagnostic accuracy and maximum agreement with the final diagnosis. There was discordance between ADC and PET in 22.9%, between rCBV and PET in 16.7% and between PET and contrast enhancement in 14.6% cases. Conclusion Amino acid PET had the highest diagnostic accuracy in identifying recurrence in post-treatment gliomas. Combination of PET with MRI further increased the AUC thus improving the diagnostic performance.

Effect of Bevacizumab Treatment in Cerebral Radiation Necrosis : Investigation of Response Predictors in a Single-Center Experience

“…Comprehensive imaging-based diagnosis is the most practical and most commonly applied method although primarily imaging-based determination cannot exclude the possibility that a small number of living tumor cells are present in or around the lesion. When the viable tumor is mixed with RN, an overlap of diffusion restriction can occur [ 2 , 13 , 14 , 35 , 41 , 45 ], particularly in cases with infiltrative pathology (e.g., glioma), and may have possibly resulted in a difference in the bevacizumab response in RN, which shows a diffusion-restriction pattern. The limitation that the pathology of the corresponding lesions were not analyzed in the present study, this should be taken into consideration when interpreting the results.…”

“…4 6 10 18 Previous studies have revealed that overexpression of VEGF in resected RN lesions and the degree of radiation injury are correlated with the amount of VEGF expression. 14 29 Since preventing VEGF from reaching its capillary targets is a logical treatment strategy for RN, bevacizumab, a humanized monoclonal antibody against VEGF, might be an effective treatment option. 11 28 Gonzalez et al…”

Tracers progress for positron emission tomography imaging of glial-related disease

“…Compared with PET/CT, it has an increased soft tissue contrast and lacks of ionizing radiation exposure, which outperforms PET/CT in many applications [ 156 ] . It has been used in both neurodegenerative disorders [ 157 – 159 ] and glioma [ 160 – 162 ] , with above-mentioned radiotracers, PET/MRI has achieved much better results than using PET or MRI individually, and also PET/CT.…”

Early Recurrence Detection of Glioma Using 18F-Fluorocholine PET/CT

“…18 Comparative studies in high-grade glioma (HGG) using amino acid PET radiotracers in parallel comparison with MRI found high sensitivity but limited specificity for contrast-enhanced MRI in TR detection of HGG, although the sensitivity was low in low-grade glioma. 23,24 For that reason, we decided to include contrast-enhanced low-grade glioma on preoperative MRI. In fact, one of these patients had a recurrence with histology of HGG.…”