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

• Published in: European journal of hybrid imaging 2021-08, Vol.5 (1), p.15-15, Article 15
• Main Authors: Jabeen, Shumyla, Arbind, Arpana, Kumar, Dinesh, Singh, Pardeep Kumar, Saini, Jitender, Sadashiva, Nishanth, Krishna, Uday, Arimappamagan, Arivazhagan, Santosh, Vani, Nagaraj, Chandana
• Format: Article
• Language: English
• Subjects: Accuracy; Amino acid PET; Amino acids; Diagnosis; Diagnostic systems; Diffusion; Discordance; Glioma; Gliomas; Histopathology; Imaging; Magnetic resonance imaging; Medical imaging; Medicine; Medicine & Public Health; Methionine; Nuclear Medicine; Original; Original Article; Perfusion; Positron emission; Radiation necrosis; Radioactive tracers; Radiology; Recurrence; Regression analysis; Technical Aspects of Hybrid Imaging; Tomography
• ISSN: 2510-3636; 2510-3636
• DOI: 10.1186/s41824-021-00109-y

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: TBR max , TBR mean , SUV max , and SUV mean from the PET images; rCBV from perfusion; and ADC mean and ADC ratio 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% 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 TBR max followed by rCBV and ADC ratio . The AUC increased significantly with a combination of rCBV and TBR max . 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.