Pre- and Posttreatment Glioma: Comparison of Amide Proton Transfer Imaging with MR Spectroscopy for Biomarkers of Tumor Proliferation

Abstract

APT imaging used as a tumor proliferation index showed moderate correlation with MR spectroscopic values and is a superior imaging method to MR spectroscopy, particularly for assessment of posttreatment gliomas.

Amide Proton Transfer Imaging Allows Detection of Glioma Grades and Tumor Proliferation: Comparison with Ki-67 Expression and Proton MR Spectroscopy Imaging

“…23 Conversely, NAA levels reflect neuronal activity and, thus, decrease in parallel with the growth of brain tumors such as gliomas. 21 Our findings on the correlations between MTRasym (3.5ppm) and choline/NAA ratios were consistent in part with those reported by Park et al, 15 who used single-voxel MR spectroscopy, and their VOIs were somewhat larger than our multivoxel MRSI findings. Because gliomas are often heterogeneous, using smaller VOIs carries a lower risk of accidentally including cystic and necrotic areas and allows more precise measurement of the tumor areas of interest, which could provide an important part of a comprehensive comparison between MR spectroscopy and APT imaging.…”

“…12 APTWI is usually reported in terms of asymmetry in the magnetization transfer ratio at 3.5 ppm [MTRasym(3.5ppm)] and is measured as a reduction in bulk water intensity caused by chemical exchange with magnetically labeled backbone amide protons (at ϳ3.5 ppm downfield of the water resonance) of endogenous mobile proteins and peptides. Previous studies have demonstrated that APTWI can detect response to therapy in glioma [13][14][15] and correlates with grade in adult diffuse gliomas. 16 However, a further consideration sustained by multiple methods with bigger samples is required to investigate whether APTWI accurately reflects cellular proliferation in patients with glioma.…”

Addition of Amide Proton Transfer Imaging to FDG-PET/CT Improves Diagnostic Accuracy in Glioma Grading: A Preliminary Study Using the Continuous Net Reclassification Analysis

“…3,[11][12][13][14][15][16][17][18] However, details of the relationships between APT imaging and other clinical imaging parameters of malignancy have yet to be fully elucidated. This study confirmed that APT imaging can be used for grading glial tumors, with a diagnostic accuracy comparable with that of other imaging biomarkers derived from DWI and FDG-PET.…”

“…22 As in previous studies, our results also demonstrated excellent interrater reproducibility in the measurement of APT. 3,[11][12][13][14][15][16] We believe that for the preoperative grading of brain tumors, APT can be considered an alternative approach to PET and other MR imaging methods such as DWI.…”

“…9 This technique has been successfully applied to human brain tumors. 3,[10][11][12][13][14][15][16] Some reports have shown that the APT asymmetry value is useful in tumor grading, allowing differentiation of pseudoprogression from recurrence 17 and the assessment of treatment response. 18,19 However, the relationship between APT and other quantitative imaging values has yet to be investigated.…”