Absolute choline concentration measured by quantitative proton MR spectroscopy correlates with cell density in meningioma

Introduction  This study was aimed to investigate the relationship between quantitative proton magnetic resonance spectroscopy (1H-MRS) and pathological changes in meningioma. Materials and methods  Twenty-two meningioma cases underwent single voxel 1H-MRS (point-resolved spectroscopy sequence, repetition time/echo time = 2,000 ms/68, 136, 272 ms). Absolute choline (Cho) concentration was calculated using tissue water as the internal reference and corrected according to intra-voxel cystic/necrotic parts. Pathological specimens were stained with MIB-1 antibody to measure cell density and proliferation index. Correlation analysis was performed between absolute Cho concentration and cell density and MIB-1 labeled proliferation index. Results  Average Cho concentration of all meningiomas before correction was 2.95 ± 0.86 mmol/kg wet weight. It was increased to 3.23 ± 1.15 mmol/kg wet weight after correction. Average cell density of all meningiomas was 333 ± 119 cells/HPF, and average proliferation index was 2.93 ± 5.72%. A linear, positive correlation between cell density and Cho concentration was observed (r = 0.650, P = 0.001). After correction of Cho concentration, the correlation became more significant (r = 0.737, P < 0.001). However, no significant correlation between Cho concentration and proliferation index was found. There seemed to be a positive correlation trend after correction of Cho concentration but did not reach significant level. Conclusion  Absolute Cho concentration, especially Cho concentration corrected according to intra-voxel cystic/necrotic parts, reflects cell density of meningioma. Grant: This study was supported by the Japan-China Sasakawa Medical Fellowship (Nippon Foundation, Japan)