Proton Magnetic Resonance Spectroscopy Study On Spinal Metastasis

Objective : To observe proton magnetic resonance spectroscopy (~1H-MRS)performance of vertebrae with metastatic tumors and healthy control vertebrae ,and to quantitatively analyze and evaluate the lipid / water ratio (LWR), percentage of fat (FF%) and its correlation with age of the two groups of vertebral bodys.Method:①23 clinically and pathologically confirmed cases with spinal metastases and 25 healthy cases were performed with conventional MRI by 3.0T MR.②~1H-MRS imaging of tumor-involved vertebral body and L2 vertebral body were obtained. Single Voxel sequence (SVS ) and point resolved spectroscopy sequence(PRESS) were selected for spectral acquisition of the vertebral body. Repetition time (TR) = 2000 ms, echo time (TE) = 35 ms, the volume of interest (VOI)= l×l×lcm~3-2×2×2cm~3, water and fat suppression not selected.③~1H-MRS wave form performance of selected vertebraes were observed.④Applicating statistical methods, the fat / water ratio (LWR), percentage of fat (FF%) and its age-correlation of the interested vertebral bodys were quantitatively analyzed comparing the metastatic tumor group with control group.Result:①Vertebral ~1H-MRS of metastases group and control group have all shown for two peaks: lipid peak and water peak. Compared with the control group, the lipid peak of vertebral metastases group is significantly reduced or disappeared, water peak increased.②On vertebral metastases group, the mean LWR is 0.038±0.024, and the mean FF% is 3.66±2.20%; On control group, the mean LWR of vertebral body is 0.64±0.20, and the mean FF% is 37.91±8.66%; LWR and FF% of metastases group are significantly lower than the control group (t = 14.7,p <0.01 and t = 19.1, p <0.01).③On patients with metastases, the mean age is59.5±10.2, LWR and FF% have no age-correlation (r=0.142,p=0.519>0.05 and r=0.151,p=0.491>0.05).On control group, the mean age is 56.2±9.3, LWR and FF% correlated with age (r=0.955; /K0.01 and r=0.936;p＜0.01).Conclusion: Compared with the healthy control group, 1H-MRS of spinalmetastases group showed significantly lower or disappeared lipid peak and high water peak, LWR and FF% values are significantly lower. The two groups have significant difference. LWR and FF% value of metastases group had no correlation with age. LWR value of the control group had a positive correlation with age, the vertebral body had increasing LWR with increasing age. FF% also has age-correlation, vertebral body has higher fat content with increasing age. Water and fat changes of metastases and control groups can be quantitatively analyzed with 1H-MRS, and the metabolism of biological information can be provided for clinic.