A Preliminary Study About The VOI Size Influence The SNR Of The MRS In Myometrium

Objective:The purpose of the study was to explore the influence on the signal to noise ratio of the proton magnetic resonance spectroscopy with different VOI by scanning the myometrium of the healthy women with MRI. Materials and Methods:Fifty healthy women of childbearing age were performed pelvis MRS scanning with the Siemens 1.5T MRI,the MRS scanning chose the single voxel that set on the myometrium of the mid-sagittal of the uterus fundus and the TE chose 144 ms, each volunteer was scanned two times with the VOI respectively using 5 mm×5 mm×10 mm (group A) and 10 mm×10 mm×10 mm (group B).Two radiologists who had rich MRS diagnostics experience evaluate the spectroscopy of the Choline、Creatine、Lactate and the substance in 2 ppm in a double-blind way.Any one of the spectroscopy peak of these four substances higher than the average baseline height was regarded as positive,while less than or equal to the average baseline height was regarded as negative. Results:There were good consistency (κA>0.75,κB>0.75) and statistical significance (PA< 0.05,PB<0.05) between two doctor’s evaluation.The positive rate was 20% in group A and 86% in group B evaluated by doctor one;The positive rate was 14% in group A and 82% in group B evaluated by doctor two,and the average of the positive rate was 17% in group A and 84% in group B. There were significantly statistical differences in two doctor’s evaluation between two groups (P1<0.05, P2<0.05), the positive rate in group B was higher than group A. Conclusion:The signal to noise ratio of the group A that the VOI chose 10 mm×10 mm×10 mm was better than the group B with the VOI chose 5 mm×5 mm×10 mm,so when we performed the MRS scanning in the uterus myometrium the VOI should not less than 1cm3.