1H-MR波谱在股骨骨髓采集中优化的初步探讨

Initial study of optimal single-voxel ~1H-MR spectroscopy parameters on femoral bone marrow

目的选择符合股骨骨髓腔解剖学特点、检查时间短、重复性良好而且图像质量高的MR 氢质子波谱(~1H-MRS)采集方法。方法采用1.5 TMR 单体素波谱激发回波探测序列对26名志愿者正常股骨骨髓进行~1H-MRS 的探索性研究。其中12名股骨~1H-MRS 采用128次采集、1 cm×1 cm×1 cm 大小的立方形感兴趣容积(VOI)在同一受检部位重复采集2～3次。另14例股骨~1H-MRS 分别采用128次和256次采集、1 cm×1 cm×1 cm 和2 cm×2 cm×2 cm 大小 VOI。结果采用1 cm×1 cm×1 cm 大小的 VOI 和128次采集获得的~1H-MRS 基线稳定,水半高宽≤8～12 Hz,信噪比为11.31,2～3次重复采集后谱线可重复率为100%。不同部位采集的~1H-MRS 表现不尽相同,最大波峰位置位于0.90 ppm(×10^(-6))或1.65 ppm 附近处。但同一部位采用不同的 VOI 大小和不同的采集次数所获得的谱线全部相同或相似。~1H-MRS 采集时间与 VOI 大小无关,128次和256次采集时间分别为199 s 和391 s。结论采用1 cm×1 cm×1 cm 大小的 VOI 和128次采集股骨骨髓。~1H-MRS 具有临床可行性,采集时间较短,图像质量高而且重复性良好,具有较强的临床实用性。

Objective To choose proper proton magnetic resonance spectroscopy （1H-MRS） parameters to fit for practical femoral marrow cavity and to produce short-timed, well-repeated and excellent 1H-MRS images. Methods The tentative study of 1H-MRS on the normal femoral bone marrow in 26 volunteers was performed with a 1.5 T MR after the informed consent. The single-voxel spectroscopy and stimulated echo acquisition mode were used for 1H-MRS collection. 1H-MRS parameters for 12 volunteers were 128 acquisitions, 1 cm × 1 cm × 1 cm volume of interest （VOI） size and repeatedly 2--3 times within the same location. 1H-MRS parameters for another 14 volunteers were different numbers of acquisition （128 and 256 times, respectively） and different VOI sizes （2 cm ×2 cm ×2 cm and 1 cm × 1 cm × 1 cm, respectively）. Results For 1H_MRS with 1 cm × 1 cm × 1 cm size of VOI and 128 times of acquisition with the full width half max of water ×〈 8--12 Hz, the base-line was steady and the signal-noise ratio was high up to 11.31. ^1 H-MRS was different in the different femoral locations showing the maximum peak sites at near 0. 90 ppm（ × 10 -6 ） or 1.65 ppm, but ^1H-MRS within the same location was always same or similar with different VOI sizes （ 1 cm × 1 cm × 1 cm or 2 cm ×2 cm ×2 cm） or different numbers of acquisition（ 128 or 256 times）. 1H-MRS acquisition time was not related with the size of VOI but with the numbers of acquisition. 128 and 256 times of acquisition cost 199 s and 391 s, respectively. Conclusion With the technique of small size of VOI （ 1 cm × 1 cm × 1 cm） and decreased numbers of acquisition （ 128 times）, it is propable to get well-repeated and excellent 1 H-MRS within less time. It is also more practical for clinics to achieve 1 H-MRS of the femoral marrow with the proper technique.