儿童毛细胞型星形细胞瘤的质子磁共振波谱特征
Proton MR spectroscopic characteristics of pediatric pilocytic astrocytomas.
作者信息
Hwang J H, Egnaczyk G F, Ballard E, Dunn R S, Holland S K, Ball W S
机构信息
Imaging Research Center, Department of Radiology, Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
出版信息
AJNR Am J Neuroradiol. 1998 Mar;19(3):535-40.
PURPOSE
We report the common characteristics of juvenile pilocytic astrocytomas revealed by proton MR spectroscopy.
METHODS
Eight children with pilocytic astrocytomas were studied with proton MR spectroscopy. The selected sampling volume was approximately 4 cm3, obtained from solid tumor. To localize the sampling volume, we used point-resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) techniques to acquire long- and short-TE spectra, respectively. Spectra from PRESS and STEAM sequences were processed using Lorentzian-to-Gaussian transformation and exponential apodization, respectively. For PRESS (2000/270) spectra, peaks of creatine, choline, N-acetylaspartate (NAA), and lactate resonances were integrated; for STEAM (2000/20) spectra, we measured the amplitude of the peaks at 3.2, 2.0, 1.3 and 0.9 ppm.
RESULTS
An elevated lactate doublet was observed in the PRESS spectra. The choline/NAA ratio was 3.40. The amplitude ratios of the lipid pattern (0.9, 1.3 and 2.0 ppm) to choline were all below one.
CONCLUSION
Despite the benign histology of the tumor, which generally lacks necrosis, a lactate signal was detected in all eight patients studied. A dominant lipid pattern was not observed.
目的
我们报告质子磁共振波谱揭示的青少年毛细胞型星形细胞瘤的共同特征。
方法
对8例毛细胞型星形细胞瘤患儿进行质子磁共振波谱研究。选定的采样体积约为4 cm³，取自实体瘤。为了定位采样体积，我们分别使用点分辨波谱（PRESS）和激励回波采集模式（STEAM）技术获取长回波时间和短回波时间的波谱。PRESS和STEAM序列的波谱分别使用洛伦兹到高斯变换和指数变迹法进行处理。对于PRESS（2000/270）波谱，对肌酸、胆碱、N-乙酰天门冬氨酸（NAA）和乳酸共振峰进行积分；对于STEAM（2000/20）波谱，我们测量了3.2、2.0、1.3和0.9 ppm处峰的幅度。
结果
在PRESS波谱中观察到乳酸双峰升高。胆碱/NAA比值为3.40。脂质模式（0.9、1.3和2.0 ppm）与胆碱的幅度比均低于1。
结论
尽管肿瘤组织学表现为良性，通常无坏死，但在所有8例研究患者中均检测到乳酸信号。未观察到占主导地位的脂质模式。
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