质子磁共振波谱用于鉴别颅内病变良恶性和肿瘤恶性程度初探

Preliminary Study of Proton MR Spectroscopy in Distinguishing Benign fromMalignant Intracranial Lesions and Predicting the Malignancy of Tumors

目的 检验质子磁共振波谱是否可用于鉴别颅内病变良恶性和肿瘤的恶性程度。资料与方法 共有2 8例颅内病变患者接受了单体素质子磁共振波谱成像检查。根据手术、病理或临床检查结果,将2 8枚病灶分为良性病变、低度和高度恶性肿瘤3组。单体素质子磁共振波谱的体素位置主要选择病灶的实质部分测定,大小为2～8cm3 。计算各病灶的胆碱(Cho) /氮乙酰天门冬氨酸(NAA)和Cho/肌酸(Cr)的代谢物比值,并与病理分组相对应,以这两个比值为坐标绘制2 8枚病灶的散点图,记录各组病灶波谱上有无脂质和乳酸波峰。结果 低度恶性肿瘤的Cho/NAA明显高于良性病变(P <0 .0 0 1) ,且两组数据无重叠。高度恶性肿瘤的Cho/NAA明显高于低度恶性者(P <0 .0 0 1) ,两者重叠很少。低度恶性肿瘤的Cho/Cr高于良性病变(P <0 .0 5 ) ,两组数据略重叠。高度恶性肿瘤的Cho/Cr高于低度恶性者,但两者重叠明显,其差别经检验无统计学意义(P >0 .0 5 )。部分肿瘤实质部分显示脂质和乳酸波峰,但良性病变未见该改变。结论 单体素质子磁共振波谱技术可用于鉴别颅内病变的良恶性,并在多数情况下鉴别肿瘤恶性程度。

Objective To test whether or not proton MR spectroscopy can be used to distinguish benign from malignant intracranial lesions and predict the malignancy of tumors.Materials and Methods A total of 28 patients with intracranial lesions were performed with single voxel proton MR spectroscopy. According to the histopathology and clinical findings, these lesions were classified into 3 groups, which were benign lesion, low grade and high grade malignancy. The single voxel proton MR spectroscopy was obtained with a voxel size of 2 to 8 cm 3 and positioned mainly on solid part of the lesions. The metabolite ratios of Cho/NAA and Cho/Cr were quantitated and correlated with different histopathologic groups. Scatter spot graph was made to show the distribution of metabolite ratios of these lesions. The presence of lipid and lactate peaks were also noted.Results The Cho/NAA in low grade malignancy was significantly higher than that in benign lesion (P<0.001), with no overlap between the two groups on the graph. Levels of Cho/NAA were also significantly elevated in high grade malignancy compared to low grade group (P<0.001), with very small overlap on the graph. Low grade malignancy group had higher Cho/Cr than that in benign group (P<0.05), although some overlap were existed. High grade malignancy was associated with higher Cho/Cr than its low grade counterpart, but due to the substantial overlap, the difference between them was not statistically significant (P>0.05). Lipid and lactate spectra were observed in some malignancies, but not in any benign lesions.Conclusion The results of this preliminary study indicate that proton MR spectroscopy is capable of differentiating benign from malignant intracranial lesions and predicting the extent of malignancy in most cases.