Chumas P, Condon B, Oluoch-Olunya D, Griffiths S, Hadley D, Teasdale G
Department of Neurosurgery, Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland.
J Neurol Neurosurg Psychiatry. 1997 Jun;62(6):590-5. doi: 10.1136/jnnp.62.6.590.
To study the mechanism of action of steroids in patients with peritumorous oedema.
To investigate early cerebral metabolic changes proton magnetic resonance spectroscopy (1H-MRS) was used before and 11 to 14 hours after treatment with dexamethasone (12 mg oral loading and 4 mg four times daily maintenance). Nine patients (two men, seven women, mean age 54) with pronounced oedema associated with various intracranial tumours (two astrocytomas, three meningiomas, two glioblastoma, and two metastases) were examined using MRI and MRS. SE1500/135 volume selected MRS (mean volume 21 ml) were performed on an oedematous region and a contralateral region. All spectra were acquired with and without water suppression. Metabolite peak area ratios were determined.
Regions of oedema had significantly (P < 0.01) higher unsuppressed water than the contralateral regions, as expected. There was no change at this early time point after dexamethasone. The ratio of the area of choline containing compounds to that creatine and phosphocreatine compounds was determined after which the serial ratios of these before and after were calculated (a serial ratio of 1.0 would indicate no change in the choline to creatine ratios after steroid administration). The mean serial ratios for the area of oedema were 1.02 (SEM 0.08) and 1.10 (0.08) for the contralateral volume of interest, indicating no significant changes. However, significant changes (P < 0.02) were found in the N-acetyl-aspartate (NAA)/choline serial ratios (0.86 (0.06) in the area of oedema, 1.20 (0.10) in contralateral brain) and the NAA/creatine serial ratios (0.86 (0.08) for the oedema, 1.25 (0.11) in contralateral brain).
Such rapid changes may be explained either by relatively large alterations in the relaxation characteristics of NAA or, more controversially, by actual changes in the amounts of NAA. It is proposed that steroids act primarily by causing early metabolic changes that are later expressed in improvements in intracranial volume relations.
研究类固醇对瘤周水肿患者的作用机制。
为研究早期脑代谢变化，在使用地塞米松治疗前及治疗后11至14小时（口服负荷剂量12mg，维持剂量4mg，每日4次）采用质子磁共振波谱（1H-MRS）进行检测。对9例（2例男性，7例女性，平均年龄54岁）伴有明显水肿的各种颅内肿瘤（2例星形细胞瘤、3例脑膜瘤、2例胶质母细胞瘤和2例转移瘤）患者进行了MRI和MRS检查。在水肿区域和对侧区域进行SE1500/135体积选择波谱（平均体积21ml）检测。所有波谱均在有水抑制和无水抑制的情况下采集。测定代谢物峰面积比。
正如预期，水肿区域未抑制水含量显著高于对侧区域（P<(0.01)）。地塞米松治疗后这个早期时间点没有变化。测定含胆碱化合物与肌酸和磷酸肌酸化合物的面积比，并计算这些比值在给药前后的系列比值（系列比值为1.0表示类固醇给药后胆碱与肌酸比值无变化）。水肿区域的平均系列比值为1.02（标准误0.08），对侧感兴趣体积的平均系列比值为1.10（0.08），表明无显著变化。然而，在N-乙酰天门冬氨酸（NAA）/胆碱系列比值（水肿区域为0.86（0.06），对侧脑区为1.20（0.10））和NAA/肌酸系列比值（水肿区域为0.86（0.08），对侧脑区为1.25（0.11））中发现了显著变化（P<(0.02)）。
如此迅速的变化可能是由于NAA弛豫特性的相对较大改变所致，或者更具争议的是，是由于NAA含量的实际变化所致。有人提出，类固醇的主要作用是引起早期代谢变化，这些变化随后表现为颅内体积关系的改善。
