耳鸣患者左侧听皮层局部葡萄糖代谢增加:正电子发射断层成像的初步研究(英文)

Regional glucose metabolic increases in left auditory cortex in tinnitus patie nts: a preliminary study with positron emission tomography

目的 观察耳鸣患者听皮层葡萄糖代谢活动与耳鸣的关系 ,探讨耳鸣的客观检测方法。方法 用正电子发射断层成像 (PET)研究 11例耳鸣患者的听皮层代谢活动 ,放射性示踪剂为18F标记的去氧葡萄糖 (18F FDG) ,10例无耳鸣者作为对照组。用感兴趣区技术 (ROI)分析左右侧听皮层放射性分布的不对称指数 { (L-R) /[(L +R) /2 ]}。结果 耳鸣组的左、右侧听皮层代谢明显不对称 ,左侧显著高于右侧 ,而且与耳鸣的侧别无关。对照组的左右侧基本对称。比较二组的不对称指数 ,差异具有极显著性意义 (t检验 ,P <0 .0 0 1)。结论 左侧听皮层高代谢活动与耳鸣有关 ,PET可为主观耳鸣提供客观证据 ,有望成为耳鸣的客观测试方法。国外多数用15O -水作示踪剂 ,进行大脑的激活实验。仅我们和Arnold用FDG进行研究。各学者报告的结果不尽相同 ,尤其对左右半球与耳鸣的相关性存在争议 ,需要进一步研究。

Objective To investigate the relationship between tinnitus and glucose metabolism in auditory cortex and whether positron emission tomography (PET) can be an objective tool in measuring tinnitus.Methods Eleven right-handed patients with severe tinnitus and ten right-handed control subjects participated in the 18 F-FDG/PET study. Analysis with regions of interests was used to calculate asymmetry indices according to the formula: ［(L-R)×100/［(L+R)÷2］］.Results Glucose metabolism in the auditory cortex of tinnitus patients was asymmetric between the left and right auditory cortices, with that of the left being much higher than that of the right. The asymmetry indices of tinnitus patients was significantly higher than that of the control group (unpaired t test, P<0.001). This revealed that the increased metabolic activity was present in the predominant left hemisphere with a significant focus on the superior and transverse temporal gyri (Brodmann areas 41 and 42, respectively corresponding to primary and secondary auditory cortex), and the results were independent of the subjective localization of the tinnitus sensation.Conclusion It is suggested that the increased metabolism in the left auditory cortex is related to the tinnitus sensation. PET is capable of providing objective evidence for tinnitus and may be used as a potential tool in measuring tinnitus.