耳鸣相关脑区的正电子发射断层成像

目的 探讨与耳鸣相关的脑区并观察听力损失、耳鸣侧别、优势半球等因素的影响。方法 用正电子发射断层成像（ｐｏｓｉｔｒｏｎ ｅｍｉｓｓｉｏｎ ｔｏｍｏｇｒａｐｈ,ＰＥＴ）研究１７例耳鸣患者的脑葡萄糖代谢活动,并与１５例无耳鸣者作对照。示踪剂为＾１８Ｆ标记的去氧葡萄糖。按有无听力损失将所有受试都分为４组,第１组耳鸣伴听力损失,１３例;第２组耳鸣但听力正常,４例;第３组无耳鸣有听力损失,２例;第４组无耳鸣且听力正常,１３例。用专门统计分析软件Ｓｔａｔｉｓｔｉｃａｌ ｐａｒａｍｅｔｅｒｓ ｍａｐｐｉｎｇ（ＳＰＭ）进行发析,按照Ｔａｌａｉｒａｃｈ坐标确定与耳鸣相关脑区的解剖部位（ｂｒｏｄｍａｎｎ ａｒｅａ,ＢＡ）结果 耳鸣相关脑区位于左侧颞横回（ＢＡ４１）、左侧颞上回（ＢＡ４２、２２）、左侧颞中回前部（ＢＡ３８）和左侧海马     

正电子发射计算机断层-CT融合显像在头颈肿瘤中的诊断价值

目的　探讨18氟 脱氧葡萄糖 (18 fluorinefluorodeoxyglucose ,18F FDG)正电子发射计算机断层显像 (positronemissiontomography ,PET) CT融合显像在头颈肿瘤的原发灶诊断、复发的检测和诊断分析未知原发肿瘤转移癌中的诊断价值。方法　 2 7例已确诊头颈部原发肿瘤或转移癌 ,进行18F FDGPET CT全身显像 ,并与临床资料对照。结果　鼻咽癌组治疗前 4例PET CT均查出原发灶 ,其中 2例确诊有颈淋巴结转移 ,与病理检查结果一致。鼻咽癌放疗后 12例中 4例PET CT检查鼻咽部及颈部淋巴结均为阴性表现 ,符合临床和病理诊断 ;2例放疗后原发灶复发经病理检查证实 ,其中 1例查出颈部淋巴结及全身多处转移经随访证实 ;6例鼻咽原发灶PET CT检查阴性表现 ,但 4例颈部显示淋巴结转移经病理检查证实 ,2例肺部、纵隔等有转移灶未经病理检查证实。未知原发肿瘤颈淋巴转移组4例患者PET CT均检出原发灶 ,3例病理检查证实 ,另 1例未经病理检查证实。其他头颈肿瘤组 7例治疗后患者中 ,2例患者无复发转移表现 ,5例不同部位肿瘤检出原发部位复发或颈淋巴结转移 ,有 4例经病理检查证实 ,1例放弃治疗未经病理检查证实。结论　18F FDGPET CT将PET提供的肿瘤代谢图像和CT提供的解剖图像结合 ,对头颈原发肿瘤诊断 ,检测治疗后肿瘤复发     

正电子发射计算机断层和CT融合显像诊断颈淋巴结转移癌

目的探讨18F-脱氧葡萄糖(18-Fluorine Fluorodeoxyglucose,FDG)正电子发射计算机断层显像(Positron Emission Tomography,PET)-CT融合显像在颈淋巴结转移癌中的诊断价值。方法17例颈部肿块病人,CT或MRI发现可疑病变28处,其中鼻咽癌放射治疗后6例,肺癌治疗后3例,甲状腺癌手术后3例,下咽癌放疗后1例,不明原发灶4例,行全身或颈部PET-CT检查,其结果与临床病理报告对照。结果17例患者,共28处PET-CT显像阳性20例,阴性8例;对照病理结果,假阳性1例,假阴性1例,18F-FDGPET-CT诊断颈淋巴结转移癌的灵敏度、特异性、准确度分别为95.0%,87.5%,92.9%。结论18F-FDGPET-CT结合PET提供肿瘤代谢图像,CT提供解剖图像,在颈淋巴结转移癌的诊断及监测复发方面具有较大的临床价值。     

听力损害时脑皮层的正电子发射断层成像

目的 探讨听力损失对脑葡萄糖代谢活动的影响。方法 对12例有听力损失但无耳鸣患者进行正电子发射断层成像(PET)研究,其中2例双耳全聋,10例双耳中度聋。分别在静息(视听封闭)和声刺激(2kHz短纯音130dBSPL)条件下进行PET成像。与13例听力正常者在静息条件下和4例听力正常者在声刺激条件下的PET作对照。PET示踪剂为~(18)F标记的去氧葡萄糖(~(18)F-FDG)。用专门统计分析软件(SPM)以及感兴趣区技术(ROI)进行统计分析。结果 2例全聋患者的听皮层葡萄糖代谢活动显著低于正常人(P<0.001),而视皮层及体感皮层的代谢活动显著高于正常人(P<0.001)。另10例听力下降患者的听皮层代谢活动低于正常人(P<0.05),声刺激后听皮层兴奋区域显著大于正常人(P<0.001)。提示听力下降引起听皮层神经元葡萄糖代谢活动的相应下降,但与听力下降相邻频率的声刺激却引起相应听皮层的代谢活动的显著增加,而且兴奋区域扩大。表明听皮层发生了功能重组。全聋患者的结果提示,视觉功能显著增强了,这是系统间功能重组的重要证据。结论 PET作为新型脑功能成像仪器,为研究听觉与脑功能提供了新方法,为听系功能重组和中枢神经系统的可塑性提供了有力证据。     

脱氧葡萄糖-正电子发射断层显像在鼻咽癌放疗后鼻咽颅底病变的诊断效果研究

目的探讨脱氧葡萄糖-正电子发射断层显像（F-18-fluoro-2-deoxyglucose positron emission tomography，FDG-PET）在鼻咽癌放疗后鼻咽颅底病变中的诊断价值。方法通过9例行FDG-PET、CT和（或）MRI检查，以及内镜下鼻咽颅底病灶探查活检术的鼻咽癌放疗后患者，比较FDG-PET、CT和（或）MRI与病理活检结果。结果9例鼻咽癌放疗后患者中CT和（或）MRI提示枕骨斜坡复发7例，可疑复发2例；FDG-PET鼻咽颅底有浓聚灶9例；病理确诊复发3例，慢性炎症和（或）骨组织部分坏死6例。PDG—PET诊断准确率是33．3％（3／9），假阳性率为66．7％（6／9）。结论FDG-PET对鼻咽癌放疗后鼻咽颅底病变诊断有一定假阳性率，确诊需根据内镜下的病理诊断。     

脱氧葡萄糖-正电子发射计算机断层显像对颈淋巴结转移癌的诊断价值

目的：探讨脱氧葡萄糖-正电子发射计算机断层[^18F-FDG-PET／CT（PET／CT）]融合显像对颈淋巴结转移癌的诊断价值。方法：对照颈淋巴结清扫术后病理结果,回顾性对比分析20例头颈癌患者颈部正电子发射断层（PET）、CT及PET／CT资料。结果：PET对颈淋巴结转移癌的诊断敏感性、特异性及准确度分别为92.3％、85.7％、90.0％,CT分别为77.0％、57.1％、70.0％,PET／CT分别为92.3％、100.0％、95.0％,PET／CT的诊断准确度显著高于CT（P〈0．05）、略优于PET。13例鼻咽癌放疗后患者,CT诊断正确7例,PET／CT诊断正确12例。7例N。患者颈淋巴结清扫术后病理证实4例存在颈淋巴结转移,术前PET／CT均诊断正确。结论：PET／CT融合显像对颈淋巴结转移癌的诊断价值优于单独的PET及CT,尤其对于治疗后的患者,其诊断优势更加突出,有望作为是否需行颈淋巴结清扫术的指征。     

正电子发射断层显像用于耳鸣的研究概况

耳鸣(tinnitus)是指在周围环境中无相应声源或电刺激存在的情况下,患者自觉耳内或颅内有声音的一种主观症状;常伴或不伴有听力下降、睡眠障碍、心烦、恼怒、注意力无法集中、焦虑、抑郁等不良心理反应.现今针对患者耳鸣属性进行的检查方法多为耳鸣的响度、音调的匹配、耳鸣掩蔽以及残余抑制检查,抑或针对耳鸣病因进行的相应检查,如内耳道部位的CT/MRI等扫描检查等,但都较难全面客观地评价耳鸣.     

正电子发射断层显像与单光子发射断层显像在耳鸣诊断中的比较

目的　探讨正电子与单光子发射断层显像在耳鸣诊断中的差异。方法　选取主诉耳鸣患者200例,将其分为正电子组和单光子组各100例,分别采用正电子发 射断层显像和单光子发射断层显像进行客观诊断,客观诊断的标准为苯二氮受体数量的减少程度;同时采用视觉模拟标尺法和耳鸣问卷调查法进行主观诊断,主观诊断以THI评分作为耳鸣严重程度的判断标准,比较两组患者的客观诊断差异。结果　正电子组患者客观诊断有效率为87.0%,单光子组患者客观诊断有效率为69.0%,两组患者的诊断差异具有非常显著性的意义（P＜0.01）。两组患者的耳鸣主观评价差异无统计学意义（P＞0.05）。结论　采用正电子发射断层显像进行耳鸣的客观诊断效果优于单光子发射断层显像,在临床中能够更加具体的显示患者耳鸣程度。     

正电子发射断层显像在听觉研究中的应用

正电子发射断层显像（Ｐｏｓｉｔｒｏｎ　ｅｍｉｓｓｉｏｎ　ｔｏｍｏｇｒａｐｈｙ、ＰＥＴ）是一种能给出放射性核素在体内分布图像的显像技术。正电子发射核素是人体天然组成元素的同位素,在体内局部的浓度直接反映生化状况;疾病发展的过程是生化和生理的改变在先,形态结构的异常变化在后,因此,对疾病的早期诊断、分期、灵敏地观察疾病的发展以及决定治疗方案和预后评估都极有价值［１］。９０年代初,ＰＥＴ对听觉的研究刚刚起步,报道不多。本文就近几年国外文献报道,综述ＰＥＴ在听觉领域的应用现状。１ＰＥＴ的原理正电子是电子…     

正电子发射断层摄影术在头颈部恶性肿瘤诊断中的应用

目的 :探讨18F FDG正电子发射断层摄影术 (PET)在头颈部恶性肿瘤诊断中的价值。方法 :回顾性分析应用18F FDGPET检查的 75例头颈部肿瘤患者 (鼻咽癌 36例 ,食管癌 18例 ,甲状腺癌 13例 ,喉癌 6例 ,下咽癌 2例 )的临床资料 ,其18F FDGPET显像结果与病理结果进行比较 ,部分与CT、MRI比较。结果 :18F FDGPET显像结果与病理结果相符率极高 ,鼻咽癌的灵敏度为 91.30 % ,特异度为 76 .92 % ,准确率为 86 .11% ;食管癌的灵敏度为 10 0 .0 0 % ,特异度为 83.33% ,准确率为 94 .4 4 % ;甲状腺癌、喉癌和下咽癌的灵敏度、特异度及准确率均为 10 0 %。结论 :18F FDGPET在头颈部恶性肿瘤的诊断中具有明显的优势。     

Positron emission tomography of tinnitus-related brain areas]

OBJECTIVE: To map the tinnitus specific central activity and foci site in brain and to investigate the effects of hearing loss, tinnitus side, right or left handed on foci site. METHODS: Glucose metabolic activity of brain was studied with positron emission tomography (PET) using 18F-FDG as radiotracer. Seventeen patients with severe tinnitus and fifteen control subjects participated in this study. All subjects were fell into four groups according to their hearing levels. There were 13 tinnitus patients with hearing loss in Group one, 4 tinnitus patients without hearing loss in Group two, 2 control subjects with hearing loss in Group three and 13 control subjects without hearing loss in Group four. Statistical parameters mapping (SPM) was used to analyze the PET data and to determine the Brodmann area (BA) according to Talairach coordinate system. RESULTS: Increase of neuronal activity caused by tinnitus occurred predominately in the left hemisphere with significant foci in the transverse temporal gyrus (BA41), superior temporal gyrus (BA42, 22), anterior middle temporal gyrus (BA38) and hippocampus. Bilateral hemispheres were concerned with the neuronal activity caused by hearing loss while foci site were located at the posterior superior temporal gyrus(BA42,22), medial portion of middle temporal gyrus(BA21), combined auditory area(BA39). Left middle frontal gyrus (BA8, 9) as well as left inferior frontal gyrus(BA45) were also link up with hearing loss. CONCLUSION: As a new path in research, PET has provided an objective evidence for tinnitus and may be used as a potential tool in objectively measuring tinnitus. Tinnitus-related brain areas and their influence factors were discussed.     

Positron emission tomography in cochlear implant and auditory brain stem implant recipients.

OBJECTIVE: The purpose of this study was to determine whether similar cortical regions are activated by speech signals in profoundly deaf patients who have received a multichannel cochlear implant (CI) or auditory brain stem implant (ABI) as in normal-hearing subjects. STUDY DESIGN: Positron emission tomography (PET) studies were performed using a variety of discrete stimulus conditions. Images obtained were superimposed on standard anatomic magnetic resonance imaging (MRI) for the CI subjects. The PET images were superimposed on the ABI subject's own MRI. SETTING: Academic, tertiary referral center. PATIENTS: Five subjects who have received a multichannel CI and one who had received an ABI. INTERVENTION: Multichannel CI and ABI. MAIN OUTCOME MEASURE: PET images. RESULTS: Similar cortical regions are activated by speech stimuli in subjects who have received an auditory prosthesis. CONCLUSIONS: Neuroimaging provides a new approach to the study of speech processing in CI and ABI subjects.     

耳鸣患者听觉皮质BOLD-fMRI研究

目的 利用血氧水平依赖（blood oxygenation leve ldependent,BOLD）功能磁共振成像（functional magnetic resonance imaging）（BOLD—fMRI）技术观察耳呜患者纯音刺激时大脑皮质区激活情况,探讨耳呜的客观检查方法。方法对7例长期耳呜患者行BOLD—fMRI检查,观察其大脑皮质区激活信号,15例健康人作为对照组。结果15例健康志愿者纯音刺激时颞叶区均出现激活,颞上回激活率最高。刺激单耳时对侧听觉皮质激活体积和信号强度明显大于同侧（P〈0．01）,表现为对侧半球传导优势。耳鸣组纯音刺激时大脑皮质激活解剖部位、激活体积和信号强度无明显规律。结论长期耳呜患者可能存在听觉皮质的异常神经活动。     

BOLD-fMRI study of auditory cortex in patients with tinnitus

Objective Blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI)was used to study activation signals in the brain cortex evoked by tone stimulation in patients with tinnitus for its potential utility as an objective indicator of tinnitus. Methods BOLD-fMRI examination was conducted in 7 patients with chronic tinnitus and 15 control subjects. The activation signal in the brain cortex was recorded. Results Significant activation was found in temporal lobe in control subjects, with greater signal volume and intensity on the contralateral than ipsilateral auditory cortex (P＜0.01). However, there was no discernable patterns in the anatomical location, volume and intensity of cortical activation signals in patients with chronic tinnitus. Conclusions Patients with chronic tinnitus may have abnormal neural activities in the auditory cortex.     

Sodium salicylate suppresses serotonin-induced enhancement of GABAergic spontaneous inhibitory postsynaptic currents in rat inferior colliculus in vitro

Available evidence suggests that sodium salicylate (SS) may produce tinnitus through altering the balance between inhibition and excitation in the central auditory system. Since serotonin (5-hydroxytryptamine, 5-HT) containing fibers preferentially innervate inhibitory GABA neurons, there exists a possibility that SS causes the imbalance between inhibition and excitation through influencing serotonergic modulation of the GABAergic synaptic transmission. In the present study, we examined the effects of SS on 5-HT-mediated GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) from neurons of the central nucleus of rat inferior colliculus with whole-cell patch-clamp technique and brain slice preparation. Perfusion of 40 microM 5-HT robustly enhanced both frequency and amplitude of GABAergic sIPSCs and this 5-HT-induced enhancement of GABAergic sIPSCs could be suppressed by 1.4mM SS. Tetrodotoxin at 0.5 microM produced a similar effect as SS did, suggesting that SS suppresses the 5-HT-induced enhancement of GABAergic sIPSCs through depressing spontaneous action potentials of GABA neurons. Our findings suggest that SS may preferentially target GABA neurons and consequently interrupt a normal level of GABAergic synaptic transmissions maintained by the serotonergic system in SS-induced tinnitus.     

Acoustic trauma-induced auditory cortex enhancement and tinnitus

There is growing evidence suggests that noise-induced cochlear damage may lead to hyperexcitability in the central auditory system (CAS) which may give rise to tinnitus. However, the correlation between the onset of the neurophysiological changes in the CAS and the onset of tinnitus has not been well studied. To investigate this relationship, chronic electrodes were implanted into the auditory cortex (AC) and sound evoked activities were measured from awake rats before and after noise exposure. The auditory brainstem response (ABR) was used to assess the degree of noise-induced hearing loss. Tinnitus was evaluated by measuring gap-induced prepulse inhibition (gap-PPI). Rats were exposed monaurally to a high-intensity narrowband noise centered at 12 kHz at a level of 120 dB SPL for 1 h. After the noise exposure, all the rats developed either permanent (>2 weeks) or temporary (<3 days) hearing loss in the exposed ear(s). The AC amplitudes increased significantly 4 h after the noise exposure. Most of the exposed rats also showed decreased gap-PPI. The post-exposure AC enhancement showed a positive correlation with the amount of hearing loss. The onset of tinnitus-like behavior was happened after the onset of AC enhancement.     

Positron emission tomography of cortical centers of tinnitus.

Tinnitus is associated with a wide variety of disorders in the auditory system. Whether generated peripherally or centrally, tinnitus is believed to be associated with activity in specific cortical regions. The present study tested the hypothesis that these cortical centers subserve the generation, perception and processing of the tinnitus stimulus and that these processes are suppressed by lidocaine and masking. Positron emission tomography was used to map the tinnitus-specific central activity. By subtracting positron emission tomography images of regional cerebral blood flow distribution obtained during suppression of the tinnitus from positron emission tomography images obtained during the habitual tinnitus sensation, we were able to identify brain areas concerned with the cerebral representation of tinnitus. Increased neuronal activity caused by tinnitus occurred predominantly in the right hemisphere with significant foci in the middle frontal and middle temporal gyri, in addition to lateral and mesial posterior sites. The results are consistent with the hypothesis that the sensation of tinnitus is associated with activity in cortical regions functionally linked to subserve attention, emotion and memory. For the first time, the functional anatomy of conditions with and without the habitual tinnitus sensation was obtained and compared in the same subjects.