民航外籍飞行员听力的调查

目的 初步调查中国民航外籍飞行员的听力状况并分析其特点. 方法 收集分析2007-2010年持有中国民航Ⅰ级体检合格证的外籍飞行员的纯音听阈测试数据,共计776例,1552耳.按不同年龄分为4组:A组(20～29岁)、B组(30～39岁)、C组(40～49岁)、D组(50～59岁),按不同测试音频率进行统计分析. 结果 民航外籍飞行员语频及高频听力损失患病率随年龄的增长而升高;语频听力损失发生率为4.38％(34例);高频听力损失发生率为19.59％(152例),其中6000 Hz处阈移程度最显著;3000 Hz处阈移发生的时间及幅度介于高频听阈与语频听阈之间;在40岁之后纯音听阈的阈移幅度逐渐增大且向3000 Hz处扩展累及(P'＜0.017). 结论 民航外籍飞行员高频听阈损失较严重,尤以6000 Hz听阈为甚;3000 Hz纯音听阈变化可能对语频听阈阈移具有一定的早期提示作用;40岁之后听力损失的发展进程加剧,听力防护应及早开展.     

招收飞行学员听力检查标准的研究

目的 通过分析招收飞行学员的纯音听阈及文献复习,提出新的招收飞行学员听力检查标准.方法 对2666名青年学生按空军统一听力检查方法进行纯音测听检查,测听频率为250～8000 Hz,分析其80%、90%、95%、99%百分位值.查阅外军飞行员选拔听力检查标准,与我军听力检查标准进行对比.结果 在第1次检查的2584耳中,80%的学生高频听力在正常范围.6000 Hz听力损失的程度和比率较高,90%分位值为30 dB,95%分位值为35 dB,99%分位值为55 dB;其次是4000 Hz和8000 Hz,95%分位值为25 dB,99%分位值为40 dB.在第2次检查的2748耳中,也有80%的学生高频听力在正常范围.6000 Hz和8000 Hz处听力损失的程度和比率较高,95%分位值为30 dB,99%分位值是45 dB;其次是4000 Hz,99%分位值是40 dB.结论 建议我军招收飞行学员听力检查标准,500～2000 Hz小于25 dB,3000 Hz、4000 Hz和6000 Hz平均听阈不超过40 dB;将低频250 Hz和高频8000 Hz两个频率去除. Abstract： Objective To raise new hearing examination standard for the selection of flying cadets by analyzing the pure tone threshold of audibility and reviewing related literatures.Methods Two thousand six hundred and sixty-six flying cadet candidates were tested by Audiomer.Testing frequencies were from 250 to 8000 Hz.Percentiles of 80%, 90%, 95% and 99% were analyzed.In literature review foreign military hearing examination standards were compared with China's.Results Hearing threshold of 80% candidates was normal in the first test of 2584 ears.Obvious audibility loss and high ratio were found at 6000 Hz and were respectively 30 dB, 35 dB and 55 dB corresponding to the percentiles of 90%, 95% and 99%.2748 ears were examined in second test and 80% of them showed normal value in high frequency range.6000 Hz and 8000 Hz were the frequencies where obvious audibility loss and high ratio of amblyacusia appeared, that was 30 dB loss for 95%percentile and 35 dB for 99 % respectively.Then 40 dB loss for 99 % percentile was got at 4000 Hz.Conclusions It is suggested that hearing standard for the selection of flying cadet should be revised and the tests at 250 Hz and 8000 Hz could be cancelled.New hearing exam standard could be suggested as less than 25 dB loss for 500-2000 Hz tests and the average hearing threshold couldn't exceed 40 dB corresponding to the tests at 3000 Hz, 4000 Hz and 6000 Hz.     

20～30岁民航飞行员畸变产物耳声发射特征分析

目的 分析20～30岁民航飞行员畸变产物耳声发射(distortion product otoacoustic emission,DPOAE)特征,探讨DPOAE对于早期发现民航飞行员噪声性听力损失的价值.方法 以39例20～30岁民航飞行员为飞行员组,31例耳科正常人为对照组,分别进行纯音测听和DPOAE测试.依据纯音测听结果,飞行员组分为飞行员A组(各频率纯音听阈均≤20 dB HL),飞行员B组(任何单一频率纯音听阈＞20 dB HL).分析比较飞行员各组与对照组纯音听阈、DPOAE结果.结果 ①飞行员组和飞行员B组纯音听阈较对照组显著升高(P＜0.05或P＜0.01),飞行员A组纯音听阈较对照组无显著差异;②飞行员各组DPOAE幅值较对照组均有明显下降(P＜0.05或P＜0.01);③DPOAE与纯音测听在0.5、6、8 kHz有显著的负相关,其他频率无明显相关性.结论 DPOAE有助于民航飞行员噪声性听力损失的早期发现,可以作为纯音测听的补充,但不能完全替代纯音测听.     

畸变产物耳声发射在飞行员早期听力损失诊断中的应用

目的 了解噪声对飞行员畸变产物耳声发射的影响,以便及早发现听力损失,为空军卫生勤务保障提供参考.方法 采用纯音听力计和耳声发射测试仪,对30名低年龄段飞行员、7名高年龄段飞行员及30名健康青年分别进行纯音听阈和畸变产物耳声发射检查.结果 飞行员听力损失主要在3 ～8 kHz,可以出现单耳高频听力损失.随着年龄增加,逐渐出现双耳高频听力损失.低年龄段飞行员和健康青年两组受试者0.5～8 kHz平均纯音听阈差异无统计学意义.低年龄段飞行员1 kHz和6 kHz畸变产物耳声发射幅值低于健康青年,两组差异具有统计学意义（t=2.11,P＜0.05;t =2.41,P＜0.05）.低年龄段飞行人员2、3、4、8 kHz畸变产物耳声发射幅值与健康青年类似,两组差异无统计学意义.低年龄段军事飞行员高频纯音听阈异常率（13.3％）和健康青年（6.7％）的差别无统计学意义.低年龄段飞行人员高频畸变产物耳声发射异常率（33.3％）高于健康青年（6.7％）,两组差异具有统计学意义（x2 =5.10,P＜0.05）.结论 畸变产物耳声发射受噪声的影响较纯音听阈敏感,畸变产物耳声发射可早期发现飞行员的噪声性听力损失.     

噪声对飞行员畸变产物耳声发射的影响

目的 了解噪声对飞行员畸变产物耳声发射（DPOAE）的影响及其与纯音听阈的关系。方法 试验对象为66名飞行员（129耳）和40名健康青年（80耳）。采用GSI-16纯音听力计和GSI-60耳声发射测试仪分别测试纯音听阈和DPOAE幅值,DPOAE测试的两个刺激声强度L1=L2=70dB（SPL）,两个刺激声频率f1和f2的变化范围在500-7000Hz,f2/f1=1.2,设定取2f1-f2处共8个频率的DPOAE幅值,结果 飞行员组DPOAE幅值与健康青年组相比明显降低。特别是飞行员纯音听阈正常组DPOAE幅值较健康青年组也明显降低。DPOAE幅值的降低并不一定伴有纯音听阈正常组DPOAE幅值较健康青年组也明显降低。DPOAE幅值的降低并不一定伴有纯音听阈的提高。结论 DPOAE受噪声的影响较纯音听阈更敏感。     

歼击机噪声对人听力及工效的影响

目的 研究歼击机噪声对人听力及工效的影响.方法 ①检查103名歼击机飞行员和62名地勤人员的听力.②测试18名歼-8D飞行员在飞机噪声暴露前、噪声暴露（40 min）后0.5 h、1.5 h和15 h的听力.③用汉语话音短语作为工效学指标,测试30名受试者在3种条件下,识听56个歼击机座舱显示信息汉语话音短语的成绩.结果①103名飞行员中,50名有高频听力损失（占48.5%）,16名有语频听力损失（占15.5%）;62名地勤人员中,43名有高频听力损失（占69.4%）,13名有语频听力损失（占21.0%）.飞行员和地勤人员高频听力损失的“V”型凹陷在6000 Hz.②飞机噪声对飞行员的暂时性听阈偏移有明显作用,噪声暴露后1.5 h,飞行员的暂时性听阈偏移有恢复的趋势,噪声暴露后15 h,飞行员的暂时性听阈偏移已有很大程度的恢复,但大部分频率的听力还未恢复至噪声暴露前水平.③30名受试者在3种条件下识听56个汉语话音短语的成绩：安静环境中佩戴无源耳罩最高,模拟飞机噪声环境中佩戴无源耳罩最低,模拟飞机噪声环境中佩戴有源耳罩居中,其差异均有显著性意义（P＜0.01）.结论 歼击机噪声大,能引起飞行员和地勤人员的听力损伤,并导致工作绩效下降.     

飞行员听神经病停飞一例

患者男性，36岁，歼-7飞行员，飞行时间1530h。因听力逐渐下降两年于2002年7月14日入院。患者自觉近两年来：双耳听力下降，逐渐加重，左耳较重，并有两次短暂性视物旋转性眩晕。入院查体：双外耳、鼓膜正常，音叉检查(512Hz)示双耳感音性聋，左耳较重，无自发性眼震。纯音听阈检查：双耳上升型感=旨性聋曲线，左耳平均气导听阈为47．5dB，右耳25dB。双耳声导抗图为     

畸变产物耳声发射检查在招飞体检中的价值研究

目的:探讨畸变产物耳声发射(DPOAE)在招收飞行人员体检听力水平客观鉴定中的应用价值。方法:选择空军招收飞行人员体检中复检合格1004例,先行纯音听力及DPOAE检查,纯音听力测试取0.25～8kHz,每倍频2个测试点,按照上升法测试双耳各频率气导听阈;DPOAE测试项目为DP图。DPOAE检查未通过者再行听觉脑干诱发电位(ABR)检查,刺激声强度为97dBnHL。结果:所有复检合格人员纯音听力测定均符合相关听力检查标准;DPOAE检查未通过26例,占2.6%。26例行ABR检查,未引出脑干诱发电位1例,占3.8%。结论:在招飞体检复检合格人员中进行DPOAE检查,能够在一定程度上反映被检者的客观听力,DPOAE检查在招飞体检听力水平客观鉴定中具有可行性。     

高压氧综合治疗突发性聋60例

突发性聋是一种常见的突然发生的感音神经性耳聋。我院自1986年6月～1999年5月应用高压氧(HBO)配合药物治疗突发性聋患者60例,较常规药物治疗取得较好的效果,现报告如下。一、临床资料1.一般资料:HBO组60例(72耳),均为海洋石油作业男性职工,其中单耳发病48例,双耳12例;年龄19～62岁,平均43.4岁。听力以500,1000,2000Hz3个频率平均听力损失计算,结果为轻度聋(10～30dB)9耳,中度聋(31～60dB)28耳,重度聋(61～90dB)31耳,全聋(>90dB)4耳。对照组41例(45耳),均为海洋石油作业男性职工,单耳发病37例,双耳4例;年龄22～57岁,平均38.5岁。听力损…     

畸变产物耳声发射在船员听力调查中的应用

目的 探讨畸变产物耳声发射(DPOAE)在船员噪声性听力损伤诊断中的应用价值.方法 100名船员(其中噪声性耳聋组52人,听阈正常组48人)为实验组,另外50名听力正常人为对照组.对2组人员进行纯音听力测定和DPOAE检测,比较2组的听阈值和DPOAE幅值及引出率.结果 噪声性聋组与对照组比较,所有频区听阚值差异均有统计学意义(P<0.05),噪声性聋组DPOAE幅值和引出率较对照组明显下降(P<0.05),随着接触噪声工龄的延长,DPOAE引出率逐渐下降(P<0.05).听阈正常组DPOAE幅值和引出率也较对照组明显下降(P<0.05).结论 船员早期噪声性听力损伤纯音听阈可能正常,应用DPOAE可用于船员噪声性听力损伤的早期诊断和评估.     

Stress MR imaging for evaluation of popliteal artery entrapment

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young healthy volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

Uterine contractions: Possible diagnostic pitfall at MR imaging

A total of 206 nongravid patients with various gynecologic problems underwent pelvic magnetic resonance (MR) examinations that included both sagittal T2-weighted and contrast agent–enhanced T1-weighted images. MR images were retrospectively reviewed to identify changes in endometrial configuration on serial images obtained during the same MR examination. In 20 MR examinations (all in women of reproductive age), endometrial distortion due to myometrial bulging was noted on T2-weighted or contrast-enhanced T1-weighted images. It was absent on other MR images obtained at different times. Myometrial bulging exhibited low signal intensity in 18 examinations. The finding resembled adenomyosis or leiomyoma on T2-weighted or contrast-enhanced T1-weighted images. These results evidence the presence of transient myometrial bulging and transient low-intensity myometrium in the nongravid uterus. This phenomenon is thought to represent uterine contraction. Clinicians should be aware of the potential presence of transient low-signal-intensity myometrial bulging that could present diagnostic problems in the normal uterus.     

Controversies in cervical spine imaging in trauma patients

No area of emergency radiology has generated as much discussion in recent years as the subject of cervical spine imaging for trauma patients. This review will be in three parts. The first will examine the indications for cervical imaging and will focus on those factors that make patients at high risk or low risk for cervical injury. The second part will discuss the merits of radiography and computed tomography as the main screening diagnostic examination. In addition to the roles of each modality in the evaluation process, such factors as efficacy of diagnosis, time (duration) of study, and cost will be discussed. Finally, the third part will explore the methods currently employed to clear the cervical spine in comatose patients.Presented at the Annual Meeting of the American Society of Emergency Radiology, Las Vegas, Nevada, 22–25 October, 2003     

Brodie Abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic “target” appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypoin-tense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.     

Right-side aortic arch with aneurysm of aberrant left subclavian artery: MR imaging appearance.

Reports of aneurysms of the subclavian artery in both normal and anomalous aortic arches have been rare. The authors describe a patient with a right-side aortic arch and an aneurysm of the aberrant left subclavian artery, which, to the authors' knowledge, is a previously unreported association. At presentation, the aneurysm appeared as a calcified left superior mediastinal mass. Magnetic resonance imaging enabled preoperative diagnosis and guided surgical planning.     

Adrenal tissue characterization with 0.5-T MR imaging: Value of T2*-weighted images

The authors investigated the value of magnetic resonance (MR) imaging at 0.5 T for distinguishing adrenal adenomas from adrenal metastases. The series included 23 adrenal adenomas (18 nonhyperfunctioning, five hyperfunctioning) and 23 adrenal metastases from various organs. Adrenal tumor–liver signal intensity ratios on T1-, T2-, and T2*-weighted images were calculated for adrenal tissue characterization. Adrenal adenomas were more precisely distinguished from adrenal metastases on T2*-weighted images (21 of 23, 91%) than on T2-weighted images (15 of 23, 65%). T1-weighted images were not useful for this distinction. In conclusion, T2*-weighted images were better than routine T2-weighted images for distinguishing adrenal adenomas from adrenal metastases. It can be postulated that the total signal intensity of adrenal adenomas, which contain some fat components, decreased on T2*-weighted images because of an out-of-phase effect.     

MR angiography of congenital heart disease: Value of segmented two-dimensional inflow technique and maximum-intensity-projection display

Magnetic resonance (MR) angiography of the cardiovascular system was evaluated in 41 patients with congenital heart disease by using a two-dimensional (2D) inflow technique based on a magnetization-prepared gradient-echo pulse sequence with segmented k-space data acquisition and electrocardiographic gating at 0.5 T. Inversion and saturation prepulses were used to suppress stationary tissue and enhance intravascular signal. Presaturation slabs were applied where certain vascular structures had to be suppressed. Sequence parameters were optimized by evaluating signal intensity and contrast characteristics for various flip angles and inversion and saturation delay times. The heart and intrathoracic vasculature were encompassed with 40–50 overlapping sections. Both 2D angiograms and maximum-intensity-projection images were evaluated. Combining data sets acquired in the sagittal and transverse orientations provided the most satisfactory information about the pulmonary arteries. The highest signal-to-noise ratios were obtained with a flip angle of 65° and short prepulse delay times. Two-dimensional MR angiography can provide useful diagnostic information but requires a thorough understanding of in-plane and hemodynamically induced signal intensity changes.