穿戴式、多参数协同监测系统设计

目的 为实现低生理、心理负荷下的人体基本生命参数的长时间、动态获取,设计了穿戴式、多参数协同监测系统.方法 将生命信息检测技术与可穿戴技术相结合,在弹性背心中嵌入各类传感器,以实现生理信号检测.两条弯曲成"正弦"状导线嵌在弹性背心的胸、腹部作为呼吸运动传感器,用自主产权的呼吸感应体积描记技术提取呼吸运动;用三导联电极提取心电信号,并探索了非粘贴电极的心动信号获取技术;用三维加速度传感器获取体位、体动信息;用负温度系数的热敏电阻测量作业过程中体温变化.结果 实现了呼吸、心电、体位、体动、体温等多生理参数的穿戴式、协同监测系统设计.结论 穿戴式的生理参数监测系统能够实现低负荷状态下的多生理参数协同获取,为一系列研究工作提供了很好的技术平台.     

呼吸感应体积描记法校准方法在不同呼吸状态下的适用性

目的 比较呼吸感应体积描记技术(RIP)的6种校准方法在人体不同呼吸状态下的适用性.方法 用平静呼吸的6种校准参数测量平静和规范用力的每次呼吸通气量,用规范用力呼吸的6种校准参数测量规范用力的每次呼吸通气量,对比分析RIP系统与呼吸速度描记仪所测量的通气量值.结果 6种校准方法中,诊断性定性校准技术(QDC)适用于在平静呼吸下校准测量平静呼吸每次呼吸通气量值以及在规范用力呼吸下校准测量规范用力呼吸每次呼吸通气量值,LSQ改进算法(ILSQ)适用于在平静呼吸下校准测量规范用力呼吸每次呼吸通气量值.结论 RIP系统在平静呼吸状态下校准测量规范用力呼吸方式下每次呼吸通气量值方法可行.     

可穿戴电容耦合式电极在载人航天心电检测中的应用

目的研究可穿戴的小尺寸电容耦合式电极在载人航天中的应用问题。方法针对电极尺寸减小对信号幅值和噪声带来的影响,在系统设计中采用动态驱动屏蔽的电极结构、噪声性能优良的阻抗转换放大器等措施提高信噪比,并采用小波阈值滤波算法去噪。结果相比直径4 cm电极,直径2 cm电容耦合式电极采集的信号幅值减小,但心电信号P波、QRS波、T波均得到完整检测,并在降低界面噪声方面具有一定的优势。小波阈值滤波有效消除噪声。结论本文所设计的使用小尺寸电容耦合式电极的心电检测系统实现了隔着衣服对心电信号的非接触式检测,信号波形清晰完整,可以满足航天医学监护要求。     

腹式呼吸放松训练缓解海军特勤人员睡眠障碍和异常情绪效应观察

目的 探讨腹式呼吸放松训练在缓解海军特勤人员睡眠障碍和异常情绪中的效应。方法 回顾性分析2017年8月-2018年8月在疗养院特勤科疗养的70例患有睡眠障碍海军特勤人员,其中对照组30例为常规疗养,干预组40例是在常规疗养的基础上进行腹式呼吸放松训练,进行为期30 d的腹式呼吸放松训练,利用匹兹堡睡眠质量指数量表(PSQI)评估睡眠质量。抑郁和焦虑分别采用抑郁自评量表(SDS)和焦虑自评量表(SAS)进行评估。情绪状态采用简明心境状态测试量表(POMS)进行评估。结果 对照组睡眠障碍海军特勤人员的PSQI总分及各维度自身干预前后对比无统计学意义（P＞0.05）。干预组PSQI总分及PSQI量表主观睡眠质量、睡眠潜伏期、睡眠时间、睡眠障碍、日间功能障碍自身干预前后对比有统计学意义（P＜0.05）,睡眠效率自身干预前后对比无统计学意义（P>0.05）。干预组与对照组比较,SDS、SAS、POMS的评分降低,提示海军特勤人员焦虑、抑郁心理障碍减轻,POMS的评分降低提示海军特勤人员疲劳和紧张的情绪得到缓解。干预组与对照组比较,PSQI总分降低,提示海军特勤人员睡眠质量得到改善,差异有统计学意义（P＜0.05）。结论 腹式呼吸放松训练治疗30天后,可以有效的改善海军特勤人员睡眠质量,缓解心理压力和焦虑,缓解海军特勤人员疲劳和紧张的异常情绪。腹式呼吸放松训练方法对疗养期间海军特勤人员进行放松训练更适合。由于坚持30 天腹式呼吸放松反馈训练依从性更高,从而降低海军特勤人员的应激水平,提高海军特勤人员睡眠质量和心理健康水平。     

一种鉴定飞行员睡眠呼吸暂停低通气综合征的新方法

目的为飞行员的睡眠呼吸暂停低通气综合征(SAHS)提供一种新的、简便、无干扰的鉴定方法。方法用微动敏感床垫式睡眠监测系统(MSMSMS)和多道睡眠图(PSG)对30例SAHS病人、8例疑有SAHS的飞行员和10名健康男性志愿者进行同步对照检测与分析；用MSMSMS检测40名健康、无鼾症飞行员并对其中20名进行重复检验。统计分析MSMSMS检测呼吸事件的敏感性和特异性。结果根据MSMSMS检测的发生睡眠呼吸事件的特征性变化，提出了用MSMSMS判别阻塞性呼吸暂停、睡眠呼吸低通气和中枢性呼吸暂停的标准。所有经MSMSMS诊断为SAHS患者的结果与PSG的诊断结果完全一致。用MSMSMS检测呼吸事件的敏感性为88．6％～94．0％；特异性为86．0％～92．7％。结论MSMSMS能可靠地鉴定飞行员的睡眠呼吸暂停低通气综合征。     

一种基于薄膜压电传感器的床垫式无负荷睡眠监测系统

目的实现一种基于薄膜压电传感器的床垫式睡眠监测系统。方法通过高灵敏的薄膜压电传感器检测睡眠中心脏跳动、呼吸以及翻身等体动导致的压力变化,经数字信号处理后分离出心脏跳动、呼吸及体动波形,再进一步提取心率、呼吸率和体动次数等信息。通过对睡眠过程中心率、呼吸率及体动等信息的融合统计分析,用于睡眠质量评估。结果以智能手机为平台,实现基于薄膜压电传感器的床垫式睡眠监测系统,心率呼吸率计算误差在5以内。结论系统实现了无负荷睡眠过程中心率、呼吸和体动等参数检测,进行睡眠质量评估,可用于航天员训练中睡眠监测,也可推广应用于普通人群家庭睡眠质量监测。     

西门子磁共振成像仪Impact射频故障3则

西门子磁共振成像仪Impact的射频系统负责磁共振激励信号的发射和感应信号的接受,射频功率放大单元RFPA E6(RF Power Amplifier)的带宽为200 kHz,可调谐范围为1 MHz,总增益为70 dB,能够将射频小信号放大到足够的功率(10 kW 峰值功率,500 W平均功率),并输出至射频线圈,激励受检部位,产生磁共振信号.RFPA由2级放大组成,第一级是驱动器(Driver)放大,末级是四极管(Tube )放大[1～3],RFPA是射频单元最易出故障的地方,本院曾出现多次故障,现将经验与同行交流.     

基于双电极的心电测量方法及仪器

目的 研究使用双电极的心电测量方法设计微型低功耗仪器.方法 分析心电测量仪器的结构及产生共模干扰的机理,使用微处理器、仪表放大器、运算放大器、RS-232收发器设计微型低功耗的心电测量电路,用PDA为测量电路供电,接收数据并运算、存储和显示.结果 研制的仪器满足心电测量的要求,且测量电路板尺寸只有4.0 cm×1.5 cm,功耗分别为15 mW(含通信电路)和3 mW(不合通信电路).结论 本文设计的基于双电极的心电测量方法和仪器,可用于植入式、穿戴式或便携式心电测量.     

阻塞性睡眠呼吸暂停综合征对老年糖尿病患者血糖的影响

目的 探讨阻塞性睡眠呼吸暂停综合征（obstructive sleep apnea syndrome,OSAS）对老年糖尿病患者血糖的影响.方法 采用RS2611床垫式睡眠呼吸监测系统监测老年糖尿病患者80例睡眠呼吸状况,分析OSAS对血糖的影响.结果 合并OSAS的患者空腹血糖、餐后2 h血糖、糖化血红蛋白、C反应蛋白（C-reactive protein,CRP）及同型半胱氨酸（homocysteine,Hcy）均较非OSAS患者增高,且OSAS越重,各测定值水平越高,差异有统计学意义（P＜0.05或P＜0.01）.空腹及餐后2 h血糖、糖化血红蛋白、Hcy、CRP与睡眠呼吸暂停低通气指数（apnea-hypopnea index,AHI）呈正相关,与夜间最低血氧饱和度（LO2）呈负相关.结论 OSAS病情越重,患者血糖水平越高,OSAS可能是糖尿病患者血糖紊乱的独立危险因素.     

持续气道正压呼吸机在治疗睡眠呼吸暂停综合征时的调压观察

睡眠呼吸暂停综合征亦称为阻塞性睡眠呼吸暂停低通气综合征(Obstructive sleep apnea syndrome／hypopnea syndrome,OSAHS),其特征是睡眠状态中反复发生上气道完全和(或)不完全阻塞。反复发生的呼吸暂停,可产生严重的甚至致命性低氧;同时,还可出现高碳酸血症,失代偿性酸中毒,此时能直接引起血液动力学和流变学改变,使组织器官的缺血、缺氧加重而导致多系统器官损害。对OSAHS的治疗包括药物、手术、无创呼吸机等。其中,持续气道正压呼吸机     

双频率阻抗法在呼吸监测中的应用研究

目的 对应用双频率阻抗测试和自适应处理技术相结合的方法消除呼吸阻抗测量中的运动干扰问题进行一些探索性的研究。方法 采用自行研制的双通道呼吸阻抗测量硬件系统以自适应抵消处理为主的软件系统进行了人体实验研究。结果 运动干扰信号基本消除。低频与高频呼吸阻抗信号的比值Ｋ随着运动强度的增加而增大。结论 应用该方法消除呼吸阻 的运动干扰具有一定的可行性，但是在实际应用中，为了得到更好的结果，应注意考虑Ｋ值的准     

Prospective respiratory-triggered multidetector row CT (MDCT) for abdominal examinations: initial experience with a prototype

PURPOSE: To develop a prototype for prospective respiratory-triggered multidetector row computed tomography (MDCT) for abdominal examinations and to assess its feasibility. MATERIALS AND METHODS: The prototype consisted of the following components: an MDCT unit, personal computer (PC), and a respiratory motion detector in the form of a wearable belt with sensors to measure differences in pressure caused by breathing excursions. The registered signals were processed by the PC. The abdominal MDCT images of 10 healthy volunteers were obtained with an incremental axial technique in the expiration phase during normal breathing. Multiplanar reformations (MPR) were then performed. On the basis of the precision of these reconstructions, two radiologists then assessed the accuracy and applicability of the system. RESULTS: Coronal and sagittal MPR images from these prospective respiratory-gated examinations were found to be accurate. In particular, the continuity of borders and surfaces of scanned organs proved the exactness of the previously acquired respiration-correlated axial source images. CONCLUSION: This prototype is feasible to perform prospective respiratory-triggered abdominal MDCT examinations during normal respiration without breathhold. This system may be useful for patients with reduced compliance in holding their breath.     

IMPACT: image-based physiological artifacts estimation and correction technique for functional MRI.

Functional MRI (fMRI) signal variation induced by respiratory and cardiac motion affects the activation signal and limits the accuracy of analysis. Current physiological motion correction methods require either synchronization with external monitoring of respiration and heartbeat, specialized pulse sequence design, or k-space data. The IMage-based Physiological Artifacts estimation and Correction Technique (IMPACT), which is free from these constraints, is described. When images are acquired fast enough to sample physiological motion without aliasing, respiratory and cardiac signals can be directly estimated from magnitude images. Physiological artifacts are removed by reordering images according to the estimated respiratory and cardiac phases and then subtracting the Fourier-fitted variation from magnitude images. Compared with the k-space-based method, this method can efficiently and effectively reduce the overall signal fluctuation in the brain and increase the activated area. With this new technique, physiological artifacts can be reduced using traditional fMRI pulse sequences, and existing data can be corrected and reanalyzed without additional experiments.     

Interleaved narrow-band PRESS sequence with adiabatic spatial-spectral refocusing pulses for 1H MRSI at 7T.

Proton magnetic resonance spectroscopic imaging ((1)H MRSI) is a useful technique for measuring metabolite levels in vivo, with Choline (Cho), Creatine (Cre), and N-Acetyl-Aspartate (NAA) being the most prominent MRS-detectable brain biochemicals. (1)H MRSI at very high fields, such as 7T, offers the advantages of higher SNR and improved spectral resolution. However, major technical challenges associated with high-field systems, such as increased B(1) and B(0) inhomogeneity as well as chemical shift localization (CSL) error, degrade the performance of conventional (1)H MRSI sequences. To address these problems, we have developed a Position Resolved Spectroscopy (PRESS) sequence with adiabatic spatial-spectral (SPSP) refocusing pulses, to acquire multiple narrow spectral bands in an interleaved fashion. The adiabatic SPSP pulses provide magnetization profiles that are largely invariant over the 40% B(1) variation measured across the brain at 7T. Additionally, there is negligible CSL error since the transmit frequency is separately adjusted for each spectral band. in vivo (1)H MRSI data were obtained from the brain of a normal volunteer using a standard PRESS sequence and the interleaved narrow-band PRESS sequence with adiabatic refocusing pulses. In comparison with conventional PRESS, this new approach generated high-quality spectra from an appreciably larger region of interest and achieved higher overall SNR.     

A case of hepatocellular carcinoma treated by MR-guided focused ultrasound ablation with respiratory gating.

Focused ultrasound surgery (FUS) is a method of noninvasive focal thermal ablation. Temperature-sensitive phase-difference magnetic resonance (MR) imaging allows monitoring of the focal point and measurement of tissue temperature elevation in real time, ensuring delivery of a therapeutic dose. A newly developed respiratory monitoring system enables us to track liver tumors, which move with respiration. We report our initial experience using MR-guided FUS with respiratory gating in successfully treating a hepatocellular carcinoma 15 mm in diameter.     

Respiratory Blur in 3D Coronary MR Imaging

3D MR imaging of coronary arteries has the potential to provide both high resolution and high signal-to-noise ratio, but it is very susceptible to respiratory artifacts, especially respiratory blurring. Resolution loss caused by respiratory blurring in 3D coronary imaging is analyzed theoretically and verified experimentally. Under normal respiration, the width for any Gaussian point spread function is increased to a new value that is at least several millimeters (about 3–4 mm). In vivo studies were performed to compare respiratory pseudo-gated 3D acquisition with breath-hold 2D acquisition. On average, the overall quality of a pseudo-gated 3D image is worse than that of the corresponding breath-hold 2D image (P = 0.005). In most cases, respiratory blur caused coronary arteries in pseudo-gated 3D data to have lower resolution than in breathhold 2D data.     

Lung imaging under free‐breathing conditions

Respiratory motion and pulsatile blood flow can generate artifacts in morphological and functional lung imaging. Total acquisition time, and thus the achievable signal to noise ratio, is limited when performing breath‐hold and/or electrocardiogram‐triggered imaging. To overcome these limitations, imaging during free respiration can be performed using respiratory gating/triggering devices or navigator echoes. However, these techniques provide only poor gating resolution and can induce saturation bands and signal fluctuations into the lung volume. In this work, acquisition schemes for nonphase encoded navigator echoes were implemented into different sequences for morphological and functional lung imaging at 1.5 Tesla (T) and 0.2T. The navigator echoes allow monitoring of respiratory motion and provide an ECG‐trigger signal for correction of the heart cycle without influencing the imaged slices. Artifact free images acquired during free respiration using a 3D GE, 2D multislice TSE or multi‐Gradient Echo sequence for oxygen‐enhanced T quantification are presented. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.     

Simultaneous image acquisition utilizing hybrid body and phased array receiver coils.

In clinical MR imaging the design and selection of receiver coil is an important step in ensuring the highest image quality. Often this choice is based on selecting a receiver coil characterized by high spatial uniformity such as the body and head volume receiver coils or a surface coil (or array of coils) that provide high signal-to-noise ratio (SNR). In the past, it has been difficult to accomplish both high SNR and spatial uniformity as both coil types achieve one of these characteristics at the expense of the other. The purpose of this study was to achieve both high SNR and spatial uniformity through the simultaneous acquisition of the MR signal using the body and a surface coil array. Results indicate that this hybrid system can provide uniformity and SNR values comparable to those achieved by the body and surface coil arrays, respectively.     

3D fast spin echo with out‐of‐slab cancellation: A technique for high‐resolution structural imaging of trabecular bone at 7 tesla

Spin‐echo‐based pulse sequences are desirable for the application of high‐resolution imaging of trabecular bone but tend to involve high‐power deposition. Increased availability of ultrahigh field scanners has opened new possibilities for imaging with increased signal‐to‐noise ratio (SNR) efficiency, but many pulse sequences that are standard at 1.5 and 3 T exceed specific absorption rate limits at 7 T. A modified, reduced specific absorption rate, three‐dimensional, fast spin‐echo pulse sequence optimized specifically for in vivo trabecular bone imaging at 7 T is introduced. The sequence involves a slab‐selective excitation pulse, low‐power nonselective refocusing pulses, and phase cycling to cancel undesired out‐of‐slab signal. In vivo images of the distal tibia were acquired using the technique at 1.5, 3, and 7 T field strengths, and SNR was found to increase at least linearly using receive coils of identical geometry. Signal dependence on the choice of refocusing flip angles in the echo train was analyzed experimentally and theoretically by combining the signal from hundreds of coherence pathways, and it is shown that a significant specific absorption rate reduction can be achieved with negligible SNR loss. Magn Reson Med 63:719–727, 2010. © 2010 Wiley‐Liss, Inc.